Quantum-dot semiconductor lasers with prominent relative intensity noise and spectral characteristics

Abstract

Relative intensity noise (RIN) behavior of a quantum dot laser (QDL) at free running and under optical injection locking (OIL) has been reported in detail. Considering the mutual effects of the inhomogeneous and homogeneous broadenings, different and also non-routine RIN characteristics of a QDL at low, intermediate, and high homogeneous broadening regimes have been discussed. Results demonstrate that an injection-locked quantum dot laser exhibit enhanced characteristic over free-running operation along with low-frequency noise behavior in a wide range of homogeneous broadening values. RIN reduction of about 25, 55, and 7 dB/Hz have been achieved for low, intermediate, and high values of homogeneous broadening which implies the spontaneous emission noise suppression even at low injection power. The promising impact of the OIL on side-mode suppression for the intermediate homogeneous broadening regime has also been discussed. Our results guarantee the single-mode and low-noise operation of the OIL-QDL at any homogeneous broadening value.

RIN in Gain-Switched Dual-State Lasing Quantum Dot Lasers Based on Multi-population Rate Equations

“…The carrier and photon rate equations including Langevin noise sources can be described as follows: V is the volume, q is the charge, Γ is the confinement factor and vg is the group velocity. (16) Nonlinear-gain in Exs and Grs is given as…”

“…al reported that carrier noise originated from excited state and ground state of Q-Dot lasers increase the RIN of Q-Dot lasers, whereas enhancing energy difference between the ground state and the excited state reduce carrier noise contribution from the excited state [15]. As a result, there have been some papers investigating RIN of Q-Dot lasers for InGaAs-GaAs and InAs-InP [9][10][11][13][14][15][16][17][18][19][20][21]. However, most of them are not enough to clearly explain the RIN spectrum of Q-Dot lasers.…”

RIN in Gain-Switched Dual-State Lasing Quantum Dot Lasers Based on Multi-population Rate Equations

“…The carrier and photon rate equations including Langevin noise sources can be described as follows: V is the volume, q is the charge, Γ is the confinement factor and vg is the group velocity. (16) Nonlinear-gain in Exs and Grs is given as…”

“…al reported that carrier noise originated from excited state and ground state of Q-Dot lasers increase the RIN of Q-Dot lasers, whereas enhancing energy difference between the ground state and the excited state reduce carrier noise contribution from the excited state [15]. As a result, there have been some papers investigating RIN of Q-Dot lasers for InGaAs-GaAs and InAs-InP [9][10][11][13][14][15][16][17][18][19][20][21]. However, most of them are not enough to clearly explain the RIN spectrum of Q-Dot lasers.…”