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

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. 1. Introduction Vertical-cavity surface-emitting lasers (VCSELs) [1, 2] and vertical-external-cavity surface-emitting lasers (VECSELs) [3–5] 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. Besides fibre-optic communications, this spectral range presents increasing interest in other fields of optics applications like gas sensors, free-space communications, biomedical, Raman optical amplifiers, and so forth. In recent years, the performance of 1310-nm and 1550-nm VCSELs has been considerably improved by the introduction of InAlGaAs QWs and tunnel junction injection, resulting in fundamental mode output close to 10？mW of wafer-fused VCSELs with AlGaAs/GaAs distributed Bragg reflectors (DBRs) [6]. Although emission in the mW range is sufficient for an important part of the mentioned applications, there is a number of emerging novel applications, such as in 1300-nm lasers for frequency doubled 650-nm high-power red lasers applied in laser displays [7] and 1300–1600-nm optical pumping of Raman amplifiers [8] at high output power levels in the range of several watts. This high optical power domain is accessible by the realization of optically pumped VECSELs that are capable of producing intense, high-quality beams from a large pumped area as initially demonstrated for short-wavelength VECSELs in 1999 [9]. In addition, VECSELs are suitable for insertion of optical elements inside the laser cavity not only for frequency doubling but