Transverse Mode Controlled Wide-Single-Stripe Lasers By Loading Modal Filters

Two kinds of modal filter for high power diode lasers with a wide stripe have been examined. The first one is a partially narrow region formed in the active region. Flared-SBA(self-aligned bent active layer) laser in which the active layer flares the width from the narrow filter region to the wide output facet oscillates in a fundamental transverse mode under cw condition up to the output power of 64mW. The second one is a partial coating at the output facet of lasers. By applying it to an SBA laser whose stripe width is 150 μm, the laser oscillates in a single lobed far-field pattern up to 300mW, whose divergent angle is as narrow as 1.7° in FAHM(full angle at half maximum) under cw conditions.