A semiconductor optical amplifier comprising highly stacked InAs quantum dots fabricated using the strain-compensation technique

Akahane, Kouichi; Yamamoto, Naokatsu; Umezawa, Toshimasa; Kanno, Atsushi; Kawanishi, Tetsuya

doi:10.7567/jjap.53.04eg02

Cited by 13 publications

(12 citation statements)

References 49 publications

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“…The polarization dependence of the gain was eliminated by growing closely stacked columnar Qdots, thus favouring vertical coupling and leading to polarization insesitive SOA gain characteristics [156]. This work was soon followed by various deomstrations of the gain characteritics of InAs/InP Qdots SOA [157,158]. For instance Kim et al [159] showed a chip gain as high as 37 dB and maximum saturation output power 17.2 dBm at 950 mA from 3×3000 µm 2 long device after determining the coupling-loss (14.4 dB) and performing the fiber-to-fiber gain (22.5 dB) measurements.…”

Section: Broad Gainmentioning

confidence: 99%

Self-assembled InAs/InP quantum dots and quantum dashes: Material structures and devices

Khan

Ooi

2014

Progress in Quantum Electronics

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The advances in lasers, electronic and photonic integrated circuits (EPIC), optical interconnects as well as the modulation techniques allow the present day society to embrace the convenience of broadband, high speed internet and mobile network connectivity. However, the steep increase in energy demand and bandwidth requirement calls for further innovation in ultra-compact EPIC technologies. In the optical domain, innovation in the laser technologies beyond the current quantum well (Qwell) based laser technologies are already taking place and presenting very promising results. Homogeneously grown quantum dot (Qdot) lasers, can serve in the future energy saving information and communication technologies (ICT) as the work-horse for transmitting information through optical fiber. The encouraging results in the zero-dimensional (0D) structures emitting at 980 nm, in the form of vertical cavity surface emitting laser (VCSEL), are already operational at low threshold current density and capable of 40 Gbps error-free transmission at 108 fJ/bit. Eventual achievements for lasers operating in the O-, C-, L-, U-bands, and beyond will eventually lay the foundation for green ICT. On the hand, the inhomogeneously grown quasi 0D quantum dash (Qdash) lasers are brilliant solutions for potential broadband connectivity in server farms or access network. A single broadband Qdash laser operating in the stimulated emission mode can replace tens of discrete narrow-band lasers in dense wavelength division multiplexing (DWDM) transmission thereby further saving energy, cost and footprint. In this article, we review the progress of both Qdots and Qdash devices based on the InAs/InGaAlAs/InP and InAs/InGaAsP/InP material systems, from the angles of growth and device performance.2

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Section: Broad Gainmentioning

confidence: 99%

Self-assembled InAs/InP quantum dots and quantum dashes: Material structures and devices

Khan

Ooi

2014

Progress in Quantum Electronics

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“…We also showed their application in LDs and SOAs on InP(311)B substrates . So far, for the QD‐SOA, we indicated a high gain of more than 25 dB for a device length of 2 mm and a clear eye‐pattern waveform of a nonreturn‐to‐zero signal of 50 Gb s −1 . However, we have not investigated pulse responses of higher than 50 GHz for highly stacked QD‐SOAs grown on an InP(311)B substrate using the strain compensation technique.…”

Section: Introductionmentioning

confidence: 91%

“…The strain compensation technique is the method that balances the strain energy between QDs and the embedded InGaAlAs layer, whose lattice constant is made slightly smaller than that of an InP substrate. This enables the fabrication of highly stacked QD layers on an InP substrate . More detail information about the growth and strain compensation technique has been reported in the Ref.…”

Section: Device Structurementioning

confidence: 99%

Dynamic characteristics of 20‐layer stacked QD‐SOA with strain compensation technique by ultrafast signals using optical frequency comb

Matsumoto

Akahane

Sakamoto

et al. 2016

Physica Status Solidi (a)

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This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.In this article, we evaluated the static and dynamic characteristics of 20-layer stacked quantum dot semiconductor optical amplifiers (QD-SOAs) grown on an InP(311)B substrate with a strain compensation technique by ultrafast signals using an optical frequency comb. The gain peak wavelength of the fabricated QD-SOA was 1520 nm, and a maximum gain of approximately 15.8 dB was obtained when the injection current was 350 mA. By using optical bit rate multiplier modules, an optical pulse, which was generated by the use of the optical frequency comb, was multiplexed. We observed the dynamic behavior of the QD-SOA with the pulse trains. The minimum interval between pulses was 4.2 ps, and we measured using an optical sampling oscilloscope. It was found the QD-SOA could respond to ultrafast pulses that were equivalent to the signals of 220 Gb s À1 class speed without any large pattern distortions. In addition, we could obtain a rather clear optical pulse waveform. We also estimated the gain recovery time of the QD-SOA to be 6.0 ps by using a pump probe-like method. One of the reasons that the fabricated QD-SOA could respond to ultrafast signals was its ultrashort gain recovery time.

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“…In contrast, quantum dot (QD) is an extremely promising material or structure for high‐performance optical devices owing to its delta function‐like density of states . Several groups have reported that laser diodes (LDs), semiconductor optical amplifiers (SOAs), and photodiodes (PDs) that utilize QD structures have displayed high performance in terms of high thermal stability, low threshold, wide operation bandwidth, and ultra‐fast response . In our previous studies, employing the strain compensation technique, we successfully fabricated QD‐SOAs and QD‐LDs in the 1.55 μm‐band grown on an InP(311)B substrate, which enables highly stacked QD structure up to more than 300 layers, and demonstrated that ultra‐fast operation over 220 Gb/s class speed of QD‐SOA and a characteristic temperature ( T 0 ) of more than 2000 K of QD‐LD utilizing a delta‐doping method of p‐dopants, could be achieved.…”

Section: Introductionmentioning

confidence: 99%

Influence and its Optimal Design of Number of Stacked Layer in Quantum‐Dot Lasers

Matsumoto

Akahane

Umezawa

et al. 2018

Phys. Status Solidi A

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This study deals with quantum dot laser-diodes (QD-LDs). The influence of highly stacked quantum dot (QD) layers in QD-LDs on the laser characteristics through experiments and numerical calculations is reported and the optimal design for the QD-stacked layer numbers is indicated. By introducing new concepts, the previously reported carrier rate equations are modified in order to include the effect of the stacked QD layer numbers. It is confirmed that the threshold current and slope efficiency between fabricated and calculated QD-LDs are almost the same. Considering low threshold current, high output power, and high slope efficiency, the optimal design of the QD-stacked layer number in our QD-LD is supposed to be 14. With this, a threshold current of 38 mA, maximum optical output power of 22.7 mW, and slope efficiency of 0.28 W/A can be obtained from the QD-LD. equipment such as industrial equipment and sensors via the Internet, Machine to Machine (M2M) technology, which shares information between industrial machines, and the edge computing, which instantaneously controls the IoT equipment in real time with edge routers, have attracted attention as crucial techniques in the field of information, communication, and industries. In order to establish such technologies, it is essential not only to develop the technologies of upper layers such as application and architecture, but also to further improve the communication capacity of the core/metro optical communication network, optical/wireless communication in access network, and the network in data centers.The traffic growth of data centers and access networks including wireless links is especially higher than in other networks [1] because the connection from the Internet to individual users is mostly based on wireless communications. Therefore, more convenient communication and connectivity are expected in the next generation communication services such as beyond 5G mobiles. In order to realize such a large capacity data center and access network, novel photonic integrated circuits (PICs), which enable ultra-fast and large capacity communication, are indispensable, [2][3][4][5][6][7][8][9][10][11][12][13] besides improving communication capacity owing to newly developed modulation and system technologies. [14][15][16][17][18] In addition, characteristics such as low cost and energy consumption, and thermal stability at high temperatures are essential if the PICs are to be integrated with other electronic devices such as large-scale integrated circuits (LSIs). The temperature stability is especially important because heat diffused from LSIs causes a high surrounding temperature, which is detrimental to the operating conditions of PICs.In contrast, quantum dot (QD) is an extremely promising material or structure for high-performance optical devices owing to its delta function-like density of states. [19] Several groups have reported that laser diodes (LDs), [20][21][22][23] semiconductor optical amplifiers (SOAs), [24][25][26] and photodiodes (PDs) [27] that utilize...

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A semiconductor optical amplifier comprising highly stacked InAs quantum dots fabricated using the strain-compensation technique

Cited by 13 publications

References 49 publications

Self-assembled InAs/InP quantum dots and quantum dashes: Material structures and devices

Self-assembled InAs/InP quantum dots and quantum dashes: Material structures and devices

Dynamic characteristics of 20‐layer stacked QD‐SOA with strain compensation technique by ultrafast signals using optical frequency comb

Influence and its Optimal Design of Number of Stacked Layer in Quantum‐Dot Lasers

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