Method and system for reducing dn/dt birefringence in a thermo-optic PLC device
US6704487B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 10, 2001 |
| Grant date | Mar 9, 2004 |
| Priority date | — |
| Expiry date | Aug 10, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/0147
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of making an optical waveguide structure for an active PLC device having a reduced dn/dt birefringence. The method includes the step of forming a waveguide core layer on a bottom cladding, the waveguide core layer having a higher refractive index than the bottom cladding. The waveguide core layer is then etched to define a waveguide core. A top cladding is subsequently formed over the waveguide core and the bottom cladding. The top cladding also has a lower refractive index than the waveguide core. The top cladding is then etched to define a first trench and a second trench parallel to the waveguide core. The first trench and the second trench are configured to relieve a stress on the waveguide core. This stress can be induced by a heater, as in a case where the active PLC is a thermo-optic PLC. The first trench and the second trench can extend from an upper surface of the top cladding to an upper surface of the bottom cladding. The first trench and the second trench can extend from the upper surface of the top cladding into a portion of the underlying substrate. The first trench and the second trench are configured to balance a tensile stress within the waveguide core. A …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.