# 90 degree optical hybrid

90 degree optical hybrids (also known as quadrature optical hybrids) are essential components in coherent transmission systems. A 90 degree optical hybrid is a six-port device consisting of two inputs and four outputs. In the ideal case, the outputs are the mixed signals of the inputs with 0, , , and relative phase shifts.

This example demonstrates the simulation of a compact and low-loss 90 degree optical hybrid based on a silicon-on-insulator platform. The device consists of a Y-branch, three 2x2 MMIs, and four 90 degree waveguide bends. Building those structures natively in Tidy3D is certainly doable but time consuming. Here, we build the device structures in a separate CAD editor and import the stl file into Tidy3D for simulation.

The device design is adapted from Hang Guan et al., “Compact and low loss 90° optical hybrid on a silicon-on-insulator platform,” Opt. Express 25, 28957-28968 (2017) (opens new window).

To view the full example in Python, please click here (opens new window).