H. K. Choi

Ho:YAG laser pumped by 1.9-/spl mu/m diode lasers

A 21-/spl mu/m Ho:YAG laser end pumped by 1.9-/spl mu/m diode lasers has generated nearly 0.7-W CW output power. Laser operation was maintained even with Ho:YAG heat sink temperatures in excess of 60/spl deg/C. >

High-efficiency high-power GaInAsSb-AlGaAsSb double-heterostructure lasers emitting at 2.3 mu m

Double-heterostructure Ga/sub 0.84/In/sub 0.16/As/sub 0.14/Sb/sub 0.86/-Al/sub 0.5/Ga/sub 0.5/As/sub 0.04/Sb/sub 0.96/ diode lasers emitting at 2.27 mu m were grown by molecular beam epitaxy on GaSb substrates. For pulsed operation of broad-stripe lasers 300 mu m wide, differential quantum efficiencies as high as 50% and output power as high as 900 mW/facet were obtained for a cavity length of 300 mu m. Values of approximately 100% for the internal quantum efficiency and 43 cm/sup -1/ for the internal loss coefficient were determined from the measured dependence of differential quantum efficiency on cavity length. The threshold current density was as low as 1.5 kA/cm/sup 2/ for a cavity length of 700 mu m. >

Organometallic vapor phase epitaxy of high-performance strained-layer InGaAs-AlGaAs diode lasers

Graded-index separate-confinement heterostructure single-quantum-well lasers incorporating a strained In/sub x/Ga/sub 1-x/As active layer, with x >

Analysis of two-section coupled-cavity semiconductor lasers

Analysis and simulation studies of the longitudinal mode behavior of two-section coupled-cavity lasers in the steady-state are presented. The laser is analyzed with a resonance amplifier model and the scattering matrix formulation. The mode selection property of this laser is explained in terms of the wavelength-dependent effective reflectance. Expressions for the effective reflectance and the mode power are derived for two different cases: the case of weak reflection from the junction and strong coupling between individual cavities, and the case of strong reflection at the junction and relatively weak coupling between cavities. It is shown to be possible to simulate the longitudinal mode behavior with respect to temperature changes and wavelength tuning by separately pumping each section of the laser.

Spectral beam combining of a broad-stripe diode laser array in an external cavity

The outputs from an 11-element, linear diode laser array with broad stripes have been beam combined into a single beam with a beam quality of ~20x diffraction limited in the plane of the junction. This beam combining was achieved by use of a common external cavity containing a grating, which simultaneously forces each array element to operate at a different, but controlled, wavelength and forces the beams from all the elements to overlap and propagate in the same direction. The power in the combined beam was 50% of the output from the bare laser array.