Method and apparatus for determining a measuring variable by means of an integrated optical sensor module

• US 5,442,169 A
• Filed: 06/02/1993
• Issued: 08/15/1995
• Est. Priority Date: 04/26/1991
• Status: Expired due to Term

• Current Assignee: Paul Scherrer-Institut (Schweizerische Eidgenossenschaft)
• Original Assignee: Paul Scherrer-Institut (Schweizerische Eidgenossenschaft)
• Inventors: Kunz, Rino E.
• Primary Examiner(s): Nelms, David C.
• Application Number:
  US07/958,121
• Time in Patent Office: 804 Days
• Field of Search: 250/227.21, 250/227.14, 250/227.17, 250/227.18, 250/227.19, 250/227.23, 250/226, 250/216, 250/237 G, 385/12
• US Class Current: 250/227.21
• CPC Class Codes: A61F 2/00 Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents as cosmetic articles, see the relevant subclasses, e.g. wigs, hair pieces, A41G3/00, A41G5/00; artificial nails A45D31/00; dental prostheses A61C13/00; materials for prostheses A61L27/00; artificial hearts A61M60/00; artificial kidneys A61M1/14
• CPC Class Codes: G01D 5/26 characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
• CPC Class Codes: G01J 2009/023 of the integrated optical type
• CPC Class Codes: G01N 2021/0112 Apparatus in one mechanical, optical or electronic block
• CPC Class Codes: G01N 21/17 Systems in which incident light is modified in accordance with the properties of the material investigated where the material investigated is optically excited causing a change in wavelength of the incident light G01N21/63
• CPC Class Codes: G01N 21/45 using interferometric methods; using Schlieren methods
• CPC Class Codes: G01N 21/552 Attenuated total reflection
• CPC Class Codes: G01N 21/63 optically excited
• CPC Class Codes: G01N 21/64 Fluorescence; Phosphorescence
• CPC Class Codes: G01N 21/65 Raman scattering
• CPC Class Codes: G01N 21/774 the reagent being on a grating or periodic structure
• CPC Class Codes: G01N 21/7743 the reagent-coated grating coupling light in or out of the waveguide

Abstract

A method that allows a plurality of variables to be measured with the aid of an integrated optical sensor module. Because all the components necessary for carrying out the method are integrated on the same substrate, the sensor becomes small, compact, stable, malfunction-free and economical. The sensor module substantially comprises a sensor field, an analyzer, and an information field. The method comprises making the variables to be measured interact in sensor fields with guided waves, analyzing the effect on the wave, determining from that the value of the measuring variables, and displaying the results in the information field.

Claims

1. A method for determining the value of one or more variables to be measured by means of an integrated optical sensor module, comprising the steps of:

providing at least one guided wave in at least one optical waveguide integrated in said sensor module;

interacting at least one of said guided waves with at least one measuring variable in at least one sensor field arranged integrated in said sensor module to receive said at least one of said guided waves;

defining the value of at least one module parameter by the action of the measuring variable on the guided wave;

converting the guided wave into at least one modified guided wave by the action of the measuring variable on the guided wave;

analyzing said modified guided wave in at least one analyzer integrated in the sensor module to ascertain a value at least one output variable corresponding to the measuring variable; and

making available said value of said at least one output variable in at least one information field integrated in the sensor module.

2. The method of claim 1, wherein said sensor field, analyzer, and information field are integrated in the sensor module monolithically.

3. The method of claim 1, wherein said value of said at least one module parameter is defined as a resonance of said interaction.

4. The method of claim 1, wherein the step of includes determining the value of the module parameter by means of said interaction, said resonance depending on a condition taken from the group consisting of location, angle, frequency, and wavelength.

5. The method of claim 4, further comprising the step of generating the location-dependent resonance condition by means of a grating in a grating region, and wherein, in the grating region, at least one of grating parameters, thickness of the waveguide, optical properties of the waveguide, and optical properties of the immediate surroundings of the waveguide are location dependent.

6. The method of claim 1, wherein said module parameter is one taken from the group consisting of the phase, amplitude, frequency, effective wavelength, and wave front of the guided wave.

7. The method of claim 1, wherein the properties of at least one of the sensor field and the analyzer are dependent on time in such a manner that a temporal weighting of the measurement effect is performed and a time-dependent resolution is attained.

8. The method of claim 1, wherein the value of the output variable is ascertained as a function of signals of further optical sensor elements.

9. The method of claim 5, wherein the excitation of the guided wave is affected as a function of a controlled variable derived by the analyzer.

10. The method of claim 5, further comprising the step of:

overcoupling the guided wave into at least one further waveguide;

interacting said overcoupled guided wave in said further waveguide with the measuring variable; and

further processing the modified guided wave in one of the following;

the further waveguide and the wave guide, after being coupled back into the waveguide.

11. The method of claim 5, further comprising the step of

further interacting the modified guided wave leaving the sensor field in at least one further sensor field with at least one further variable to be measured;

analyzing the further modified wave after said further interaction; and

storing information representing the collective interaction of the measuring variables in the information field.

12. The method of claim 1, wherein said sensor field, analyzer, and information field are integrated in the sensor module as a set of compatible processes.

13. The method of claim 1, wherein the properties of at least one of the sensor field and the analyzer are made dependent on location in such a manner that a spatial weighting of the measurement effect is performed and a location-dependent resolution is attained.

14. The method of claim 1, wherein the properties of at least one of the sensor field and the analyzer are made dependent on both location and time in such a manner that both a spatial and temporal weighting of the measurement effect is performed and both a location-dependent and time-dependent resolution are attained.

15. The method of claim 1, wherein the output variable is ascertained as a function of signals of further non-optical sensor elements.

16. The method of claim 1, wherein the output variable is ascertained as a function of signals of further optical and non-optical sensor elements.

17. An apparatus comprising:

an integrated optical sensor module, the sensor module including;

at least one optical waveguide integrated in said sensor module;

at least one guided wave in said at least one optical waveguide;

at least one sensor integrated in said sensor module field for ascertaining the interaction of the guided wave with at least one measuring variable;

at least one analyzer integrated in said sensor module for ascertaining at least one output variable corresponding to the measuring variable; and

at least one information field integrated in said sensor module for making the output variable available.

18. The apparatus of claim 17, wherein the sensor module components are on a single substrate, and the components arrangement is a monolithic structure in one or more layers.

19. The apparatus of claim 17, further comprising a light source integral with the sensor module to excite the guided wave.

20. The apparatus of claim 19, wherein the light source is one of a laser diode and a light-emitting diode.

21. The apparatus of claim 17, further comprising an energy source for supplying energy required to operate the sensor module, said energy source being external to the sensor module and in the form of one of a battery, a chemical energy source, and a nuclear energy source.

22. The apparatus of claim 17, further comprising an external light source to excite the guided wave in the form of one of a laser diode and a light-emitting diode optically coupled to said waveguide by an optical fiber.

23. The apparatus of claim 17, wherein said at least one sensor field is a subregion of the waveguide, wherein the optical properties of said subregion are influenced by the measuring variable, said subregion having a property taken from the group consisting of magnetooptical, electrooptical, nonlinear optical, piezooptical, thermooptical, chemooptical, elastooptical, biooptical acoustooptical, optical properties dependent on the type of incident particle radiation, and optical properties dependent on an intensity of incident particle radiation.

24. The apparatus of claim 17, wherein the sensor field contains at least one sensor layer, said sensor layer having a property taken from the group consisting of magnetooptical, electrooptical, nonlinear optical, piezooptical, thermooptical, chemooptical, elastooptical, biooptical, acoustooptical properties, optical properties dependent on the type of incident particle radiation, and optical properties dependent on an intensity of incident particle radiation.

25. The apparatus of claim 17, wherein the value of the output variable is one of an electrical signal, optical signal, acoustical signal, electromagnetic signal, chemical signal, and a mechanical signal.

26. The apparatus of claim 17, wherein the information field includes one of an electrical contact, at least one optical fiber connection, at least one optical display field, at least one acoustical emitter, at least one high-frequency emitter, at least one chemically active boundary junction, at least one mechanical force coupler, and at least one thermal coupler.

27. The apparatus of claim 17, wherein said at least one sensor field includes a uniform Bragg grating, which is disposed in the region of a nonuniform waveguide.

28. The apparatus of claim 17, wherein said at least one sensor field includes a nonuniform Bragg grating which is disposed in the region of a uniform and nonuniform waveguide.

29. The apparatus of claim 17, wherein the analyzer further comprises at least one detector and at least one mask in front of said at least one detector to increase sensitivity.

30. The apparatus of claim 17, further comprising at least one further waveguide, and at least one coupling element disposed to couple said at least one optical waveguide and said at least one further waveguide, the sensor field being disposed in the region of the coupling element.

31. The apparatus of claim 30, wherein the coupling element includes a buffer layer with a property taken from the group consisting of a location-dependent thickness and a location-dependent refractive index.

32. The apparatus of claim 30, wherein said coupling element includes a grating in a grating region, and wherein grating parameters of said grating region are location dependent.

33. The apparatus of claim 17, further comprising at least one plasmon filter between said sensor field and said analyzer for filtering undesirable guided waves.

34. The apparatus of claim 17, wherein the sensor module includes one of the following:

further optical and nonoptical sensor elements on the same substrate.

35. The apparatus of claim 27, wherein said analyzer derives a controlled variable for influencing one of a light source, a light forming stage, and an optical filter.

36. The apparatus of claim 27, wherein said at least one guided wave and said at least one sensor field are located in a strip waveguide, and means for processing the guided wave leaving the sensor field are provided in the strip waveguide.

37. The apparatus of claim 36, further comprising a means for generating the guided wave, said generating means being disposed in the strip waveguide.

38. The apparatus of claim 27, further comprising an optical filter for generating the frequency-dependent resonance condition, said optical filter being tuneable by the measuring variable by means of a variation in the effective refractive index in the region of a Bragg grating.

39. The apparatus of claim 38, wherein the filter is one of a resonant-reflective filter and a resonant-transmissive filter.

40. The apparatus of claim 23, further comprising at least one grating for overcoupling of the guided wave form said at least one waveguide into at least one further waveguide.

41. The apparatus of claim 40, wherein the further waveguide is disposed in at least one of the following locations:

next to the waveguide in the same layer, in a layer system above the waveguide, on the other side of a substrate upon which said waveguide is located, and further comprising at least one buffer layer located between the waveguide and the further waveguide.

42. The apparatus of claim 17, further comprising an energy source for supplying energy required to operate the sensor module, said energy source being integral to the sensor module and in the form of one of a battery, a chemical energy source, and a nuclear energy source.

43. The apparatus of claim 17, wherein said at least one sensor field is a subregion physically proximate to said waveguide wherein the optical properties of said subregion are influenced by the measuring variable, said subregion having a property taken from the group consisting of magnetooptical, electrooptical, nonlinear optical, piezooptical, thermooptical, chemooptical, elastooptical, biooptical, acoustooptical, optical properties dependent on a type of incident particle radiation, and optical properties dependent on an intensity of incident particle radiation.

44. The apparatus of claim 17, wherein at least one sensor field includes a nonuniform Bragg grating.

45. The apparatus of claim 27, wherein said at least one guided wave and said at least one sensor field are located in a strip waveguide, and means for processing the guided wave leaving the sensor field are provided parallel to the strip waveguide.