Optical temperature compensation of spectral modulation sensors by ratiometric interrogation having dichroic filters

An optical temperature compensation system for spectral modulation sensors, comprising:

• a plurality of spectral modulation sensors;
• a light director optically coupled to said plurality of spectral modulation sensors for receiving excitation light and for delivering respective sensor portions of the excitation light to said spectral modulation sensors;
• a source monitoring component for receiving a source portion of the excitation light from said light director, said source monitoring component comprising offset optics optically coupled to said light director, a source dichroic filter for splitting the light from said offset optics, a first photodetector for receiving wavelengths above the effective cutoff wavelength of said source dichroic filter, and a second source photodetector for receiving wavelengths below the effective cutoff wavelength of said source dichroic filter;
• and
• a detection monitoring component for receiving modulated light from said plurality of spectral modulation sensors, said detection monitoring component comprising a detection dichroic filter for splitting light from said plurality of spectral modulation sensors, a first detection photodetector for receiving wavelengths above the effective cutoff wavelength of said detection dichroic filter, and a second detection photodetector for receiving wavelengths below the effective cutoff wavelength of said detection dichroic filter.

An optical temperature compensation system for spectral modulation sensors, comprising:

• means for splitting excitation light into two excitation portions;
• means for spectrally modulating one of said two excitation portions of said excitation light;
• means for splitting the modulated portion of said excitation light into a first modulated portion having wavelengths above a cutoff wavelength and a second modulated portion having wavelengths below said cutoff wavelength;
• means for optically detecting said first and second modulated portions;
• means for optically offsetting the other of said two excitation portions of said excitation light;
• means for splitting the offset portion of said excitation light into a first offset portion having wavelengths above a cutoff wavelength and a second offset portion having wavelengths below said cutoff wavelength;
• means for optically detecting said first and second offset portions;
• and
• means for determining a first ratio of the detected modulated portions of modulated light and a second ratio of the detected offset portions of offset light and multiplying the first and second ratios.

A method of achieving temperature compensation for spectral modulation sensors, comprising the steps of:

• providing excitation light;
• splitting the excitation light into two excitation portions;
• spectrally modulating one of said two excitation portions of said excitation light;
• splitting said modulated portion of said excitation light into a first modulated portion having wavelengths above a cutoff wavelength and a second modulated portion having wavelengths below said cutoff wavelength;
• optically detecting the first and second modulated portions;
• optically offsetting the second excitation portion of said excitation light;
• splitting the offset portion of said excitation light into a first offset portion having wavelengths above a cutoff wavelength and a second offset portion having wavelengths below said cutoff wavelength;
• optically detecting the first and second offset portions;
• and
• determining the ratios of the detected modulated portions of modulated light and of the detected offset portions of offset light.