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Updated: Jul 4, 2026

Differential Imaging of Biological Structures with Doubly-resonant Coherent Anti-stokes Raman Scattering (CARS)
Published on: October 17, 2010
Simultaneous pulse carving misalignment and pi-phase-shift monitoring of a return-to-zero differential phase-shift
1State Key Laboratory on Integrated Optoelectronics, Tsinghua National Laboratory for Information Science and Technology, Department of Electronic Engineering, Tsinghua University, Beijing, China. wen-he@mail.tsinghua.edu.cn
Abstract:
A technique for monitoring both the pulse carving misalignment and pi phase shift in a return-to-zero (RZ) differential phase-shift keying (DPSK) system based on a phase modulator is proposed and demonstrated. By monitoring the mean-power variation of a hybrid local oscillation lightwave with the modulated signal lightwave without any deliberated control, the technique can provide the information on pulse carving misalignment and phase modulation index simultaneously, as the power variation reflects the asymmetric distribution of RZ-DPSK in a signal constellation diagram. It is characterized as transparent to signal bit rate, central wavelength, and absolute power level. Both the simulation and experiment results show that more than +/- 15% bit duration misalignment and +/- 5% phase shift deviated from pi can be detected.
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