Automatic bias stabilization of dual-polarization in-phase and quadrature optical modulator
US9494810B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 24, 2016 |
| Grant date | Nov 15, 2016 |
| Priority date | — |
| Expiry date | Mar 24, 2036 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/548
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Embodiments include a method and apparatus used for automatic bias stabilization of a DP IQM based on MZM for transmitting DP-QPSK optical data and/or DP-16QAM optical data. The apparatus simultaneously dithers DC-bias voltages of in-phase child, quadrature-phase child, and parent MZMs with three different dither patterns in time-domain which are mutually orthogonal to each other in the frequency-domain for X and Y polarization IQ modulators. Tap monitor photodiodes detect an interference term between these three dither patterns for each polarization. The interference term is sampled using an ADC in the time domain. The time-synchronous detection method may solve a set of three simultaneous linear partial differential equations with three unknowns to compute controlled DC-bias voltages to set on the respective MZM with a solution set which may iteratively converge to a unique solution, thereby biasing the child MZM in dual-polarization IQM to transmission minimum and parent MZM in quadrature transmission.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.