An integrated optical waveguide isolator based on multi mode interference by wafer direct bonding

An integrated optical waveguide isolator by wafer direct bonding between the InGaAsP and Ce:YIG is reported. The layer structure of multi-mode section of the optical isolator is Ce:YIG/InGaAsP/InP. An external magnetic field is applied to the device to measure the optical isolation ratio. The isolation ratio was found to be 2.9 dB.