Optical Waveguide filter and production process thereof
Core comprises a main stem which is formed on a substrate (10), linearly extending in the beam propagating direction and short branches (12a,12b) with a certain length which extend perpendicularly to the beam propagating direction (16) toward both sides along the plane of the substrate and are arranged at regular intervals in the beam propagating direction. Thus, the branches are arranged in a ladder geometry when it is viewed from the top, forming a rectangular waveform arrangement. The core (12) constitutes a grating structure in which the width of the core is made to vary periodically with the branches in the beam propagating direction. <IMAGE>