Single mode (SM) fiber optical reader system and method for interrogating resonant waveguide-grating sensor(s)

Abstract

An optical reader system is described herein which has a single mode (SM) optical fiber launch/receive system that uses one or more SM optical fibers to interrogate a biosensor and does not use multimode (MM) optical fibers to interrogate the biosensor. The use of the SM optical fiber launch/receive system effectively reduces angular sensitivity, reduces unwanted system reflections, improves overall angular tolerance, and improves resonant peak reflectivity and resonant peak width. Two specific embodiments of the SM optical fiber launch/receive system are described herein which include: (1) a dual fiber collimator launch/receive system; and (2) a single fiber launch/receive system that interrogates the biosensor at a normal incidence.

1. A optical reader system, suitable for use with a biosensor when placed in an operative position relative to the optical reader system, said system comprising:
 a light source; 
 a light detector resonance shift detection system; and 
 a launch/receive system which includes:
 a single mode optical fiber; and 
 a lens, wherein said single mode optical fiber is interfaced with said light source and said light detector resonance shift detection system, wherein said single mode optical fiber is physically separated from said lens and said lens is physically separated from a biosensor when placed in the operative position, wherein said single mode optical fiber emits a light beam generated by said light source such that the emitted light beam is focused by said lens before interfacing at a substantially normal incidence with the a biosensor when placed in the operative position, wherein said a biosensor, when placed in the operative position, reflects the light beam such that the reflected light beam passes through said lens and said single mode optical fiber and is received by said light detector resonance shift detection system. 
 
 
     
     
       2. The system of  claim 1 , wherein said launch/receive system further comprising comprises an optical isolator which is positioned between said lens and said a biosensor, when placed in the operative position, and wherein said optical sensor isolator is physically separated from said lens and said a biosensor, when placed in the operative position. 
     
     
       3. The system of  claim 2 , wherein said optical isolator includes a circular polarizer which rejects Fresnel reflections and parasitic reflections that are created during interrogation of the biosensor. 
     
     
       4. The system of  claim 1 , wherein the use of the single mode optical fiber within said launch/receive system eliminates undesirable spatial modes which would be present if one or more multimode optical fibers were used within said launch/receive system. 
     
     
       5. The system of  claim 1 , wherein the use of the single mode optical fiber within said launch/receive system causes said launch/receive system to have less sensitivity, in terms of wavelength variation, to angular deviations of the a biosensor than if one or more multimode optical fibers were used within said launch/receive system. 
     
     
       6. The system of  claim 1 , wherein the use of the single mode optical fiber within said launch/receive system causes a resonant wavelength associated with the a biosensor to be more stable than if one or more multimode optical fibers were used within said launch/receive system. 
     
     
       7. The system of  claim 1 , wherein said launch/receive system by interrogating the a biosensor, when placed in the operative position, at normal incidence effectively minimizes said fiber launch/receive system sensitivity to angular deviations of the a biosensor, when placed in the operative position, in terms of power fluctuations and minimizes a resonant peak width while simultaneously maximizing an angular tolerance and maximizing a resonance reflection efficiency. 
     
     
       8. The system of  claim 1 , wherein said biosensor is system is suitable to receive a resonant waveguide grating sensor in the operative position. 
     
     
       9. A method for interrogating a biosensor, said method comprising the steps step of:
 using a launch/receive system which has a single mode optical fiber incorporated therein to interrogate the biosensor and does not have a multimode optical fiber incorporated therein to interrogate the biosensor, wherein said launch/receive system includes:
 a single mode optical fiber; and 
 a lens, wherein said single mode optical fiber is interfaced with said a light source and said light detector a resonance shift detection system, wherein said single mode optical fiber is physically separated from said lens and said lens is physically separated from a biosensor, wherein said single mode optical fiber emits a light beam generated by said light source such that the emitted light beam is focused by said lens before interfacing at a substantially normal incidence with the biosensor, wherein said biosensor reflects the light beam such that the reflected light beam passes through said lens and said single mode optical fiber and is received by said light detector resonance shift detection system. 
 
 
     
     
       10. The method of  claim 9 , wherein said launch/receive system further comprising comprises an optical isolator which is positioned between said lens and said biosensor, and wherein said optical sensor isolator is physically separated from said lens and said biosensor. 
     
     
       11. The method of  claim 10 , wherein said optical isolator includes a circular polarizer which rejects Fresnel reflections and parasitic reflections that are created during interrogation of the biosensor. 
     
     
       12. The method of  claim 9 , wherein the use of the single mode optical fiber within said launch/receive system eliminates undesirable spatial modes which would be present if one or more multimode optical fibers were used within said launch/receive system. 
     
     
       13. The method of  claim 9 , wherein the use of the single mode optical fiber within said launch/receive system causes said launch/receive system to have less sensitivity, in terms of wavelength variation, to angular deviations of the biosensor than if one or more multimode optical fibers were used within said launch/receive system. 
     
     
       14. The method of  claim 9 , wherein the use of the single mode optical fiber within said launch/receive system causes a resonant wavelength associated with the biosensor to be more stable than if one or more multimode optical fibers were used within said launch/receive system. 
     
     
       15. The method of  claim 9 , wherein said launch/receive system by interrogating the biosensor at normal incidence effectively minimizes said launch/receive system sensitivity to angular deviations of the biosensor and minimizes a resonant peak width while simultaneously maximizing an angular tolerance and maximizing a resonance reflection efficiency. 
     
     
       16. The method of  claim 9 , wherein said biosensor is a resonant waveguide grating sensor. 
     
     
       17. An optical reader system suitable for use with a sensor when placed in an operative position relative to the optical reader system, said system comprising:
 a light source;   a resonance shift detection system; and   a launch/receive system including:
 a single mode optical fiber; and 
 a lens, wherein said single mode optical fiber is interfaced with said light source and said resonance shift detection system, wherein said single mode optical fiber emits a light beam generated by said light source such that the emitted light beam is focused by said lens and interfaces at a substantially normal incidence with a sensor when placed in the operative position, wherein a sensor, when placed in the operative position, reflects the light beam such that the reflected light beam passes through said lens and said single mode optical fiber and is received by said resonance shift detection system. 
   
     
     
       18. The system of claim 17, wherein said launch/receive system further comprises an optical isolator which is positioned between said lens and a sensor when placed in the operative position, and wherein said optical isolator is physically separated from said lens and a sensor when placed in the operative position. 
     
     
       19. The system of claim 18, wherein said optical isolator includes a circular polarizer which rejects Fresnel reflections and parasitic reflections that are created during interrogation of a sensor when placed in the operative position. 
     
     
       20. A combination comprising:
 the system of claim 17 and   a sensor.   
     
     
       21. The combination of claim 20, wherein said sensor is a biosensor. 
     
     
       22. The combination of claim 20, wherein said sensor is a resonant waveguide grating sensor. 
     
     
       23. A method for interrogating a sensor, said method comprising:
 providing a launch/receive system which comprises:
 a single mode optical fiber to interrogate the sensor 
 a lens, wherein said single mode optical fiber is interfaced with a light source and a resonance shift detection system and 
   passing a light beam from the light source into the launch/receive system, wherein the light beam emitted from said single mode optical fiber is focused by said lens to a substantially normal incidence with the sensor, wherein said sensor reflects the light beam such that the reflected light beam passes through said lens and said single mode optical fiber and is received by said resonance shift detection system.   
     
     
       24. The method of claim 23, wherein said launch/receive system further comprises an optical isolator which is positioned between said lens and said sensor, and wherein said optical isolator is physically separated from said lens and said sensor. 
     
     
       25. The method of claim 24, wherein said optical isolator includes a circular polarizer which rejects Fresnel reflections and parasitic reflections that are created during interrogation of the sensor. 
     
     
       26. The method of claim 23, wherein said sensor is a biosensor. 
     
     
       27. The method of claim 23, wherein said sensor is a resonant waveguide grating sensor. 
     
     
       28. An optical reader system suitable for use with a sensor when placed in an operative position relative to the optical reader system, said system comprising:
 a light source;   a resonance shift detection system; and   a launch/receive system including:
 a single mode optical fiber interfaced with said light source and said resonance shift detection system, wherein said single mode optical fiber emits a light beam generated by said light source such that the emitted light beam is focused and interfaces at a substantially normal incidence with a sensor when placed in the operative position, wherein a sensor, when placed in the operative position, reflects the light beam such that the reflected light beam passes through said single mode optical fiber and is received by said resonance shift detection system. 
   
     
     
       29. The system of claim 28, wherein said launch/receive system further comprises an optical isolator which is positioned between said optical fiber and a sensor when placed in the operative position, and wherein said optical isolator is physically separated from a sensor when placed in the operative position. 
     
     
       30. The system of claim 29, wherein said optical isolator includes a circular polarizer which rejects Fresnel reflections and parasitic reflections that are created during interrogation of a sensor when placed in the operative position. 
     
     
       31. A combination comprising:
 the system of claim 28 and   a sensor.   
     
     
       32. The combination of claim 31, wherein said sensor is a biosensor. 
     
     
       33. The combination of claim 31, wherein said sensor is a resonant waveguide grating sensor. 
     
     
       34. A method for interrogating a sensor, said method comprising:
 providing a launch/receive system which comprises a single mode optical fiber incorporated therein to interrogate the sensor, wherein said single mode optical fiber is interfaced with a light source and a resonance shift detection system and   passing a light beam from the light source into the launch/receive system, wherein the light beam emitted from said single mode optical fiber is focused to a substantially normal incidence with the sensor, wherein said sensor reflects the light beam such that the reflected light beam passes through said single mode optical fiber and is received by said resonance shift detection system.   
     
     
       35. The method of claim 34, wherein said launch/receive system further comprises an optical isolator positioned between said optical fiber and said sensor, and wherein said optical isolator is physically separated from said sensor. 
     
     
       36. The method of claim 35, wherein said optical isolator includes a circular polarizer which rejects Fresnel reflections and parasitic reflections that are created during interrogation of the sensor. 
     
     
       37. The method of claim 34, wherein said sensor is a biosensor. 
     
     
       38. The method of claim 34, wherein said sensor is a resonant waveguide grating sensor. 
     
     
       39. An optical reader system suitable for use with a sensor when placed in an operative position relative to the optical reader system, said system comprising:
 a light source;   a light detector; and   a launch/receive system which includes:
 a single mode optical fiber; 
 a lens, wherein said single mode optical fiber is interfaced with said light source and said light detector, wherein said single mode optical fiber is physically separated from said lens and said lens is physically separated from a sensor when placed in the operative position, wherein said single mode optical fiber emits a light beam generated by said light source such that the emitted light beam is focused by said lens before interfacing at a substantially normal incidence with a sensor when placed in the operative position, wherein a sensor, when placed in the operative position, reflects the light beam such that the reflected light beam passes through said lens and said single mode optical fiber and is received by said light detector; and 
 an optical isolator positioned between and physically separated from said lens and a sensor when placed in the operative position, wherein said optical isolator includes a circular polarizer which rejects Fresnel reflections and parasitic reflections that are created during interrogation of a sensor when placed in the operative position. 
   
     
     
       40. A combination comprising:
 the system of claim 39 and   a sensor.   
     
     
       41. The combination of claim 40, wherein the sensor is a biosensor. 
     
     
       42. The combination of claim 40, wherein said sensor is a grating sensor on which events to be monitored take place. 
     
     
       43. A method for interrogating a sensor, said method comprising:
 providing a launch/receive system which comprises:
 a single mode optical fiber to interrogate the sensor; 
 a lens, wherein said single mode optical fiber is interfaced with a light source and a light detector; and 
 an optical isolator comprising a circular polarizer which rejects Fresnel reflections and parasitic reflections that are created during interrogation of said sensor, wherein the optical isolator is positioned between and physically separated from said lens and said sensor and 
   passing a light beam from the light source into the launch/receive system, wherein the light beam emitted from said single mode optical fiber is focused by said lens to a substantially normal incidence with the sensor, wherein said sensor reflects the light beam such that the reflected light beam passes through said lens and said single mode optical fiber and is received by said light detector.   
     
     
       44. The method of claim 43, wherein said sensor is a biosensor. 
     
     
       45. The method of claim 44, wherein said sensor is a grating sensor on which events to be monitored take place. 
     
     
       46. A combination comprising:
 the system of claim 1 and   a biosensor.   
     
     
       47. The system of claim 1, wherein the resonance shift detection system comprises a spectrometer for analyzing a spectrum of the reflected light beam. 
     
     
       48. The system of claim 1, wherein the light source comprises a tunable optical element and the resonance shift detection system comprises a photodiode. 
     
     
       49. The system of claim 17, wherein the resonance shift detection system comprises a spectrometer for analyzing a spectrum of the reflected light beam. 
     
     
       50. The system of claim 17, wherein the light source comprises a tunable optical element and the resonance shift detection system comprises a photodiode. 
     
     
       51. The system of claim 28, wherein the resonance shift detection system comprises a spectrometer for analyzing a spectrum of the reflected light beam. 
     
     
       52. The system of claim 28, wherein the light source comprises a tunable optical element and the resonance shift detection system comprises a photodiode.