Tunable cascading micro-ring filter

Abstract

The invention discloses a tunable cascading micro-ring filter which comprises input waveguide, a first-stage micro-ring resonant cavity, a first heater, connection waveguide, a second-stage micro-ring resonant cavity, a second heater and output waveguide. The input waveguide is the input waveguide of the first-stage micro-ring resonant cavity. The first heater is located on the first-stage micro-ring resonant cavity. The connection waveguide is the connection waveguide between the first-stage micro-ring resonant cavity and the second-stage micro-ring resonant cavity. The second heater is located on the second-stage micro-ring resonant cavity. The output waveguide is the output waveguide of the second-stage micro-ring resonant cavity. The first heater and the second heater heat the first-stage micro-ring resonant cavity and the second-stage micro-ring resonant cavity respectively so as to change the resonant wavelength of the first-stage micro-ring resonant cavity and the second-stage micro-ring resonant cavity.

Description

technical field [0001] The invention relates to the field of integrated optics, and provides a thermo-optic tunable cascaded microring filter capable of quasi-continuous filtering in an ultra-large free spectral range. Background technique [0002] In modern optical network technology, a reconfigurable optical add / drop wavelength division multiplexer (ROADM) can flexibly allocate capacity and reconstruct a dense wavelength division multiplexing (DWDM) network, and is a key device for automatic switching of optical networks. Although the FFP filter has been commercialized and can be used to realize low-speed optical network applications, its application is limited because its tuning range is smaller than the EDFA band. Liquid crystal filter has similar performance to FFP, although it has a wider tunable range and faster tuning speed, but it has not been commercially available on a large scale. Due to the reliability problems of MEMS filters, MEMS devices cannot be industrial...

AI Technical Summary

Problems solved by technology

Due to the reliability problems of MEMS filters, MEMS devices cannot be industrialized in the end

FBG filters do not have the problem of alignment with optical fibers, and have been commercially available. However, the tuning range of FBG is very small and cannot meet the requirements of wide-range wavelength tuning.

Acousto-optic tunable filters have also been commercially available to achieve multi-wavelength frequency selection, but there are problems such as large bandwidth, high side lobes, and frequency shift.

Active tunable filters have great potential for ultra-high speed and narrow bandwidth, but their requirements for temperature and current stability are still a problem

In 2008, Joonoh Park et al. from Kwangwoon University in South Korea reported a thermal-optic photonics based on a polymer Ploymer waveguide coupled microring on IEEE Photonics Technology Letters, VOL.20, NO.12, 2008, pp.988-990. Tunable filter, the specific structure is a single waveguide coupled double microring structure, and the two microrings are also in a coupled state, its disadvantage is that the filter spectrum is a multi-peak envelope structure, and it cannot achieve a single peak with a high side mode suppression ratio filter spectrum

Although the single microring resonator filter based on SOI photonic wire waveguide has the advantages of small size and narrow passband bandwidth, its disadvantage is that it needs a large heating current to obtain relatively large wavelength tuning.

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