Preliminary Experiment for Polymer Waveguide-Type Optical Isolator: A Pulsed Optical Isolator Operation in Poly(l-Menthylmethacrylate/Benzylmethacrylate) Copolymer Slab Waveguide

A copolymer of l -menthylmethacrylate (MtMA) and benzylmethacrylate (BzMA), poly(MtMA/BzMA) was synthesized to construct a polymer slab waveguide-type optical isolator operating in the blue wavelength region. This isolator is based on the simultaneously occuring reciprocal and nonreciprocal TE–TM mode conversions in a three-layered slab waveguide which consists of the poly(MtMA/BzMA) copolymer core on a fused quartz substrate. When a high magnetic field of about 18 kOe was applied to a device with a core thickness of 4.5 µm and a 5 cm propagation length, a pulsed optical isolator operation with an isolation ratio of approximately 15 dB was obtained at a wavelength of 441.6 nm, for the first time.