Research On 4×10Gbit/s QSFP+ Parallel Optical Transceiver Module

With the new business of the Ethernet emerging, people’s demand of bandwidth become higher, then it becomes necessary to upgrade the data center servers.In the past, Gigabit Ethernet and board LAN servers are "free" to use, but now the 10G port not only cost much higher than the cost of the past, but also has the problem of high power consumption and size, restricted the development of the whole communication industry. Google, Facebook and Microsoft have invested a lot of money to build and upgrade the so-called "million data center", make the rate higher to 40G,100G. The core technology of 40G is the optical module, as a solution for short distance high speed interconnect transmission,4×10Gbit/s QSFP+ parallel optical transceiver module can provide larger transmission capacity, higher transmission rate, higher port density, lower power consumption and lower cost, so it is the favour to the equipment manufacturers.This paper is intended to research and develop an QSFP+ parallel optical transceiver which compliant with IEEE802.3ba and SFF-8436, and the total data rate is 41.25Gbit/s. This paper consists of four parts:Firstly, this paper introduces the background of this research, the characteristics of 40G QSFP+ parallel optical transceiver module, and the development of domestic and international research. Then the protocols and standards of the QSFP+ optical transceiver are analysed, especially the physical model, electrical interface, optical interface standard and digital diagnostic monitoring function.Secondly, this paper describes the whole design scheme of 40G QSFP+ parallel optical transceiver module, mainly introduces the composition, working principle, the design of optical devices and the overall design objectives. The design of the optical device, different from previous optical module structure is chip to device to module, but omitting the device packaging and useing the design of the photoelectric chip array to the module directly. The advantages of the VCSEL laser and PIN photodiode array and the chips principle are introduced in this section.Thirdly, this paper expatiates the design of the high speed circuit and the parallel optical path of the 40G QSFP+ parallel optical transceiver. The design of high speed circuit includes the design of the high speed interface, compensation circuit, transmitting circuit and receiving circuit. The scheme of parallel optical path and the coupling efficiency are also analysed.At the end of this article, through the experiments, the results of this research aretested and analysed, they are approved that the performance of the 40G QSFP+ parallel optical transceiver module can meet the related standards, and the graduation design is summarized.