Optical phase difference measurement and correction using AlGaAs integrated guided-wave components

A Y-junction interferometer phase measurement technique that is independent of the power or power ratio in the input arms has been developed. The technique is intended for use in the basic module of a proposed integrated optical system for use at GaAs wavelengths that produces a flat-phase output wavefront. A proof-of-concept AlGaAs guided-wave Mach-Zehnder interferometer was used to demonstrate measurement and correction of a phase difference between the arms using this phase measurement technique. Results have been obtained for the cases of successive steps in the phase difference between the interferometer arms, of random phase differences, and of a power imbalance of up to 30% between the arms.<
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