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• A flared waveguide is proposed to control the lateral divergence of diode lasers. • An epitaxial structure was presented with low loss and high power. • We showed an efficient reduction of the lateral divergence angle at high power. • We demonstrated 34.5 W output and reliable operation employing these designs. Broad-area diode lasers with high output power and low lateral divergence angle are highly desired for extensive scientific and industrial applications. Here, we report on the epitaxial design for higher output power and a flared waveguide design for reduced divergence, which leads to high power operation with a low lateral divergence angle. A vertically asymmetric epitaxial structure was employed and optimized for low internal optical loss and high efficiency to realize high output power operation. Using a flared waveguide design, the lateral divergence angle was efficiently reduced by decreasing the number of high-order lateral optical modes significantly. The flared waveguide design introduces a smooth modification of the ridge width along the cavity without deteriorating laser performance. Based on the optimized epitaxial and waveguide design, we scaled the waveguide width to realize high continuous-wave power of 34.5 W at 25 °C. A low lateral divergence angle of 8° and high power conversion efficiency of 60% were achieved at the operating power level of 25 W. The life test data (30 A at 45 °C for 39 units, 0 failures in 1000 h) demonstrated reliable operation illustrating the efficient design for reduced lateral divergence angle and high operating power. [ABSTRACT FROM AUTHOR]

A monolithic ~1.55-μm colliding-pulse mode-locked AlGaInAs/InP laser with a three-quantum-well active layer incorporating a passive far-held reduction layer has been demonstrated. The device emits pulses at 162 GHz, with a pulsewidth of 0.98 ps, a pulse energy of 0.13 pJ, and a time-bandwidth product of 0.52, while demonstrating a low divergence angle (12.7° × 26.3°) with a twofold improvement in butt coupling efficiency to a flat cleaved single-mode fiber, compared to the conventional mode-locked lasers. [ABSTRACT FROM PUBLISHER]

Selectively oxidized InGaAs vertical-cavity surface emitting lasers (VCSELs) at an emission wavelength of λ=980 mm are investigated for high-power applications. Densely packed arrays consisting of 19 single devices with an active diameter of 50 μm emit 1.08 W of continuous-wave (CW) optical output power at room temperature. At 10°C, heat sink temperature the output power increases to 1.4 W, which corresponds to a chip size averaged power density of 1 kW·cm2. Low divergence angle of less than 16° full-width at half-maximum (FWHM) and the circularly symmetric far-field pattern allow for simple focusing of the beam with power densities above 10 kW·cm2 [ABSTRACT FROM PUBLISHER]