Optical DQPSK transmitter phase monitor and control
US7953328B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 22, 2007 |
| Grant date | May 31, 2011 |
| Priority date | — |
| Expiry date | Mar 26, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/5561
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An apparatus and a method for a I-Q quadrature modulation transmitter monitor a phase bias between an I branch and a Q branch of the I-Q quadrature modulation transmitter. The I-Q quadrature modulation transmitter includes the I-branch, the Q-branch equipped with a phase bias, and a tap. The apparatus is installed between the tap and the phase bias, and monitors the phase between the I branch and the Q branch which phase is introduced by the phase bias. The apparatus includes the following components: a module squarer, receiving signal from the tap and outputting a module square of the received signal; a multiplier, to multiplying data of the I-branch, data of the Q-branch and the module square to output a multiplied signal; and an averager, averaging the multiplied signal output by the multiplier. The phase between the I branch and the Q branch may be corrected according to monitoring results.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.