Optical devices engaged to fibers with angle-polished facets

• US 20020114566A1
• Filed: 04/09/2001
• Published: 08/22/2002
• Est. Priority Date: 02/21/2001
• Status: Active Grant

• Current Assignee: Oclaro Incorporated (Lumentum Holdings Inc.)
• Original Assignee: Avanex Corporation (Oclaro (North America), Inc.)
• Inventors: Schwartz, Tom, Hajjar, Roger A., Dalziel, Warren, Fairchild, Scot C.
• Granted Patent: US 6,654,517 B2
• Time in Patent Office: Days
• US Class Current: 385/33
• CPC Class Codes: G02B 6/266 the optical element being an attenuator
• CPC Class Codes: G02B 6/29362 Serial cascade of filters or filtering operations, e.g. for a large number of channels
• CPC Class Codes: G02B 6/29365 in a multireflection configuration, i.e. beam following a zigzag path between filters or filtering operations
• CPC Class Codes: G02B 6/327 with angled interfaces to reduce reflections
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• CPC Class Codes: G02B 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3556 NxM switch, i.e. regular arrays of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3582 Housing means or package or arranging details of the switching elements, e.g. for thermal isolation
• CPC Class Codes: G02B 6/359 of the position of the moving element itself during switching, i.e. without monitoring the switched beams
• CPC Class Codes: G02B 6/3594 Characterised by additional functional means, e.g. means for variably attenuating or branching or means for switching differently polarized beams
• CPC Class Codes: G02B 6/4207 with optical elements reducing the sensitivity to optical feedback anti-reflection devices specially adapted for lasers, see H01S3/0064
• CPC Class Codes: G02B 6/4208 using non-reciprocal elements or birefringent plates, i.e. quasi-isolators optical isolators per se G02F1/093, G02F1/0955
• CPC Class Codes: G02B 6/4225 by a direct measurement of the degree of coupling, e.g. the amount of light power coupled to the fibre or the opto-electronic element
• CPC Class Codes: G02B 6/423 using guiding surfaces for the alignment
• CPC Class Codes: G02B 6/4292 the light guide being disconnectable from the opto-electronic element, e.g. mutually self aligning arrangements

Abstract

Techniques and devices for using fibers that are angle-polished to reduce the adverse effects of optical reflection. Each fiber is mounted so that the longitudinal direction of the fiber core forms an angle with respect to an optical axis of a device along which an optical beam is coupled to or from the angle-polished end facet of the fiber.

Claims

1. A device, comprising:

a light source configured to produce a light beam;

a fiber coupler module having a collimator lens which defines a collimator optic axis and a fiber which has one end facet facing said collimator lens and forms an angle with respect to a fiber optic axis of said fiber, said collimator lens positioned to couple said light beam into said fiber through said end facet, wherein said fiber coupler module is configured to hold said fiber at a tilted angle with respect to said collimator optic axis so that an output beam from said fiber is received and collimated by said collimator lens to propagate along said collimator optic axis;

a support module having a first part to mount said light source and a second part with a support platform over which said fiber coupler module is positioned in optical alignment with said light source, said support platform having a top surface facing said fiber coupler module and first and second opposing side surfaces substantially parallel to an optical path of said light beam;

first and second vertical elongated engagement members having first distal ends affixed to said first side surface to space from each other and second distal ends affixed to said fiber coupler module;

a third vertical elongated engagement member having a first distal end affixed to said second side surface in a position between positions of said first and second vertical elongated engagement members along said optical path of said light beam, said third vertical elongated engagement member having a second distal end affixed to said fiber coupler module;

a first horizontal engagement member having a first part engaged to said fiber coupler module and a second part elongated in a direction nominally perpendicular to said first and second side surfaces and engaged to said support platform at a first location close to said first side surface; and

a second horizontal engagement member having a first part engaged to said fiber coupler module at a location different from said first horizontal engagement member, and having a second part elongated in a direction nominally parallel to said second elongated part of said first horizontal engagement member and engaged to said support platform at a second location close to said second side surface.

2. The device as in claim 1, wherein each engagement member is slightly deflected to apply a pressure towards said fiber coupler module.

3. The device as in claim 1, wherein said fiber coupler module includes a housing and said collimator lens is directly engaged to a surface of said housing.

4. The device as in claim 3, wherein said housing includes a cylindrical through channel to transmit said light beam and to hold at least a portion of said collimator lens.

5. The device as in claim 3, wherein said fiber coupler module includes a fiber fitting unit to engage said fiber to said housing with said tilted angle.

6. The device as in claim 5, wherein said fiber fitting unit includes a fiber sleeve that forms said tilted angle with respect to said collimator optic axis and holds said fiber.

7. The device as in claim 1, wherein said fiber coupler module includes:

a receiving port to hold at least a portion of said collimator lens;

a first substrate fabricated to have a first groove to which said collimator lens is engaged; and

a second substrate fabricated to have a second groove to hold said fiber in parallel to said second substrate, said second substrate engaged to said first substrate at said tilted angle to place said end facet of said fiber to face said collimator lens.

8. The device as in claim 7, further comprising at least two ball members with different diameters positioned between and engaged to said first and said second substrates to tilt said second substrate at said tiled angle.

9. A device, comprising:

a switching element to direct an optical signal beam to one or more switching directions;

a fiber with an angle-polished end facet positioned to send said optical signal beam to or receive said optical signal beam from said switching element;

a fiber coupler module holding said fiber and a collimator lens in an optical path between said angle-polished end facet and said switching element, wherein said fiber coupler module is configured to hold said fiber at a tilted angle with respect to a collimator optic axis of said collimator lens so that an output beam from said fiber is received and collimated by said collimator lens to propagate along said collimator optic axis;

an optical position sensor adopted to use an optical servo beam to measure a property of said switching element to produce a position signal indicative of a deviation between an actual switching direction and a desired switching direction of said signal beam; and

a control unit to respond to said position signal to control said switching element so as to reduce said deviation to direct said signal beam substantially in said desired switching direction.

10. The device as in claim 9, wherein said signal beam has a wavelength different from a wavelength of said servo beam.

11. The device as in claim 9, wherein said switching element includes a reflector having a signal reflective surface to reflect said signal beam and a servo reflective surface to reflect said servo beam, and an actuator coupled to adjust and control an orientation of said reflector.

12. The device as in claim 11, wherein said optical position sensor includes a light source to generate said servo beam to said reflector and a position-sensing photodetector to measure a position of said servo beam upon reflection from said reflector, said photodetector operable to produce said position signal.

13. The device as in claim 12, wherein said photodetector includes discrete photosensing areas.

14. The device as in claim 12, wherein said photodetector includes a PIN photodiode with at least one uniform, resistive surface to provide continuous position data.

15. The device as in claim 11, wherein said actuator is operable to adjust said orientation of said reflector around a single rotation axis.

16. The device as in claim 11, wherein said actuator is operable to adjust said orientation of said reflector around two different rotation axes.

17. The device as in claim 11, wherein said actuator includes a galvanometer or a MEMS actuator.

18. The device as in claim 9, further comprising:

another optical position sensor coupled to said optical fiber coupler module to measure a position of said signal beam on said angle-polished end facet to produce a second position signal,

wherein said switching element is operable to respond to said second position signal to further control said actual switching direction of said signal beam to direct said signal beam at a desired position on said angle-polished end facet.

19. The device as in claim 9, wherein said second optical position sensor includes:

an optical coupler coupled to said fiber to split a portion of optical energy received by said angle-polished end facet;

a photodetector to receive said portion of optical energy to produce a detector signal indicating an amount of said optical energy received by said angle-polished end facet.

20. The device as in claim 19, wherein said portion includes an optical servo beam at a wavelength different a signal wavelength of a signal beam in said optical beam, and wherein said optical coupler is a dichroic optical coupler.

21. The device as in claim 19, wherein said portion is a part of said signal beam.

22. The device as in claim 9, wherein said fiber coupler module includes a fiber fitting unit to engage said fiber with said tilted angle.

23. The device as in claim 22, wherein said fiber fitting unit includes a fiber sleeve that forms said tilted angle with respect to said collimator optic axis and holds said fiber.

24. The device as in claim 9, wherein said fiber coupler module includes:

a receiving port to hold at least a portion of said collimator lens;

a first substrate fabricated to have a first groove to which said collimator lens is engaged; and

a second substrate fabricated to have a second groove to hold said fiber in parallel to said second substrate, said second substrate engaged to said first substrate at said tilted angle to place said angle-polished end facet of said fiber to face said collimator lens.

25. The device as in claim 24, wherein said fiber coupler module further comprises at least two ball members with different diameters positioned between and engaged to said first and said second substrates to tilt said second substrate at said tiled angle.

27. The device as in claim 26, wherein an input signal beam is directed once by one switching element in said first array and once by a switching element in said second array to produce an output signal beam at a desired output direction.

28. The device as in claim 27, further comprising:

a terminal optical position sensor coupled to a fiber port, which receives said output signal beam, to measure a position of said output signal beam on said angle-polished end facet of a respective fiber to produce a terminal position signal,

wherein at least one of said switching element in said first array and said switching element in said second array is operable to respond to said terminal position signal to further direct a direction of said output signal beam to a desired position on said fiber port.

29. The device as in claim 26, wherein each switching element includes a reflector that has a first reflective surface to reflect a signal beam and a second reflective surface to reflect a servo beam, wherein each of said first and said second optical position sensors includes:

a light source to produce said servo beam; and

a photodetector having a position-sensing surface to receive said servo beam reflected from said second reflective surface and to produce a position signal.

30. The device as in claim 29, wherein each of said first and said second optical position sensor includes a beam splitter positioned to direct said servo beam from said light source to said second reflective surface and to direct said servo beam reflected from said second reflective surface to said photodetector.

31. The device as in claim 30, wherein said servo beam is linearly polarized and said beam splitter is a polarization beam splitter, wherein each optical position sensor further includes a polarization rotator to rotate a polarization of said servo beam reflected by said second reflective surface by about 90 degrees from a polarization of said servo beam incident to said second reflective surface.

32. The device as in claim 29, wherein each switching element includes an actuator engaged to said reflector to adjust an orientation of said reflector in two orthogonal directions.

33. The device as in claim 32, wherein said actuator includes a galvanometer.

34. The device as in claim 26, each switching element in said first and said second arrays is operable to adjust a direction of a beam in two orthogonal directions.

35. The device as in claim 26, wherein each fiber port includes a fiber fitting unit to engage said fiber with said tilted angle.

36. The device as in claim 35, wherein said fiber fitting unit includes a fiber sleeve that forms said tilted angle with respect to said collimator optic axis and holds said fiber.

37. The device as in claim 26, wherein each fiber port includes:

a receiving port to hold at least a portion of said collimator lens;

a first substrate fabricated to have a first groove to which said collimator lens is engaged; and

a second substrate fabricated to have a second groove to hold said fiber in parallel to said second substrate, said second substrate engaged to said first substrate at said tilted angle to place said angle-polished end facet of said fiber to face said collimator lens.

38. The device as in claim 37, wherein each fiber port further comprises at least two ball members with different diameters positioned between and engaged to said first and said second substrates to tilt said second substrate at said tiled angle.

40. The device as in claim 39, further comprising an adjustable optical attenuator located in an optical path of said add-channel beam before entering said second optical bandpass filter and operable to adjust a power level of said add-channel beam.

41. The device as in claim 40, wherein said adjustable optical attenuator includes an adjustable optical aperture.

42. The device as in claim 39, further comprising a base configured to support and mount said first and said second optical bandpass filters and said fiber ports.

43. The device as in claim 42, further comprising at least one optical reflector in an optical path of a beam, which is selected from said input optical signal, said add-channel beam, said drop-channel beam, and said second reflected optical beam, wherein said optical reflector is positioned to change a direction of said beam.

44. The device as in claim 39, further comprising a third optical bandpass filter operable to transmit light at said transmission wavelength and to reflect light at other wavelengths, said third optical bandpass filter positioned in an optical path of said first reflected optical beam between said first and said second optical bandpass filters to reflect and direct said first reflected optical beam to said second optical bandpass filter.

45. The device as in claim 39, wherein each fiber port includes a fiber fitting unit to engage a respective fiber with said tilted angle.

46. The device as in claim 45, wherein said fiber fitting unit includes a fiber sleeve that forms said tilted angle with respect to said collimator optic axis and holds said respective fiber.

47. The device as in claim 39, wherein each fiber port includes:

a receiving port to hold at least a portion of said collimator lens;

a first substrate fabricated to have a first groove to which said collimator lens is engaged; and

a second substrate fabricated to have a second groove to hold said fiber in parallel to said second substrate, said second substrate engaged to said first substrate at said tilted angle to place said angle-polished end facet of said fiber to face said collimator lens.

48. The device as in claim 47, wherein each fiber port further comprises at least two ball members with different diameters positioned between and engaged to said first and said second substrates to tilt said second substrate at said tiled angle.

26. A device, comprising:

a first array of switching elements and a second array of switching elements, each switching element operable to direct a signal beam from one direction to another direction, wherein each switching element in one of said first and said second arrays is operable to direct an incident beam to each and every switching element in another of said first and said second arrays;

a first optical position sensor to use at least a first optical servo beam to measure a property of each switching element in said first array to produce a first position signal indicative of a deviation between an actual switching direction and a desired switching direction of a first signal beam received by said each switching element in said first array;

a second optical position sensor to use at least a second optical servo beam to measure a property of each switching element in said second array to produce a second position signal indicative of a deviation between an actual switching direction and a desired switching direction of a second signal beam received by said each switching element in said second array,

wherein each switching element in said first array is operable to reduce said deviation to direct said first signal beam substantially in said desired switching direction, and wherein each switching element in said second array is operable to reduce said deviation to direct said second signal beam substantially in said desired switching direction;

a first array of fiber ports positioned to optically communicate with said first array of switching elements and configured to hold fibers with angle-polished end facets respectively facing said first array of switching elements; and

a second array of fiber ports positioned to optically communicate with said second array of switching elements and configured to hold fibers with angle-polished end facets respectively facing said second array of switching elements,

wherein each fiber port includes a collimator lens in an optical path between an angle-polished end facet of a respective fiber and a respective switching element and is configured to hold said respective fiber at a tilted angle with respect to a collimator optic axis of said collimator lens so that an output beam from said fiber is received and collimated by said collimator lens to propagate along said collimator optic axis.

39. A device, comprising:

a first optical bandpass filter operable to receive an input optical signal with a plurality of wavelength-division multiplexed (WDM) channels and to transmit light at a transmission wavelength to produce a drop-channel beam while reflecting light at other wavelengths to produce a first reflected beam;

a second optical bandpass filter operable to transmit light at said transmission wavelength and to reflect light at other wavelengths, said second optical bandpass filter positioned to receive and reflect said first reflected optical beam from said first optical bandpass filter through free space as a second reflected optical beam,

wherein said second optical bandpass filter is operable to receive and transmit an add-channel beam at said transmission wavelength to merge into said second reflected optical beam;

an input fiber port engaged to an input fiber which carries said input optical signal and positioned to send said input optical signals to said first optical bandpass filter;

a drop fiber port engaged to a drop fiber and positioned to receive said drop-channel beam;

an add fiber port engaged to an add fiber which is operable to carry said add-channel beam and positioned to send said add-channel beam to said second optical bandpass filter; and

an output fiber port engaged to an output fiber and positioned to receive second reflected optical beam,

wherein each fiber port has a collimator lens which defines a collimator optic axis, wherein and each fiber has one end facet facing said collimator lens and forms an angle with respect to a fiber optic axis of said fiber, each collimator lens positioned in an optical path between a respective optical bandpass filter and a respective fiber wherein each fiber port is configured to hold said fiber at a tilted angle with respect to said collimator optic axis so that an output beam from said fiber is received and collimated by said collimator lens to propagate along said collimator optic axis.