Integrated spectroscopy system

Abstract

Integrated spectroscopy systems are disclosed. In some examples, integrated tunable detectors, using one or multiple Fabry-Perot tunable filters, are provided. Other examples use integrated tunable sources. The tunable source combines one or multiple diodes, such as superluminescent light emitting diodes (SLED), and a Fabry Perot tunable filter or etalon. The advantages associated with the use of the tunable etalon are that it can be small, relatively low power consumption device. For example, newer microelectrical mechanical system (MEMS) implementations of these devices make them the size of a chip. This increases their robustness and also their performance. In some examples, an isolator, amplifier, and/or reference system is further provided integrated.

What is claimed is: 
     
       1. A tunable light source spectroscopy system, comprising:
 a superluminescent light emitting diode for generating broadband light; and 
 a tunable Fabry Perot filter for spectrally filtering the broadband light from the broadband source to generate a tunable signal; 
 an optical fiber for carrying the tunable signal to irradiate a sample; 
 a detector for detecting a response of the sample to the tunable signal to determine a spectroscopic response of the sample; and 
 an isolator interposed between the superluminescent light emitting diode and the tunable filter for preventing back reflections from the tunable filter into the superluminescent light emitting diode. 
 
     
     
       2. A tunable light source spectroscopy system as claimed in  claim 1 , wherein the superluminescent light emitting diode and the Fabry Perot filter are installed in common on an optical bench. 
     
     
       3. A tunable light source spectroscopy system as claimed in  claim 1 , wherein the superluminescent light emitting diode, isolator, and tunable filter are integrated on a common optical bench. 
     
     
       4. A tunable light source spectroscopy system as claimed in  claim 1 , comprising an amplifier for amplifying the tunable signal. 
     
     
       5. A tunable light source spectroscopy system, comprising:
 a superluminescent light emitting diode for generating broadband light; and 
 a tunable Fabry Perot filter for spectrally filtering the broadband light from the broadband source to generate a tunable signal; 
 an optical fiber for carrying the tunable signal to irradiate a sample; 
 a detector for detecting a response of the sample to the tunable signal to determine a spectroscopic response of the sample; and 
 an amplifier for amplifying the tunable signal, wherein the amplifier is a semiconductor optical amplifier. 
 
     
     
       6. A tunable light source spectroscopy system as claimed in  claim 5 , further comprising an isolator interposed between the superluminescent light emitting diode and the tunable filter for preventing back reflections from the tunable filter into the broadband source. 
     
     
       7. A tunable light source spectroscopy system, comprising:
 a superluminescent light emitting diode for generating broadband light; and 
 a tunable Fabry Perot filter for spectrally filtering the broadband light from the broadband source to generate a tunable signal; 
 an optical fiber for carrying the tunable signal to irradiate a sample; 
 a detector for detecting a response of the sample to the tunable signal to determine a spectroscopic response of the sample; and 
 an amplifier for amplifying the tunable signal, wherein the amplifier is a fiber amplifier. 
 
     
     
       8. A tunable light source spectroscopy system as claimed in  claim 7 , wherein the fiber amplifier is one of an erbium, ytterbium, thulium or Raman fiber amplifier. 
     
     
       9. A tandem filtered amplified spontaneous emission (ASE) scanning optical source, comprising:
 an ASE source for generating broadband light in a spectral band;   a first tunable Fabry Perot filter having a first passband that is tuned over a scanband in the spectral band of the ASE source for filtering the broadband light;   an isolation system between the ASE source and the first tunable Fabry Perot filter for preventing back reflections from the tunable first Fabry Perot filter into the ASE source;   a second tunable Fabry Perot filter having a second passband that is tuned over a scanband in the spectral band of the ASE source for filtering light from the first tunable Fabry Perot filter; and   a second isolation system between the first tunable Fabry Perot filter and the second tunable Fabry Perot filter;   wherein the first tunable Fabry Perot filter and the second tunable Fabry Perot filter form a filter system that has a peak transmissivity to the broadband light where the first passband and the second passband are coincident.   
     
     
       10. A source as claimed in claim 9, wherein the first tunable Fabry Perot filter and the second tunable Fabry Perot have different free spectral ranges. 
     
     
       11. A source as claimed in claim 9, wherein the isolation system is an isolator. 
     
     
       12. A source as claimed in claim 9, wherein the isolation system is a quarterwave plate. 
     
     
       13. A source as claimed in claim 9, wherein the ASE source is a superluminescent light emitting diode. 
     
     
       14. A source as claimed in claim 9, wherein the first and second tunable Fabry-Perot filters are MEMS tunable Fabry-Perot filters. 
     
     
       15. A source as claimed in claim 9, further comprising an optical bench, the ASE source, first tunable Fabry Perot filter, and second tunable Fabry Perot filter being integrated together on the optical bench. 
     
     
       16. A source as claimed in claim 9, further comprising a reference detector for detecting part of a tunable optical signal from the filter system and a spectral reference for generating a fringe pattern on the detector during scanning of the tunable optical signal. 
     
     
       17. A source as claimed in claim 9, further comprising two or more broadband sources for generating broadband light that is converted into a tunable optical signal by the first tunable Fabry Perot filter and the second tunable Fabry Perot filter. 
     
     
       18. A source as claimed in claim 9, further comprising lenses for collecting the broadband light emitted from the ASE source and coupling the broadband light into the first tunable Fabry Perot filter and for collecting a tunable optical signal from the first tunable Fabry Perot filter and coupling the tunable optical signal into the second tunable Fabry Perot filter.