Fully Integrated, 80 GHz Bandwidth, 1.3μ m InAs/InGaAs CW-PW Quantum Dot Passively Colliding-Pulse Mode-Locked (CPM) Lasers for IR Sensing Application

Integrated quantum dot passively mode-locked lasers: IQDMLLs open opportunities for IR sensing. Therefore, here, we investigated structure of quantum dot passively mode-locked lasers (QDMLLs) with colliding-pulse mode-locked (CPM) method in order to reinforce the performance of QDMLLs for ultrahigh-bit-rate compared to self-colliding pulse mode-locking (SCPM) method. The proposed structure is numerically based on finite difference traveling wave (FDTW) method. By considering bias current of 80 mA, which is the bias applied to the gain section, the laser is at its maximum output power. Finally, by comparing the QDMLLs with self-colliding pulse mode-locking (SCPM) method, it is shown that due to the grating caused by the collision of the two counter-propagating pulses in the saturable absorber, the laser bit rate in the structure of CPM is twice the bit rate in structure of SCPM somehow bit rate from 40 GHz in SCPM method increased to 80 GHz in CPM method. Also, grating coupling factor (GCF) changes due to the proposed structure has been shown, so that in the range of
$1cm^{ - 1} \le \kappa \le 5cm^{ - 1}$
the laser output power is pulsed wave (PW), while after this range the laser output power changes from a pulsed regime to a continuous wave (CW) regime.