摘要 |
A variable light controlling device comprising a substrate (11), an optical waveguide structure having cladding layers (22,33) and waveguides (13-3,14-3) disposed on the substrate, a first heater (15-2) and a second heater (16-2) to change the optical waveguide structure's temperature is fabricated. And a total amount of the power supplied to the first and the second heater, or a total amount of heat emitted from both of the first and second heater, is maintained substantially constant. Then, the substrate is protected from temperature changes, thereby, stable and quick wavelength tuning operations are realized. |