Magnetooptic Waveguide with SiO2 Cladding Layer Integrated on InP Substrate by Wafer Direct Bonding

Abstract
Magnetooptic waveguides with a SiO2 cladding layer were fabricated on an InP substrate by the wafer direct bonding technique for the purpose of integrating a laser diode and an optical isolator. First, direct bonding between InP and sputter-deposited SiO2 on a Gd3Ga5O12 substrate was investigated. Bonding was achieved by surface treatment of both wafers and subsequent heat treatment in H2 ambient. By applying heat treatment in H2 ambient at temperatures ranging between 110 and 220° C, the magnetooptic waveguides were bonded to the InP substrate without deterioration of their optical properties.