Integrated Transceiver of Optical Vortex Signals with PAM-4

The paper presents a design of integrated optical transceiver with a transmission rate of 200 Gbit/s or more based on the joint use of wavelength division multiplexing and spatial division multiplexing. The transmission is carried out at three wavelengths, while the carriers are optical vortex beams. At one of the wavelengths, two signals with different orders of orbital angular momentum are simultaneously transmitted. The emission of optical vortices out of chip plane and their multiplexing in orbital angular momentum is carried out by means of a microring resonator with periodic inhomogeneities. We use PAM-4 modulation for each of four channels. The results of numerical modeling of the resonator and the distribution of the electromagnetic field in each channel are presented, as well as a numerical model for obtaining an eye diagram in each channel. The proposed device can be used in high-performance incoherent short-range communication, for example, in data centers.