Quantum dot-in-a-well (QDWELL) laser dynamics under optical injection

Abstract

Abstract-We investigated theoretically the optical injection influence on the dynamics of a quantum dot (QD) in a quantum well (QDWELL) laser. The carrier dynamics is synchronized due to the optical injection, and QDWELL laser manifests a high performance at repetition frequencies up to 25GHz. I. INTRODUCTIONA novel type of quantum dot (QD) laser with the-dotin-a-well (DWELL) structure based on InAs QDs grown in the strained InGaAs quantum well (QW) characterized by an extremely low threshold current density of 42.6A · cm −2 and a lasing wavelength near 1.3µm has been recently proposed [1]. However, the QDWELL laser modulation bandwidth of 7GHz is limited by the relaxation oscillation (RO) frequency. In order to improve the performance of directly modulated semiconductor lasers, the optical injection locking (OIL) of semiconductor lasers can be used providing a single-mode regime with side-mode suppression, strongly enhanced RO frequency, enhanced bandwidth, reduced nonlinearity, reduced relative intensity noise (RIN), reduced chirp, increased link gain, and near-single-sideband modulation [2]. The complicated dynamics of optically injected QDWELL lasers has been investigated both theoretically and experimentally using the Lüdge-Schöll (LS) model [3], [4]. We have shown that due to the optical injection, the electron and hole dynamics in QW and QDs is synchronized, and consequently, the QDWELL laser demonstrates a high performance in the large signal regime for the moderate bias current level at the repetition frequencies up to 25GHz.

Quantum Dot-Semiconductor Optical Amplifiers (QD-SOA): Dynamics and Applications

“…operation rate of QDWELL SOA is limited by the desynchronized recovery dynamics of electrons and holes caused by the different microscopic scattering rates [15]. We have shown theoretically that the electron and hole dynamics in QDWELL lasers and SOA can be synchronized by a sufficiently strong optical injection and consequently the QDWELL lasers and SOA performance including the operation rate can be significantly improved [18][19][20][21][22].…”