IQ modulator bias voltage control method and system of single carrier

Abstract

The invention discloses an IQ modulator bias voltage control method of single carrier, and relates to the field of the light signal modulation. The method comprises the following steps: respectively sending incident light to an X polarization arm and a Y polarization arm of the IQ modulator; loading a real part VI and a virtual part VQ of an electric signal to a light domain through two MZM, and controlling phase difference through a light phase shifter; acquiring light signals output by two polarization arms, firstly acquiring an initial value of the bias voltage according to the light power,and then obtaining DC component PDC and AC component PAC with two different light power by firstly increasing and then reducing the bias voltage by using a stepping value; taking the bias voltage corresponding to less PDC as the new bias voltage, and repeatedly iterating to finally obtain the optical IQ bias voltage; taking the bias voltage corresponding to less PAC as the new bias voltage, repeatedly iterating to finally obtain the optical phase difference bias voltage. The bias voltage control method and system disclosed by the invention are suitable for the high-order modulation format, the precise bias voltage control is realized, and the signal quality stabilization is guaranteed.

Description

technical field [0001] The invention relates to the field of optical signal modulation, in particular to a single carrier IQ modulator bias control method and system. Background technique [0002] At present, optical communication is developing towards higher speed and higher capacity. In a high-speed optical transmitter, the modulation of an optical signal usually requires a dual-polarization IQ (in-phase quadrature) modulator based on an MZM (Mach-Zehnder Modulator, Mach-Zehnder modulator). [0003] However, the IQ modulator itself is easily affected by some environmental factors such as temperature, etc., which will cause its quiescent operating point to shift and degrade the system performance. In order to ensure the stability of the signal quality without affecting the system performance, it is necessary to monitor and control the bias voltage of the two polarization arms of the IQ modulator at the same time, so that both polarization arms work at the best static opera...

AI Technical Summary

Problems solved by technology

But these techniques are only suitable for low-order modulation formats, and there is no good solution for high-order modulation formats

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