A digital coherent detection system and method based on a virtual minimum phase signal

Abstract

The invention discloses a digital coherent detection system and a digital coherent detection method based on a virtual minimum phase signal. The system comprises a local oscillator laser device, a 3dBcoupler, a light balance detector, a radio frequency amplifier, an electric filter, an analog-to-digital converter (ADC) and a digital signal processor (DSP). A signal and local oscillator light areinput to the light balance detector after being subjected to wave combination performed by the 3dB coupler. A radio frequency electric signal output by the light balance detector is amplified by the radio frequency amplifier, and converted into a digital signal via the ADC and input into the DSP after being filtered by the electric filter. The DSP synthesizes the input digital signal into a sampling value of light intensity variation of the virtual optical minimum phase signal, extracts signal optical phase information via Hilbert conversion, and at last rebuilds a signal optical field based on the strength and phase information. According to the system and the method provided by the invention, the digital coherent detection of the signal optical field can be achieved by using the single light balance detector and the single ADC, the structure is simple, the cost is low, the power consumption is small, the noise is low, and the damage resistant capacity is strong.

Description

technical field [0001] The invention belongs to the fields of optical fiber communication, free space optical communication, optical signal detection and digital signal processing, and more specifically relates to a digital coherent detection system and method based on a virtual minimum phase signal. Background technique [0002] At present, optical communication systems mainly use intensity modulation and direct detection technology. The optical receiver based on the direct detection technology uses a single photodiode to convert the optical signal into an electrical signal. The intensity information of the signal light is detected. Since the intensity modulation does not make full use of all the modulatable dimensions of the light field, the transmission efficiency is low, and it is difficult to meet the growing needs of high-speed and large-capacity communication systems. Coherent detection can detect the intensity, frequency, phase and polarization of signal light in v...

AI Technical Summary

Problems solved by technology

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a digital coherent detection system and method based on a virtual minimum phase signal, thereby solving the requirement of the current linearization technology based on a minimum phase signal that the DC optical power is far away Technical problems that are far greater than signal optical power, poor compatibility with existing optical communication systems, poor practicability, low 3dB multiplexing loss, and strong relative intensity noise

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