nrz to prz code conversion fiber grating design method and device

Abstract

The invention discloses a non return to zero (NRZ)-to-pseudo return to zero (PRZ) code pattern conversion optical fiber grating design method and a non return to zero (NRZ)-to-pseudo return to zero (PRZ) code pattern conversion device. The non return to zero (NRZ)-to-pseudo return to zero (PRZ) code pattern conversion optical fiber grating design method comprises the following steps that: the reflectivity and transmissivity of a fiber bragg grating are described through using a super Gaussian function; two decibel values of a reflection spectrum and the difference of bandwidths of the decibel values are selected; the bandwidth value of one decibel value of the reflection spectrum is set so as to solve the super Gaussian function, such that a transmissivity function can be obtained; the frequency spectrum of inputted non return to zero (NRZ) code streams is multiplied by the transmissivity function such that the frequency spectrum of code streams after filtering can be obtained, and then, inverse Fourier transform is performed on the frequency spectrum of the code streams so as to obtain code steam waveform of time domain after filtering; Q values of the code streams are calculated; different bandwidth values of one decibel value are selected so as to obtain a plurality Q values; a maximum Q value and an optimal bandwidth value are found out, and a corresponding transmissivity function is the transmission spectrum of the fiber bragg grating; a refractive index modulation function and a local chirp function are obtained through adopting methods comprising a discrete inversion layer stripping method. The non return to zero (NRZ)-to-pseudo return to zero (PRZ) code pattern conversion optical fiber grating design method of the invention has the advantages of larger pass-band, higher Q value, optimally-designable wave notching and filtering characteristics, optimal filtering effect and high-quality code pattern conversion.

Description

technical field [0001] The present invention relates to the technical field of optical communication, in particular to an all-optical code conversion optical grating design method and a conversion device thereof from non-return-to-zero code (NRZ) to pseudo-return-to-zero code (PRZ). Background technique [0002] All-optical clock recovery is an important technology for future high-speed and large-capacity optical communication systems. As for the return-to-zero (RZ) code pattern, because the clock component in its frequency spectrum is very strong, it is very convenient to directly extract the clock. However, for the non-return-to-zero (NRZ) code pattern, the clock component in its frequency spectrum is very weak, and it is impossible to directly extract the clock component, and preprocessing is required first. Since the pseudo-return-to-zero (PRZ) pattern contains a strong clock component in its spectrum, and the conversion from NRZ pattern to PRZ pattern is much simpler t...

AI Technical Summary

Problems solved by technology

Among them, SOALOM has a large volume, is not easy to integrate, and is very sensitive to polarization. It can work well at 10Gb / s and 20Gb / s rates. For higher rates, there will be serious pattern effects.

On the basis of SOALOM, the SOA series filter scheme is further simplified, which greatly simplifies the experimental equipment, but it will still be affected by the SOA carrier recovery time

Fiber delay interferometer DI is a passive device, has nothing to do with polarization, and there is no SOA pattern effect and ASE noise, etc., but DI needs a temperature control device, which is difficult to manufacture in high-speed applications

The optical bandpass filter detuning filtering solution has a simple structure and can work passively. It is suitable for high-speed code conversion, but the power loss caused by the bandpass filter is large, the Q factor is low, and the conversion effect is not ideal. In particular, it needs The DC component is suppressed by increasing the detuning amount of the filter. In this case, the power loss also increases accordingly, which makes the impact of noise very obvious, so the quality of the converted PRZ signal will drop sharply, which is not conducive to the next step of clock recovery. realization of

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