Uncooled Operation of 53-GBd PAM4 (106-Gb/s) EA/DFB Lasers With Extremely Low Drive Voltage With 0.9 Vpp

We developed a high-bandwidth 1.3-
μ
m uncooled electro-absorption modulator-integrated distributed-feedback laser and demonstrated uncooled 53-GBd four-level pulse amplitude modulation (PAM4) operation with low drive voltage for the first time. Specifically, 53-GBd PAM4 operation with the drive voltage of 0.9
V
_pp
from 20 to 85 °C was achieved. The extinction ratio of more than 4.9 dB and transmission dispersion eye closure quaternary of less than 2.3 dB were obtained from 20 to 85 °C in the 53 GBd-PAM4 operation.