Z.J. Jiao

A

A passive InAs/InP quantum dot (QD) semiconductor mode-locked laser (MLL) emitting 403-GHz repetition rate pulses with 268- and 563-fs pulse durations is demonstrated experimentally around 1.54 μm. The QD MLL consists of a QD Fabry-Pérot laser and external cavities that include eight fiber Bragg gratings (FBGs). The mode-locking is realized by four-wave mixing in the QD waveguide between the longitudinal modes selected by the FBGs.

C

A short pulse train with pulsewidth was generated in a quantum dot mode-locked laser (QD MLL). Due to the short dispersion length, it is required to include group-velocity dispersion (GVD) in modeling pulse train generation and evolution from QD MLLs. On the other hand, Kerr effect is also required to consider due to high peak power density in the laser cavity, and its induced self-phase modulation (SPM) also contributes to the pulse evolution. In this paper, a time domain traveling wave model, including the effect of GVD and SPM, combined with rate equations, is established to model the pulse evolution in a single-section QD MLL. It is shown that the pulse evolution calculated by this model is in reasonable agreement with the experiments. The contribution to the pulse evolution by the GVD and SPM impact is discussed.

-Band InAs/InP Quantum Dot Semiconductor Mode-Locked Laser Emitting 403-GHz Repetition Rate Pulses

Tunable terahertz beat signal generation is demonstrated by using a C-band InAs/InP quantum-dot (QD) mode-locked laser combined with external cavity of two fiber Bragg gratings (FBGs), where one of the FBGs is tunable in wavelength. Beat signals with ultra-high repetition rates quasi-continuously from 1 to 2.21 THz are observed between the two modes, which are phase-correlated due to intracavity four-wave mixing effect in the QD waveguide.

Modeling of Single-Section Quantum Dot Mode-Locked Lasers: Impact of Group Velocity Dispersion and Self Phase Modulation

We demonstrate a broadband supercontinuum (SC) generation that covers an optical spectrum from 1300 to 2000 nm with output power of 1.3 W. The SC generation is realized using a fiber ring cavity that mainly consists of erbium-ytterbium-doped fiber pumped by multimode 975-nm pump lasers, and highly nonlinear fiber (HNLF). Moreover, we investigate the role of four-wave mixing (FWM) in the SC generation by using two different HNLFs, one having normal and the other having anomalous dispersion. It is found that FWM plays a critical role for broadening and flattening of the SC generation in addition to stimulated Raman scattering.

Tunable Terahertz Beat Signal Generation From an InAs/InP Quantum-Dot Mode-Locked Laser Combined With External-Cavity

Single-mode InAs/InP quantum dot DFB lasers with side-mode suppression ratio greater than 62 dB are demonstrated, operating CW up to 80°C. Relative intensity noise was less than −153 dB/Hz from 1 MHz to 10 GHz.

Experimental Investigation of the Role of Four-Wave Mixing in Supercontinuum Generation From a Multimode 975-nm Pumped Fiber Ring Cavity

We report on our most recent results on quantum dot (QD) laser devices around 1550 nm based on InAs/InP QD gain materials. These devices include monolithic QD multi-wavelength lasers (MWLs), mode-locked lasers (MLLs) and distributed feedback (DFB) lasers. The performance and potential applications of fiber communications will be discussed.

Single-mode 1.52 µm InAs/InP quantum dot DFB lasers

Linewidth enhancement factor (LEF) of InAs/InP quantum dot (QD) multi-wavelength lasers (MWL) emitting at 1.53 μm are investigated both above and below threshold. Above threshold, LEFs at three different wavelengths around the gain peak by injection locking technique are obtained to be 1.63, 1.37 and 1.59, respectively. Then by Hakki-Paoli method LEF is found to decrease with increased current and shows a value of less than 1 below threshold. These small LEF values have confirmed our InAs/InP QDs are perfect gain materials for laser devices around 1.5 μm.