A novel hybrid coupler based on antiresonant reflecting optical waveguides

A novel hybrid coupler based on the antiresonant reflecting optical waveguides (ARROWs) is presented. This device consists of two parallel antiresonant reflecting optical waveguides with a tapered outermost cladding layer. Such a device can provide advantageous features of low radiation loss, low crosstalk at the output end, and compatible core dimensions and indexes with single-mode optical fibers. The staircase approximation and the eigenmode expansion analysis are used to analyze and optimize this device. In our design on a Si-substrate, radiation losses below 0.38 dB and extinction ratios below -20 dB for two waveguide channels are achieved. The beam propagation method (BPM) is also used to verify our design and analysis results.