Active-cavity photonic molecule optical data wavelength converter for silicon photonics platforms

Abstract: We demonstrate an optical data wavelength converter based on an electrically driven photonic molecule structure comprising two coupled active silicon microring resonators. The converter, supplied by a continuous-wave (CW) microwave drive signal equal in frequency to the desired wavelength shift, replicates an input optical signal at a new wavelength. The optical coupled-cavity system matches supermode resonances to the input and wavelength-converted optical waves maximizing the conversion efficiency. Two device designs that perform wavelength up- and down-conversion by 0.19 nm (24 GHz) with -13 dB conversion efficiency and 6 GHz bandwidth; and by 0.45 nm (56 GHz) with -18 dB efficiency and 5 GHz bandwidth are demonstrated. A 4 Gbps non-return-to-zero (NRZ) optical data stream is shifted in wavelength and successfully recovered. This architecture accepts CMOS-level RF drive voltages and can be integrated in monolithic CMOS electronic-photonic platforms with a simple signal source circuit as part of a self-contained subsystem on chip that generates and carries out the wavelength conversion, requiring no high-frequency (optical or electrical) and high-power external pump input to the chip. This type of device may become a new standard element in the component libraries of silicon and CMOS photonics processes.