A compact ROSA module for serial 40-Gb/s optical transceiver

We have implemented and successfully demonstrated a serial 40-Gb/s receiver optical sub-assembly (ROSA) module by employing a popularly used TO-CAN package and a flexible printed circuit board (FPCB). We propose the orthogonally connected scheme between the TO-CAN package and the FPCB for a serial 40-Gb/s data transmission. The proposed scheme has adopted the structure on the FPCB to guarantee a return-current path for signal and optimize a gap between signal and ground pads for signal integrity. For 40 Gb/s, the receiver sensitivity o f t he RO SA module was measured as below -10 dBm at extinction ratio of 7 dB and bit error rate of 10^-12.