Design and Implementation of High Power Pulse Operation Broadened Waveguide 1.5 mum InGaAsP/InP MQW Lasers

Abstract

Abstract : Broad stripe 1.5 micrometers InGaAsP/InP MQW graded index SCH lasers with different waveguide widths and doping profiles were designed, fabricated and characterized. Studies of the characteristics of lasers with different p-doping profiles as well as modeling data show that the heterobarrier electron leakage is responsible for the effect of optical power saturation with current. Broadened waveguide devices containing higher Zn concentration in the vicinity of p-cladding/SCH interface yielded maximum output optical pulsed power density giving more than 16W from l00 micrometers aperture. Direct measurements of optical loss for BW lasers with different doping profiles have shown that doping can increase the internal loss of the device by more than two times, which explains the reduction of the device slope efficiency with doping. We have found that the benefit associated with the suppression of heterobarrier electron leakage outweighs lower efficiency near threshold leading to improved linearity of the light-current characteristics and higher output optical power and brightness. Broadened waveguide lasers with doped p-cladding/SCH interface have twice as high output optical power density and brightness compared to undoped BW devices.