Optical bandpass filter based on double microring-Mach Zehnder interference structure

Abstract

The invention discloses an optical bandpass filter based on a double microring-Mach Zehnder interference structure. The optical bandpass filter is composed of a first multi-mode interference coupler, a second multi-mode interference coupler, a third multi-mode interference coupler, a first coupling grating, a second coupling grating, a first heating electrode, a second heating electrode, a third heating electrode, a fourth heating electrode, a first upload-download type micro ring, and a second upload-download type micro ring. According to the invention, on the basis of the design of the coupling states of two upload-download type micro rings, fully destructive interference is introduced based on a cascaded adjustable Mach Zehnder interference (MZI) structure; amplitude regulation is realized by adjusting the bias voltage on the heating electrode of the MZI1, so that amplitudes of passband external light signals of an upper arm and a lower arm becomes identical; and phase regulation is realized by adjusting the bias voltage on the heating electrode of the MZI2, so that phases of passband external light signals of the upper arm and the lower arm are opposite. Therefore, the extinction ratio of the filter increases under the circumstance that the passband insertion loss is not increased. The provided optical bandpass filter has advantages of narrow bandwidth, high extinction ratio, and low insertion loss.

Description

technical field [0001] The invention belongs to the technical field of optical filters, and relates to a semiconductor integrated optical band-pass filter which realizes ultra-high extinction ratio on the basis of narrow bandwidth and low insertion loss. Background technique [0002] Optical filters select optical signals of specific wavelengths to pass through and filter out optical signals of other wavelengths. They are important devices in all-optical signal processing and wavelength division multiplexing systems. At present, optical filters with various structures have been produced, including Mach-Zehnder interferometer filters, Fabry-Perot interferometer filters, fiber Bragg grating filters, etc. However, these structures have problems such as large size and difficult fabrication of some devices, making it difficult to realize integration. [0003] Microring filter is a kind of optical filter. Its basic unit microring has inherent advantages of integration, and is wi...

AI Technical Summary

Problems solved by technology

Therefore, in the design and production, the parameters of the microring often need to choose a compromise value, which limits the 3dB bandwidth, extinction ratio and insertion loss of this type of device, and affects its filtering performance.

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