Fiber-optic circuit for direct phase conversion with two outputs in quadrature

The authors model and demonstrate a fiber-optic circuit configuration that maps optical phase shifts into electrical phase shifts in the fundamental and second harmonics of an imposed modulation frequency. This optical circuit allows simple electronic phase detectors to extract these phase shifts, which are demonstrated to be linear over a full 2 pi radians, opposite in slope, and offset by pi /2 from each other in a phase relation similar to quadrature.<
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