Short wave SFF small form factor transceivers

Abstract

In recent years, high-speed optical networking protocols like Fibre Channel and Gigabit Ethernet are expanding, and the demand for high-speed optical transceivers is increasing rapidly. Moreover, the number of ports per unit needs to be greater than that of the ancient systems. So, we developed a small form-factor (SFF) optical transceiver for those demands. It is half the size of the previous generation's transceiver like the 1/spl times/9 transceiver, and has excellent cost performance. We have also produced a small form-factor pluggable (SFP) optical transceiver. This transceiver has the same performance as a SFF transceiver, with additionally features of hot pluggability and serial ID. It looks like a half sized GBIC transceiver. We choose a short wave (850 nm) vertical cavity surface emitting laser (VCSEL) as the light source which was driven by a thoroughly designed peaking circuit to improve the rise and fall time. We designed the circuit board to implement a transmitter/receiver circuit into a simple 4-layer single circuit board. With such a simple circuit board, we realized excellent electronic and optical performance and also good cost performance on it. Also, two options are available for small optical front end connector interface, the MT-RJ and LC. The VCSEL, pin PD, optical wave guide, and the receptacle are integrated into a small optical front end making the assembly of the SFF and SFP transceiver is very simple and easy. We implemented the slow start circuit and serial ROM into a 6-layer single circuit board and realized hot pluggable transceivers. Both transceivers have good transmitter/receiver performance at 2.125 Gbps Fiber Channel standard. And they can receive 1.0625 Gbps optical signals from previous generation transceivers which have CD-LD with low relaxation oscillation frequency (ROF is about 2.2 GHz).