Novel design scheme for high-speed MQW lasers with enhanced differential gain and reduced carrier transport effect

Matsui, Yasuhiro; Murai, Hitoshi; Arahira, S.; Ogawa, Y.; Suzuki, Akira

doi:10.1109/3.736104

Cited by 18 publications

(9 citation statements)

References 28 publications

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“…While this increased the modulation bandwidth at a given bias current, it gave little improvement in the K-factor and f max (0.26 ns and 34 GHz, respectively) because of corresponding increases in the non-linear gain coefficient. However, periodic p-type doping within the stop bands of the active layer both enhanced g 0 and decreased the K-factor in accordance with earlier predictions [15,27,[38][39][40][41][42]. The maximum possible intrinsic bandwidth was estimated to be 63 GHz (K = 0.14 ns and ε = 4.6 × 10 −17 cm 3 ).…”

Section: Quantum-well Lasers and Carrier-transport Effectssupporting

confidence: 88%

“…Early theoretical studies [16] predicted a twofold or threefold increase for multi-quantumwell (MQW) lasers compared to bulk lasers of the same material composition and geometry. Experimental results confirmed this [26,27]. Further experimental [21] and theoretical [28] investigations have shown that g 0 is strongly dependent on the number of quantum wells.…”

Section: Quantum-well Lasers and Carrier-transport Effectssupporting

confidence: 73%

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Fast phenomena in semiconductor lasers

2000

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Although diode lasers are almost ideal sources for ultrahigh-speed data communication systems, system performance remains critically dependent on the quality of the optical pulses that they generate. Uniquely among lasers, the output power can be modulated directly by modulating the diode current. However, this leads to relaxation oscillations and a roll-off at high frequencies that is superimposed on the frequency response of the drive circuit. This is limited by parasitics and maximum modulation frequencies range from 1 to 70 GHz, depending on the type of laser and its packaging. The higher values are obtained with short cavity lengths and tight optical confinement, the highest frequencies being achieved in vertical-cavity devices. Modulation bandwidth is usually limited by circuit parasitics, device heating and the maximum power-handling capability of the laser facets.The generation of picosecond and femtosecond pulses demands special techniques and three-gain switching, Q-switching and mode locking-are discussed in detail, with their relative advantages and disadvantages compared. Very short pulses inherently contain a significant spread of wavelengths and their generation requires the optical gain in the laser medium to extend across that wavelength range. While diode lasers satisfy this criterion better than many other types, the effect of gain non-linearities and carrier-transport effects prevent the Fourier-transform limit from being achieved in practice. As a result, external pulse-compression techniques, which exploit the detailed temporal and spectral properties of the laser pulses, such as frequency chirping, self-phase modulation and group velocity dispersion, are becoming more important, and diode lasers are increasingly challenged as primary sources by compact, efficient, diode-pumped solid-state lasers.The paper summarizes the levels of maximum pulse power and minimum duration that have been achieved using the various techniques.

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Section: Quantum-well Lasers and Carrier-transport Effectssupporting

confidence: 88%

Section: Quantum-well Lasers and Carrier-transport Effectssupporting

confidence: 73%

Fast phenomena in semiconductor lasers

2000

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“…A high-speed DML typically requires a larger differential gain which can be achieved with proper MQW design by optimizing the material composition and number of wells. For example, by using 20-well InGaAlAs-InGaAsP straincompensated MQWs, >14x10 -20 m 2 differential gain can be obtained [42]. The TLLM modeling adopted here does not include the simulation of gain spectrum of the MQW.…”

Section: Simulation Resultsmentioning

confidence: 99%

Improvement on Direct Modulation Responses and Stability by Partially Corrugated Gratings Based DFB Lasers With Passive Feedback

2021

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DFB lasers with ultrashort cavities or integrated DFB lasers with passive waveguide reflectors are frequently proposed to realize directly modulated lasers (DMLs) for carrying ultrahigh data rate signals. The former suffers from poor heatsink and laser cleavage yield, while the single-mode stability of the latter scheme is seldom addressed. The mode selection and device performance of a DFB laser is well known to be very sensitive to the facet reflection and external optical feedback. The DFB lasers with partial corrugated gratings and passive feedback (PCG-PFL) are proposed here to overcome the challenging issues for the aforementioned two schemes. With PCG structure, the DFB lasers can maintain high single-mode yield (SMY) even with a high-reflection-coating on the rear facet and strong reflection from the integrated passive section. This provides the robustness in applying the integrated passive reflector to reshape the modulation response or to enhance the 3-dB bandwidth by using the photon-photon resonance (PPR) effect. By designing the PCG-PFL to have 150-m long laser section, 50-m long passive section, and 30% front-facet reflectivity, it can have about 86% of SMY, reduced resonant peak in the intensity modulation response, and reduced waveform overshoot and undershoot for transmitting 56-Gbaud/s PAM-4 signals. By using a longer passive reflector, enhanced bandwidth can be achieved by the PPR effect.

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“…This phenomenon is known as the carrier transport effect, and it adversely affects the development of monolithic GaN-based LEDs, as does the difficulty of growing InGaN with high indium content. [47] In addition to structures using InGaN/GaN MQWs, several other methods to produce white light based on monolithic GaN LEDs have been tried. InGaN/GaN MQWs that incorporated quantum dots capable of amber emission with two dominant emission peaks spanning from 1.7 eV to 2.2 eV were also unsuccessful attempts to circumvent the uniform carrier injection problem.…”

Section: Monolithic Gan-based White Ledsmentioning

confidence: 99%

Phosphor-free white light-emitting diodes

Guo

Liu

et al. 2015

Chinese Phys. B

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The multiple color-matching schemes that could improve the color rendering index for phosphor-free white LEDs are discussed. Then we review a few of the recent research directions for phosphor-free white LEDs, which include the development of monolithic GaN-based white LEDs and hybrid integrated GaN-based and AlGaInP-based white LEDs. These development paths will pave the way toward commercial application of phosphor-free white LEDs in the coming years.

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Novel design scheme for high-speed MQW lasers with enhanced differential gain and reduced carrier transport effect

Cited by 18 publications

References 28 publications

Fast phenomena in semiconductor lasers

Fast phenomena in semiconductor lasers

Improvement on Direct Modulation Responses and Stability by Partially Corrugated Gratings Based DFB Lasers With Passive Feedback

Phosphor-free white light-emitting diodes

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