Continuous-wave operation of ultra-short cavity distributed bragg reflector lasers on Si substrates

We have fabricated ultra-short cavity membrane distributed Bragg reflector lasers on SiO2/Si substrate for constructing chip-to-chip optical links. To reduce the power consumption of transmitters, reducing cavity length is important. Since the membrane structure enables us to achieve a large optical confinement factor and a surface grating with a large coupling coefficient, we have successfully reduced cavity length to 10 μm. The device exhibits a threshold current of 0.17 mA with a side-mode suppression ratio of 39.1 dB. We have also demonstrated direct modulation using 25.8-Gbit/s NRZ signal and achieved eye opening with a bias current of 1.8 mA.