Equalization method and apparatus for long distance transmitting optical power

Abstract

A balancing method and its device for long distance transmitting light power of a multiroad multiplex communication includes a multistage linear amplified multistage transmission link in signal transmission lines characterizing in applying an adjustable attenuation synthesizer to connect power amplifier to prebalance eath light source power at the signal sending end, then to balance light power by a balancing unit of a gain flat filter to make up of a gain flat filter balancing unit, then to balance light power by an adjustable attenuation synthesizer balance unit connecting to a power amplifier and a monitor feed back device in it to sample, analyse and process the output signal data.

Description

technical field [0001] The invention relates to multiplexing communication, in particular to a method and device for equalizing optical power in long-distance transmission. Background technique [0002] Due to the fact that the gain spectrum of erbium-doped fiber EDFA and Raman Raman amplifier is not absolutely flat, the attenuation spectrum of dispersion compensation module DCM and fiber is not flat, and the stimulated Raman scattering of fiber, etc., dense wavelength division multiplexing DWDM signal increases with the transmission distance. increase, its power unevenness will increase cumulatively, this situation can be ignored in medium and short-distance dense wavelength division multiplexing DWDM transmission with unlimited optical signal-to-noise ratio OSNR, but it must not be used in long-distance or even ultra-long-distance transmission Regardless, take the 100GHz interval C-Band 40-wave dense wavelength division multiplexing DWDM system as an example. After 500 kil...

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Problems solved by technology

[0004] Although the gain flattening filter GFF is currently widely used in medium and short-distance transmission, there is inconsistency in the power spectrum of the actual equalization unit. In actual engineering design, it is impossible to customize the gain flattening filter GFF one by one. Therefore, use Gain flattening filter GFF of the same specification will cause additional power unevenness after multi-stage equalization, which is especially obvious in long-distance or ultra-long-distance situations. The flexibility of this equalization scheme is poor, and it is difficult to upgrade the system configuration

[0005] The use of the adjustable attenuation combiner VMUX equalization unit in the transmission line can limit the unevenness of the optical power of the system to a small range, but the equalization power of the adjustable attenuation combiner VMUX is expensive. If each adjustable attenuation combiner VMUX Multi-stage cascading of equalization units will increase the system power budget, and the cost will increase accordingly. Moreover, during ultra-long-distance transmission, due to the manufacturing accuracy of the gain-flattening filter GFF and the normalization requirements of the gain-flattening filter GFF device, after the gain-flattening filter GFF After the flat filter GFF equalization, each gain flat filter GFF equalization unit will still have about 2dB optical power unevenness, after cascade transmission of four gain flat filter GFF equalization units, the optical power unevenness will reach more than 5dB, The optical signal-to-noise ratio (OSNR) of some channels has deteriorated to the point that it cannot be received normally. The amplifier used to compensate the power will degrade the optical signal-to-noise ratio (OSNR), which limits the transmission distance

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