| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To suppress an increase in polarization dependent loss, to obtain large attenuation and to reduce power consumption with simple construction in an optical attenuator. <P>SOLUTION: The optical attenuator 1 is provided with an optical waveguide 4 constructed with a core part 3 having a narrow core part 31 composed of a thermo-optical material with a narrow width and a cladding part 2, a heat dissipating substrate 41 supporting the optical waveguide 4 and a heater 5 disposed on a surface of the cladding part 2 in the vicinity of the narrow core part 31 and displaced from an optical axis of the narrow core part 31 in a width direction of the narrow core part 31 as shown with an arrow d so as not to overlap with the core part. As a result of displacing the heater 5, temperature gradient in an oblique direction with respect to the narrow core part 31 is formed and distribution of light does not reach the heat dissipating substrate 41 and difference in attenuation between TE and TM mode light is suppressed and the polarization dependent loss is consequently suppressed. As a result of imparting the optical attenuator a narrow width structure of the narrow core part 31, filtering out of light to the cladding part 2 is increased and heating thereto is facilitated to thereby increase the attenuation and to expand a dynamic range while reducing power consumption. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
