A Filter Based on Axial Apodized Grating

Abstract

The present invention discloses a filter based on axial direction apodized grating. Input single mode waveguide is connected with the upper end port of the left end of an asymmetrical gradual changing directional coupler through input gradual changing waveguide, and the lower end port of the left end of the asymmetrical gradual changing directional coupler is connected with bending waveguide to realize reflection signal download; and the upper end port of the right end of the asymmetrical gradual changing directional coupler is connected with the left end of an antisymmetrical multimode waveguide grating, and the right end of the antisymmetrical multimode waveguide grating is connected with the output single mode waveguide through output gradual changing waveguide. The separation of grating reflection signals employs the asymmetrical gradual changing directional coupler with large tolerance and small insertion loss to realize download of the grating signals; based on a grating filter, the filter based on axial direction apodized grating is large in tolerance and wide in bandwidth regulation range and cannot be limited by the FSR so as to realize filters with various different bandwidth demands; and moreover, the axial direction position regulation of grating teeth realizes apodization so as to realize a grating filter with large sideband suppression ratio and greatly improve the performance of the grating filter.

Description

technical field [0001] The present invention relates to a grating filter, in particular to a filter based on an axially apodized grating. Background technique [0002] Since the 21st century, the development of integrated optical devices, especially silicon-based integrated optoelectronic devices, has been very rapid. Silicon-based integrated optoelectronic devices have become an important research direction for the development of integrated optical devices, and various new optical devices have been reported continuously. Since silicon-based optical devices can be combined with the existing mature CMOS process, the production cost is low, the performance reliability is high, it is convenient for mass production, and it can be combined with the circuit system to form a multifunctional photoelectric hybrid module and system. It has been widely used in many fields such as communication, sensing, military affairs, and biology, and has a very bright prospect. Therefore, higher r...

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Problems solved by technology

[0003] Scholars have carried out a series of explorations on silicon-based filters by combining the advantages of silicon materials such as large refractive index difference, low loss, and compatibility with CMOS. Although filters based on microrings and Mach-Zehnder interferometers have narrow bandwidths , but limited by its own FSR, the wavelength range of wavelength division multiplexing is limited, and it cannot cover all the C-band, while the grating is not limited by FSR, and the wavelength range can cover the entire communication band

However, due to the influence of side lobes, the current grating has a relatively large crosstalk to adjacent channels, and it is difficult to achieve dense wavelength division multiplexing. Therefore, it is of great significance to realize an apodized filter based on silicon-based waveguide gratings.

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