Assessment of the limits to peak power of 1100nm broad area single emitter diode lasers under short pulse conditions

Abstract

ABSTRACT High power diode lasers are the root source of optical energy in all high performance laser systems. As their performance advances, diode lasers are increasingly taking the place of other sources. Short pulse, sub-microsecond-class, high power lasers are important for many applications but historically, diode lasers have not been able to reach high enough peak pulse powers with adequate reliability, limited by physical effects such as facet failure. By combining robust facet passivation with thick super large optical cavity waveguides, greatly increased optical output power can be achieved. We present here the results of a study using commercial high current short pulse sources (>200A, <500ns) to assess the performance and endurance limits of high power broad area devices. We find that our lasers can be driven with a peak power density of over 110MWcm -2 without failure for more than 3×10 7 pulses. For example, on testing to 240A, single emitter 200m stripe 1100nm broad area devices reach 124W (46J) without failure, and 60m stripes reach 88W. In practice, high injection effects such as carrier accumulation in waveguide typically limit peak power. We review these remaining limitations, and discuss how they can be overcome. Keywords: Short pulse, diode laser, high power, COMD, reliability