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Simultaneous Laser Diode Emission and Detection for Optical Fiber Sensors

K. B. Rochford and A. H. Rose, National Institute of Standards and Technology, Boulder, Colo.

Reflective fiber optic intensity sensors often use a coupler to guide part of the reflected light back to a photodetector. We have demonstrated a sensor that requires no coupler, and instead uses the emitting laser diode for photodetection. A laser diode operating at constant current can detect light reflected into the junction region if the terminal voltage is monitored. We used a self-detecting source to sense rotation using a simple magneto-optic transducer and single-fiber sensor system.