Temperature compensation for fiber optic sensors

A fiber optic system comprising:

• two light sources for providing light at two different wavelengths;
• a length of optical fiber communicating with the light sources for passing light at two different wavelengths through the optical fiber, the length of optical fiber having an active leg receiving light at a first wavelength and a reference leg receiving light at a second wavelength at a location in the length of fiber;
• detection means for detecting the light passed at two different wavelengths through the optical fiber;
• an active microbend sensor on the active leg of the optical fiber for producing an active signal;
• a reference microbend sensor on the reference leg of the optical fiber for producing a reference signal the reference sensor being positioned near the active microbend sensor;
• the active signal and the reference signal being provided to the detection means;
• and
• process means communicating with the detection means for determining a compensation for the active microbend sensor based on the active signal and the reference signal.

A sensor for microbending an optical fiber, the sensor comprising;

• a frame having a top, a bottom, and sides with an open area within the frame, the frame also having a first aperture through the frame near the bottom for passing an optical fiber through the frame across the bottom;
• a block movably mounted within the frame in the open area, the block being engageable with the bottom of the frame for compressing the optical fiber;
• an adjuster for controlling the movement of the block, the adjuster extending through the top of the frame and being connected to the block;
• and
• means for locking the block in position, the locking means extending through a second aperture in the frame.