A Polarization-Independent Coherent Receiver

Abstract

The invention belongs to the technical field of optical communication, and discloses a polarization-independent coherent receiver, comprising: a local oscillator light source, which generates linearly polarized local oscillator light; a local oscillator light modulation unit, which converts the local oscillator light into modulated local oscillator light; frequency mixing The device receives and modulates the local oscillator light and the signal light, and performs mixing to generate a mixed signal light; the photoelectric conversion module receives the mixed signal light and converts it into an intermediate frequency signal for output; wherein, the local oscillator light modulation unit includes: a polarization beam splitter , a phase modulator and a polarization beam combiner; a polarization beam splitter receives linearly polarized light and splits it into first and second linear polarizations with equal power and perpendicular polarization states; the phase modulator and polarization beam splitter connected to receive the first linearly polarized light and adjust its phase to generate the third linearly polarized light; the third linearly polarized light and the second linearly polarized light generate a modulated phase difference; the polarization beam combiner receives the third linearly polarized light and the second linearly polarized light and combines them, Generate modulated local oscillator light. The invention has simple structure, easy control and low cost.

Description

technical field [0001] The invention relates to the technical field of optical communication, in particular to a polarization-independent coherent receiver. Background technique [0002] In the field of optoelectronic communication, larger bandwidth, longer transmission distance, and higher receiving sensitivity are always the development goals of optoelectronic communication technology. Due to its huge trend in sensitivity, coherent optical detection technology can greatly extend the relay distance, effectively guarantee the bandwidth advantage of optical carrier, greatly improve the communication capacity, and alleviate the problem of traditional optical communication bandwidth and power limitation. Become the main development direction of the optical communication system in the future. [0003] However, as the core device of a coherent optical communication system, an optical coherent receiver has very strict requirements for coherent reception, which greatly increases t...

AI Technical Summary

Problems solved by technology

[0003] However, as the core device of a coherent optical communication system, an optical coherent receiver has very strict requirements for coherent reception, which greatly increases the cost of optical and electronic components of the system and limits the wide-scale application of coherent communication technology.

Polarization sensitivity is an inherent difficulty in coherent detection. Only when the polarization states of the signal light and the local oscillator light are exactly the same, the coherent receiver can obtain the maximum coherent gain and good receiving sensitivity. The practical application in coherent communication systems In the case of optical channels, under the influence of the environment, the polarization state of the transmitted signal light will be randomly disturbed, which further increases the polarization matching difficulty of the coherent receiver.

The current commercial solution is to realize the polarization independence of coherent receivers through polarization diversity technology, but this greatly increases the complexity of the system and limits its application range.

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