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Vertical-Cavity Lasers, Technologies for a Global Information Infrastructure, WDM Components Technology, Advanced Semiconductor Lasers and Applications, Gallium Nitride Materials, Processing, and Devi

Date 11-13 Aug. 1997

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Displaying Results 1 - 25 of 170
  • 1997 digest of the ieee/leos summer topical meeting: vertical-cavity lasers/technologies for a global information infrastructure/wdm components technology/advanced semiconductor lasers and applications/gallium nitride materials, processing, and devices [front matter and table of contents]

    Publication Year: 1997
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    Freely Available from IEEE
  • New materials and process technologies for vertical cavity surface emitting lasers

    Publication Year: 1997 , Page(s): 3 - 4
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    Surface emitting (SE) lasers or vertical cavity SE lasers (VCSELs) are now considered to be utilized as devices in various optical systems such as networks, optical parallel interconnects, laser printers, and ultra-parallel optoelectronics. The author reviews the progress of VCSELs for a wide range of optical spectra based on GaInAsP, GaIn(N)As, GaAlAs, AlGaInP, ZnSe, GaN, and related compounds and discusses some new aspects. The materials for semiconductor lasers now cover most III-V compound alloys. The problems which should be seriously considered for making vertical cavity SE lasers are: (A) Highly reflective and transparent DBRs; (B) Minimization of optical losses; (C) Maximization of optical-field and gain overlap; (D) Electrode-formation to reduce the resistivity for high efficiency operation; and (E) Heat sinking for high temperature and high power operation. The present technical status of VCSELs is reviewed in various spectral regions (a) 1550 nm: The epitaxial bonding of GaInAsP-InP/GaAs-AlAs mirrors exhibit CW operation up to 64 /spl deg/C. Further development may be necessary to compete with edge emitters employing DFB and spotsize transformer (SST) structures. (b) 1300 nm: A buried structure is utilized together with a thermally conductive MgO/Si mirror demonstrating the first room temperature (RT) CW operation. The highest operation is up to 34 /spl deg/C. View full abstract»

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  • VCSEL research, development and applications at Honeywell

    Publication Year: 1997 , Page(s): 5 - 6
    Cited by:  Papers (1)
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    The recent commercialization of VCSELs has opened up the possibility of VCSELs in numerous evolving technologies. Many of the present application include optical links, LED and CD replacements in printing, storage, duplication, and sensors. As VCSEL components have exhibited "silicon-like" manufacturability, the ubiquity of VCSEL-based optoelectronic circuits appears bright. VCSEL-array-based smart pixel processors have the potential to enable ultrafast interconnect-intensive processors. VCSELs and VCSEL arrays appear promising between, and even within, computers, backplanes, and multichip modules (MCMs). Tke possibility of RF-VCSELs is speculated. Beyond present "commercial-grade" development, there have been a number of exciting research advancements in decreasing the threshold currents and speed of VCSELs. This may enable even lower power dissipation, higher speeds, and extensions to arrays, and expedite extensions to other spectral regions. View full abstract»

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  • Future prospects of VCSELs: industrial view

    Publication Year: 1997 , Page(s): 7 - 8
    Cited by:  Papers (2)
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    Research and development of vertical-cavity surface-emitting lasers (VCSELs) has made rapid progress in recent years. VCSEL array link modules have been developed with increasing speed by American consortiums such as OETC and POLO. On the other hand, high-performance VCSELs, such as low-threshold or high wall-plug efficiency ones, are being developed using AlAs selective oxidation. With this background, we describe the future prospects of VCSELs from an industrial viewpoint. The topics discussed include: reliability; low-voltage and low-power operations; and module assembly techniques. The authors conclude that the VCSEL is a promising device for achieving optical interconnections. View full abstract»

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  • Towards microcavity vertical cavity lasers: aperture and cavity design for high efficiency and low threshold

    Publication Year: 1997 , Page(s): 9 - 10
    Cited by:  Papers (1)
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    We have fabricated /spl lambda/=980 nm vertical cavity lasers with a tapered oxide profile which is produced by placing a 10.5 nm layer of AlAs within the first p-mirror layer which is a 230 nm (3/4 /spl lambda/) thick Al/sub 0.9/Ga/sub 0.1/As layer. We have plotted the scattering loss (as determined from the differential efficiency of tapered and abrupt apertured devices) vs. the radius of the opening in the oxide. Simulations of 980 nm AlAs/GaAs VCLs with quarter-wave thick apertures tapered over more than /spl sim/3 /spl mu/m show they have no excess loss. Although for a given mode size, scattering losses from such a "long" tapered aperture are much lower than for an abrupt aperture, the apertures close off before the mode size can shrink below a l/e/sup 2/ radius of /spl sim/1.5 /spl mu/m. Tapering quarter-wave thick apertures over a shorter distance (/spl sim/1 /spl mu/m) not only lowers scattering losses at the small aperture sizes, but also confines the mode to the smallest sizes. Ultimately, the smallest size mode confined by a single aperture (obtained by using a parabolic (ideal lens) profile) is limited by the angular stop-band of the DBR mirror. For 980 nm VCLs with AlAs/GaAs mirrors the smallest mode size has a l/e/sup 2/ radius of /spl sim/0.6 /spl mu/m. To reduce this size further one would need to turn to dielectric mirrors or use multiple apertures which are thin so as not to introduce additional losses. View full abstract»

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  • Uniform and high power selectively oxidized 8/spl times/8 VCSEL array

    Publication Year: 1997 , Page(s): 11 - 12
    Cited by:  Papers (1)
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    We report the uniform characteristics of an 8/spl times/8 individually addressable high power 850 nm VCSEL array. To achieve 2-dimensional array uniformity, both growth and fabrication uniformity issues must be considered. The VCSEL wafer is grown by metalorganic vapor phase epitaxy using an EMCORE reactor designed and calibrated for high growth uniformity. The distributed Bragg reflector (DBR) mirrors are composed of Al/sub 0.16/Ga/sub 0.84/As/Al/sub 0.94/Ga/sub 0.06/As layers with continuous compositional grading at the interfaces. In the 6 DBR periods on each side of the optical cavity the doping profile is decreased to as low as 5/spl times/10/sup 17/ cm/sup -3/ for reduced optical absorption. This design enhances the output power at the expense of relatively higher threshold voltage. View full abstract»

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  • High efficiency 850 nm wavelength GaAs VCSELs

    Publication Year: 1997 , Page(s): 13 - 14
    Cited by:  Papers (1)
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    We report on the optimization of selectively oxidized VCSELs incorporating GaAs quantum wells for multimode emission around 850 nm wavelength. Devices with active diameters between 5 and 12 /spl mu/m show maximum wallplug efficiencies exceeding 55%. Continuous wave operation is achieved up to +185/spl deg/C and the maximum single-mode output power corresponding to 30 dB sidemode suppression ratio is increased to 2.25 mW with layer structures exhibiting reduced index guiding of the optical wave. View full abstract»

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  • 850 nm VCSEL's with buried Al/sub x/O/sub y/ current apertures

    Publication Year: 1997 , Page(s): 15 - 16
    Cited by:  Papers (1)
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    Vertical cavity surface emitting lasers (VCSELs) with 850 nm emission wavelength are of great interest for short haul optical interconnections because of the compatibility with standard Si or GaAs based receivers. Low current and high wall plug efficiency VCSELs are needed. In this presentation, 850nm GaAs-AlGaAs DBR QW VCSELs using buried Al/sub x/O/sub y/ current apertures with low threshold current and peak optical output of 1.2 mW are reported. View full abstract»

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  • Visible VCSELs: recent advances and applications

    Publication Year: 1997 , Page(s): 17 - 18
    Cited by:  Papers (3)
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    In this talk, we will present results on recent improvements in the performance of AlGaInP visible VCSEL structures brought about by new heterostructure designs; in particular high temperature performance. View full abstract»

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  • Self-pulsating VCSEL with controllable quantum-well saturable absorber

    Publication Year: 1997 , Page(s): 19 - 20
    Cited by:  Patents (1)
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    We experimentally demonstrate the first self-pulsating VCSEL with a controllable quantum-well saturable absorber. Self-pulsation frequencies as high as 2 GHz were obtained. Self-pulsating lasers have proven extremely useful in applications where elimination of optical feedback and high-speed driving circuitry is needed. In this work, we present the first demonstrated InGaAs DBR QW VCSEL with self-pulsations occurring through a voltage-controlled saturable absorber. View full abstract»

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  • Tera bytes optical disk with electric tracking control using micro-cavity VCSEL array and PD array

    Publication Year: 1997 , Page(s): 21 - 22
    Cited by:  Papers (3)
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    We have already developed a lensless optical floppy disk system. In this paper an ultra high density optical memory disk system of T bits/inch/sup 2/ with G bits/s data transfer rate is newly proposed using near field optics, of which tracks are electric controlled. The optical heads in this system use 100/spl times/100 microcavity VCSEL arrays. One track width on the disk is 20 nm which is fine controlled by an electrical method using a 150/spl times/150 photo-diode array and the whole head is controlled by a conventional optical and electric-mechanical method in seeking tracks. View full abstract»

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  • Integrated VCL/PIN arrays for optical computing applications

    Publication Year: 1997 , Page(s): 23 - 24
    Cited by:  Papers (1)
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    High speed, dense arrays of vertical cavity lasers (VCLs) and detectors are at the core of many optically-interconnected computers and optical processors. In both applications, desired VCL properties include low threshold current and voltage, high single-mode power, high contrast and excellent array uniformity; desired detector characteristics include high speed and responsivity. In this paper, we present a general purpose optical interconnect device for optical computing applications. The device is comprised of a monolithically integrated vertical-cavity laser (VCL) and PIN photodiode array. View full abstract»

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  • Hybrid integration of VCSELs to foundry fabricated smart pixels

    Publication Year: 1997 , Page(s): 25 - 26
    Cited by:  Papers (1)  |  Patents (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    An opto-electronic integrated circuit (OEIC) smart pixel is a structure composed of optical inputs and/or outputs interconnected to electronic processing circuitry. The optical I/O allows the data to be read in 2-D page oriented formats. This circumvents the bottlenecks in the electrical interconnections and improves speed by reducing the capacitance and inductance of the wirebonds. Recently, we have reported the successful hybrid integration of VCSELs to a foundry fabricated OEIC by flip-chip bump-bonding a back-emitting VCSEL array. In this paper we present the results of improved integration processing and VCSEL design that will increase yields and mechanical and electrical robustness. In addition, a new approach to bonding VCSELs directly to the smart pixels is presented. View full abstract»

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  • 4/spl times/4 broadband optoelectronic switch using VCSELs

    Publication Year: 1997 , Page(s): 27 - 28
    Cited by:  Papers (1)
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    Future optical networks which employ wavelength division multiplexing (WDM) will require switches that are bit rate/code rate transparent, and allow spatial and wavelength reconfiguration of a channel. Optoelectronic cross-bar switches (OECBS) are able to perform all the required functionalities. In this paper we describe initial work on a free-space 4/spl times/4 OECBS which utilizes a 850 nm VCSEL array on 500 /spl mu/m centers as the optical sources within the switch. The signal-to-noise ratio (SNR) of the entire system for a 2 GHz bandwidth calculated from the measured data is 24.84 dB. The principal noise source is the receiver thermal noise (SNR/sub TH/=26.43 dB). The second dominant source of noise in the present system is the laser noise, both RIN (SNR/sub RIN/=31.98) and adjacent channel electrical cross-talk noise (SNR/sub ECN/=35 dB). By employing VCSELs with higher output powers and MSMs with better responsivity, it is possible to improve the S/N ratio to a level at which the laser noise would dominate, establishing a S/N ceiling. The S/N ceiling for the present system is estimated to be /spl sim/30 dB. If further improvements in the S/N is desired, VCSELs with lower intrinsic RIN and lower device crosstalk would be required. View full abstract»

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  • VCSEL based high performance ATM switch

    Publication Year: 1997 , Page(s): 29 - 30
    Cited by:  Papers (2)  |  Patents (1)
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    Large-broadband ATM switching nodes will require novel hardware solutions which could benefit from the inclusion of optical interconnect technology, since electronic solutions are limited by pin out and by the capacitance/inductance ofthe interconnections. This paper describes, analyzes and provides preliminary data from a new three stage free space optical switch which utilizes VCSELs for the optical interconnections, a liquid crystal spatial light modulator (SLM) as a reconfigurable shutter and relatively simple optics for fan out and fan in. A custom CMOS chip is required to introduce a time delay in the optical bit stream and to drive the VCSELs. Analysis shows that the switch should be scaleable to 1024 input and output channels. This size switch requires an array of 2048 VCSELs. A detailed optical power budget calculation indicates that each of the VCSELs in the array must have a maximum optical output of /spl sim/2 mW. View full abstract»

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  • Low-threshold continuous-wave operation of an oxide-confined vertical-cavity surface-emitting laser based on a quantum dot active region and half-wave cavity

    Publication Year: 1997 , Page(s): 33 - 34
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    We describe the first room-temperature continuous-wave (CW) lasing characteristics of a QD active region placed in an oxide-confined half-wave vertical-cavity surface-emitting laser (VCSEL) structure. We have maintained nearly the same cavity design as used with an InGaAs QW by choosing the active material as In/sub 0.50/Ga/sub 0.35/Al/sub 0.15/As to generate QD emission centered around 0.97 /spl mu/m. Light versus current curves are shown for a 7 /spl mu/m, a 3 /spl mu/m and a 1.5 /spl mu/m square QD VCSEL, CW at room-temperature. The lowest threshold current is 235 /spl mu/A for the 7 /spl mu/m device which yields a threshold current density of /spl sim/480 A/cm2. This is lower than for QD room-temperature lasers reported elsewhere. The 3 /spl mu/m and 1.5 /spl mu/m have increasingly higher thresholds of 435 /spl mu/A and 1.14 mA. The electroluminescence is also shown from a 7 /spl mu/m VCSEL device before the deposition of any upper MgF/ZnSe pairs with the lasing spectra from the 7 /spl mu/m VCSEL overlaid. View full abstract»

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  • Dynamically stable polarization characteristics of oxide-confinement vertical-cavity surface-emitting lasers grown on GaAs(311)A substrate

    Publication Year: 1997 , Page(s): 35 - 36
    Cited by:  Papers (1)  |  Patents (1)
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    We experimentally demonstrated that the polarization mode of a VCSEL can be well controlled even under direct modulation by using the optical anisotropy of (n11)-oriented QWs. A schematic diagram is shown of a (311)A-oriented VCSEL with an oxide confinement structure. The epitaxial layer was grown on a GaAs(311)A substrate by molecular beam epitaxy. The active region consists of In/sub 0.2/Ga/sub 0.8/As double quantum wells centered in a single-wavelength-thick Al/sub 0.5/Ga/sub 0.5/As cavity. The upper and bottom DBR mirrors consist of a 25- and 22.5-pair AlAs/GaAs quarter-wave stack, respectively. A typical L-I characteristic is shown under continuous wave (CW) operation at 25/spl deg/C. The threshold current is 1.0 mA, and the lasing wavelength is around 990 nm. View full abstract»

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  • Multiple-wavelength VCSEL arrays on patterned substrates

    Publication Year: 1997 , Page(s): 37 - 38
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    The lasing wavelength of a VCSEL is primarily determined by the effective cavity thickness which can be varied by changing the thickness of the /spl lambda/-spacer or the DBR layers. There have been many efforts in making MW-VCSEL arrays, where different methods of varying the effective cavity thickness were explored. Among all these methods, patterned-substrate MBE growth presents a very attractive approach since only a single growth is necessary and wide and accurate wavelength spans can be achieved with in-situ monitoring. In this paper, we review two patterned substrate methods. Both lead to simultaneous achievements of wide /spl lambda/ spacing, high yield and high performance. The comparison between the two methods is discussed. View full abstract»

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  • p-type modulation carbon-doping to InGaAs/AlGaAs quantum wells by MOCVD auto-doping for surface-emitting lasers

    Publication Year: 1997 , Page(s): 39 - 40
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    We have proposed a novel structure of p-type modulation doped QWs using a carbon auto doping method, and demonstrated carbon auto doping into AlAs layers by LP-MOCVD. We grew p-type modulation doped InGaAs/AlGaAs QWs, and fabricated edge emitting lasers using the QWs and achieved the reduction of the threshold current density for the first time. We estimated threshold current density (160 A/cm/sup 2/ for 1/spl times/10/sup 19/ cm/sup -3/ modulation doped three QWs edge emitting lasers), and showed the threshold reduction compared with undoped and n-type modulation QW VCSELs. The obtained result shows that the p-type modulation doping could improve the laser performance in terms of reduction of turn-on delay time, resulting in the possibility of future parallel optical transmission systems. View full abstract»

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  • AlGaAsSb/AlAsSb Bragg mirrors on InP for 1.3 and 1.55 /spl mu/m vertical cavity surface emitting lasers

    Publication Year: 1997 , Page(s): 41 - 42
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    The AlGaAsSb system appears very suitable to elaborate high reflective DBRs with a low number of pairs operating at wavelengths of interest for telecommunications (1.3 and 1.55 /spl mu/m). Very high reflectivities of 99.2% at 1.56 /spl mu/m and for the first time 98.8% at 1.3 /spl mu/m have been obtained. We are now investigating this antimonide approach for fabricating monolithic VCSELs. Thus the elaboration of an active layer composed of InGaAs wells encapsulated within AlGaInAs barriers is under evaluation. View full abstract»

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  • 120/spl deg/C pulsed operation from a 1.55 /spl mu/m vertical-cavity laser

    Publication Year: 1997 , Page(s): 43 - 44
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    Summary form only given. In this presentation we will focus on the design of InP-InGaAsP MQW vertical cavity lasers to achieve high temperature operation. We have concluded that the key to such design is the reduction of round trip cavity loss. We show the low loss double-fused laterally oxidized structure used in our work. This structure allows for high mirror reflectivities using GaAs based mirrors reducing the necessary gain at threshold. View full abstract»

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  • High performance 1.3 /spl mu/m vertical-cavity surface-emitting lasers with oxygen-implanted confinement regions and wafer-bonded mirrors

    Publication Year: 1997 , Page(s): 45 - 46
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    We show schematically the oxygen-implanted VCSELs. The devices consist of an oxygen implanted p-GaAs-AlGaAs (28 pairs) mirror, AlGaInAs-InP strain-compensated multiple quantum well (SC-MQW) cavity layers, and a top ZnSe/MgF (6 pairs) dielectric mirror. View full abstract»

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  • Long wavelength VCSELs with monolithic integrated GaInAsP/lnP mirror

    Publication Year: 1997 , Page(s): 47 - 48
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    A promising VCSEL structure for 1.55 /spl mu/m operation is a monolithic GaInAsP-InP structure for n-side mirror and active layer together with a dielectric p-side DBR. The conductive mirror helps to flatten the carrier profile and to dissipate the generated heat. Mesas can be etched either above or through the active region for electrical and optical confinement. The first VCSEL with a monolithic GaInAsP-InP mirror operated pulsed at 77K with a threshold current of 120mA. View full abstract»

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  • Metamorphic GaAs/AlAs Bragg mirrors deposited on InP for 1.3/1.55 /spl mu/m vertical cavity losers

    Publication Year: 1997 , Page(s): 49 - 50
    Cited by:  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (126 KB)  

    Long wavelength (1.3/1.5 /spl mu/m) GaAs-GaAlAs vertical cavity surface emitting lasers (VCSEL) with Bragg mirror (GaAs/AlAs) wafer fused on InP substrate exhibits low threshold current and cw operation at room temperature. However the wafer fusion technique requires additional substrate, epitaxy and technological steps. Furthermore the wafer fusion is difficult to achieve on a full 2 inches substrate. A new approach is proposed which consists in the metamorphic growth of GaAs-AlAs Bragg mirrors on InP by gas source molecular beam epitaxy. View full abstract»

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  • High-speed vertical cavity surface emitting lasers

    Publication Year: 1997 , Page(s): 53 - 54
    Cited by:  Papers (12)  |  Patents (1)
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    We have previously demonstrated record modulation bandwidths for oxide-confined vertical cavity surface emitting lasers (VCSELs) based on strained InGaAs-GaAs quantum wells. The monolithic oxide-confined structure provides good optical confinement, low thresholds, efficient operation, and acceptable thermal resistance; these qualities promote high speed operation. Here we report work on nominally 850 nm wavelength oxide-confined VCSELs with modulation bandwidths in excess of 20 GHz. View full abstract»

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