Polarization converter with apodized acoustic waveguide
US5218653A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 8, 1991 |
| Grant date | Jun 8, 1993 |
| Priority date | — |
| Expiry date | Nov 8, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F2203/06
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An apodized acousto-optic polarization converter in which two acoustic waveguides are (14, 20) are formed in a substrate and are separated by a small gap (18) such that the two acoustic waveguides act as a directional coupler in which acoustic power is transferred back and forth. An interdigitated transducer (12) launches a surface acoustic wave in the first acoustic waveguide, and an optical waveguide is formed in the middle of the second waveguide. An acoustic absorber (26) is formed over both acoustic waveguides at a distance from the transducer such that the acoustic wave is transferred from the first to the second waveguide and back again. Thereby, the optical signal in the optical waveguide is exposed to an acoustic power density that slowly increases to a maximum and then decreases with the result that the side lobes of the frequency spectrum for the converted signal are greatly reduced. The converter may be used as an electrically tunable optical filter using orthogonal input and output polarizers (30, 32).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.