| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a waveguide type variable optical attenuator which does not lower productivity and which has little polarization dependent loss. <P>SOLUTION: An optical waveguide 101 constitutes a Mach-Zehnder interferometer using two directional couplers 102, 102. At the same time, a thin film heater 104 to vary the phase of light by a thermo-optical effect is disposed on the upper face of the optical waveguide 101. Furthermore, part of an arm optical waveguide 109, which is one out of two arm optical waveguides 108, 109 being the optical waveguides between the two directional couplers 102, 102, is made to be a waveguide 107 of a larger width so as to adjust the birefringence of the arm optical waveguide 109 to a specified value. <P>COPYRIGHT: (C)2004,JPO</p> |
