A method for extracting local oscillator light in a super-channel co-ofdm system

Abstract

The invention relates to the optical communication technology. In the Super-channel CO-OFDM system, the optical injection locking combined with the optical phase-locked loop method is used to extract the local oscillator light, which can effectively reduce the complexity of the optical receiver for frequency offset and phase compensation, and further Reduce the power consumption and cost of the receiver. The photon carrier extracted after the optical injection locking and phase locking in the present invention is used as the local oscillator light, which can keep the same frequency and phase as the signal photon carrier, which can greatly reduce the complexity of the digital signal processing algorithm in the coherent optical receiver. With power consumption, the performance advantages of CO‑OFDM such as receiver sensitivity, spectrum utilization and robustness to polarization dispersion are better exploited. In addition, the present invention can make the CO-OFDM system have higher operation efficiency, and can effectively reduce the drop of coherent receiving efficiency caused by the frequency deviation between the local laser and the laser at the transmitting end.

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...

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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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