Study And Design Of PAM-4 Optical Transmitter Based On Dual Ring Modulators

With the continuous advancement of information technology,global data centers and high-efficiency computing centers are faced with the challenge of limited communication efficiency and system power.In the traditional optical interconnection communication technology,the adoption of higher-order modulation can effectively increase the communication bandwidth and reduce the interconnection efficiency.Among them,the silicon optical transmitter adopting four-level amplitude pulse modulation(four-level pulse amplitude modulation,PAM-4)integrates multi-level modulation technology and electro-optical integration technology,and has obvious advantages in transmission rate,communication power and integration level.It has become a key technology for interconnecting high-bandwidth,low-power optical interconnects in data centers and high-performance computers.Communication bandwidth requirements,focusing on the design of optical PAM4 transmitters.First,based on the PAM-4 optical transmitter based on the micro-ring modulator,the PAM-4 transmitter system architecture based on the dual-loop modulator is proposed by analyzing the physical effects of the micro-ring modulator and the method of optical signal conversion.In the above,the behavior level model of the micro-loop modulator is constructed,and the model is simulated and analyzed.Then,a photoelectric integrated simulation model of the transmitter is constructed to verify the rationality of the transmitter structure.Finally,based on the i SSi PP50G advanced silicon photonics process and28nm TSMC CMOS process,the electrical driver and silicon photonic chip simulation design work has been completed,including the input stage circuit design,transistor amplifier design,output stage circuit design and micro-ring modulation layout design On this basis,by extracting the parasitic parameters of the circuit,the photoelectric joint post-simulation of the system is completed.Simulation results show that the chip area of the PAM-4 optical transmitter designed in this paper is 0.0312mm~2,which can achieve a PAM-4 communication bandwidth of 112Gbps.The RLM of PAM-4 eye diagram is 96.4%.The power under 1V power supply voltage is only 1.03pJ/bit.