OPTICAL FILTER HAVING PLURALITY OF INTERFERENCE STAGES

摘要

PURPOSE: To provide an wavelength divided multiplexer(WDM) based on a planar waveguide to be simply manufactured by especially using silicon optical bench(SiOB) technology, i.e., III-V group planar waveguide technlogy. CONSTITUTION: An interferometer channel falling filter includes a pair of planar wavegudes 20, 30, which are mutually separated only by a distance to be periodically changed along the vertical axis of the filter in order to attain periodical optical coupling between these waveguides. Each waveguide includes at least three coupling positions 40 related to respective constants and these two waveguides have nominally equal effective retractive indexes. In the preferable example, these coupling constants are symmetrically attenuated from the center of the filter to both the ends.