A Simple Multi-Functional Optical Chip With High Reconfigurability

Unlike the application-specific optical chips, reconfigurable optical chip can offer various optical signal processing functions, which can dynamically meet the various requirements in different application scenarios. To achieve multiple functions, relatively complex optical chip configuration is usually needed, which poses the difficulty to control. Here, we propose a highly reconfigurable integrated silicon nitride optical chip by simply cascading Mach-Zehnder interferometers (MZIs) and coupled resonator optical waveguide (CROW). By dynamically reconfiguring the optical propagation path in the proposed chip, as many as six different types of optical functional structures have been obtained, which can achieve optical switch with ultra-high extinction ratio (ER), box-like interleaver, optical filters with tunable bandwidth, spectral shape and free spectral range (FSR) reconfigurabilities. Experimental results show that optical switch achieves an ER of 52 dB, optical interleaver achieves the shape factor about 1.32, in-band ripple of 0.2 dB and crosstalk of -21 dB. Meanwhile, as a reconfigurable optical filter, various spectral shapes such as Fano, flat-top, Lorentz, triangular, sinusoidal, square, tangent-like responses have also been obtained. In addition, by adopting different modulation schemes, bandstop microwave photonic filters (MPFs), lowpass MPFs and bandpass MPFs have been demonstrated. Our proposed chip could provide a simple and highly reconfigurable solution for various applications in optical communication, sensing and microwave photonics signal processing systems.