High-power 980 nm quantum dot broad area lasers

High-power quantum dot broad area lasers emitting at 980 nm are presented. Continuous-wave output powers of 4.3 W from a 50 /spl mu/m stripe width laser and of 6.3 W from a 100 /spl mu/m stripe width laser were achieved at 15/spl deg/C     

10W continuous-wave monolithically integrated master-oscillator power-amplifier

A semiconductor-based master-oscillator power-amplifier operating at 977 nm is demonstrated to emit more than 10 W continuous wave in a nearly diffraction limited beam with a narrow spectral bandwidth. The device consists of a distributed Bragg reflector laser and a flared amplifier monolithically integrated on a single chip     

Nonlinear properties of tapered laser cavities

The nonlinear phenomena accompanying the process of light generation in high-power tapered semiconductor lasers are studied using a combination of simulation and experiment. Optical pumping, electrical overpumping, filamentation, and spatial hole burning are shown to be the key nonlinear phenomena influencing the operation of tapered lasers at high output powers. In the particular tapered laser studied, the optical pumping effect is found to have the largest impact on the output beam quality. The simulation model used in this study employs the wide-angle finite-difference beam propagation method for the analysis of the optical propagation within the cavity. Quasi-three-dimensional (3-D) thermal and electrical models are used for the calculation of the 3-D distributions of the temperature, electrons, holes, and electrical potential. The simulation results reproduce key features and the experimental trends.     

Effect of growth temperature on performance of AIGaAs/lnGaAs/GaAs QW laser diodes

Growth and characterization results are presented for high-power laser diodes with AlGaAs cladding and waveguide layers and strained In_1-xGa_xAs quantum wells with 0.09 < x < 0.25 grown by metalorganic vapor phase epitaxy at different temperatures. Photoluminescence at 300 and 10K, Auger spectroscopy, and high-resolution x-ray measurements are discussed. Broad area laser diodes have been fabricated with different cavity length and threshold current densities, absorption coefficients, internal efficiencies, and degradation rates have been measured.     

Compact hybrid master oscillator power amplifier with 3.1-W CW output power at wavelengths around 1061 nm

A hybrid master oscillator power amplifier (MOPA) laser source has been realized by coupling a single-mode three-section distributed Bragg reflector (DBR) laser as master oscillator and a tapered power amplifier with a single lens only. A maximum continuous-wave optical output power of 3.1 W was achieved. The emission spectrum was completely determined by the DBR laser. Single longitudinal mode operation at a wavelength of /spl lambda/=1061 nm was maintained over the whole power range. Up to an output power of 1.8 W, the beam propagation factor M/sup 2/was less than 1.6.     

High-power highly strained InGaAs quantum-well lasers operating at1.2 μm

High-power highly strained In_xGa_1-xAs quantum-well lasers operating at 1.2 μm are demonstrated. The edge emitting broad area (BA) laser diode structures are grown by metal organic vapor phase epitaxy at low growth temperatures using trimethylgallium, trimethylindium, and arsine sources. In the laser structure, an InGaAs QW is sandwiched between the GaAs waveguide and AlGaAs cladding layers. The operating wavelength for the laser diode at room temperature (20°C) is about 1206 nm, which redshifts to 1219 nm at 46°C. The transparency current density for the BA laser diodes is as low as 52 A/cm² and the characteristic temperature value is 76 K. High-power laser operation in the pulse mode (about 1.6 W) at room temperature was achieved     

Narrow Vertical Far-Field 975-nm Broad-Area DFB Lasers for Wide Temperature Range Operation

We report on 100-mum-wide 975-nm distributed-feedback lasers with a cavity length of 2 mm, which deliver 2.4 W within a 14deg vertical far-field angle (full-width at half-maximum) and 35% power conversion efficiency in combination with a spectral linewidth of 0.27 nm (95% power content). The epitaxial design is a compromise between a narrow vertical far-field and a good power conversion efficiency, as required for application as a pump source. Narrow linewidth operation is sustained to 100degC, enabled by use of a grating with a high coupling coefficient.     

High-power highly reliable Al-free 940-nm diode lasers

Al-free diode lasers emitting at 930 nm having a broadened step-index waveguide structure and a single active InGaAs quantum well have been realized by MOVPE. The impact of waveguide thickness on device performance has been studied. The highest wall plug efficiency of about 60% has been obtained with diode lasers having a 1-μm-thick waveguide. Increasing the waveguide thickness to 1.5 μm resulted in record low degradation rates below 10^-5 h^-1 for 3-W output power (100 μm stripe width). The same diode lasers showed a good long-term reliability even at an output power of 4 W. The best beam quality had diode lasers with a 2-μm-thick waveguide, at the expense of a reduced temperature stability     

Optimization of GaAsP/AlGaAs-based QW laser structures for high power 800 nm operation

We present a detailed study of the MOVPE growth of 800 nm diode laser structures based on the combination of a GaAsP quantum well with well-established AlGaAs waveguide structures. By optimizing the strain and thickness of the quantum well highly-reliable diode lasers with low threshold current and high efficiency were demonstrated. 100 μm aperture “broad area” devices mounted epi-side up achieve a CW output power of 8.9 W with a wall-plug efficiency of 50%. These output powers represent record values for diode lasers in this wavelength range. Reliability measurements at 1.5 W and 50°C ambient temperature suggest lifetimes >10 000 h.     

Reliable 1-W CW operation of high-brightness tapered diode lasers at 735 nm

The long-term stability of high-brightness diode lasers at 735 nm was investigated. The diodes consist of an index-guided straight section and a gain-guided tapered section. A 1-W continuous-wave operation for 2-mm-long tapered lasers over 3200 h is reported. The experiments demonstrate high reliability with degradation rates below 3.2/spl times/10/sup -5/ h/sup -1/.