Compact High Power Diode Laser MOPA System With 5.5 nm Wavelength Tunability

A hybrid master oscillator power amplifier (MOPA) diode laser with 6.2 W output power at 971.8 nm is presented. It consists of a distributed Bragg reflector (DBR) laser, which is collimated and focused into a tapered amplifier using cylindrical micro-lenses. The emitted light has a spectral width of about 20 pm and a propagation factor of M
_1/e2
²
= 1.3 in the slow axis. The emission is nearly diffraction limited with 79% of the total power within the central lobe (4.9 W diffraction limited). The MOPA system, including the micro-lenses, is realized on a compact conduction cooled package with a footprint of 25 mm × 25 mm. In addition, a micro-heater is embedded on top of the DBR-grating, which can provide up to 5.5 nm of electrical wavelength tuning. The output power is thoroughly constant (6.22 W ± 0.01 W) over the entire tuning range.