초록 ▼

An analog, optical-fiber measuring system compensates for variations in the level of light attenuation occurring in the optical path of the measuring system. The analog, optical-fiber measuring system utilizes a "reference" light transmitted along a common optical-fiber path as the actual "sensing"

An analog, optical-fiber measuring system compensates for variations in the level of light attenuation occurring in the optical path of the measuring system. The analog, optical-fiber measuring system utilizes a "reference" light transmitted along a common optical-fiber path as the actual "sensing" light. The reference light has a wavelength which differs from the sensing light's wavelength. Effects of the variations in the level of light attenuation are eliminated by monitoring the variations in the attenuation experienced by the reference light along the common optical-fiber path and adjusting the respective intensities of the reference light and the sensing light as a function of the variations. Because the effects of the variations in the level of light attenuation are compensated by an analog scheme, accurate measurement of the selected physical parameter is insured without the need for a microprocessor. The analog, optical-fiber measuring system facilitates discrete optical fibers to be separated and reconnected without significantly affecting the integrity of the optical signal obtained via these discrete optical fibers.

대표청구항 ▼

[ I claim:] [1.] An analog, optical-fiber sensing system comprising:an optical-fiber network with at least one optical fiber, said network having a first end and a second end;a first light source optically coupled to said first end of said optical-fiber network for generating and introducing into sa

[ I claim:] [1.] An analog, optical-fiber sensing system comprising:an optical-fiber network with at least one optical fiber, said network having a first end and a second end;a first light source optically coupled to said first end of said optical-fiber network for generating and introducing into said first end of said optical-fiber network a reference light having a first wavelength;a second light source optically coupled to said first end of said optical-fiber network for generating and introducing into said first end of said optical-fiber network a sensing light having a second wavelength;a filter located at said second end of said optical-fiber network, said filter reflecting said reference light back through said optical-fiber network and transmitting said sensing light;a sensor optically coupled to said second end of said optical-fiber network, said filter being positioned between said second end of said optical-fiber network and said sensor, said sensor variably modulating said sensing light back through said optical-fiber network, optical characteristics of said sensor varying as a function of a selected environmental parameter to be measured;a detector optically coupled to said first end of said optical-fiber network for detecting respective intensities of the reflected reference light and the modulated sensing light; anda controller for adjusting the intensities of said reference light and said sensing light generated by said first light source and said second light source, respectively, in response to a variation between the intensity of the reflected reference light and a predetermined intensity.