Coherent Optical Receiver System with Balanced Photodetection

摘要

We report the development of a coherent heterodyne balanced fiber optic receiver with a small laboratory footprint. The receiver incorporates a DFB or a solid state laser local oscillator, fiber optic combiner/splitter, adjustable fiber optic delay line, balanced PIN photodiodes, RF post amplifier, optical phase lock loop, polarization control, and precision power supplies in a small instrument case. We will show shot noise limited detection of amplitude modulated signals, cancellation of laser RIN noise, and line narrowing of the IF signal. Several examples of coherent balanced detection as enabling technology for high value applications in fiber optic communication and remote sensing will be presented.