MOVPE epitaxial growth and design optimisation of 1.5 mum vertical cavity surface emitting lasers (VCSELs) for high power, single mode and high-temperature operation are presented. The VCSEL structure comprises a strain compensated In AlGaAs MQW active region, a p(++)/n(++) In(Al)GaAs tunnel junction and top and bottom AlGaAs/ GaAs fused distributed Bragg reflectors. All epitaxial layers were grown by low-pressure MOVPE in nitrogen atmosphere. Excellent optical and electrical confinement is obtained by wafer-bonding of the top mirror on tunnel junction pre-etched mesas. Devices with 7 pm aperture show single transverse mode CW operation up to 4 mW at room temperature, with 30-35 dB side-mode suppression ratio and a far field divergence angle of 9degrees. At 85 degreesC, a record single mode high emission power up to 1.7mW is demonstrated. (C) 2004 Published by Elsevier B.V.