Electromagnetic device for use in e.g. angular position measuring sensor, has waveguide propagating light in two propagation modes, where refractive index of waveguide is greater than specific times of refractive index of substrate

摘要

The device has a corrugated layer of transparent material deposited on a face (100) of a transparent substrate (11) to form a waveguide (10). A transparent superstrate (A) is attached to a face (101) of the waveguide, where the device is illuminated by a light source (20). The waveguide propagates the light in two propagation modes (TE0, TE1), where the refractive index of the waveguide is greater than 1.8 times the refractive index of the substrate, and a depth (P12) of corrugations (12) of the waveguide is between 80 and 110 percent of the thickness (W10) of the waveguide.