Furukawa Electric Review No.55Development of an External Laser Source for Co-Packaged Optics

Taketsugu Sawamura, Kazuhiko Kashima, Kyoko Nagai, Daiki Takeda, Tsunetoshi Saito, Kouhei Umeta, Masayoshi Kimura, Hideyuki Nasu, Nitidet Thudsalingkarnsakul, Rattanaporn Suksomboon, Sanguan Anantathanasarn

We designed and fabricated an external laser source (ELS) for a network switch equipment employing the Co-Packaged Optics (CPO). This ELS integrates a newly developed uncooled 8-channel Transmitter Optical Sub-Assembly (TOSA) and a control circuitries into a Quad Small Form Pluggable (QSFP) housing, widely employed for optical transceivers. In order to obtain a high fiber-coupled power with low power consumption, we employed our high-power Distributed-Feed Back (DFB) laser diode, and we designed a heat dissipation structure and an optical system, a power-saving control circuitries. At a housing temperature of 55°C, the ELS achieved an optical fiber-coupled power of 20 dBm with power consumption of 5.6 W and power conversion efficiency (PCE) of 14.3% which is the best in the industry. The ELS achieved Polarization extinction ratio (PER) of >20 dB and Side-Mode Suppression Ratio (SMSR) of >50 dB respectively.