Patent ID: 7221815

Claim:
A system for determining the values of a plurality of sensors provided in a hostile environment, comprising: a plurality of optical emitters, each optical emitter producing a particular narrow band of wavelengths of optical energy; a first waveguide; a second waveguide; a multiplexer in connection with said plurality of optical emitters for producing a wavelength division multiplexed spectrum combining the narrow band of wavelengths produced by each of said optical emitters to be transmitted along said first waveguide; a plurality of optical drop taps periodically provided along said first waveguide, each of said optical drop taps associated with one of said sensors, each of said optical drop taps sensitive to the narrow band of wavelength of one of said optical emitters, thereby diverting only a narrow band of wavelengths from said spectrum to its respective sensor; a plurality of add taps periodically provided along said second waveguide, each of said optical add taps associated with one of the sensors for receiving a signal from the sensor, modulating a narrow band of wavelengths transmitted to the sensor from one of said optical drop taps; and a spectrometer receiving all of the wavelength division multiplexed spectrum, a portion of the spectrum modulated by each of the sensors and carried by said second waveguide, said spectrometer analyzing said wavelength division multiplexed spectrum including the portions of said narrow band of wavelengths modulated by the sensors; wherein at least one of the sensors operates to vary the ratio of absorbance between wave energy having two different wavelengths passing through said sensor.