Wavelength-dependent femtosecond pulse amplification in wideband tapered-waveguide quantum well semiconductor optical amplifiers

This paper reports a new model for strained quantum well lasers, which are based on the quantum well transmission line modeling method where effects of both carrier transport and carrier heating have been included. We have applied this new model and studied the effect of carrier transport on the output waveform of a strained quantum well laser both in time and frequency domains. It has been found that the carrier transport increases the turn-on, turn-off delay times and damping of the quantum well laser transient response. Also, analysis in the frequency domain indicates that the carrier transport causes the output spectrum of the quantum well laser in steady state to exhibit a redshift which has a narrower bandwidth and lower magnitude. The simulation results of turning-on transients obtained by the proposed model are compared with those obtained by the rate equation laser model. The new model has also been used to study the effects of pump current spikes on the laser output waveforms properties, and it was found that the presence of current spikes causes (i) wavelength blueshift, (ii) larger bandwidth, and (iii) reduces the magnitude and decreases the side-lobe suppression ratio of the laser output spectrum. Analysis in both frequency and time domains confirms that the new proposed model can accurately predict the temporal and spectral behaviors of strained quantum well lasers.

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“…is obtained by adding all outputs of parallel Q-TLM units multiplied by the gain coefficient 0 G given below [22]:…”

Section: A Theoretical Model Descriptionmentioning

confidence: 99%

“…where, 0 E is the energy of a photon, 1 T is the lifetime of the exited state. The characteristic admittance values and the weight coefficients of the parallel QW-TLM units in the spontaneous emission source are given in Ref [22]. The output electric filed ) , ( 2t z E can be expressed as…”

Section: A Theoretical Model Descriptionmentioning

confidence: 99%

Transmission line model for strained quantum well lasers including carrier transport and carrier heating effects

Xia

Ghafouri‐Shiraz

2016

Appl. Opt.

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“…Semiconductor optical amplifiers (SOAs) have become the key devices in the integrated optical systems and passive optical networks (PON) for the advantages of high energy-efficient, wide operational bandwidth and small size [1][2][3][4][5][6][7]. However, the gain saturation mechanism in SOAs causes the distortion of the amplified output pulse.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, it is significantly important to choose a suitable bias current for high-speed pulse train amplification in SOA. The pulse amplification in semiconductor optical amplifiers has been theoretical analyzed using the rate equations [20][21], the systematical analytical method [22] and the transmission line modelling method [6]. However, these theoretical analyses have made assumptions to obtain the analytic solutions or to aid the numerical computation, which has restricted the accuracy of the simulation results.…”

Section: Introductionmentioning

confidence: 99%

High-speed pulse train amplification in semiconductor optical amplifiers with optimized bias current

et al. 2017

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In this paper we have experimentally investigated the optimized bias current of semiconductor optical amplifiers (SOAs) in order to achieve the high-speed input pulse train amplification with high gain and low distortion. Variations of the amplified output pulse duration with the amplifier bias currents have been analyzed and it is found that compared with the input pulse duration, the amplified output pulse duration is broadened; as the SOA bias current decreases from the high level (larger than the saturated bias current) to the low level, the broadened pulse duration of the amplified output pulse initially decreases slowly and then rapidly. Based on the analysis, an optimized bias current of SOA for high-speed pulse train amplification is introduced. The relations between the SOA optimized bias current and the parameters of the input pulse train (pulse duration, power and repetition rate) are experimentally studied. It is found that the larger input pulse duration, the lower input pulse power or the higher repetition rate can lead to a larger SOA optimized bias current, which corresponds to a larger optimized SOA gain. The effects of assist light injection and different amplifier temperatures on the SOA optimized bias current are studied and it is found that assist light injection can effectively increase the SOA optimized bias current while SOA has the lower optimized bias current at the temperature 20°C than that at other temperatures.

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“…From the theory, both intersubband transitions and interband transitions can be modelled by the Q-TLM method. This method adopts topological structures to describe the dynamic photon-electron interaction processes, and has been successfully employed to model quantum well devices in the near-infrared wavelength range [28]. This approach is adapted from transmission line matrix (TLM) theory, which was initially used to solve field equations and describe microwave propagation in microwave circuits [29][30].…”

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confidence: 99%

Quantum Transmission Line Modeling and Experimental Investigation of the Output Characteristics of a Terahertz Quantum Cascade Laser

Xia

Rubino

et al. 2020

IEEE Trans. THz Sci. Technol.

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We describe a new approach to modelling the optoelectronic properties of a terahertz-frequency quantum cascade laser (THz QCL) based on a quantum transmission line modelling (Q-TLM) method. Parallel quantum cascade transmission line modelling units are employed to describe the dynamic optical processes in a nine-well THz QCL in both the time and frequency domains. The model is used to simulate the current-power characteristics of a QCL device and good agreement is found with experimental measurements, including an accurate prediction of the threshold current and emitted power. It is also confirmed that the Q-TLM model can accurately predict the Stark-induced blue shift of the emission spectrum of the THz QCL with increasing injection current. Furthermore, we establish the new Q-TLM model to describe the properties of a THz QCL device incorporating a photonic lattice patterned on the laser ridge, by linking the transmission line structure to each scattering module. The predicted effects of the lattice structure on the steadystate emission spectra of the THz QCL, including the side-mode suppression, are found to be in good agreement with experimental results. Our Q-TLM modelling approach is a promising tool for the future design of THz QCLs and analysis of their temporal and spectral behaviors.

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Wavelength-dependent femtosecond pulse amplification in wideband tapered-waveguide quantum well semiconductor optical amplifiers

Cited by 10 publications

References 18 publications

Transmission line model for strained quantum well lasers including carrier transport and carrier heating effects

Transmission line model for strained quantum well lasers including carrier transport and carrier heating effects

High-speed pulse train amplification in semiconductor optical amplifiers with optimized bias current

Quantum Transmission Line Modeling and Experimental Investigation of the Output Characteristics of a Terahertz Quantum Cascade Laser

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