Integration of a Faraday rotator and a mode selector for a magnetic field sensor

We have demonstrated an integrated magnetic field sensor consisting of a Faraday rotator and a mode selector for the first time. The sensor is a loaded waveguide which has a waveguide layer made of a garnet with magneto-optical effect for Faraday rotation and a metal clad layer for mode selection. The magnetic field can be measured by detecting the change of optical output power from the waveguide. An output power change of ±5% has been observed as the magnetic field is changed from zero to ±60 Oe.