High-power 980-nm monolithically integrated master-oscillator power-amplifier

Diode lasers emitting single-frequency, diffraction limited beams at a continuous-wave (CW) optical power of several Watts are required for many applications including frequency conversion, free-space communications, and pumping of fibre lasers and fibre amplifiers. The spectral region around 980 nm is of particular interest for the pumping of erbium and ytterbium doped fibres as well as for the second harmonic generation of laser radiation at 488 nm replacing Ar ion lasers in material analytics. One of the most promising devices is the monolithically integrated master-oscillator power-amplifier (MOPA), where either a distributed Bragg reflector (DBR) laser or a distributed feedback (DFB) laser acting as the master oscillator and a straight or tapered gain-region power-amplifier are combined on a single chip. Here, a MOPA consisting of a DBR laser and a tapered amplifier is demonstrated which emits a CW power of more than 10 W at 977 nm in a nearly diffraction limited beam and narrow spectral bandwidth of 40 pm. To the authors´ knowledge, the 10 W reported here is the highest nearly diffraction-limited single-frequency power ever demonstrated from a single-chip diode laser at any wavelength.