Research And Implementation Of 40Gbps Active Optical Cable Technology

With the rapid development of the information industry, the amount of global data increase greatly, which has tremendously promoted the development of the cloud computing system and data centre market. With the increase of data throughput, the data exchange rate of hight speed device is growing from 10 Gbps to 40 Gbps and 100 Gbps. Traditional electric interconnection used in has been already unable to meet the demands of high-speed interconnection due to restrictions of bandwidth and transmission distance. In order to solve the problem of high-speed interconnection, people turn attention to optical fiber interconnection method. Active optical cable(AOC) is created in this background. In recent years, with gradual commercialization of switch, server and router equipped with 40 Gbps QSFP+( Quad Small Form-factor Pluggable Plus) interface, the market demand for 40 Gbps QSFP+ active optical cable increase greatly.This paper studies on key technologies of 40 Gbps QSFP+ active optical cable, a low cost and low power 40 Gbps QSFP+ active optical cable was developed. The main research contents of this paper are as follows:The basic framework of hardware circuit and software were determined by studying on SFF-8436 specification. Base on the application background and actual requirement of this design, we completed the design of hardware circuit method and schematic circuit diagram. And optical scheme was completed, using45 degree fiber array technology to realize Laser array and Detector array optical coupling.The PCB(Printed Circuit Board) design was completed based on signal integrity theory, which included Material selecting, stackup design, impedance design and placement. Bonding finger and via which had influence on signal integrity were studied by simulation. A method of constructing antipad on the reference strata was presented, which could compensate this impedance change. Main structure parameters of via were studied, which provided reference for via optimization design.System embedded software was developed with the method of modularization design. A testing system for the active optical cable was built, the main parameters of the transmitter and receiver had been tested. Test results showed that all parameters met the specification.