System and method for measuring the phase of a modulated optical signal
US9213085B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 15, 2013 |
| Grant date | Dec 15, 2015 |
| Priority date | — |
| Expiry date | Dec 20, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/70
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention is related to phase detection in lidar systems using single photon detectors (SPDs). The frequency at which the SPDs are time gated is related to but not an integer multiple of the frequency of the transmitted optical pulses. Each return optical pulse arrives with a particular temporal position with respect to the nearest gate, and thus is detected with a related detection efficiency. The SPD output can be segmented into multiple time-multiplexed signals whose relative detection efficiency reveals the phase of the optical return pulses, and no such phases have negligible detection efficiency for all the time-multiplexed signals. To mitigate the impact of afterpulsing and other saturation effects, when a first optical pulse is detected with high detection efficiency the next optical pulse that is detected with high detection efficiency is separated by a time period about equal to or greater than the detector dead time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.