Fig. 1. (a) Illustration of epitaxial layers of InAs QD lasers; (b) cross-sectional SEM image of fabricated QD-CPML; (c) schematic of this 200 GHz QD-CMPL (inset, the top-view microscopic image of 200 GHz QD-CPML); (d) photograph of device after wire-bonding and butterfly packaging.

Fig. 2. (a) L-I characteristics of 200 GHz fourth-order CPML under changed temperature from 20°C to 85°C at reverse bias of 0 V and (b) changed reverse bias from 0 to 5 V at room temperature; (c) optical spectrum with 12 channels within 3 dB optical bandwidth at I=237  mA, VR=4.1  V, T=23°C; (d) optical mapping of this device under current from 40 to 250 mA and reverse bias from 0 to 5 V at room temperature.

Fig. 3. (a) Experimental setup for the measurement of FROG (I), linewidth (II) and RIN (III); (b) optical spectrum of this QD-CPML at I=165  mA, VR=1.5  V, T=23°C; (c) time-resolved spectrum and autocorrelation curve measured by FROG; (d) RIN and (e) optical linewidth of four individual channels after optical bandpass filter; (c), (d), and (e) are characterized at the same set of working conditions as (b).

Fig. 4. (a) Experimental arrangement for transmission measurements, including optical bandpass filter, polarization controller, arbitrary waveform generator, RF amplifier, thin-film lithium niobate Mach–Zehnder modulator, and optical sampling oscilloscope; (b) 100 Gbaud PAM-4 and (c) 90 Gbaud PAM-8 optical eye diagrams with outer extinction ratio of four individual comb lines.