Local phase-locked orthogonal polarization free-space coherent optical communication device

Abstract

A local phase-locked orthogonal polarization free-space coherent optical communication device, which consists of a single-frequency single-mode laser, a fiber polarization beam splitter, a fiber stretcher, a first optical phase modulator, a second optical phase modulator, a data Signal generator, microwave amplifier, first fiber collimator, second fiber collimator, first emitting half-wave plate, second emitting half-wave plate, first polarizing beam splitting prism, third emitting half-wave plate, second Two polarization beam-splitting prisms, the first right-angle prism, the first focusing lens, the second focusing lens, the first balanced detector, loop filter, receiving half-wave plate, the third polarization beam-splitting prism, the second right-angle prism, the first Three focusing lenses, a fourth focusing lens, a second balanced detector and an A / D converter. The invention emits coaxial orthogonally polarized signal light and self-interferentially receives the structure at the receiving end, which can effectively overcome the phase error; the phase-locked structure is located at the transmitting end, which simplifies the structure of the receiving end; the system can be flexibly adjusted without any adjustment of the optical path communication rate.

Description

technical field [0001] The invention relates to free-space coherent optical communication, in particular to a local phase-locked orthogonal polarization free-space coherent optical communication device. Background technique [0002] In satellite-to-ground laser communication, a larger amount of data requires a higher communication rate. Compared with the optical communication method of direct detection by intensity modulation, the coherent optical communication mechanism is due to its higher theoretical limit sensitivity, higher spectral efficiency and better The characteristics of anti-background light noise interference have attracted extensive attention of researchers. Atmospheric interference, especially atmospheric turbulence, which causes the space-time random variation of atmospheric refractive index, is one of the main factors affecting satellite-ground coherent laser communication. Compared with the homodyne or heterodyne coherent detection method using the local o...

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Problems solved by technology

[0004] The invention provides a local phase-locked orthogonal polarization free-space coherent optical communication device, which can overcome the phase interference of atmospheric turbulence and does not require complex optical phase-locked loops or electric phase-locked loops in combination with self-differential interference reception in satellite-ground coherent laser communication Advantages, a local phase-locked orthogonal polarization is designed for the shortcomings of the DPSK receiving structure, which is not easy to adjust the communication rate and the pupil matching system must be introduced. The device introduces a local phase-locked system at the transmitter to compensate for the phase error between the transmitted orthogonal polarization optical paths , the emitted orthogonally polarized light is phase-modulated by the forward and reverse microwave data signals respectively and combined into a coaxial beam for emission. The signal light received at the receiving end is received by the polarization interference self-difference and detected by the balance detector, and finally recovered. transmitted data signal

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