An integrated optical XY coupler for phase-sensitive optical-power combining and suppression of radiated light

We have designed and fabricated a new type of XY coupler for phase-sensitive combining of coherent light in waveguide PIC's. The XY coupler uses two input waveguides and couples in-phase light into the middle of its three output waveguides. Out-of-phase light is coupled into the two outer waveguides. 15.5-dB extinction ratio is demonstrated in a Mach-Zehnder interferometer using this new XY coupler. Switching from the inner to the outer waveguides at the output is also demonstrated.<
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