By incorporating a broad transverse waveguide ͑1.3 m͒ in 0.97-m-emitting InGaAs͑P͒/InGaP/ GaAs separate-confinement-heterostructure quantum-well diode-laser structures we obtain record-high continuous-wave ͑cw͒ output powers for any type of InGaAs-active diode lasers: 10.6-11.0 W from 100-m-wide-aperture devices at 10°C heatsink temperature, mounted on either diamond or Cu heatsinks. Built-in discrimination against the second-order transverse mode allows pure fundamental-transverse-mode operation ( Ќ ϭ36°) to at least 20-W-peak pulsed power, at 68ϫthreshold. The internal optical power density at catastrophic optical mirror damage ͑COMD͒ P COMD is found to be 18-18.5 MW/cm 2 for these conventionally facet-passivated diodes. The lasers are 2-mm-long with 5%/95% reflectivity for front/back facet coating. A low internal loss coefficient (␣ i ϭ1 cm Ϫ1 ) allows for high external differential quantum efficiency d ͑85%͒. The characteristic temperatures for the threshold current T 0 and the differential quantum efficiency T 1 are 210 and 1800 K, respectively. Low differential series resistance R s : 26 m⍀; leads to electrical-to-optical power conversion efficiencies in excess of 40% from 1 W up to 10.6 W cw output power, and as much as 50% higher than those of 0.97-m-emitting Al-containing devices. © 1998 American Institute of Physics. ͓S0003-6951͑98͒03335-X͔ Broad-stripe, InGaAs-active diode lasers ͑ ϭ0.89-1.06 m͒ are routinely used for pumping solid-state fiber lasers, frequency doubling, and for numerous medical applications. Al-free devices ͑i.e., InGaAs/InGaP/GaAs structures͒ have superior ''wallplug'' efficiency compared with conventional Al-containing devices 1 due to their low differential series resistance. 1,2 Furthermore, the low oxidation rate of InGaP permits high-quality epitaxial regrowths over gratings for longitudinal-mode control ͑i.e., distributed-feedback lasers͒ 3,4 or over etched structures for lateral-mode control. 5-9 Thus, the Al-free material system is highly desirable for both broad-stripe spatially incoherent devices as well as for temporally and/or spatially coherent index-guided diode lasers.Recently, we have reported 10 continuous-wave ͑cw͒ output powers of 8 W from 0.98-m-emitting InGaAs/InGaP/ GaP lasers of a 100-m-wide stripe, 4-mm-long cavity, 1-m-thick transverse waveguide, and mounted on Cu heatsinks. Such broad-waveguide ͑BW͒ devices also demonstrated fundamental-transverse-mode operation to high drive levels, 11 as expected since the cutoff thickness for the second-order transverse mode is 1.05 m. BW devices with a waveguide thickness of 1.3 m exhibited lasing in both the fundamental and the second-order transverse modes. 12 We report here maximum cw output powers of 10.6-11 W, record-high values for any type of InGaAs-active-region diode lasers. The devices show pure fundamental-transversemode operation to at least 20 W peak pulsed power. We achieve these results using a 1.3-m-waveguide structure, designed to suppress oscillation of the second-order transverse mode.The InGaAs͑P͒/In...

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Wide-stripe, 0.97 m emitting Al-free InGaAs͑P͒/InGaP/GaAs broad-waveguide separate confinement heterostructure quantum-well lasers demonstrate a record value for quasicontinuous wave ͑QCW͒ output power: 14.3 W ͑100-m-wide stripe, 100 s-wide pulses͒; and reach catastrophic optical mirror damage ͑COMD͒ in QCW operation at an optical power density of 22.5 MW/cm 2 ; that is, 40% higher than COMD levels in cw operation. The devices have low internal losses (␣ i ϭ1 cm Ϫ1 ) and high external differential quantum efficiency ͑86% for 2-mm-long lasers͒, and exhibit only 10-20°C temperature rises in the active region at 10 W QCW power. We also show that long-cavity, large-contact-area devices exhibit relatively little spectral broadening with increased output power. © 1997 American Institute of Physics. ͓S0003-6951͑97͒01235-7͔Broad-waveguide separate confinement heterostructure quantum-well ͑BW-SCH-QW͒ diode lasers have shown high cw powers from Al-free 0.97 m emitting devices 1 as well as from 1.5 m emitting devices. 2 Low internal losses and very high external differential quantum efficiencies in BWtype lasers enable the use of 2-to 4-mm-long cavity devices, that have recently allowed the achievement of record-high cw powers for these wavelengths. 3,4 The quasicontinuous wave ͑QCW͒ regime for diode laser operation is important for solid-state laser and fiber laser pumping, as well as for many medical applications, since higher peak output powers are available in the QCW regime than in the cw regime. In the QCW operation the current-pulse duration ͑ ͒ is longer than the diode's thermal time constant, which is about 1 s, so that the laser reaches its steady-state temperature near the beginning of the pulse. Therefore, the QCW regime is useful to investigate the laser's high-power behavior, since very high peak output powers can be obtained and overheating of the mount and laser itself can be discriminated by varying the current-pulse duration.Here we demonstrate the achievement of record QCW power for ϭ0.97-m-wide stripe (100 mϫ2 mm) lasers, using the BW structure shown in Fig. 1. The QCW result ͑100-s-wide pulses͒ is 14.3 W, which is 80% higher than the best previously published result 5 for 100 m stripe devices. We also show that 200 mϫ4 mm stripe devices have significantly reduced spectral broadening with increased output power compared with devices of smaller stripe area (100 mϫ2 mm).The InGaAs͑P͒/InGaP/GaAs laser structure was grown by low-pressure metalorganic chemical vapor deposition ͑LP-MOCVD͒ in an Aixtron A-200 system on nominally exact-oriented ͑100͒ GaAs substrates. 1 The structure consists of a 1.2-m-wide InGaAsP (E g ϭ1.6 eV) waveguide region, In 0.51 Ga 0.49 P cladding layers, and a p ϩ carbon-doped GaAs cap layer for low contact resistance. The lasing wavelength at 15°C was 0.97 m. Similar structures, for short-cavity length ͑i.e., 0.5 mm͒, have demonstrated record-high cw wallplug efficiency ͑66%͒ values, 6 due to low internal loss and the intrinsically lower series resistance of Al-free devices compared ...

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An above-threshold analysis of 8–10-μm-core antiresonant reflecting optical waveguide (ARROW) lasers is performed, including the carrier-induced index depression, carrier diffusion, and gain spatial hole burning (GSHB). The study is done as a function of the (transverse) optical-mode confinement factor Γ and the core width. Just as for index-guided devices, it is found that ARROW devices (i.e., index-antiguided devices) are much less immune to multimoding via GSHB the smaller the value of Γ. For the case Γ=3%, the high-order mode of most concern reaches the threshold much earlier than for the case Γ=1%, due both to gain-profile distortion as well as to distortion of the effective-index profile (in the device core) with increasing drive level. Devices of 8.5-μm-wide cores and Γ=1%, are found to stay single-mode to at least 40× threshold, which in turn allows the projection of stable, single-mode operation to 1.2 W output power. In contrast, 10-μm-core devices become multimode at around 10× threshold. Preliminary experimental results from 10-μm-wide core ARROW lasers, with Γ=1.5%, are stable, single-mode operation to 300 mW at 10× threshold, in good agreement with the presented study.