Structure of interleaver based on cascaded optical fiber circulator and design method thereof

Abstract

The invention relates to a structure of an interleaver based on a cascaded optical fiber circulator and a design method thereof, and belongs to an interleaver technology, which is used for solving the problems of the existing optical multiplexer such as poor spectral transmittance, uneven output spectrum and low isolation. In the method, frequency domains in the formulas of two output port spectrums are converted into z domains by adopting a digital signal processing mode, and then pole-zero characteristics in the z domains are analyzed; the output spectrums with equal bandwidth can be obtained only if all poles in the formulas of the output spectrums are positioned on an imaginary axis; length of various cascaded annular cavities and length difference of MZ (Mach-Zehnder) interference arms can be obtained in combination with orders of an elliptic filter; and the coupling angles of couplers for various fiber annular cavities are solved by virtue of the pole values of the elliptic filter. The interleaver with equal bandwidth designed by the method has two output spectrums which have the characteristics of high flatness, high bandwidth utilization ratio, high isolation and the like; and especially under the condition of the cascaded optical annular cavities with more stages, the interleaver has the advantages of simple computation and high accuracy.

Description

technical field [0001] The present invention relates to the structure and design method of a kind of odd-even number signal separator, especially a kind of infinite impulse response (referred to as IIR) design method in digital signal processing, design a whole class based on cascaded optical fiber circulator Mach-Zehnder type parity interleaver. Background technique [0002] With the increase in the number of multiplexed channels and narrower channel intervals, Dense Wavelength Division Multiplexing (DWDM) technology has emerged. Today, the optical transport network with DWDM technology as the core is becoming the main transmission platform for telecommunication networks and the Internet. Of course, the optical filtering technology as the core of the multiplexer / demultiplexer will also attract much attention. The continuous increase in the number of channels leads to a continuous decrease in the channel spacing, which poses a serious challenge to the traditional multiplexe...

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Problems solved by technology

[0007] Compared with the prior art [1] and [2], the above-mentioned prior art [3] and [4] introduced the optical fiber ring cavity and the design idea of ​​infinite impulse response, which can use a lower order to obtain a better Output spectral transmittance, but it uses traditional programming to search and solve parameters, and the calculation is cumbersome, especially when the number of annular cavities is large, it is particularly complicated, and the calculation of solving structural parameters is very large, and the parameters calculated by cyclic programming will be consistent with The actual accurate value has a large deviation

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