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DBR tapered lasers reach output powers of more than 10 W, narrow spectral linewidth, and nearly diffraction limited beam quality. Partly independent, the ridge waveguide (RW) current controls the fundamental mode and tapered current the output power. Concerning spectral stability and tuning, Master Oscillator Power Amplifiers (MOPAs) promise higher independent control. Recently, devices with 9.5 W output power, narrow spectral emission, and a beam quality factor of 1.5 were presented. In this contribution, the reliability of 1064 nm 6 mm long DBR tapered lasers and monolithic MOPAs will be investigated. 7th order DBR-gratings were implemented together with a 3.5 mm long tapered sections with full taper angles of 6°. The tapered lasers consist of 1.0 mm DBR-grating, 1.5 mm RW-section, and tapered section. The MOPA devices consist of 1.0 mm DBR-grating, 0.75 mm RW-section, 0.25 mm DBR grating, 0.5 mm RW preamplifier and tapered section. 3 different MOPA layouts including a straight design, 4° tilted master oscillator and 4° tilted power amplifier (PA) were tested. The reliability of two devices from each layout was investigated. At 5 W, the DBR tapered lasers reach a Mean Time To Failure (MTTF) of 2,800 h, whereas the MOPA devices with tilted PA show a MTTF of 13,000 h. For such devices tests at 7 W demonstrate reliable operation over 5,000 h. Intermediate measurements of spectral and beam parameters show, that before the occurrence of a failure, the spectral width remains smaller than 20 pm and the beam quality factor smaller than five.
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