| 摘要 |
<p>A waveguide type optical multiplexer/demultiplexer in which a directional coupler made of a three-layer structure wherein core waveguides (3-1, 3-2) having a refractive index nc and a cladding (4) having a refractive index nr < nc are successively stacked on a low refractive index layer (2) having a refractive index nb < nc, is provided with a thin film heater (5) in or on the cladding (4) wherein a voltage is applied across the heater.</p> |
