Heming Huang

Non-degenerate four-wave mixing in an optically injection-locked InAs/InP quantum dot Fabry–Perot laser

Non-degenerate four-wave mixing in an InAs/InP quantum dot Fabry–Perot laser is investigated with an optical injection-locking scheme. Wavelength conversion is obtained for frequency detunings ranging from +2.5 THz to −3.5 THz. The normalized conversion efficiency is maintained above −40 dB between −1.5 and +0.5 THz with an optical signal-to-noise ratio above 20 dB and a maximal third-order nonlinear susceptibility normalized to material gain of 2 × 10−19 m3/V2. In addition, we show that injection-locking at different positions in the gain spectrum has an impact on the nonlinear conversion process and the symmetry between up- and down- converted signals.

Highly efficient non-degenerate four-wave mixing under dual-mode injection in InP/InAs quantum-dash and quantum-dot lasers at 1.55 μm

This work reports on non-degenerate four-wave mixing under dual-mode injection in metalorganic vapor phase epitaxy grown InP/InAs quantum-dash and quantum dot Fabry-Perot laser operating at 1550 nm. High values of normalized conversion efficiency of −18.6 dB, optical signal-to-noise ratio of 37 dB, and third order optical susceptibility normalized to material gain χ(3)/g0 of ∼4 × 10−19 m3/V3 are measured for 1490 μm long quantum-dash lasers. These values are similar to those obtained with distributed-feedback lasers and semiconductor optical amplifiers, which are much more complicated to fabricate. On the other hand, due to the faster gain saturation and enhanced modulation of carrier populations, quantum-dot lasers demonstrate 12 dB lower conversion efficiency and 4 times lower χ(3)/g0 compared to quantum dash lasers.

Multimode optical feedback dynamics in InAs/GaAs quantum dot lasers emitting exclusively on ground or excited states: transition from short- to long-delay regimes

The optical feedback dynamics of two multimode InAs/GaAs quantum dot lasers emitting exclusively on sole ground or excited lasing states is investigated. The transition from long- to short-delay regimes is analyzed, while the boundaries associated to the birth of periodic and chaotic oscillations are unveiled to be a function of the external cavity length. The results show that depending on the initial lasing state, different routes to chaos are observed. These results are of importance for the development of isolator-free transmitters in short-reach networks.

Multimode optical feedback dynamics of InAs/GaAs quantum-dot lasers emitting on different lasing states

Quantum dot lasers are envisioned to be the next generation of optical transmitters used for short-reach communication links, owing to their low threshold current and high temperature operation. However, in a context of steady increase in both speed and reach, quantum dot lasers emitting on their upper energy levels have been recently of greater interest as they are touted for their faster modulation dynamics. This work aims at further evaluating the potential impact of such lasers in communication links by characterizing their long-delay optical feedback responses as well as the role of the lasing states on the multimode dynamics of InAs/GaAs quantum-dot Fabry-Perot devices sharing the same design. Results unveil that the excited-state laser shows a much larger sensitivity to optical feedback, with a more complex route to chaos, and a first destabilization point occurring at lower feedback strengths than for a comparable ground-state laser, which remains almost unaffected.

Comparison of optical feedback dynamics of InAs/GaAs quantum-dot lasers emitting solely on ground or excited states

We experimentally compare the dynamics of InAs/GaAs quantum dot lasers under optical feedback emitting exclusively on ground states (GSs) or excited states (ESs). By varying the feedback parameters and putting focus either on their short or long cavity regions, various periodic and chaotic oscillatory states are found. The GS laser is shown to be more resistant to feedback, benefiting from its strong relaxation oscillation damping. In contrast, the ES laser can easily be driven into complex dynamics. While the GS laser is of importance for the development of isolator-free transmitters, the ES laser is essential for applications taking advantages of chaos.

Semiconductor quantum dot lasers epitaxially grown on silicon with low linewidth enhancement factor

This work reports on the ultra-low linewidth enhancement factor (αH-factor) of semiconductor quantum dot lasers epitaxially grown on silicon. Owing to the low density of threading dislocations and resultant high gain, an αH value of 0.13 that is rather independent of the temperature range (288 K–308 K) is measured. Above the laser threshold, the linewidth enhancement factor does not increase extensively with the bias current which is very promising for the realization of future integrated circuits including high performance laser sources.

Linewidth Rebroadening in Quantum Dot Semiconductor Lasers

We investigate the interplay between linewidth and

Efficiency of four-wave mixing in injection-locked InAs/GaAs quantum-dot lasers

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Self-referenced technique for monitoring and analysing the non-linear dynamics of semiconductor lasers

-factor in quantum dot lasers using experimental data and a minimal quantum dot laser rate equation model. The rebroadening of the laser linewidth found experimentally at high injection currents is explained by analytical means and traced back to nonlinear scattering processes. Important differences of the pump current dependent linewidth evolution of quantum dot lasers are highlighted especially if compared to conventional laser devices. Furthermore, we provide a scheme to extract the amplitude-phase coupling as well as effective carrier scattering rates with standard characterization techniques, i.e., linewidth, light versus injected pump current and modulation response measurements.

Recent advances in InAs/GaAs quantum dot lasers with short optical feedback

Frequency conversion using highly non-degenerate four-wave mixing is investigated in optically injection-locked InAs/GaAs quantum-dot Fabry-Perot lasers with different ridge waveguide dimensions. Conversion efficiencies up to -16 dB with a large optical signal-to-noise ratios of 36 dB are unveiled. The conversion bandwidth is extended to 4 THz with a quasi-symmetrical response between up- and down-converted signals.