Method and device for eliminating phase jump in single-carrier coherent optical communication system

A technology of coherent optical communication and carrier phase, which can be used in modulation carrier systems, transmission systems, digital transmission systems, etc., and can solve complex problems

Active Publication Date: 2018-06-05
BEIJING UNIV OF POSTS & TELECOMM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The technical problem solved by the present invention is: how to avoid complicated steps to locate the position where the phase jump occurs

Method used

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  • Method and device for eliminating phase jump in single-carrier coherent optical communication system
  • Method and device for eliminating phase jump in single-carrier coherent optical communication system
  • Method and device for eliminating phase jump in single-carrier coherent optical communication system

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Embodiment 1

[0060] An embodiment of the present invention provides a phase jump elimination device for a single-carrier coherent optical communication system, such as figure 1 As shown, it includes a transmitter 110, a receiver 120, and a transmission unit 130 disposed between them.

[0061] In the embodiment of the present invention, the transmitter 110 includes: a data input 111 , an encoding unit 113 , a pulse shaping unit 115 and a modulation unit 117 .

[0062] Wherein, the data input 111 is bit stream data composed of digital signals 0 and 1, which may be input from outside or generated by a data signal source inside the transmitter 110 . The encoding unit 113 can be implemented by any available general-purpose processor, and its function is to encode the data input 111 into a predefined frame format. The main function of the pulse shaping unit 115 is to convert the digital signal output by the encoding unit 113 into an analog electrical signal, which may include two-level or four-...

Embodiment 2

[0087] According to the device described in Embodiment 1 above, in order to transmit and receive optical signals over long distances, currently the transmitter 110 mainly uses various high-order modulation techniques including, for example, QPSK (Quadrature Phase Shift Keying), 16QAM, DP-QPSK ( Dual Polarization Quadrature Phase Shift Keying), DP-16QAM, etc., where the data is identified by the amplitude, phase and polarization of the optical carrier. The narrow-linewidth laser used as the light source at the modulation unit 117 of the transmitter 110, and the narrow-linewidth laser used as the local oscillator at the demodulation unit 127 of the receiver 120, which typically can provide a linewidth in the range of 100KHz External cavity laser. However, as both the light source and the local oscillator laser are affected by the limited line width, the phase of the optical carrier cannot be kept stable; and the local oscillator frequency between the two lasers will always have ...

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Abstract

The present invention provides a method and device for eliminating phase hopping in a single-carrier coherent optical communication system, comprising: receiving a data stream including pilot symbols, estimating the carrier phase by detecting the data stream, and obtaining a reference carrier according to the pilot symbols phase; compare the estimated carrier phase with the previous carrier phase to obtain an unwrapped phase; compare the unwrapped phase with the interpolated reference phase, thereby eliminating phase jumps. The present invention compares the obtained unwrapped phase with the interpolated reference phase by comparing the estimated carrier phase with the previous carrier phase, thereby eliminating phase jumping.

Description

technical field [0001] The present invention relates to the technical field of digital coherent communication, in particular to a phase jump elimination method and device for a single-carrier coherent optical communication system. Background technique [0002] In order to improve the data transmission rate and spectral efficiency, phase modulation or quadrature intensity modulation technology is widely used in modern optical communication systems. The receiver adopts phase and polarization diversity reception to detect all information of the optical carrier electric field, and digital coherent reception technology is adopted. Eliminate polarization crosstalk, frequency offset between optical carrier and local oscillator laser, and laser phase noise through digital signal processing algorithms. For low-order modulation patterns such as BPSK, QPSK, etc., blind phase recovery algorithms such as M-power algorithms tend to be used, but blind phase recovery algorithms have phase a...

Claims

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Application Information

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Patent Type & AuthorityPatents(China)
IPC IPC(8): H04L27/227H04B10/61
Inventor伍剑程海全李岩虞淼臧继召
OwnerBEIJING UNIV OF POSTS & TELECOMM