An Ultra-Broadband Polarization-Insensitive Optical Hybrid Using Multiplane Light Conversion

We designed, fabricated, and tested a 90° optical hybrid using multiplane light conversion. The device supports an octave of bandwidth (900–1800 nm) in simulations. The measured phase errors are below 3° for free space output, and below 8° with a fiber array output, across a measurement bandwidth of 390 nm. The fully-packaged device (with input and output fiber arrays) has a measured insertion loss of 5.52 dB at 1550 nm. A high-speed transmission experiment with QPSK format was conducted to verify the performance of the fully-packaged device.