Bi-pass mach-zehnder interferometer type polarization-independence top-comb-shaped optical fiber filter

Abstract

The invention discloses a bi-pass mach-zehnder interferometer type polarization-independence top-comb-shaped optical fiber filter. The optical fiber filter comprises two optical fiber couplers, a polarization controller and a section of high birefringence optical fiber, wherein the first optical fiber coupler and the second optical fiber coupler are cascaded to form a mach-zehnder interferometer, and are connected in series to from a first closed loop; and the polarization controller, the high birefringence optical fiber and the second coupler are connected in series to form a second closed loop, so that the bi-pass mach-zehnder interferometer is formed. According to the fiber filter, the output of the polarization-independence top-comb-shaped band pass can be realized, the requirement on the wavelength of a DWSM (dense wavelength division multiplexing) system is lowered greatly as the tolerance for the drifting of signal wavelength is high, and the system cost is saved.

Description

technical field [0001] The invention belongs to the field of optical fiber technology and relates to a polarization-independent flat-top comb fiber filter based on a Mach-Zehnder interferometer. Background technique [0002] With the development of communication technology, communication services will turn to broadband services represented by high-speed IP data and multimedia, which puts higher and higher requirements on the bandwidth and capacity of optical communication networks. Dense Wavelength Division Multiplexing (DWDM) technology has become the main technical means of increasing the capacity of optical fiber transmission network because of its great improvement of the capacity of optical fiber communication system. [0003] The multi-channel filter is an important device in the DWDM optical fiber communication system, and its performance is directly related to the transmission quality of the optical fiber communication network. Among them, fiber grating is currently...

AI Technical Summary

Problems solved by technology

Among them, fiber grating is currently the most mature type of fiber-optic filter, but the temperature stability of fiber grating filter is not very good, thus limiting its application range

In addition, due to the small 3dB bandwidth of the fiber grating, the signal fidelity and signal wavelength drift tolerance are poor when it is used as a filter, which increases the requirements of the DWDM system for wavelength control and increases the cost.

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