Scalable High-CW-Power High-Speed 980-nm VCSEL Arrays

Safaisini, Rashid; Joseph, John R.; Lear, K.L.

doi:10.1109/jqe.2010.2053917

Cited by 32 publications

(21 citation statements)

References 32 publications

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“…Vertical-cavity surface-emitting lasers (VCSELs) are key components for communication and sensing applications due to their ease of fabrication and testing, low-power consumption, high beam quality, and high modulation speeds [1][2][3]. In particular, VCSELs operating in the 850-nm wavelength band constitute an important class of VCSELs.…”

Section: Introductionmentioning

confidence: 99%

Assessment of VCSEL thermal rollover mechanisms from measurements and empirical modeling

et al. 2011

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Abstract:We use an empirical model together with experimental measurements for studying mechanisms contributing to thermal rollover in vertical-cavity surface-emitting lasers (VCSELs). The model is based on extraction of the temperature dependence of threshold current, internal quantum efficiency, internal optical loss, series resistance and thermal impedance from measurements of output power, voltage and lasing wavelength as a function of bias current over an ambient temperature range of 15-100 • C. We apply the model to an oxide-confined, 850-nm VCSEL, fabricated with a 9-μm inner-aperture diameter and optimized for highspeed operation, and show for this specific device that power dissipation due to linear power dissipation (sum total of optical absorption, carrier thermalization, carrier leakage and spontaneous carrier recombination) exceeds power dissipation across the series resistance (quadratic power dissipation) at any ambient temperature and bias current. We further show that the dominant contributors to self-heating for this particular VCSEL are quadratic power dissipation, internal optical loss, and carrier leakage. A rapid reduction of the internal quantum efficiency at high bias currents (resulting in high temperatures) is identified as being the major cause of thermal rollover. Our method is applicable to any VCSEL and is useful for identifying the mechanisms limiting the thermal performance of the device and to formulate design strategies to ameliorate them. Vertical-Cavity Surface-Emitting Lasers: Design, Fabrication, Characterization, and Applications, (Cambridge Univ. Press, 1999). 23. C. J. Chang-Hasnain, C. E. Zah, G. Hasnain, J. P. Harbison, L. T. Florez, N. G. Stoffel, and T. P. Lee, "Effect of operating electric power on the dynamic behavior of quantum well vertical-cavity surface-emitting lasers," Appl.

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Section: Introductionmentioning

confidence: 99%

Assessment of VCSEL thermal rollover mechanisms from measurements and empirical modeling

et al. 2011

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“…Fig. 4 presents a summary of previously published R th of VCSELs that were realized using different techniques [4,6,11,[13][14][15][20][21][22]. Using the measured R th values, the VCSEL active region temperature was estimated as described in [14].…”

Section: Resultsmentioning

confidence: 99%

“…VCSELs with high emitted optical power and/or frequency modulation bandwidth are of importance for various applications such as Gigabit Ethernet local area networks (LANs), optical interconnects, fiber laser pumping, and optical communication, [2]. While continuous-wave (CW) operation of 2-dimensional VCSEL arrays with a collective output optical power in the Watt regime realized [3], realizing VCSEL arrays with higher output optical power that have the potential of high frequency modulation bandwidth is of importance for many applications such as night vision, laser printing, laser treatment, encoders, and displays [4,5].…”

Section: Introductionmentioning

confidence: 99%

Top-emitting 980-nm vertical-cavity surface-emitting laser diodes with improved optical power

Al-Omari

Alias

Lear

2012

2012 IEEE 3rd International Conference on Photonics

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Top-emitting, oxide-confined, polyimideplanarized 980-nm VCSELs with copper-plated heatsinks were fabricated and characterized. Increasing the plated heatsink radius from 0-μ μ μ μm to 4-μ μ μ μm larger than the mesa diameter for lasers with 8-μ μ μ μm oxide aperture diameter reduced the measured thermal impedance, increased the maximum bias current density, and increased the maximum output optical power achieved by a 29%, 37%, and 73%, respectively. VCSELs with oxide aperture diameter and heatsink overlap of 8-μ μ μ μm and 4-μ μ μ μm, respectively, demonstrated 17ºC decrease in the internal device temperature (i.e. active region temperature) at the maximum output optical power. Devices with similar mesa diameters of 26-μ μ μ μm and different heatsink overlaps exhibited a threshold bias current and a total series resistance of (630±4%)μ μ μ μA and ~95Ω Ω Ω Ω, respectively.

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“…Proton implantation and selective oxide have been used to confine the laser threshold current [5,6] . The proton implanted depth and profile are two main parameters to affect the threshold current in VCSELs.…”

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confidence: 99%

Threshold control in VCSELs by proton implanted depth

Zhao

Sun

Wang

et al. 2011

Optoelectron. Lett.

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The proton implantation is one of key procedures to confine the current diffusion in vertical cavity surface emitting lasers (VCSELs), in which the proton implanted depth and profile are main parameters. Threshold characteristics of VCSELs with various proton implanted depths are studied after optical, electrical and thermal fields have been simulated self-consistently in three dimensions. It is found that for VCSELs with confinement radius of 2 m, increasing proton implanted depth can reduce the injected current threshold power and enhance the laser temperature in active region. Numerical results also indicate that there are optimal values for current aperture in proton implanted VCSELs. The minimum injected current threshold can be achieved in VCSELs with proton implantation near the active region and confinement radius of 1.5 m, while the VCSELs with proton implantation in the middle of p-type distributed Bragg reflectors (DBRs) and confinement radius of 2.5 m can realize the minimum temperature.VCSELs are widely used for optical communications and interconnections because of the grteatly improved far-field divergence angle [1][2][3][4] . Proton implantation and selective oxide have been used to confine the laser threshold current [5,6] . The proton implanted depth and profile are two main parameters to affect the threshold current in VCSELs. A high power VCSEL with the maximum continuous wave optical output of 46 mW at room temperature was reported [7] , and various studies on thermal fields were presented in Refs. [8][9][10][11][12][13]. However, the influence of proton implanted depth on threshold thermal fields and other characteristics of VCSELs were not given in these studies.The purpose of this work is to find the optimal threshold current in VCSELs for different implanted depths.The laser is sandwiched between a pair of p and n type DBRs consisting of 20 and 27 alternating quarter-wavelength layers of AlAs and Al 0.16 Ga 0.84 As, respectively. The active region is made up of three undoped In 0.2 Ga 0.8 As quantum wells (QWs) separated by the 100 Å GaAs layer. The thickness of QW is 80 Å. In our simulation, the device is fabricated by using the H + implantation for lateral current confinement, and the potential satisfies Poisson's equation in substrate, p type and n type DBRs. 2 2 2 2 , , 1 , z z r V r z r V r r z r V .(1)The injected current density iswhere is conductivity. The carrier density N diffusion in the active region can be written aswhere d is the thickness of active region, and D n is the diffusion constant. The optical transverse i-mode i (r) in VCSELs is governed by 0 ) ( ) ( 1 2 2 2 0 2 0 r r m k r r r r r i z i i .(4)The steady-state thermal conduction equation in the laser is written as, ( ) , ( 1 l 2 2 z r Q z z r T r z r T r r r i .

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Scalable High-CW-Power High-Speed 980-nm VCSEL Arrays

Cited by 32 publications

References 32 publications

Assessment of VCSEL thermal rollover mechanisms from measurements and empirical modeling

Assessment of VCSEL thermal rollover mechanisms from measurements and empirical modeling

Top-emitting 980-nm vertical-cavity surface-emitting laser diodes with improved optical power

Threshold control in VCSELs by proton implanted depth

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