Multi-parameter fiber optic probes

• US 20020041723A1
• Filed: 09/07/2001
• Published: 04/11/2002
• Est. Priority Date: 09/07/2000
• Status: Abandoned Application

• Current Assignee: OptoMed, Inc.
• Original Assignee: OptoMed, Inc.
• Inventors: Ronnekleiv, Erlend, Kringlebotn, Jon Thomas, Hjelme, Dag Roar
• Application Number:
  US09/948,427
• Publication Number:
  US 20020041723A1
• Time in Patent Office: Days
• US Class Current: 385/12
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/031 Intracranial pressure

Abstract

A body compatible fiber optic sensor probe is provided. The probe includes at least one optical fiber and the fiber or fibers include at least one sensing region adapted and arranged such that the probe has simultaneously measurable respective optical properties that are responsive to respective different parameters within the body, such properties being dependent upon mechanical strain established in the fiber or fibers in response to said parameters. Such a probe is suitable for invasive medical use.

Claims

1. A body compatible fiber optic sensor probe for invasive medical use, the probe including at least one optical fiber, the fiber or fibers including at least one sensing region adapted and arranged such that the probe has simultaneously measurable respective optical properties responsive to respective different parameters within the body, such properties being dependent upon mechanical strain established in the fiber or fibers in response to said parameters.

2. A probe as claimed in claim 1 wherein the at least one sensing region comprises a mass of reactive material configured to create mechanical strain within the fiber in such a way as to change its optical response.

3. A probe as claimed in claim 1 comprising one or more fiber Bragg gratings (FBG'"'"'s) written into the optical fiber core.

4. A probe as claimed in claim 1 comprising an active fiber laser including said fiber.

6. A probe as claimed in claim 1 wherein the fiber has a fiber length, said one or more fibers being provided with sensing regions responsive primarily to different parameters at axially spaced locations along the fiber length.

7. A probe as claimed in claim 1 wherein the probe is configured to measure first and second parameters, quantify said first parameter and use the measurement of the second parameter to correct the measurement of the first parameter.

8. A probe as claimed in claim 1 having a first optical property which changes in accordance with a first parameter, and a second optical property different from the first which changes in accordance with a second parameter, such that through the use of a suitable interrogation system said first and second parameters can be measured independently.

9. A probe as claimed in claim 1 wherein said optical fiber has a fiber length, said probe further comprising a plurality of sensing regions, said sensing regions being responsive primarily to different parameters and arranged at axially spaced locations along the fiber length.

10. A probe as claimed in claim 1 comprising a tubular housing, wherein the housing contains therewithin a portion of the optical fiber, and wherein the housing is arranged such that the fiber, in the sensing region(s) thereof, is exposed to the parameter to be measured.

11. A probe as claimed in claim 10 having two or more fibers arranged side-by-side within the housing, wherein the fibers have respective sensing regions which are responsive to different parameters or measurands.

12. A probe as claimed in claim 10 wherein the housing is filled with a liquid or gel such that one or more parameters to be measured are transferred to the one or more sensing regions of the fiber or fibers within the housing.

13. A probe as claimed in claim 12 wherein one or more of said parameters transferred by the liquid is selected from the group comprising temperature, pressure and biological or chemical substances which can diffuse through the liquid or gel.

14. A probe as claimed in claim 12 wherein the housing is filled with a liquid or gel such that a pressure applied to the housing is transmitted to the surface of a pressure sensitive region of the optical fiber within the housing.

15. A probe as claimed in claim 12 wherein the housing includes one or more apertures covered by a flexible membrane, through which external pressure is transmitted to the liquid or gel and thereby applied to the optical fiber.

16. A probe as claimed in claim 1 for measuring a biological or chemical parameter comprising a tubular housing filed with liquid or gel wherein the liquid or gel within the housing provides a transfer medium to enable particular target molecules to diffuse through the liquid and thereby be transferred to one or more optical fibers located within the housing, such fiber(s) having a suitable reactive sensing element coupled to the fiber providing a change in optical response.

17. A probe as claimed in claim 1 including a sealed tubular housing comprising a liquid or flowable gel disposed within the housing and surrounding the at least one fiber, the liquid or gel permitting the transfer of at least one parameter to be measured from a region outside the housing to the at least one sensing region of the fiber.

18. A probe as claimed in claim 17 the housing including one or more apertures covered by a membrane, the membrane allowing the application of pressure to the liquid or gel from the surrounding environment and/or allowing the selective diffusion of target molecules through the membrane.

19. A probe as claimed in claim 12 wherein the liquid is isotonic saline.

20. A probe as claimed in claim 10 including a temperature sensing region within one or more of the optical fibers and wherein the housing is formed of a material of good thermal conductivity.

21. A probe as claimed in claim 1 wherein one of the parameters to be detected is fluid pressure in the body and wherein the optical fiber is configured in at least one sensing region to provide a changing optical property depending on the pressure applied to the fiber.

22. A probe as claimed in claim 1 wherein the optical properties are spectral peaks or troughs at different wavelengths, said different wavelengths undergoing respective wavelength shifts in use in response to different parameters within the body.

23. A probe as claimed in claim 1 wherein one optical property of the sensor probe is the absolute wavelength of one or more spectral peaks of the fiber'"'"'s optical response, and a further optical property is the spacing between spectral peaks or troughs in the mutually orthogonal polarization planes of the fiber.

24. A probe as claimed in claim 1 wherein the at least one sensing region comprises a sensing element formed of a material which undergoes a change in volume upon exposure to a parameter or measurand to be measured, such change in volume creating a strain within the fiber whereby a detectable change in optical response is obtained.

25. A probe as claimed in claim 1 wherein the optical fiber is birefringent.

26. A probe as claimed in claim 25 wherein the fiber comprises one or more side holes at the sensing region.

27. A probe as claimed in claim 26 wherein a sensing element is provided in said side hole said sensing element being arranged to swell when exposed to a measurand.

28. A probe as claimed in claim 25 comprising a birefringent fiber wherein the strain established in the fiber is one of longitudinal strain, bending strain, and/or generally radially directed strain, such that there is a change both in an absolute wavelength of the optical response or output of the fiber, and a change in a distance between spectral peaks in mutually orthogonal polarization planes.

29. A probe as claimed in claim 1 wherein the sensing region comprises a sensing element including a coating of reactive material provided on the fiber.

30. A probe as claimed in claim 29 wherein the coating is configured to apply longitudinal and/or radial strain to the fiber when exposed to a measurand.

31. A probe as claimed in claim 1 wherein the sensing region comprises a sensing element including a piston and cylinder arrangement and wherein the sensing element is configured to expand and provide a longitudinal strain within the fiber when exposed to a measurand.

32. A probe as claimed in claim 1 wherein the sensing region comprises a material reactive to one or more of non-ionizing radiation, ionizing radiation and chemical or biological, including immunological, interactions.

33. A probe as claimed in claim 1 wherein the sensing region comprises a reactive material immobilized on a solid support medium.

34. A probe as claimed in claim 33 wherein the immobilization method is mechanical, electrostatic or chemical.

35. A probe as claimed in claim 33 or 34 wherein the solid support medium is a polymer, a copolymer, a glass.

36. A probe as claimed in claim 33 wherein the support medium is inert to the measurand being analysed.

37. A probe as claimed in claim 33 wherein the support itself acts as a selective element.

38. A probe as claimed in claim 37 wherein the support is selective through controlled porosity.

39. A probe as claimed in claim 1 wherein one or more than one of the sensing regions comprises a material immobilized in a fluid or gel, wherein the fluid or gel is arranged to swell or to contract in response to a target measurand.

40. A probe as claimed in claim 1 wherein a separate body compatible membrane is provided to cover or enclose the sensing region.

41. A probe as claimed in claim 40 wherein the membrane is arranged to select the measurand species based on one of size selectivity through controlled porosity of the membrane, chemical/biochemical selectivity through chemical reactions, or ionic selectivity through electrostatic interactions.

42. A probe as claimed in claim 1 wherein the sensing region comprises a coating of paint or bonding material such as a polymer gel network.

43. A probe as claimed in claim 42 wherein the sensing region is or comprises a biochemical key-lock pair, such as biotin-avidin or lectin-saccharide.

44. A probe as claimed in claim 1 wherein the sensing region comprises a coating of a porous material such as sol-gel glass or ceramics.

45. A probe as claimed in claim 1 wherein the sensing region comprises micro-spherical balls, provided with additives arranged to generate chemical selectivity for a selected group of molecules.

46. A probe as claimed in claim 1 wherein the sensing region comprises ionic N-Isopropylacrylamide (NIPA) polymer gel copolymerised by sodium acrylate (SA).

47. A probe as claimed in claim 1 wherein the sensing region is or comprises a hydrogel.

48. A probe as claimed in claim 1 comprising a tubular housing mounting therewithin in side-by-side arrangement two or more optical fibers, at least one of such fibers being provided with a sensing element responsive to a first parameter to be measured, and another fiber being absent such first sensing element, or provided with a second sensing element to detect a second parameter different from the first.

49. A probe as claimed in claim 48 wherein the second fiber is absent the sensing element, and wherein the optical response from said second fiber is used to correct the output from the first fiber provided with said sensing element.

50. A probe as claimed in claim 1 comprising a tubular housing mounting therewith optical fibers in side-by-side relation, a first fiber arranged to provide a birefringent response dependent on pressure applied to the fiber, and a second fiber arranged to provide a temperature dependent response which is used to correct measurements based on the optical output of said first fiber.

51. A probe as claimed in claim 1 comprising three fibers extending along a probe housing wherein a first fiber has at least one pressure sensitive region provided with a reactive coating;

a second fiber has at least one pressure sensitive region but not provided with said reactive coating; and

the third fiber is sensitive to temperature and/or longitudinal strain.

52. A probe as claimed in claim 1 comprising a plurality of fibers each having a distal end, the distal ends of said fibers being connected via a fiber minibend.

53. A probe as claimed in claim 1 wherein the optical fiber or fibers are located in a body compatible protective housing.

183. A probe as claimed in claim 10 wherein the housing is filled with a liquid or gel such that said temperature and pressure are transferred to one or more sensing regions of the first and second fibers within the housing.

224. A method of medical or biological treatment, analysis or diagnosis, involving the use of one or more probes or sensors as claimed in claim 1.

225. A sterile pack including one or more probes as claimed in claim 1.

5. A body compatible fiber optic sensor probe for invasive medical use, the probe including at least one optical fiber, the fiber or fibers including at least one sensing region adapted and arranged such that the probe has simultaneously measurable respective optical properties responsive to respective different parameters within the body, such properties being dependent upon mechanical strain established in the fiber or fibers in response to said parameters, said fiber comprising a pair of pi phase-shifted fiber Bragg gratings.

54. A fiber optic sensor device comprising a housing mounting therewithin at least two optical fibers mounted side-by-side, the fibers including respective sensing regions responsive primarily to respective different parameters to be measured.

55. A probe as claimed in claim 54 wherein at least one of the respective sensing regions comprises a mass of reactive material configured to create mechanical strain within the fiber in such a way as to change its optical response.

56. A probe as claimed in claim 54 wherein said two optical fibers each have an optical fiber core, at least one of said fibers comprising one or more fiber Bragg gratings (FBG'"'"'s) written into the optical fiber core.

57. A probe as claimed in claim 54 comprising an active fiber laser including at least one of said fibers.

59. A probe as claimed in claim 54 wherein the fibers each have a fiber length, at least one of said fibers being provided with sensing regions responsive primarily to different parameters at axially spaced locations along the fiber length.

60. A probe as claimed in claim 54 wherein the probe is configured to measure first and second parameters, quantify said first parameter and use the measurement of the second parameter to correct the measurement of the first parameter.

61. A probe as claimed in claim 54 having a first optical property which changes in accordance with a first parameter, and a second optical property different from the first which changes in accordance with a second parameter, such that through the use of a suitable interrogation system said first and second parameters can be measured independently.

62. A probe as claimed in claim 54 wherein the housing is filled with a liquid or gel such that one or more parameters to be measured are transferred to the one or more sensing regions of the fiber or fibers within the housing.

63. A probe as claimed in claim 62 wherein one or more of said parameters transferred by the liquid is selected from the group comprising temperature, pressure and biological or chemical substances which can diffuse through the liquid or gel.

64. A probe as claimed in claim 54 wherein the housing is filled with a liquid or gel such that a pressure applied to the housing is transmitted to the surface of a pressure sensitive region of the optical fiber within the housing.

65. A probe as claimed in claim 62 wherein the housing includes one or more apertures covered by a flexible membrane, through which external pressure is transmitted to the liquid or gel and thereby applied to the optical fiber.

66. A probe as claimed in claim 54 for measuring a biological or chemical parameter wherein the housing is filled with liquid or gel and wherein the liquid or gel within the housing provides a transfer medium to enable particular target molecules to diffuse through the liquid and thereby be transferred to one or more optical fibers located within the housing, such fiber(s) having a suitable reactive sensing element coupled to the fiber providing a change in optical response.

67. A probe as claimed in claim 54 wherein the housing comprises a liquid or flowable gel disposed within the housing and surrounding the fibers, the liquid or gel permitting the transfer of at least one parameter to be measured from a region outside the housing to at least one of the sensing regions of the fiber.

68. A probe as claimed in claim 67 the housing including one or more apertures covered by a membrane, the membrane allowing the application of pressure to the liquid or gel from the surrounding environment and/or allowing the selective diffusion of target molecules through the membrane.

69. A probe as claimed in claim 62 wherein the liquid is isotonic saline.

70. A probe as claimed in claim 54 including a temperature sensing region within one or more of the optical fibers and wherein the housing is formed of a material of good thermal conductivity.

71. A probe as claimed in claim 54 wherein one of the parameters to be detected is fluid pressure in the body and wherein at least one of the optical fibers is configured in at least one sensing region to provide a changing optical property depending on the pressure applied to the fiber.

72. A probe as claimed in claim 54 wherein said different parameters are measurable through different optical properties, the optical properties being spectral peaks or troughs at different wavelengths, said different wavelengths undergoing respective wavelength shifts in use in response to said different parameters..

73. A probe as claimed in claim 54 wherein said different parameters are measurable through different optical properties, one of said optical properties being the absolute wavelength of one or more spectral peaks of the fiber'"'"'s optical response, and a further optical property being the spacing between spectral peaks or troughs in the mutually orthogonal polarization planes of the fiber.

74. A probe as claimed in claim 54 wherein at least one of the sensing regions comprises a sensing element formed of a material which undergoes a change in volume upon exposure to a parameter or measurand to be measured, such change in volume creating a strain within the fiber whereby a detectable change in optical response is obtained.

75. A probe as claimed in claim 54 wherein at least one of the optical fibers is birefringent.

76. A probe as claimed in claim 75 wherein the fiber comprises one or more side holes at the sensing region.

77. A probe as claimed in claim 76 wherein a sensing element is provided in said side hole said sensing element being arranged to swell when exposed to a measurand.

78. A probe as claimed in claim 75 comprising a birefringent fiber wherein the strain established in the fiber is one of longitudinal strain, bending strain, and/or generally radially directed strain, such that there is a change both in an absolute wavelength of the optical response or output of the fiber, and a change in a distance between spectral peaks in mutually orthogonal polarization planes.

79. A probe as claimed in claim 54 wherein at least one of the sensing regions comprises a sensing element including a coating of reactive material provided on the fiber.

80. A probe as claimed in claim 79 wherein the coating is configured to apply longitudinal and/or radial strain to the fiber when exposed to a measurand.

81. A probe as claimed in claim 54 wherein at least one of the sensing regions comprises a sensing element including a piston and cylinder arrangement and wherein the sensing element is configured to expand and provide a longitudinal strain within the fiber when exposed to a measurand.

82. A probe as claimed in claim 54 wherein at least one of the sensing regions comprises a material reactive to one or more of non-ionizing radiation, ionizing radiation and chemical or biological, including immunological, interactions.

83. A probe as claimed in claim 54 wherein at least one of the sensing regions comprises a reactive material immobilized on a solid support medium.

84. A probe as claimed in claim 83 wherein the support itself acts as a selective element.

85. A probe as claimed in claim 54 wherein one or more than one of the sensing regions comprises a material immobilized in a fluid or gel, wherein the fluid or gel is arranged to swell or to contract in response to a target measurand.

86. A probe as claimed in claim 54 wherein a separate body compatible membrane is provided to cover or enclose at least one of the sensing regions.

87. A probe as claimed in claim 86 wherein the membrane is arranged to select the measurand species based on one of size selectivity through controlled porosity of the membrane, chemical/biochemical selectivity through chemical reactions, or ionic selectivity through electrostatic interactions.

88. A probe as claimed in claim 54 wherein at least one of the sensing regions comprises a coating of paint or bonding material such as a polymer gel network.

89. A probe as claimed in claim 88 wherein at least one of the sensing regions is or comprises a biochemical key-lock pair, such as biotin-avidin or lectin-saccharide.

90. A probe as claimed in claim 54 wherein at least one of the sensing regions comprises a coating of a porous material such as sol-gel glass or ceramics.

91. A probe as claimed in claim 54 wherein at least one of the sensing regions comprises micro-spherical balls, provided with additives arranged to generate chemical selectivity for a selected group of molecules.

92. A probe as claimed in claim 54 wherein at least one of the sensing regions comprises ionic N-Isopropylacrylamide (NIPA) polymer gel copolymerised by sodium acrylate (SA).

93. A probe as claimed in claim 54 wherein the sensing region is or comprises a hydrogel.

94. A probe as claimed in claim 54 wherein a first one of the fibers comprises a sensing element and wherein the second fiber is absent the sensing element, and wherein the optical response from said second fiber is used to correct the output from the first fiber provided with said sensing element.

95. A probe as claimed in claim 54 wherein said fibers each have a distal end, the distal ends of said fibers being connected via a fiber minibend.

96. A probe as claimed in claim 54 wherein the optical fibers are located in a body compatible protective housing.

58. A fiber optic sensor device comprising a housing mounting therewithin at least two optical fibers mounted side-by-side, the fibers including respective sensing regions responsive primarily to respective different parameters to be measured, at least one of said optical fibers further comprising a pair of pi phase-shifted fiber Bragg gratings.

97. A body compatible fiber optic sensor probe for invasive medical use, provided with at least one optical fiber having axially spaced sensing regions, the sensing regions providing in use distinguishable optical responses or outputs dependent primarily on different parameters within the body.

98. A probe as claimed in claim 97 wherein at least one of the sensing regions comprises a mass of reactive material configured to create mechanical strain within the fiber in such a way as to change its optical response.

99. A probe as claimed in claim 97 comprising one or more fiber Bragg gratings (FBG'"'"'s) written into the optical fiber core.

100. A probe as claimed in claim 97 comprising an active fiber laser including said fiber.

102. A probe as claimed in claim 97 wherein the probe is configured to measure first and second parameters, quantify said first parameter and use the measurement of the second parameter to correct the measurement of the first parameter.

103. A probe as claimed in claim 97 comprising a tubular housing, wherein the housing contains therewithin a portion of the optical fiber, and wherein the housing is arranged such that the fiber, in the sensing regions thereof, is exposed to the parameters to be measured.

104. A probe as claimed in claim 103 having two or more fibers arranged side-by-side within the housing, wherein the fibers have respective sensing regions which are responsive to different parameters or measurands.

105. A probe as claimed in claim 103 wherein the housing is filled with a liquid or gel such that one or more parameters to be measured are transferred to the one or more sensing regions of the fiber or fibers within the housing.

106. A probe as claimed in claim 103 wherein one or more of said parameters transferred by the liquid is selected from the group comprising temperature, pressure and biological or chemical substances which can diffuse through the liquid or gel.

107. A probe as claimed in claim 105 wherein a pressure applied to the housing is transmitted to the surface of a pressure sensitive region of the optical fiber within the housing.

108. A probe as claimed in claim 107 wherein the housing includes one or more apertures covered by a flexible membrane, through which external pressure is transmitted to the liquid or gel and thereby applied to the optical fiber.

109. A probe as claimed in claim 97 for measuring a biological or chemical parameter comprising a tubular housing filled with liquid or gel wherein the liquid or gel within the housing provides a transfer medium to enable particular target molecules to diffuse through the liquid and thereby be transferred to one or more optical fibers located within the housing, such fiber(s) having a suitable reactive sensing element coupled to the fiber providing a change in optical response.

110. A probe as claimed in claim 97 including a sealed tubular housing comprising a liquid or flowable gel disposed within the housing and surrounding the fiber, the liquid or gel permitting the transfer of at least one parameter to be measured from a region outside the housing to the at least one sensing region of the fiber.

111. A probe as claimed in claim 110 wherein said housing includes one or more apertures covered by a membrane, the membrane allowing the application of pressure to the liquid or gel from the surrounding environment and/or allowing the selective diffusion of target molecules through the membrane.

112. A probe as claimed in claim 105 wherein the liquid is isotonic saline.

113. A probe as claimed in claim 103 including a temperature sensing region within one or more of the optical fibers and wherein the housing is formed of a material of good thermal conductivity.

114. A probe as claimed in claim 97 wherein one of the parameters to be detected is fluid pressure in the body and wherein the optical fiber is configured in at least one sensing region to provide a changing optical property depending on the pressure applied to the fiber.

115. A probe as claimed in claim 97 wherein the optical properties are spectral peaks or troughs at different wavelengths, said different wavelengths undergoing respective wavelength shifts in use in response to different parameters within the body.

116. A probe as claimed in claim 97 wherein one optical property of the sensor probe is the absolute wavelength of one or more spectral peaks of the fiber'"'"'s optical response, and a further optical property is the spacing between spectral peaks or troughs in the mutually orthogonal polarization planes of the fiber.

117. A probe as claimed in claim 97 wherein at least one of the sensing regions comprises a sensing element formed of a material which undergoes a change in volume upon exposure to a parameter or measurand to be measured, such change in volume creating a strain within the fiber whereby a detectable change in optical response is obtained.

118. A probe as claimed in claim 97 wherein the optical fiber is birefringent.

119. A probe as claimed in claim 118 wherein the fiber comprises one or more side holes at the sensing region.

120. A probe as claimed in claim 119 wherein a sensing element is provided in said side hole said sensing element being arranged to swell when exposed to a measurand.

121. A probe as claimed in claim 97 wherein the fiber is birefringent and wherein a strain established in the fiber is one of longitudinal strain, bending strain, and/or generally radially directed strain, such that there is a change both in an absolute wavelength of the optical response or output of the fiber, and a change in a distance between spectral peaks in mutually orthogonal polarization planes.

122. A probe as claimed in claim 97 wherein at least one of the sensing regions comprises a sensing element including a coating of reactive material provided on the fiber.

123. A probe as claimed in claim 122 wherein the coating is configured to apply longitudinal and/or radial strain to the fiber when exposed to a measurand.

124. A probe as claimed in claim 97 wherein at least one of the sensing regions comprises a sensing element including a piston and cylinder arrangement and wherein the sensing element is configured to expand and provide a longitudinal strain within the fiber when exposed to a measurand.

125. A probe as claimed in claim 97 wherein at least one of the sensing regions comprises a material reactive to one or more of non-ionizing radiation, ionizing radiation and chemical or biological, including immunological, interactions.

126. A probe as claimed in claim 97 wherein at least one of the sensing regions comprises a reactive material immobilized on a solid support medium.

127. A probe as claimed in claim 126 wherein the support itself acts as a selective element.

128. A probe as claimed in claim 97 wherein one or more than one of the sensing regions comprises a material immobilized in a fluid or gel, wherein the fluid or gel is arranged to swell or to contract in response to a target measurand.

129. A probe as claimed in claim 97 wherein a separate body compatible membrane is provided to cover or enclose at least one of the sensing regions.

130. A probe as claimed in claim 129 wherein the membrane is arranged to select the measurand species based on one of size selectivity through controlled porosity of the membrane, chemical/biochemical selectivity through chemical reactions, or ionic selectivity through electrostatic interactions.

131. A probe as claimed in claim 97 wherein at least one of the sensing regions comprises a coating of paint or bonding material such as a polymer gel network.

132. A probe as claimed in claim 131 wherein at least one of the sensing regions is or comprises a biochemical key-lock pair, such as biotin-avidin or lectin-saccharide.

133. A probe as claimed in claim 97 wherein at least one of the sensing regions comprises a coating of a porous material such as sol-gel glass or ceramics.

134. A probe as claimed in claim 97 wherein at least one of the sensing regions comprises micro-spherical balls, provided with additives arranged to generate chemical selectivity for a selected group of molecules.

135. A probe as claimed in claim 97 wherein at least one of the sensing regions comprises ionic N-Isopropylacrylamide (NIPA) polymer gel copolymerised by sodium acrylate (SA).

136. A probe as claimed in claim 97 wherein at least one of the sensing regions is or comprises a hydrogel.

137. A probe as claimed in claim 97 comprising three fibers extending along a probe housing wherein a first fiber has at least one pressure sensitive region provided with a reactive coating;

a second fiber has at least one pressure sensitive region but not provided with said reactive coating; and

the third fiber is sensitive to temperature and/or longitudinal strain.

138. A probe as claimed in claim 97 comprising a plurality of fibers each having a distal end, the distal ends of said fibers being connected via a fiber minibend.

139. A probe as claimed in claim 97 wherein the optical fiber or fibers are located in a body compatible protective housing.

142. A probe as claimed in claim 140 comprising one or more fiber Bragg gratings (FBG'"'"'s) written into the optical fiber core.

143. A probe as claimed in claim 140 comprising an active fiber laser including said fiber.

145. A probe as claimed in claim 140 wherein the fiber has a fiber length, said fiber being provided with sensing regions responsive primarily to different parameters at axially spaced locations along the fiber length.

146. A probe as claimed in claim 140 wherein the probe is configured to measure first and second parameters, quantify said first parameter and use the measurement of the second parameter to correct the measurement of the first parameter.

147. A probe as claimed in claim 140 having a first optical property which changes in accordance with a first parameter, and a second optical property different from the first which changes in accordance with a second parameter, such that through the use of a suitable interrogation system said first and second parameters can be measured independently.

148. A probe as claimed in claim 140 having two or more fibers each having a fiber length, at least one of said fibers having sensing regions responsive primarily to different parameters and arranged at axially spaced locations along the fiber length.

149. A probe as claimed in claim 140 having two or more fibers arranged side-by-side within the housing, wherein the fibers have respective sensing regions which are responsive to different parameters or measurands.

150. A probe as claimed in claim 140 wherein one or more of said parameters transferred by the liquid is selected from the group comprising temperature, pressure and biological or chemical substances which can diffuse through the liquid or gel.

151. A probe as claimed in claim 140 wherein the housing includes one or more apertures covered by a flexible membrane, through which external pressure is transmitted to the liquid or gel and thereby applied to the optical fiber.

152. A probe as claimed in claim 140 for measuring a biological or chemical parameter wherein the liquid or gel within the housing provides a transfer medium to enable particular target molecules to diffuse through the liquid and thereby be transferred to one or more optical fibers located within the housing, such fiber(s) having a suitable reactive sensing element coupled to the fiber providing a change in optical response.

153. A probe as claimed in claim 152 the housing including one or more apertures covered by a membrane, the membrane allowing the application of pressure to the liquid or gel from the surrounding environment and/or allowing the selective diffusion of target molecules through the membrane.

154. A probe as claimed in claim 140 wherein the liquid is isotonic saline.

155. A probe as claimed in claim 140 including a temperature sensing region within one or more of the optical fibers and wherein the housing is formed of a material of good thermal conductivity.

156. A probe as claimed in claim 140 wherein one of the parameters to be detected is fluid pressure in the body and wherein the optical fiber is configured in at least one of the sensing regions to provide a changing optical property depending on the pressure applied to the fiber.

157. A probe as claimed in claim 140 wherein at least one of the sensing regions comprises a sensing element formed of a material which undergoes a change in volume upon exposure to a parameter or measurand to be measured, such change in volume creating a strain within the fiber whereby a detectable change in optical response is obtained.

158. A probe as claimed in claim 140 wherein the optical fiber is birefringent.

159. A probe as claimed in claim 158 wherein the fiber comprises one or more side holes at the sensing region.

160. A probe as claimed in claim 159 wherein a sensing element is provided in said side hole said sensing element being arranged to swell when exposed to a measurand.

161. A probe as claimed in claim 157 wherein the fiber is birefringent fiber and wherein a strain established in the fiber is one of longitudinal strain, bending strain, and/or generally radially directed strain, such that there is a change both in an absolute wavelength of the optical response or output of the fiber, and a change in a distance between spectral peaks in mutually orthogonal polarization planes.

162. A probe as claimed in claim 140 wherein the sensing region comprises a sensing element including a coating of reactive material provided on the fiber.

163. A probe as claimed in claim 162 wherein the coating is configured to apply longitudinal and/or radial strain to the fiber when exposed to a measurand.

164. A probe as claimed in claim 140 wherein the sensing region comprises a material reactive to one or more of non-ionizing radiation, ionizing radiation and chemical or biological, including immunological, interactions.

165. A probe as claimed in claim 140 wherein the sensing region comprises a reactive material immobilized on a solid support medium.

166. A probe as claimed in claim 165 wherein the support itself acts as a selective element.

167. A probe as claimed in claim 140 wherein a separate body compatible membrane is provided to cover or enclose the sensing region.

168. A probe as claimed in claim 167 wherein the membrane is arranged to select the measurand species based on one of size selectivity through controlled porosity of the membrane, chemical/biochemical selectivity through chemical reactions, or ionic selectivity through electrostatic interactions.

169. A probe as claimed in claim 140 wherein the sensing region comprises a coating of paint or bonding material such as a polymer gel network.

170. A probe as claimed in claim 168 wherein the sensing region is or comprises a biochemical key-lock pair, such as biotin-avidin or lectin-saccharide.

171. A probe as claimed in claim 140 wherein the sensing region comprises a coating of a porous material such as sol-gel glass or ceramics.

172. A probe as claimed in claim 140 wherein the sensing region comprises micro-spherical balls, provided with additives arranged to generate chemical selectivity for a selected group of molecules.

173. A probe as claimed in claim 140 wherein the sensing region comprises ionic N-Isopropylacrylamide (NIPA) polymer gel copolymerised by sodium acrylate (SA).

174. A probe as claimed in claim 140 wherein the sensing region is or comprises a hydrogel.

175. A probe as claimed in claim 140 comprising within the tubular housing in side-by-side arrangement two or more optical fibers, at least one of such fibers being provided with a sensing element responsive to a first parameter to be measured, and another fiber being absent such first sensing element, or provided with a second sensing element to detect a second parameter different from the first.

176. A probe as claimed in claim 175 wherein the second fiber is absent the sensing element, and wherein the optical response from said second fiber is used to correct the output from the first fiber provided with said sensing element.

177. A probe as claimed in claim 140 comprising a tubular housing mounting therewith optical fibers in side-by-side relation, a first fiber arranged to provide a birefringent response dependent on pressure applied to the fiber, and a second fiber arranged to provide a temperature dependent response which is used to correct measurements based on the optical output of said first fiber.

178. A probe as claimed in claim 140 wherein the optical fiber or fibers are located in a body compatible protective housing.

180. A probe as claimed in claim 179 comprising one or more fiber Bragg gratings (FBG'"'"'s) written into the optical fiber core of at least one of said first or second optical fibers.

181. A probe as claimed in claim 179 comprising an active fiber laser including at least one of said fibers.

182. A probe as claimed in claim 179 wherein said first or second optical fibers comprises a pair of pi phase-shifted fiber Bragg gratings.

184. A probe as claimed in claim 183 wherein the housing includes one or more apertures covered by a flexible membrane, through which external pressure is transmitted to the liquid or gel and thereby applied to the optical fiber.

185. A probe as claimed in claim 183 wherein the liquid is isotonic saline.

186. A probe as claimed in claim 179 wherein a strain is established in the first fiber is one of longitudinal strain, bending strain, and/or generally radially directed strain, such that there is a change both in an absolute wavelength of the optical response or output of the fiber, and a change in a distance between spectral peaks in mutually orthogonal polarization planes.

187. A probe as claimed in claim 179 wherein a separate body compatible membrane is provided to cover or enclose a sensing region of the probe.

188. A probe as claimed in claim 179 wherein the optical fibers are located in a body compatible protective housing.

190. A probe as claimed in claim 189 wherein at least one of the fibers comprises one or more fiber Bragg gratings (FBG'"'"'s) written into the optical fiber core.

191. A probe as claimed in claim 189 wherein at least one of the fibers comprises an active fiber laser including said fiber.

192. A probe as claimed in claim 189 wherein at least one of the fibers comprises a pair of pi phase-shifted fiber Bragg gratings.

193. A probe as claimed in claim 189 wherein the housing is filled with a liquid or gel such that one or more parameters to be measured are transferred to the one or more sensing regions of the fiber or fibers within the housing.

194. A probe as claimed in claim 189 wherein the housing is filled with a liquid or gel such that a pressure applied to the housing is transmitted to the surface of a pressure sensitive region of the optical fiber within the housing.

195. A probe as claimed in claim 194 wherein the housing includes one or more apertures covered by a flexible membrane, through which external pressure is transmitted to the liquid or gel and thereby applied to the optical fiber.

196. A probe as claimed in claim 193 wherein the liquid is isotonic saline.

197. A probe as claimed in claim 189 wherein said first fiber comprises one or more side holes at a sensing region.

198. A probe as claimed in claim 189 wherein a strain is established in said first fiber, said strain being one of longitudinal strain, bending strain, and/or generally radially directed strain, such that there is a change both in an absolute wavelength of the optical response or output of the first fiber, and a change in a distance between spectral peaks in mutually orthogonal polarization planes.

199. A probe as claimed in claim 189 wherein the coating is configured to apply longitudinal and/or radial strain to the fiber when exposed to a measurand.

200. A probe as claimed in claim 189 wherein a separate body compatible membrane is provided to cover or enclose a sensing region of the probe.

201. A probe as claimed in claim 200 wherein the membrane is arranged to select the measurand species based on one of size selectivity through controlled porosity of the membrane, chemical/biochemical selectivity through chemical reactions, or ionic selectivity through electrostatic interactions.

202. A probe as claimed in claim 189 wherein the first fiber comprises a coating of paint or bonding material such as a polymer gel network.

203. A probe as claimed in claim 202 wherein the sensing region is or comprises a biochemical key-lock pair, such as biotin-avidin or lectin-saccharide.

204. A probe as claimed in claim 189 wherein the first fiber comprises a coating of a porous material such as sol-gel glass or ceramics.

205. A probe as claimed in claim 189 wherein the reactive coating region comprises micro-spherical balls, provided with additives arranged to generate chemical selectivity for a selected group of molecules.

206. A probe as claimed in claim 189 wherein the reactive coating comprises ionic N-Isopropylacrylamide (NIPA) polymer gel copolymerised by sodium acrylate (SA).

207. A probe as claimed in claim 189 wherein the reactive coating comprises a hydrogel.

208. A probe as claimed in claim 189 wherein said three fibers each have a distal end, the distal ends of said fibers are connected via a fiber minibend.

209. A probe as claimed in claim 189 wherein the optical fibers are located in a body compatible protective housing.

101. A body compatible fiber optic sensor probe for invasive medical use, provided with at least one optical fiber having axially spaced sensing regions, the sensing regions providing in use distinguishable optical responses or outputs dependent primarily on different parameters within the body said fiber further comprising a pair of pi phase-shifted fiber Bragg gratings.

140. An optical fiber sensor device including a sealed tubular housing containing therewithin at least one optical fiber having at least one sensing region, there being a liquid or flowable gel disposed within the housing and surrounding the fiber, the liquid or gel permitting the transfer of at least one parameter to be measured from a region outside the housing to a sensing region of the fiber.

141. An optical fiber sensor device including a sealed tubular housing containing therewithin at least one optical fiber having at least one sensing region, there being a liquid or flowable gel disposed within the housing and surrounding the fiber, the liquid or gel permitting the transfer of at least one parameter to be measured from a region outside the housing to a sensing region of the fiber, the at least one sensing region comprising a mass of reactive material configured to create mechanical strain within the fiber in such a way as to change its optical response.

144. An optical fiber sensor device including a sealed tubular housing containing therewithin at least one optical fiber having at least one sensing region, there being a liquid or flowable gel disposed within the housing and surrounding the fiber, the liquid or gel permitting the transfer of at least one parameter to be measured from a region outside the housing to a sensing region of the fiber said fiber comprising a pair of pi phase-shifted fiber Bragg gratings.

179. A fiber optic sensor device comprising a tubular housing mounting therewith optical fibers in side-by-side relation, a first fiber providing a birefringent response dependent on pressure applied to the fiber, and the second fiber providing a temperature dependent response which may be used to correct measurements based on the optical output of the first fiber.

189. A fiber optic sensor device comprising three fibers extending along a probe housing wherein a first fiber has at least one pressure sensitive region provided with a reactive coating;

a second fiber has at least one pressure sensitive region but not provided with the reactive coating; and

the third fiber is sensitive to temperature and/or longitudinal strain.

210. A fiber optic sensor device, comprising a fiber or fibers having respective sensing regions located within a sealed tubular housing wherein a liquid is interposed between said sensing regions and the wall of the housing, having a first sensing region primarily pressure dependent, and having a second sensing region primarily temperature dependent.

211. A probe as claimed in claim 210 wherein at least one of said fibers comprises one or more fiber Bragg gratings (FBG'"'"'s) written into the optical fiber core.

212. A probe as claimed in claim 210 wherein at least one of said fibers comprises an active fiber laser including said fiber.

213. A probe as claimed in claim 210 wherein at least one of said fibers comprises a pair of pi phase-shifted fiber Bragg gratings.

214. A probe as claimed in claim 210 having a first optical property which changes in accordance with pressure, and a second optical property different from the first which changes in accordance with temperature, such that through the use of a suitable interrogation system pressure and temperature can be measured independently.

215. A probe as claimed in claim 210 having two or more fibers arranged side-by-side within the housing, wherein the fibers have respective sensing regions which are responsive to different parameters or measurands.

216. A probe as claimed in claim 210 wherein the liquid is isotonic saline.

217. A probe as claimed in claim 210 wherein at least one of said sensing regions comprises a sensing element formed of a material which undergoes a change in volume upon exposure to a parameter or measurand to be measured, such change in volume creating a strain within the fiber whereby a detectable change in optical response is obtained.

218. A probe as claimed in claim 210 wherein the optical fiber is birefringent.

219. A probe as claimed in claim 218 wherein the fiber comprises one or more side holes at the sensing region.

220. A probe as claimed in claim 210 comprising a birefringent fiber wherein the strain established in the fiber is one of longitudinal strain, bending strain, and/or generally radially directed strain, such that there is a change both in an absolute wavelength of the optical response or output of the fiber, and a change in a distance between spectral peaks in mutually orthogonal polarization planes.

221. A probe as claimed in claim 210 wherein a separate body compatible membrane is provided to cover or enclose a sensing region.

222. A probe as claimed in claim 210 comprising a plurality of fibers each having a distal end, the distal ends of said fibers being connected via a fiber minibend.

223. A probe as claimed in claim 210 wherein the optical fiber or fibers are located in a body compatible protective housing.

226. A method of medical treatment comprising the simultaneous sensing of different parameters within the body through the use a fiber optic probe having a sensing region or regions with measurable optical properties dependent on mechanical strain established in one or more optical fibers wherein the probe is responsive to at least two different parameters within the body.

227. A dual parameter fiber optic sensing system, comprising a pair of birefringent optical fibers each having at least one sensor configured to provide a birefringent optical output dependent upon a respective parameter, and detecting means having signal processing means adapted to provide an electrical output signal indicative of the birefringence of each of said fiber.