Dynamical regimes in a monolithic passively mode-locked quantum dot laser (original) (raw)
Related papers
2010
Operation regimes of a two section monolithic quantum dot (QD) mode-locked laser are studied experimentally and theoretically, using a model that takes into account carrier exchange between QD ground state and 2D reservoir of a QD-in-a-well structure, and experimentally. It is shown analytically and numerically that, when the absorber section is long enough, the laser exhibits bistability between laser off state and different mode-locking regimes. The Q-switching instability leading to slow modulation of the mode-locked pulse peak intensity is completely eliminated in this case. When, on the contrary, the absorber length is rather short, in addition to usual Q-switched mode-locking, pure Q-switching regimes are predicted theoretically and observed experimentally.
Stability of the mode-locked regime in quantum dot lasers
Applied Physics Letters, 2007
We report on experimental and theoretical studies of the stability regime of passive mode-locked quantum dot lasers, which is decisively larger than in quantum well lasers. A small range of Q-switched instability is observed at low gain currents. Transition to Q switching is inhibited due to fast damping of the relaxation oscillations. A double pulse mode-locking regime appears for longer cavities, and exhibits bistability and coupling to the fundamental mode-locking operation.
Bifurcations in a model of monolithic passively mode-locked semiconductor laser
2009
Operation regimes of a two section monolithic quantum dot mode-locked laser are studied theoretically using a model that takes into account carrier exchange between quantum dots and wetting layer. It is shown that when the absorber section length is large enough the laser exhibits bistability between laser off state and different mode-locking regimes. Q-switching instability leading to slow modulation of the mode-locked pulse peak intensity is completely eliminated in this case.
Automated analysis of stable operation in two-section quantum dot passively mode locked lasers
2007
In this paper, two-section mode-locked lasers consisting of monolithic quantum dot gain and absorber sections are studied as a function of absorber voltage, injected current to the gain region, and relative section lengths. We map the regions of stable mode-locking as measured by the electrical and optical spectra. A simple algorithm is presented that evaluates the quality of mode locking and allows automated characterization of devices. The relative advantages of increasing the absorber length compared to increasing the absorber reverse bias voltage are analyzed. Initial data indicate that doubling the absorber length from 1.4 to 2.8-mm in a 5 GHz repetition rate device increases the region of stable mode-locking by at least 25%, while increasing the absorber reverse bias can more than double the mode-locking regime. Nonetheless, in these devices, stable mode-locking over greater than a 100 mA bias range is realized with a grounded absorber making single bias control of a passively mode-locked semiconductor laser feasible.
2010 12th International Conference on Transparent Optical Networks, ICTON 2010, 2010
We present both experimental and theoretical investigations of the so-called reverse emission state dynamics in a two-section InAs/InGaAs Quantum Dot (QD) laser. In contrast to the classical state scenario, we demonstrate by properly designing the laser cavity and the QD active region, a reversal of the emission state transition: At a certain gain current Excited-state (ES) lasing and mode-locking (ML) starts first and then, with increasing gain current, a transition to simultaneous ES and ground-state (GS) ML takes place. This enables a novel approach to wavelength-switching of the mode-locked pulses over a range of 63 nm: the realization of a two-section QD laser with a resistor Self-Electro-optic Effect Device (SEED) configuration. These results are reviewed together with the state-of-the-art realization of InAs/InGaAs two-section QD lasers operating in two-state ML regime . Keywords: two-state and dual-wavelength emission, passive mode-locking, optical wavelength switching, quantum dot laser emission hierarchy, two-section quantum dot semiconductor laser, stable picosecond pulse generation, quantum dot resistor Self-Electro-optic Effect Device (SEED).
Automated analysis of stable operation in two-section quantum dot passively mode locked lasers
Physics and Simulation of Optoelectronic Devices XV, 2007
In this paper, two-section mode-locked lasers consisting of monolithic quantum dot gain and absorber sections are studied as a function of absorber voltage, injected current to the gain region, and relative section lengths. We map the regions of stable mode-locking as measured by the electrical and optical spectra. A simple algorithm is presented that evaluates the quality of mode locking and allows automated characterization of devices. The relative advantages of increasing the absorber length compared to increasing the absorber reverse bias voltage are analyzed. Initial data indicate that doubling the absorber length from 1.4 to 2.8-mm in a 5 GHz repetition rate device increases the region of stable mode-locking by at least 25%, while increasing the absorber reverse bias can more than double the mode-locking regime. Nonetheless, in these devices, stable mode-locking over greater than a 100 mA bias range is realized with a grounded absorber making single bias control of a passively mode-locked semiconductor laser feasible.
IEEE Journal of Quantum Electronics, 2000
We present a modified version of the multisection delayed differential equation model, for quantum dot passively mode-locked (ML) lasers when competition between ground state (GS) and excited state (ES) ML takes place. The model takes into account the difference in the group velocity of GS and ES fields. Sole GS, sole ES, and dual-state lasing and ML have been studied. The results are verified with time domain traveling wave simulations and compared, when possible, with experimental results. These tests confirmed the reliability of the model. We found that, in two-section ML lasers, GS lasing and mode locking are always more easily established. For instance, GS lasing can be either self-starting or induced by the initial lasing from the higher energy ES. On the contrary, GS lasing tends to inhibit, to a certain extent, the onset of ES lasing, especially at low injection current and low reverse voltage. Moreover, ES shows less potential to achieve stable ML than GS. Based on these findings, we propose proper theoretical explanation of the achieved lasing and ML regimes in realized devices. Especially, we demonstrate a novel stable dual-state ML regime with remarkable enhanced pulse peak power and pulse width.
Analysis of hybrid mode-locking of two-section quantum dot lasers operating at 15 μm
Optics Express, 2009
For the first time a detailed study of hybrid mode-locking in twosection InAs/InP quantum dot Fabry-Pérot-type lasers is presented. The output pulses have a typical upchirp of approximately 8 ps/nm, leading to very elongated pulses. The mechanism leading to this typical pulse shape and the phase noise is investigated by detailed radio-frequency and optical spectral studies as well as time-domain studies. The pulse shaping mechanism in these lasers is found to be fundamentally different than the mechanism observed in conventional mode-locked laser diodes, based on quantum well gain or bulk material.
IEEE Journal of Quantum Electronics, 2000
In this paper, we numerically investigate the role of gain and absorber dynamics on the operation of monolithic twosection mode-locked quantum-dot lasers under optical feedback. The analysis is carried out by means of a time-domain traveling wave model for propagation in the gain and absorbing sections. The obtained results indicate that in devices with slow dynamics, pulse duration tends to increase significantly with feedback. On the contrary, devices with fast dynamics exhibit an operation that depends primarily on the external cavity length.