DISTRIBUTED-BRAGG-REFLECTOR RING OSCILLATORS - A LARGE-APERTURE SOURCE OF HIGH SINGLE-MODE OPTICAL POWER

Distributed Bragg reflector (DBR) ring oscillators are the first monol ithic semiconductor lasers containing broad-area active regions which operate in a single mode to several times their threshold current. Ort hogonally oriented diffraction gratings surrounding an unpatterned act ive region select a single spatial and temporal mode of oscillation. T his paper presents both analytic and experimental verification of sing le mode operation for active dimensions up to 368 x 1000 mum. Threshol d current densities under 200 A/cm2 and total differential efficiencie s greater than 60% have been measured. DBR ring oscillators have demon strated over 1 W of single frequency output power, 460 mW of spatially coherent, single frequency output power, and nearly circular diffract ion limited output to 4 x I(th). The performance potential of these de vices is enormous, considering that the output apertures are nearly tw o orders of magnitude wider than conventional single mode sources whic h generate up to 0.2 W of coherent output.