High-Power 1060 nm Ridge Waveguide Lasers with Low-Index Quantum Barriers for Narrow Vertical Divergence Angle

Diode lasers with narrow far field are commercially important for low cost, high efficiency coupling into optical systems. It is particularly important to minimize the emission angle that contains 95% of the emitted optical power. This eliminates stray light in the optical system and is a pre-requisite for commercial application of narrow far field lasers.

FBH scientists have recently demonstrated high-power ridge waveguides with extremely narrow lateral and vertical far field angles of 12° x 17° respectively (95% power content), that operate kink-free in a single lateral mode to continuous wave powers in excess of 1 W, and reach a peak power of over 2.5 W.

Two design developments were required to deliver such narrow far fields. Firstly, very thick (8.6 µm) super large optical cavities were used, for large near field and consequent small far field. However, when the waveguide reaches these thicknesses, the active region plays an increasingly large role in the waveguide, significantly broadening the full width. To compensate, special low refractive index quantum barriers were developed, that compensate for the high index in the wells, and enable much narrower far fields to be achieved. The results shown here were obtained using ridge waveguides that were fabricated from these designs with 6 mm cavity length, 7 µm stripe width and mounted junction p-side down on c-mount.

Publication:

A. Pietrzak et al. "High Power 1060 nm Ridge Waveguide Lasers with Low-Index Quantum Barriers for Narrow Divergence Angle", Tech. Dig. CLEO/QELS 2010, paper CWE2 (2010).

FBH research: 22.09.2010