Multiplexable fiber-optic strain sensor system with temperature compensation capability

A fiber-optic sensor system comprising:

• a first sensor grating and a second sensor grating;
• a first optical splitter and a second optical splitter, each said splitter having a source port, a filter port, and a sensor port, wherein optical energy applied to said sensor port is divided between said source port and said filter port, and wherein optical energy applied to said source port travels to said sensor port, said first optical splitter sensor port coupled to said first sensor grating, and said second optical splitter sensor port coupled to said second sensor grating;
• a third splitter having an input and a first and second output wherein optical energy applied to said input divides equally between said first output and said second output;
• a fourth splitter having an input and a first and second output wherein optical energy applied to said input divides equally between said first output and said second output;
• a coarse wavelength discriminator having a first and a second input, and a first and a second output, said first coarse wavelength discriminator input coupled to said first output of said third splitter, said coarse wavelength discriminator second input coupled to said fourth splitter first output;
• a fine wavelength discriminator having a first and a second input, and a first and a second output, said first fine wavelength discriminator input coupled to said second output of said third splitter, said fine wavelength discriminator second input coupled to said fourth splitter second output;
• a first coarse detector converting an optical input to an electrical response, said optical input coupled to said first coarse wavelength discriminator output;
• a second coarse detector converting an optical input to an electrical response, said optical input coupled to said second coarse discriminator output;
• a first fine detector converting an optical input to an electrical response, said optical input coupled to said first fine wavelength discrimintator output;
• a second fine detector converting an optical input to an electrical response, said optical input coupled to said second fine discriminator output;
• wherein optical energy present in said coarse wavelength discriminator first or second input produces said first detector and said second detector responses which vary monotonically from a first discriminator wavelength to a final discriminator wavelength, said monotonic relationship between said detector response and a wavelength stored in said controller;
• said first optical source and said second optical source each said source having an enable input and producing an optical output when said enable input is active, said first optical source output coupled to said first splitter source port, and said second optical source output coupled to said second splitter source port;
• a controller having a first enable output coupled to said first optical source, a second enable output coupled to said second optical source, a first coarse input coupled to said first coarse detector, and a second coarse input coupled to said second coarse detector, a first fine input coupled to said first fine detector, and a second fine input coupled to said second fine detector, said controller producing said first enable output and said second enable output during mutually exclusive time intervals, and recording said coarse detector responses and said fine detector responses.