A Reconfigurable Optical All-Pass Filter

Abstract

The invention discloses a reconfigurable optical all-pass filter, comprising: three optical couplers, N+2 optical phase shifters and N microrings; the output end of the first optical coupler, the second optical coupler The input terminal and the first optical phase shifter constitute the MZI 1 Structure, the output end of the second optical coupler, the input end of the third optical coupler, the second optical phase shifter, the third optical phase shifter and the first microring constitute the MZI 2 structure. The invention utilizes the interference characteristics of the Mach-Zehnder interferometer and the resonance characteristics of the microring to input the signal into the chip and pass through the MZI 1 structure is divided into two inputs to the MZI 2 structure, one signal is filtered by the microring, the other one passes through the phase shifter and waveguide, the two signals are processed by multiple cascaded all-pass microrings after the interference of the third optical coupler, and finally from the second coupling grating output. The invention realizes a flat amplitude-frequency response by changing the amplitude ratio and phase difference of the two signals and adjusting the coupling coefficient of the micro-ring, thereby realizing an all-pass filter.

Description

Technical field [0001] The present invention belongs to the field of optical filter and microwave photonic technology, more particularly, relates to a reconfigurable optical all-pass filter. Background [0002] An all-pass filter is a special filter that maintains a constant amplitude in a certain frequency range and only changes the phase information, which can also be called an all-pass network (phase filter). The traditional filter achieves signal filtering through the change of its own amplitude-frequency response, while the all-pass filter changes the phase information of the signal through its own phase frequency response characteristics, except for the fixed insertion loss, which has no effect on the amplitude of the signal. In electricity, this feature is often used to eliminate unwanted phase effects in the system and introduce delay into specific signals; in the field of optics, the phase response of the all-pass filter can be designed accordingly to construct optical d...

AI Technical Summary

Problems solved by technology

But in reality, the loss of the waveguide cannot be ignored, so the amplitude response of the microring resonator is no longer a straight line constant at 1, but a concave curve

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