High power, high brightness, single emitter laser diodes with different apertures from 5 μm to 1000 μm are
reported on, in the wavelength range from 780 nm to 1060 nm. On going progress at Axcel Photonics for both single-mode
and multi-mode laser diodes will be presented. These diode lasers show high slope efficiency, low threshold
current and low voltage, etc. Laser diodes with different emitting apertures at 5μm, 50 μm, 90 μm, 200 μm, 400 μm,
1000 μm, are reported on and discussed in detail. The reliability data for different sized emitters is presented. These
results demonstrated that Axcel's technologies enable laser diodes made from Al based material grown on GaAs
substrates, which can reliably operate at high brightness and high power in the near infrared-wavelength range under
wide range of emitting apertures. These laser diodes are suitable for a wide variety of applications including medical,
material processing, graphics, pumping solid-state lasers and fiber lasers.
High brightness, high power, and highly reliable 915nm InAlGaAs laser diodes with optimized design are reported in
this paper. The laser diodes exhibit excellent performance, such as, high slope efficiency, low threshold current, low
voltage, etc., which make them suitable for high brightness operation. The aging test data shows no failures during aging
test and more than 220,000 hours estimated lifetime for 90um emitter laser diodes at 8W CW operation. The aging test
with the same emitter size at higher stress conditions showed sudden failure that corresponds to catastrophic optical
damage (COD) on the facet. A novel large optical cavity (LOC) epi-structure with flat-top near field intensity
distribution was developed. The maximum output power is up to 23W under CW testing condition at 25 °C, which is
highest level achieved so far. The output power is limited by thermal roll over and there is no COD occurring. This data
shows Axcel's technologies can further increase the brightness to over 110mW per micron for 915nm laser diodes. This
type of laser diodes is essential for pumping fiber lasers to replace CO2 lasers for industry applications.
High power laser diodes and diode arrays emitting at the wavelength of 808nm are widely used for pumping
neodymium (Nd+) doped solid state lasers and fiber lasers, medical surgery, dental treatment and material processing. In
general, the power is limited by catastrophic optical mirror damage (COMD) and heat dissipation. In this paper we
demonstrate 29W CW output power at 808 nm from a 400 &mgr;m single emitter with 2mm cavity length. The device
thermally rolls over due to the excess heat. The L-I curve rolls over at 29.5W, the laser is still alive, and we can repeat
the test again and again without catastrophic optical mirror-damage (COMD). The device consists of an
InAlGaAs/AlGaAs/GaAs, optimized special graded-index separated-confinement heterostructure (GRINSCH) broad
waveguide (BW), single quantum well (SQW) and barriers between waveguide and cladding layers. A weak temperature
dependence characteristic, which is desirable for high power and reliable operation, is obtained from these devices.
High power, 1060 nm, InGaAs/GaAs/AlGaAs graded-index, separate-confinement (GRINSCH), strained single quantum-well (SQW), single mode (SM) laser diodes grown by Metal-Organic Chemical-Vapor Deposition (MOCVD) are reported. The high quality quantum well with high strain, which is the key issue to make high performance 1060 nm laser diode, was obtained by optimizing growth conditions. For realizing SM lasers and modules, the ridge-waveguide lasers with 5 um width and 1500 μm cavity length are successfully fabricated and mounted epitaxial-side up onto AlN submounts using eutectic Au80Sn20 solder to allow easy access to the emission region for fiber coupling and to minimize the effects of die bonding stress on the ridge. These devices exhibit threshold current of less than 30 mA, slope efficiency of up to 1.0 W/A and high kink-free power of 500 mW at 25°C. The devices that were subjected to long-term aging test at 85°C, operating at 300 mW, first show very good reliability. The coupled module with more than 70% fiber coupling efficiency and more than 200 mW output power from a single mode fiber or polarization maintained (PM) fiber in 14-pin butterfly case is demonstrated.