Electro-optical modulator bias control device and method based on Sagnac ring

Abstract

The invention discloses a system device and method for controlling the bias voltage of an electro-optical modulator, provides an automatic bias control system based on a Sagnac ring and a direct-current power detecting algorithm and mainly relates to the field of the optical communication technology and automatic control. According to the system device and method for controlling the bias voltage of the electro-optical modulator, an optical carrier is split into two paths at the output end of a light source with a polarization controller and a polarization beam splitter and enters the Sagnac ring, wherein the clockwise optical carrier is subjected to intensity modulation, while the anticlockwise optical carrier is not modulated with radio-frequency signals due to the reverse modulation characteristic of the electro-optical modulator; optical signals output by the Sagnac ring pass through the polarization controller and the polarization beam splitter so as to make the unmodulated optical signals enter a bias control module through a photoelectric detector, judgment and compensation can be carried out on direct-current drifting with a direct-current power detection method, and thus a direct-current working point of the modulator is locked. According to the scheme, the defect that the direct-current power detection method is affected by radiofrequency signals is overcome with the Sagnac ring, and automatic bias control irrelevant to the radiofrequency signals is achieved.

Description

Technical field [0001] The present invention relates to the field of optical communication technology and automatic control, in particular to a device and method for realizing bias control of an electro-optic modulator based on a Sagnac ring. Background technique [0002] Radio over Fiber (RoF) technology uses the respective advantages of optical fiber and high-frequency radio waves to realize low-cost, large-capacity radio frequency signal optical fiber transmission and wireless access, which is an inevitable trend in the development of broadband access in the future. Electro-optical modulators based on lithium niobate materials are widely used in RoF systems because of their large modulation bandwidth, low loss, and zero chirp. Their performance plays a decisive role in the signal transmission quality of the entire system. [0003] The transfer function of the electro-optical modulator is generally a sine function. Due to the limitation of the modulation material and structure, t...

AI Technical Summary

Problems solved by technology

But its main disadvantage is that the DC component is affected by the RF signal, especially when it works near the minimum operating point. When the RF signal changes, the DC component will change significantly, so that when the DC component remains unchanged, the DC cannot be locked. operating point, which affects the bias control

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