抄録
Directly modulated lasers are deployed in data centers as small, cost-effective, and low-power-consumption
transmitters. However, their maximum operating speed and temperature are limited mainly due to
the gain reduction in the active region caused by a temperature increase under current injection.
Therefore, how to reduce the thermal resistance of devices is a crucial issue. In this review, we show that
a high-thermal-conductivity SiC single-crystal substrate is a suitable membrane laser platform for decreasing
the thermal resistance as well as for obtaining a high optical confinement in the active region,
both of which drastically improve laser operation characteristics. The membrane laser fabricated on SiC
is capable of continuous-wave operation at temperatures up to 130°C. The bandwidth reaches 60 GHz
thanks to the high relaxation oscillation frequency of 42 GHz. In addition, with the photon-photon resonance
effect, we demonstrate uncooled 100-GBaud operation at temperatures up to 85°C.
