G. Trankle

5-W DBR Tapered Lasers Emitting at 1060 nm With a Narrow Spectral Linewidth and a Nearly Diffraction-Limited Beam Quality

Distributed Bragg reflector tapered lasers emitting at a wavelength of about 1060 nm were realized. The expitaxial layer structure leads to a vertical far-field angle of 15deg (full-width at half-maximum). The devices with a total length of 4 mm consist of 2-mm-long ridge waveguide and tapered sections. The input currents to both sections can be independently controlled. The laser reached 5-W output power with a narrow spectral linewidth below 40 pm (95% power) and a nearly diffraction-limited beam quality.

High-power 808-nm tapered diode lasers with nearly diffraction-limited beam quality of M/sup 2/=1.9 at P=4.4 W

High-power 808-nm tapered diode lasers mounted as single emitters with very good brightness were manufactured and analyzed. The beam propagation ratio M² is 1.9 at 4.4 W; a very low beam propagation ratio M² of 1.3 is achieved at 3.9 W. At 808 nm, the high brightness of 460 MWmiddotcm^-2 sr^-1 never reported before is a step forward toward new applications of tapered diode lasers

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 Diode Lasers Optimized for Low-Loss Smile-Insensitive External Spectral Stabilization

High powers can be produced within narrow spectral widths by stabilizing diode lasers with external volume holographic gratings, but this typically introduces additional optical losses. We compared the influence of diode laser design on stabilization performance by comparing devices with super large optical waveguides (4.8 μm) and narrow vertical far fields with reference designs with thinner waveguides (1.6 μm). We found that the use of diode lasers with super large optical waveguides substantially improves the stabilization performance, with lower losses and wider operation ranges sustained even in the presence of significant (>;1 μm) bar smile.

Passively Cooled TM Polarized 808-nm Laser Bars With 70% Power Conversion at 80-W and 55-W Peak Power per 100-

Many solid state laser systems rely on transverse- magnetic polarized 808-nm diode lasers, whose efficiency is limited by the transparency current of the quantum well and whose peak power is limited by facet failure. Using optimized epitaxial growth, low voltage designs, and optimized facet reflectivity, we demonstrate 70% power conversion efficiency at 80 W in 1-cm laser bars under continuous-wave (CW) test conditions. We assess peak power limits in single emitters and find that 100-mum stripe lasers roll thermally under the CW condition at 13 W without failure, then reach >50 W under 300-ns pulse condition, where they fail at internal defects.

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High power, high beam quality and narrow, stable spectra are achieved simultaneously using a truncated-tapered optical amplifier in a master-oscillator power amplifier-system. We compare the influence of lateral geometric design on amplifier performance, by using devices with super large optical waveguide (4.8 μm) and relative low confinement factor (Γ = 1%) . We find that the use of an amplifier with a larger active region results in both high power and high beam quality. An abandonment of cavity spoiling grooves leads to strongly improved beam characteristics.

m Stripe Width

In this letter, we demonstrate how the coupling efficiency of a tapered diode laser (TPL) into a single-mode fiber under specified conditions can be predicted from measured Wigner distribution functions (WDFs). The WDFs were measured with a simple setup similar to the method of measuring the beam propagation ratio M2 as specified in the ISO standard 11146. We used the measured WDFs to predict the coupling efficiencies of the beam into a single-mode fiber by using a predefined and well-known optical system. We then realized the fiber coupling and compared the measured coupling efficiencies to the predicted values. For this comparison we used the beam of a distributed Bragg reflector TPL which emits a fairly complex and structured beam. The predictions fitted the experimental result with relative deviations below 10%.

17-W Near-Diffraction-Limited 970-nm Output From a Tapered Semiconductor Optical Amplifier

A 10-mm-long four-section distributed Bragg reflector laser with a double-quantum-well heterostructure at 920 nm was realized. A maximum optical pulse power of 3.6 W with a repetition rate of 4.1 GHz corresponding to the laser length was reached. The full-width at half-maximum of the pulses was 7 ps measured with an autocorrelator. A maximum pulse energy of 25 pJ was reached.

Prediction of Single-Mode Fiber Coupling Efficiencies of a Tapered Diode Laser From Measured Wigner Distribution Functions

InGaAs SQW /spl alpha/-DFB waveguide lasers emitting around 1060nm with a beam propagation factor of M/sup 2//spl les/ 1.3 up to 13W output power (M/sup 2/ =3.2 @ P=2.1 W) have been fabricated and characterized.

High-Power Picosecond Pulse Generation Due to Mode-Locking With a Monolithic 10-mm-Long Four-Section DBR Laser at 920 nm

A dual-wavelength master oscillator (MO) power amplifier (PA) diode-laser system emitting at 785 nm suitable for shifted excitation Raman difference spectroscopy is presented. The laser system consists of a distributed Bragg reflector V-branch diode laser as a dual-wavelength MO and a ridge waveguide PA. The system reaches an optical output power of more than 750 mW at 25 °C. Optical spectra show wavelength stabilized single mode emission at 784.60 and 785.22 nm over the whole power range with a spectral width ≤10 pm (≤0.5 cm-1) and a spectral distance of 0.62 nm (≤10.1 cm -1).