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Journal ArticleDOI

Effect of carrier diffusion in oxidized vertical-cavity surface-emitting lasers determined from lateral spontaneous emission

19 May 1997-Applied Physics Letters (American Institute of Physics)-Vol. 70, Iss: 20, pp 2652-2654
TL;DR: In this article, the effect of carrier diffusion on threshold current was studied quantitatively for the oxide-aperturbed 780 nm vertical-cavity surface-emitting lasers (VCSEL) from the measured spontaneous emission.
Abstract: The effect of carrier diffusion on threshold current is studied quantitatively for the oxide-aperturbed 780 nm vertical-cavity surface-emitting lasers (VCSEL) from the measured spontaneous emission. The oxide aperture size of 2–10 μm is prepared and characterized. The diffusion coefficient of 4.6 cm2/s and the nonradiative recombination coefficient of 6.8×107/s are obtained using the independence of the nonradiative recombination coefficient on the laser aperture size. The contribution of carrier diffusion loss is 42% of the threshold current for the 2 μm VCSEL. The relative contribution of the diffusion becomes smaller for the larger devices as is expected.
Citations
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Journal ArticleDOI
TL;DR: The results indicate significant improvement of the proposed k-means 2D SD without training using prior-known sequences, which can be realized by additional consideration of nonlinearity, level-dependent noise and ISI.
Abstract: In this work, we proposed an intelligent 2-dimensional soft decision (2D SD) enabled by k-means clustering, for vertical-cavity surface-emitting laser (VCSEL) based 112-Gbps PAM-4 and PAM-8 optical interconnection. At high modulation speed, VCSEL based link suffers from severe level nonlinearity, level-dependent noise and inter-symbol interference (ISI). For characterizing the above-mentioned three distortions, 2D signaling is performed through time-slotted mapping of PAM. Without extra requirement of Monte Carlo approach, channel conditional probability density function (PDF) can be intelligently estimated using inline data, thanks to 2D k-means machine learning. Thus, improved precision of log likelihood ratio (LLR) can be realized by additional consideration of nonlinearity, level-dependent noise and ISI. Both simulations and experiments have been carried out for proof-of-concept investigations on VCSEL and multimode fiber (MMF) links. 112-Gbps PAM-4 and PAM-8 signaling have been experimentally realized using a commercial-product-level VCSEL with 100-m MMF transmission. The results indicate significant improvement of the proposed k-means 2D SD without training using prior-known sequences.

17 citations


Cites background from "Effect of carrier diffusion in oxid..."

  • ...According to [40], error-free GMI threshold is 1....

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  • ...carrier lifetime has been theoretically investigated in [22], [40]....

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Proceedings ArticleDOI
08 Sep 2004
TL;DR: In this article, the authors investigated a simpler solution based on a standard VCSEL array, using in plane optical waveguiding of spontaneous emission in the intrinsic central zone of the devices.
Abstract: VCSELs (Vertical Cavity Surface Emitting Lasers) are nowadays more and more exploited in optoelectronic applications, monitoring their lasing power in a compact and low cost manner becomes crucial. To collect and control the output light, an external photodetector associated with an optical microlens array can be used. Integrated solutions based on the use of a bulk or QW photodetection section added in single-or double-cavity structures have also been proposed. Here, we have investigated a simpler solution based on a standard VCSEL array. Light emitted by a VCSEL has been electrically detected by adjacent VCSELs located in the same array, using in plane optical waveguiding of spontaneous emission in the intrinsic central zone of the devices. We show that the detected photocurrent can be related to the power of the emitting VCSEL. Signal intensity has been studied as a function of VCSELs distance. This method could lead to a more efficient way to monitor VCSEL emission.

12 citations


Cites methods from "Effect of carrier diffusion in oxid..."

  • ...The sample was cleaved and the output was coupled to an optical fiber [18] which was carefully butted onto the facet, and signal was displayed by means of a spectrum analyzer....

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Journal ArticleDOI
TL;DR: In this article, a quantum structure intermixing from the lateral direction of the mesa sidewall is proposed as an improvement method of the performance of vertical-cavity surface-emitting lasers (VCSELs).
Abstract: A quantum structure intermixing from the lateral direction of the mesa sidewall is proposed as an improvement method of the performance of vertical-cavity surface-emitting lasers (VCSELs). Threshold current reduction of 70%, a differential quantum efficiency increase of 75% and a two times increase in output power were achieved by suppression of the surface recombination current and by the carrier confinement in the post-type VCSEL.

10 citations

Journal ArticleDOI
TL;DR: In this paper, the authors show that a rotation of the polarization direction by up to 90 degrees when the pump rate approaches the lasing threshold is possible for broad-area vertical-cavity surface-emitting lasers.
Abstract: For highly divergent emission of broad-area vertical-cavity surface-emitting lasers, a rotation of the polarization direction by up to ${90}^{\ifmmode^\circ\else\textdegree\fi{}}$ occurs when the pump rate approaches the lasing threshold. Well below threshold the polarization is parallel to the direction of the transverse wave vector and is determined by the transmissive properties of the Bragg reflectors that form the cavity mirrors. In contrast, near-threshold and above-threshold emission is more affected by the reflective properties of the reflectors and is predominantly perpendicular to the direction of transverse wave vectors. Two qualitatively different types of polarization transition are demonstrated: an abrupt transition, where the light polarization vanishes at the point of the transition, and a smooth transition, where it is significantly nonzero during the transition.

9 citations

Journal ArticleDOI
TL;DR: In this article, the selfconsistent optical-electrical-thermal gain model of the oxide-confined long-wavelength 1.3-μm quantum-dot (InGa)As/GaAs diode laser is demonstrated.
Abstract: In the paper, the self-consistent optical–electrical–thermal-gain model of the oxide-confined long-wavelength 1.3-μm quantum-dot (InGa)As/GaAs diode laser is demonstrated. The model has been applied to analyse room-temperature (RT) threshold-operation characteristics of the advanced laser of this kind. It may be used to describe physics of the above arsenide-based diode lasers to better understand their threshold performance and finally to optimize their structures.

8 citations

References
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Book
01 Jan 1993
TL;DR: In this article, the origin of Quantum Wells and the Quantum Well Laser is discussed and the effect of intrinsic relaxation on optical spectra is discussed, as well as the properties of Quantum Well Lasers.
Abstract: Foreword: The Origin of Quantum Wells and the Quantum Well Laser. Optical Gain in III-V Bulk and Quantum Well Semiconductors. Intraband Relaxation Effect on Optical Spectra. Multiquantum Well Lasers: Threshold Considerations. Ultra-Low Threshold Quantum Well Lasers. Dynamics of Quantum Well Lasers. Single Quantum Well Ingaasp and Algaas Lasers: A Study of Some Peculiarities. Valence Band Engineering in Quantum Well Lasers. Strained Layer Quantum Well Heterostructure Lasers. Algainp Quantum Well Lasers. Quantum Wire Semiconductor Lasers. Chapter References. Index.

559 citations

Journal ArticleDOI
TL;DR: In this paper, the InGaAs single quantum well vertical-cavity surface-emitting laser with an intracavity p-contact fabricated by selective oxidation of AlAs and distributed Bragg reflectors composed of binary materials (AlAs/GaAs).
Abstract: The authors report InGaAs single quantum well vertical-cavity surface-emitting lasers with an intracavity p-contact fabricated by selective oxidation of AlAs and distributed Bragg reflectors composed of binary materials (AlAs/GaAs). Record low threshold currents of 8.7 µA in ~3 µm square devices and 140 µA in 10 µm square devices with maximum output powers over 1.2 mW are achieved.

357 citations

Journal ArticleDOI
TL;DR: In this article, an index-guided InGaAs/GaAlAs vertical-cavity surface-emitting laser with a native oxide confinement structure has been proposed and fabricated.
Abstract: An index-guided InGaAs/GaAlAs vertical-cavity surface-emitting laser with a native oxide confinement structure has been proposed and fabricated. A record threshold current of 70 µA was achieved with a 5 µm-diameter core device. The proposed structure provides strong electrical and optical confinements. Also a reduction in nonradiative recombination and an improvement in the thermal resistance can be expected.

179 citations

Journal ArticleDOI
TL;DR: In this paper, the authors characterized half-wavelength vertical-cavity surface-emitting laser defined by a nativeoxide ring in which the native oxide is 200 A from the single quantum well.
Abstract: Data are presented characterising half-wavelength vertical-cavity surface-emitting lasers defined by a native-oxide ring in which the native oxide is 200 A from the single quantum well. The lowest threshold is achieved with a 2 µm square active region, with a minimum threshold current of 91 µA continuous-wave at room temperature.

127 citations

Journal ArticleDOI
TL;DR: In this article, the authors report the high yield fabrication and reproducible performance of selectively oxidized vertical-cavity surface emitting lasers. Butler et al. showed that linear oxidation rates of AlGaAs without an induction period allows reproducible fabrication of buried oxide current apertures within monolithic distributed Bragg reflectors.
Abstract: We report the high yield fabrication and reproducible performance of selectively oxidized vertical-cavity surface emitting lasers. We show that linear oxidation rates of AlGaAs without an induction period allows reproducible fabrication of buried oxide current apertures within monolithic distributed Bragg reflectors. The oxide layers do not induce obvious crystalline defects, and continuous wave operation in excess of 650 h has been obtained. The high yield fabrication enables relatively high laser performance over a wide wavelength span. We observe submilliamp threshold currents over a wavelength range of up to 75 nm, and power conversion efficiencies at 1 mW output power of greater than 20% over a 50-nm wavelength range. >

126 citations