Wafer-Fused Optically Pumped VECSELs Emitting in the 1310-nm and 1550-nm Wavebands

A Sirbu,N Volet,T Czyszanowski,M Wasiak,Q Zhu,A Caliman,J Lyytikäinen,V Iakovlev,A Mereuta,O Okhotnikov,E Kapon,J Rautiainen,J Walczak

doi:10.1155/2011/209093

Abstract

1300-nm, 1550-nm, and 1480-nm wavelength, optically pumped VECSELs based on wafer-fused InAlGaAs/InP-AlGaAs/GaAs gain mirrors with intracavity diamond heat spreaders are described. These devices demonstrate very low thermal impedance of 4 K/W. Maximum CW output of devices with 5 groups of quantum wells shows CW output power of 2.7 W from 180 μm apertures in both the 1300-nm and the 1550-nm bands. Devices with 3 groups of quantum wells emitting at 1480 nm and with the same aperture size show CW output of 4.8 W. These VECSELs emit a high-quality beam with beam parameter below 1.6 allowing reaching a coupling efficiency as high as 70% into a single-mode fiber. Maximum value of output power of 6.6 W was reached for 1300 nm wavelength devices with 290 μm aperture size. Based on these VECSELs, second harmonic emission at 650 nm wavelength with a record output of 3 W and Raman fiber lasers with 0.5 W emission at 1600 nm have been demonstrated.

Highlights

Vertical-cavity surface-emitting lasers (VCSELs) [1, 2] and vertical-external-cavity surface-emitting lasers (VECSELs) [3,4,5] emitting in the 1310-nm and 1550-nm wavelength bands are ideally based on gain medium grown in the InP material system, with InGaAsP or InAlGaAs quantum wells (QWs) that produce high optical gain in the spectral region from 1270 nm to 1610 nm
Advances in Optical Technologies material system as the multi-QW (MQW) active region, the heat dissipation through the InP-based quaternary alloys (InGaAsP or InAlGaAs) that form the distributed Bragg reflectors (DBRs) is hampered by the very low thermal conductivity of these materials, resulting in thermal impedance as high as 470 K/W [3]. One solution to this problem consists of replacing the as-grown InP-based DBR with an AlGaAs/GaAs DBR with better thermal conductivity either in the form of a metamorphic mirror grown on the InP-based MQW active region [4] or bonded to the active region by wafer fusion as implemented in wafer-fused long-wavelength VCSELs [5]
We have developed wafer-fused InAlGaAs/AlGaAs optically pumped VECSELs with intracavity diamond heat spreaders emitting at wavelengths of 1300, 1550, and 1480 nm, based on a modified wafer-fusion process allowing reduced defect formation in the active region

Summary

Introduction

Vertical-cavity surface-emitting lasers (VCSELs) [1, 2] and vertical-external-cavity surface-emitting lasers (VECSELs) [3,4,5] emitting in the 1310-nm and 1550-nm wavelength bands are ideally based on gain medium grown in the InP material system, with InGaAsP or InAlGaAs quantum wells (QWs) that produce high optical gain in the spectral region from 1270 nm to 1610 nm. Advances in Optical Technologies material system as the multi-QW (MQW) active region, the heat dissipation through the InP-based quaternary alloys (InGaAsP or InAlGaAs) that form the DBR is hampered by the very low thermal conductivity of these materials, resulting in thermal impedance as high as 470 K/W [3] One solution to this problem consists of replacing the as-grown InP-based DBR with an AlGaAs/GaAs DBR with better thermal conductivity either in the form of a metamorphic mirror grown on the InP-based MQW active region [4] or bonded to the active region by wafer fusion as implemented in wafer-fused long-wavelength VCSELs [5]. We demonstrate thermal impedance as low as 4 K/W, room-temperature (RT) CW output power values of 2.7–6.6 W and high-quality beam emission with 70% coupling efficiency into single-mode fibres

Gain Mirror Development

VECSEL Characteristics

Findings

Conclusions