1.6 W continuous-wave coherent power from large-index-step (Δn≈0.1) near-resonant, antiguided diode laser arrays

Abstract

Near-diffraction-limited-beam continuous-wave (cw) operation has been achieved to high powers from antiguided arrays with a large effective-index step between element and interelement regions. InGaAs/InGa(As)P/GaAs 40-element arrays (λ=0.985 μm) emit in beams 2×diffraction-limit (0.67°) at 1.6 W and 9×threshold in cw operation. 1 W of the coherent cw power resides in the central lobe. The external differential quantum efficiency and the threshold current are 40% and 0.4 A, respectively, for 1-mm-long devices of 191 μm emitting aperture. The overall electrical to optical power conversion efficiency at 1.6 W output power is 23%. Modeling of the thermal effects in cw operation on the array modes reveals that for high-index-step (∼0.1) near-resonant antiguided arrays thermal lensing hardly affects high-order modes, and as a consequence, 2×diffraction-limited beams can be maintained to watt-range cw powers.

5.5 W near-diffraction-limited power from resonant leaky-wave coupled phase-locked arrays of quantum cascade lasers

“…11 Furthermore, in quasi-CW and CW operation, high index contrast prevents multimoding due to thermal lensing. [5][6][7] However, for resonant transmission between elements, the Bragg condition needs to be exactly satisfied 8 and the range in interelement width s, Ds, over which the in-phase mode is favored to lase is proportional to the wavelength k. 12 Then, for near-IR arrays, the fabrication tolerance Ds is rather small ($0.1 lm). In contrast, when resonant leaky-wave coupling was recently applied to phase-locking THz quantum cascade lasers (QCLs), 13,14 the fabrication tolerance significantly increased due to much longer wavelengths.…”

Intersubband Quantum‐Box Lasers: Progress and Potential as Uncooled Mid‐Infrared Sources

“…22 Called resonant-opticalwaveguide (ROW) arrays, such devices have shown operation in near diffractionlimited beams to 10 W peak-pulsed power 23 and 1.6 W cw power. 24 In contrast to the vast majority of APC-type devices, for ROW arrays the gain is preferentially enhanced on the low-index crystal sites, 22 see Fig. 5(a).…”

High-Performance Low-Divergence Angled Laser Diodes With Two-Dimensionally Tilted Sidewalls

“…However, the far-field patterns (FFPs) in the fast and slow axes of the semiconductor lasers are extremely poor. In the slow axis, various approaches have been proposed to improve the lateral FFP, including reducing the divergence angle by tapered lasers [1], [2], converting multi-lobe profiles to single-lobe ones by optimal diode laser arrays [3], [4] and stabilizing the far-field profile by antiguided diode laser arrays [5]. In the fast axis, the divergence angle remains very large (∼40°), although the beam quality M 2…”