Birefringence compensated integrated optical switching or modulation device
US6760499B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 8, 2002 |
| Grant date | Jul 6, 2004 |
| Priority date | — |
| Expiry date | Nov 28, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F2203/48
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A planar waveguide Mach-Zehnder interferometer (MZ) has improved performance as a variable optical attenuator as well as a thermo-optic switch (TOS) with reduced polarization dependent loss (PDL) in high attenuation states. The PDL was reduced by correcting for the increased birefringence that occurs on heating one waveguide arm by making the two waveguides inherently asymmetric, such that when one of the waveguides is heated, the differential birefringence of the two arms becomes zero. This asymmetry can be realized simply by changing the width of one of the waveguides. The modified device allows for very small PDL in the high attenuation state of a VOA and for theoretically perfect contrast in a TOS in the off state, with only a small penalty in PDL of the on state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.