Tunable electro‐modulated laser with 32 channels and 106 Gb/s modulation per channel

We report a monolithically integrated tunable electro‐modulated laser (TEML) that supports 106 Gb/s pulse‐amplitude modulation level 4 (PAM‐4) per wavelength across 32 wavelength‐division multiplexing (WDM) channels with 100 GHz spacing in the 1.29 μm window. A distributed Bragg reflector laser diode and electro‐absorption modulator are monolithically integrated on a single chip. We focus on the systematic characterization of static spectral properties, including the threshold, lasing wavelength, side‐mode suppression ratio (SMSR), and dynamic modulation performance according to the thermoelectric cooler (TEC) setpoint and channel wavelength. The TEML exhibits an approximately 18 nm tuning range with an SMSR of approximately 40 dB in the central tuning region. Under 106 Gb/s PAM‐4 modulation, all 32 channels show clear eye openings after equalization; at a TEC setpoint of 50°C the device provides an outer extinction ratio greater than 4.2 dB and an optical modulation amplitude exceeding 0.8 dBm. The results support the viability of TEMLs as compact light sources for high‐capacity fronthaul and access networks.