Method for extracting local oscillating light in Super-channel CO-OFDM system

Abstract

The invention relates to the optical communication technology, in particular to a method for extracting local oscillating light in a Super-channel CO-OFDM system. The local oscillating light is extracted in the Super-channel CO-OFDM system with the method that optical injection locking is combined with an optical phase-locked loop, the complexity of an optical receiver to be used for compensating for frequency offset and phases can be effectively lowered, and the power consumption, the cost and the like of the receiver can be further reduced. According to the method, as photon carriers extracted after processing such as optical injection locking and phase locking is carried out serve as the local oscillating light, the local oscillating light can be kept the same as the signal photon carriers in frequency and phase, the complexity of a digital signal processing algorithm in the coherent optical receiver can be greatly lowered, the power consumption of the digital signal processing algorithm in the coherent optical receiver can be greatly reduced, and the performance advantages, including the receiver sensitivity, the spectral efficiency and the robustness to polarization dispersion, of the CO-OFDM can be better developed. In addition, by means of the method, the CO-OFDM system can have the high operation efficiency, and reduction, caused by the frequency deviation between a local laser apparatus and a transmitting-end laser apparatus, of the coherent receiving efficiency can be effectively reduced.

Description

technical field [0001] The invention relates to optical communication technology, in particular to a method for extracting local oscillator light in a large-capacity optical transmission system CO-OFDM. Background technique [0002] With the explosive growth of network bandwidth and the advent of the era of cloud computing, ultra-large-capacity optical fiber transmission systems have become the main solution to future traffic growth. With the gradual improvement of the commercial deployment of single-channel 100Gb / s systems, the multi-channel multiplexing optical fiber transmission system of single-channel 100Tb / s and single-fiber 100Tb / s has become a hot research topic. At present, the industry has proposed a terabit optical fiber transmission system that integrates multiple channel multiplexing technologies. The multiplexing of such arbitrary optical signals (with spectral intervals or seamless) to achieve ultra-large-capacity transmission can be unified into a super-chann...

AI Technical Summary

Problems solved by technology

However, in the super-channel CO-OFDM system, the subcarriers are orthogonal to each other, and the subcarrier frequency band spacing is on the order of 100MHz. Traditional methods at the receiving end, such as optical filtering and optical injection locking, cannot extract the required optical subcarriers.

For example, using the seamless multiplexing method, the optical frequency comb interval in the simulation is 10GHz, the OFDM signal bandwidth is 10GHz, and the spectrum diagram of the broadband optical OFDM signal after 32 channels are seamlessly multiplexed is as follows figure 1 As shown, what the circle marks indicate is that the photon carriers on different multiplexed channels need to be extracted, and the local oscillator light that can be received as coherent light after extraction. In this case, it is impossible to use the traditional photon carrier extraction method to extract the required LO

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