WAVEGUIDE TYPE DIRECTIONAL COUPLER

摘要

PURPOSE:To provide the waveguide type directional coupler which is improved in the yield of productivity and obtains an optional branch ratio and also has small wavelength dependency over a wide wavelength band. CONSTITUTION:The waveguide type directional coupler is constituted by forming two cores 12 and 13 in a clad 11 closely to each other. The core 12 is thin at an intermediate point between the incidence and projection end and thick at the incidence end and projection end, which are tapered symmetrically about the intermediate point; and the core 13 is close to the core 12 at an intermediate point and the incidence end and projection end are formed in a symmetrically curved shape about the intermediate point.