Optical sensor based on a broadband light source and cascaded waveguide filters

Patent metadata

Field	Value
Publication number	US-9052291-B2
Application number	US-201113575602-A
Country	US
Kind code	B2
Filing date	Jan 21, 2011
Priority date	Jan 29, 2010
Publication date	Jun 9, 2015
Grant date	Jun 9, 2015

Abstract

An optical sensor based on a broadband light source and cascaded waveguide filters comprises a broadband light source, an input waveguide, a reference ring resonator coupled with the input waveguide, a common bus waveguide coupled with the reference ring resonator, a sensing ring resonator coupled with the common bus waveguide, an output waveguide coupled with the sensing ring resonator, and two optical power detectors. At least a portion of the sensing ring resonator is influenced by the physical parameter to be measured or in contact with an analyte. The variation of the physical parameter to be measured or the variation of the analyte induces a shift of the transmission spectrum of the sensing ring resonator. By using the cascaded filtering effect of the double resonators, the wavelength shift can be translated into a variation of the total output power. Consequently the physical parameter to be measured can be easily deduced.

First claim

What is claimed is:

1. An optical sensor comprising: a broadband light source 0 , an input waveguide 1 coupled with the broadband light source 0 , a reference ring resonator 10 coupled with the input waveguide, a common bus waveguide 3 coupled with the reference ring resonator 10 , a sensing ring resonator 20 coupled with the common bus waveguide 3 , an output waveguide 2 coupled with the sensing ring resonator 20 , an optical power detector 42 coupled with the output waveguide 2 for measuring the output power; the optical path lengths of said reference ring resonator and sensing ring resonator are substantially the same, the resonant frequencies of said reference ring resonator 10 correspond to a series of equally spaced peaks in its transmission spectrum, the resonant frequencies of said sensing ring resonator 20 substantially coincide with the resonant frequencies of said reference ring resonator 10 ; at least a portion of the waveguide of the sensing ring resonator 20 is effected by the physical parameter to be measured or is in contact with the analyte while the waveguide of the reference ring resonator 10 is covered by a cladding layer that prevents it from being effected by the physical parameter to be measured or from being in contact with the analyte, the change of the physical parameter to be measured or the analyte causes a shift of the transmission peaks of the sensing ring resonator 20 with respect to those of the reference ring resonator 10 , which consequently causes a change of the output power.

2. An optical sensor as defined in claim 1 , wherein the waveguides and the ring resonators are coupled by directional couplers or multimode interference couplers.

3. An optical sensor as defined in claim 1 , wherein the broadband light source is a light emitting diode.

4. An optical sensor as defined in claim 1 , wherein the other end of the input waveguide 1 is coupled with a second optical power detector 41 .

5. An optical sensor as defined in claim 1 , wherein the physical parameter to be measured is stress or temperature, and the analyte is a liquid or a gas.

6. An optical sensor comprising: a broadband light source 0 , an input waveguide 1 , a reference optical filter 101 , a common bus waveguide 3 , an sensing optical filter 102 , an output waveguide 2 , and an optical power detector 42 , which are coupled in sequence; the transmission frequencies of said reference optical filter 101 correspond to a series of equally spaced peaks in its transmission spectrum, the transmission frequencies of said sensing optical filter 102 substantially coincide with the transmission frequencies of said reference optical filter 101 ; at least a portion of the waveguide of the sensing optical filter 102 is effected by the physical parameter to be measured or is in contact with the analyte while the waveguide of the reference optical filter 101 is covered by a cladding layer that prevents it from being effected by the physical parameter to be measured or from being in contact with the analyte, the change of the physical parameter to be measured or the analyte causes a shift of the transmission peaks of the sensing optical filter 102 with respect to those of the reference optical filter 101 , which consequently causes a change of the output power.

7. An optical sensor as defined in claim 6 , wherein the waveguides and the optical filters are comprised of fibers or planar integrated waveguides.

8. An optical sensor as defined in claim 6 , wherein the optical filters are comprised of one or several Mach-Zehnder interferometers, or array waveguide gratings, or Fabre-Perot interferometers.

9. An optical sensor comprising: a broadband light source 0 , an input waveguide 1 coupled with the broadband light source 0 , a reference ring resonator 10 coupled with the input waveguide, a common bus waveguide 3 coupled with the reference ring resonator 10 , a sensing ring resonator 20 coupled with the common bus waveguide 3 , an output waveguide 2 coupled with the sensing ring resonator 20 , an optical power detector 42 coupled with the output waveguide 2 for measuring the output power; the optical path lengths of said reference ring resonator and sensing ring resonator are slightly different so that the resonant frequency of said reference ring resonator 10 correspond to a series of equally spaced peaks in its transmission spectrum, and when one resonant frequency of said sensing ring resonator 20 coincides with one resonant frequency of said reference ring resonator 10 , the adjacent resonant peaks do not overlap completely; at least a portion of the waveguide of the sensing ring resonator 20 is effected by the physical parameter to be measured or is in contact with the analyte while the waveguide of the reference ring resonator 10 is covered by a cladding layer that prevents it from being effected by the physical parameter to be measured or from being in contact with the analyte, the change of the physical parameter to be measured or the analyte causes a shift of the transmission peaks of the sensing ring resonator 20 with respect to those of the reference ring resonator 10 , which consequently causes a change of the output power.

10. An optical sensor as defined in claim 9 , wherein the couplers between the input waveguide 1 , the common bus waveguide 3 and the reference ring resonator 10 are directional couplers or multimode interference couplers; the couplers between the output waveguide 2 , the common bus waveguide 3 and the sensing ring resonator 20 are directional couplers or multimode interference couplers.

11. An optical sensor as defined in claim 9 , wherein the broadband light source is a light emitting diode.

12. An optical sensor as defined in claim 9 , wherein the other end of the input waveguide 1 is coupled with a second optical power detector 41 .

13. An optical sensor as defined in claim 9 , wherein the physical parameter to be measured is stress or temperature, and the analyte is a liquid or a gas.

14. An optical sensor comprising: a broadband light source 0 , an input waveguide 1 , a reference optical filter 101 , a common bus waveguide 3 , a sensing optical filter 102 , an output waveguide 2 , an optical power detector 42 , which are coupled in sequence; the transmission frequency of said reference optical filter 101 correspond to a series of equally spaced peaks in its transmission spectrum, and when one transmission frequency of said sensing optical filter 102 coincides with one transmission frequency of said reference optical filter 101 , the adjacent transmission peaks are not overlapped completely; at least a portion of the waveguide of the sensing optical filter 102 is effected by the physical parameter to be measured or is in contact with the analyte while the waveguide of the reference optical filter 101 is covered by a cladding layer that prevents it from being effected by the physical parameter to be measured or from being in contact with the analyte, the change of the physical parameter to be measured or the analyte causes a shift of the transmission peaks of the sensing optical filter 102 with respect to those of the reference optical filter 101 , which consequently causes a change of the output power.

15. An optical sensor as defined in claim 14 , wherein the input waveguide 1 , the output waveguide 2 , the common bus waveguide 3 , the reference optical filter 101 and the sensing optical filter 102 are comprised of fibers or planar integrated waveguides.

16. An optical sensor as defined in cla

Assignees

• He Jian-Jun
• Jin Lei
• Li Mingyu
• Univ Zhejiang

Inventors

• He Jian-Jun
• Jin Lei
• Li Mingyu

Classifications

• H01P7/00

  Resonators of the waveguide type · CPC title

• H01P11/007

  Manufacturing frequency-selective devices (resonators H01P11/008) · CPC title

• G01K11/00

  Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 · CPC title

• G01J1/04

  Optical or mechanical part {supplementary adjustable parts} · CPC title

• H01P11/00

  Apparatus or processes specially adapted for manufacturing waveguides or resonators, lines, or other devices of the waveguide type · CPC title