Evaluating the effects of optical and carrier losses in etched-post vertical cavity lasers

Thibeault, B.J.; Strand, T. A.; Wipiejewski, T.; Peters, M.G.; Young, D.B.; Corzine, S.; Coldren, L.A.; Scott, J.W.

doi:10.1063/1.360588

Cited by 39 publications

(15 citation statements)

References 16 publications

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“…The excess loss generally turns on sharply [3], [4] (roughly as where is the device radius) and will have an exponentially greater effect on threshold. These losses have been dramatically reduced by confining the mode with apertures rather than etched pillars [4], [5]. Our previous work with thin apertures [6] and tapered apertures [7] has demonstrated further reductions in scattering loss.…”

mentioning

confidence: 88%

“…5. This excess optical loss is calculated by using the slope efficiency to extract the total optical loss and then subtracting the loss found in large ( 20-m diameter) devices [4], [5]. Calculating the total optical loss (per pass) (1) relies upon calculating the output mirror transmission estimating the injection efficiency and the substrate transmission which was lower for the highly doped n-substrate under the "first Peak" VCSEL's.…”

Section: Optical Confinementmentioning

confidence: 99%

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High-performance small vertical-cavity lasers: a comparison of measured improvements in optical and current confinement in devices using tapered apertures

Hegblom

Margalit

Fiore

et al. 1999

IEEE J. Select. Topics Quantum Electron.

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mentioning

confidence: 88%

Section: Optical Confinementmentioning

confidence: 99%

High-performance small vertical-cavity lasers: a comparison of measured improvements in optical and current confinement in devices using tapered apertures

Hegblom

Margalit

Fiore

et al. 1999

IEEE J. Select. Topics Quantum Electron.

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“…͑2͒ including the diffusion term to get a more accurate estimation of the diffusion influence. 15 However, for devices investigated here the simple approximations are still valid, leading to a consistent set of recombination parameters and diffusion coefficient.…”

Section: ͑1͒mentioning

confidence: 99%

Differential carrier lifetime in oxide-confined vertical cavity lasers obtained from electrical impedance measurements

Giudice¹,

Kuksenkov²,

Temkin³

et al. 1999

Applied Physics Letters

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Differential carrier lifetime measurements were performed on index-guided oxide-confined vertical cavity surface emitting lasers operating at 980 nm. Lifetimes were extracted from laser impedance measurements at subthreshold currents, with device size as a parameter, using a simple small-signal model. The carrier lifetimes ranged from 21 ns at 9 A, to about 1 ns at a bias close to threshold. For a 6ϫ6 m 2 oxide aperture device the threshold carrier density was n th ϳ2ϫ10 18 cm Ϫ3 . The effect of carrier diffusion was also considered. An ambipolar diffusion coefficient of D ϳ11 cm 2 s Ϫ1 was obtained. © 1999 American Institute of Physics. ͓S0003-6951͑99͒00507-0͔Carrier lifetime measurements are an important tool in semiconductor laser characterization. 1,2 Recently, a new electrical technique for differential carrier lifetime measurements was developed. 2 It originally applied to edge emitting lasers with bulk active region. More recently, it has been applied to vertical cavity surface emitting lasers ͑VCSELs͒ 3 with quantum wells ͑QWs͒ in the active region. In this letter, experimental results on differential carrier lifetimes in indexguided oxide-confined VCSELs are reported. Lifetimes were obtained from laser impedance measurements at subthreshold currents and the equivalent circuit modeling. Threshold carrier densities and the corresponding recombination parameters were calculated as a function of device size. In addition, the effect of lateral carrier diffusion out of the active region was also considered.Devices studied in this work were oxide-confined InGaAs VCSELs lasing at 980 nm. The current aperture was obtained by partial oxidation of two quarter-wavelength GaAlAs layers. 4 Lasers with aperture sizes in the range of 6-12 m had room temperature threshold currents from 220 to 600 A. The laser impedance was measured from 1 MHz up to 3 GHz. Measurements were performed for bias currents between 9 A and threshold. Figure 1 presents the frequency dependence of the measured impedance of a device with a ϳ8ϫ8 m 2 active region, with a threshold current I th Ϸ240 A, at 40 A of drive current. The measured laser impedance was modeled using the small-signal subthreshold equivalent circuit shown in the inset of Fig. 1. The parameters included in this model were the following: an inductance L associated with a bond wire, a parallel combination of a resistance R m and capacitance C m associated with the top mirror interfaces, and a parallel combination of a resistance R d and a capacitance C a representing the active region. The impedance of the bottom mirror was neglected. The total impedance of the circuit can be written aswhere d ϭR d C a is the characteristic time equal to the differential carrier lifetime. 5,6 This model does not consider the carrier transport and capture dynamics discussed elsewhere 7,8 because it was assumed that the capture time is small and the escape time from the wells is very large compared to the carrier lifetime in the wells. In this simple model, d is the effective lifetime of the carri...

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“…In addition, optical loss increases with greater etch depth and smaller air-post diameter, due to diffraction [64] and scattering from imperfections in the sidewalls [65], respectively. An additional consideration is the high thermal impedance of these structures, due to the absence of an effective heat sink in contact with the laser cavity.…”

Section: A Air-post Structuresmentioning

confidence: 99%

Design, fabrication, and performance of infrared and visible vertical-cavity surface-emitting lasers

Chow

Choquette

Crawford

et al. 1997

IEEE J. Quantum Electron.

206

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Abstract-This paper discusses the issues involving the design and fabrication of vertical-cavity surface-emitting lasers (VCSEL's). A review of the basic experimental structures is given, with emphasis on recent developments in distributed Bragg reflectors, gain media, as well as current and optical confinement techniques. The paper describes present VCSEL performance, in particular, those involving selective oxidation and visible wavelength operation.

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Evaluating the effects of optical and carrier losses in etched-post vertical cavity lasers

Cited by 39 publications

References 16 publications

High-performance small vertical-cavity lasers: a comparison of measured improvements in optical and current confinement in devices using tapered apertures

High-performance small vertical-cavity lasers: a comparison of measured improvements in optical and current confinement in devices using tapered apertures

Differential carrier lifetime in oxide-confined vertical cavity lasers obtained from electrical impedance measurements

Design, fabrication, and performance of infrared and visible vertical-cavity surface-emitting lasers

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