Direct optical N-state phase shift keying
US6798557B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | May 22, 2003 |
| Grant date | Sep 28, 2004 |
| Priority date | — |
| Expiry date | May 22, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2096
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A unique optical encoder is employed that utilizes an optical phase modulator, in which an arbitrary phase shift can be realized. The phase modulator is driven by an electrical signal, where the voltage amplitude is proportional to a desired arbitrary phase shift. However, any amplitude noise or poor rise and fall times of the driving voltage translates directly into phase errors. These problems are eliminated by employing a digital phase switch. One encoder, in accordance with the invention, employs an optical phase modulator that can switch the optical phase in a binary manner, wherein the two phase states of the modulator can be chosen to differ by any desired arbitrary angle depending on the splitting ratio of the optical signal to be modulated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.