A TO-CAN DFB Laser With Transmission Line Impedance Transformer for Analog Optical Link

Abstract

A transmission line (TL) impedance transformer of through-hole (TO)-CAN distributed feedback (DFB) laser is proposed and fabricated. The gain and noise factor (NF) of analog optical link can be improved by optimizing the laser impedance matching network. The radio frequency (RF) package of DFB is optimized to extend bandwidth and reduce return loss. In this paper, a flexible printed circuit (FPC) with low-loss impedance matching network is designed to improved the RF characteristics of TO-CAN DFB laser. The return path between FPC and TO-CAN is optimized to eliminate microwave resonances. The small signal model of an analog optical link is analyzed in detail. The measured frequency response of the TO-CAN DFB is 18.4 GHz. The microwave reflection is below −10 dB. The measured results correlates perfectly with the simulated results. The gain of analog optical link is increased by 3 dB. The NF is also reduced by about 2.5 dB.

Keywords

• DFB
• transformer of through-hole (TO)-CAN
• radio over fiber
• optical module
• optical transimmion