Extreme triple asymmetric (ETAS) epitaxial designs for increased efficiency at high powers in 9xx-nm diode lasers

Kaul, T.; Erbert, G.; Maaßdorf, A.; Martin, D.; Crump, P.

doi:10.1117/12.2288284

Cited by 13 publications

(11 citation statements)

References 8 publications

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“…In this case, not just the position of the active layer, but also the refractive index steps at the waveguide-cladding interfaces are asymmetric, with the refractive index step between the OCL and the n-cladding being much smaller than that between the OCL and the p-cladding [6]. Structures with a broadened asymmetric waveguide and with an active region located very near to the p-cladding were implemented in AlGaAs/GaAs and AlGaAs/GaAs/InGaAs lasers operating at λ <∼ 1 μm [14]- [18] in both gain switched [14] and steady state [15]- [18] regimes. Structures of this type (termed by the authors Extreme Double [15], [17], or Triple- [18] Asymmetry Structures, or Asymmetric Decoupled Confinement Heterostructure [16]) showed increased radiation power and reduced series and thermal resistances compared to a typical structure with the active layer near the middle of the OCL.…”

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confidence: 99%

High Power $1.5\mu$ m Pulsed Laser Diode With Asymmetric Waveguide and Active Layer Nearp-cladding

Hallman

Ryvkin

Avrutin

et al. 2019

IEEE Photon. Technol. Lett.

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We report first experimental results on a highpower pulsed semiconductor laser operating in the eye-safe spectral range (wavelength around 1.5 µm) with an asymmetric waveguide structure. The laser has a bulk active layer positioned very close to the p-cladding in order to eliminate current-induced nonuniform carrier accumulation in the p-side of the waveguide and the associated carrier losses. Moderate doping of the n-side of the waveguide is used to strongly suppress nonuniform carrier accumulation within this part of the waveguide. Highly p-doped InP p-cladding facilitates low series resistance. An as-cleaved sample with a stripe width of 90 µm exhibits an output power of about 18 W at a pumping current amplitude of 80 A. Theoretical calculations, validated by comparison to experiment, suggest that the performance of lasers of this type can be improved further by optimization of the waveguide thickness and doping as well as improvement of injection efficiency.

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confidence: 99%

High Power $1.5\mu$ m Pulsed Laser Diode With Asymmetric Waveguide and Active Layer Nearp-cladding

Hallman

Ryvkin

Avrutin

et al. 2019

IEEE Photon. Technol. Lett.

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“…As is well known, highly efficient operation of a semiconductor laser requires, firstly, low parasitic losses (both built-in and injection-dependent) and, secondly, high injection efficiency (which in turn requires low electron current leakage into the p-cladding). As discussed in the Introduction, it has been already shown that the first of these effects is effectively suppressed (at any wavelength) in the double-asymmetric structure of the type shown here, with both bulk and QW AL [1][2][3][4][5][6][13][14][15][16]. Therefore we shall concentrate on the second of the two considerations, the current leakage, which is known to be a significant threat in visible-range emitting lasers (see e.g.…”

Section: Analysis Of Laser Efficiencymentioning

confidence: 74%

Semiconductor laser design with an asymmetric large optical cavity waveguide and a bulk active layer near p-cladding for efficient high-power red light emission

Avrutin

Ryvkin

2022

Semicond. Sci. Technol.

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A semiconductor laser design for efficient, high power, high brightness red light emission is proposed, using a large optical cavity asymmetric waveguide and a bulk active layer positioned very close to the p-cladding. The low threshold carrier density associated with the broad active layer, as well as the proximity of the active layer to the p-cladding, ensure that the electron leakage current, the major detrimental factor in red lasers, stays modest in a broad range of excitation levels. This in turn promises high-power, efficient operation.

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“…This local variation enables comparable doping-dependent loss, waveguide composition and mode size to be maintained in all structures. The design process will be described in detail in [25,26] and subsequent articles. Exemplary devices were prepared uncoated and unmounted with front and back reflectivities of…”

Section: Loss Estimation In the Quantum Wellmentioning

confidence: 99%

Suppressed power saturation due to optimized optical confinement in 9xx nm high-power diode lasers that use extreme double asymmetric vertical designs

Kaul

Erbert

Maaßdorf

et al. 2018

Semicond. Sci. Technol.

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Broad area lasers with novel extreme double asymmetric structure (EDAS) vertical designs featuring increased optical confinement in the quantum well, Γ, are shown to have improved temperature stability without compromising series resistance, internal efficiency or losses. Specifically, we present here vertical design considerations for the improved continuous wave (CW) performance of devices operating at 940 nm, based on systematically increasing Γ from 0.26% to 1.1%, and discuss the impact on power saturation mechanisms. The results indicate that key power saturation mechanisms at high temperatures originate in high threshold carrier densities, which arise in the quantum well at low Γ. The characteristic temperatures, T 0 and T 1 , are determined under short pulse conditions and are used to clarify the thermal contribution to power limiting mechanisms. Although increased Γ reduces thermal power saturation, it is accompanied by increased optical absorption losses in the active region, which has a significant impact on the differential external quantum efficiency, h diff . To quantify the impact of internal optical losses contributed by the quantum well, a resonator length-dependent simulation of h diff is performed and compared to the experiment, which also allows the estimation of experimental values for the light absorption cross sections of electrons and holes inside the quantum well. Overall, the analysis enables vertical designs to be developed, for devices with maximized power conversion efficiency at high CW optical power and high temperatures, in a trade-off between absorption in the well and power saturation. The best balance to date is achieved in devices using EDAS designs with G = 0.54%, which deliver efficiencies of 50% at 14 W optical output power at an elevated junction temperature of 105 °C.

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Extreme triple asymmetric (ETAS) epitaxial designs for increased efficiency at high powers in 9xx-nm diode lasers

Cited by 13 publications

References 8 publications

High Power $1.5\mu$ m Pulsed Laser Diode With Asymmetric Waveguide and Active Layer Nearp-cladding

High Power $1.5\mu$ m Pulsed Laser Diode With Asymmetric Waveguide and Active Layer Nearp-cladding

Semiconductor laser design with an asymmetric large optical cavity waveguide and a bulk active layer near p-cladding for efficient high-power red light emission

Suppressed power saturation due to optimized optical confinement in 9xx nm high-power diode lasers that use extreme double asymmetric vertical designs

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