Buried tunnel junction vertical-cavity surface-emitting lasers (BTJ-VCSELs) are demonstrated as light sources in the wavelength range from 1.3 to 2.0 mum. Continuous-wave operation at room temperature could be achieved for the whole wavelength range. This emphasizes not only the sophisticated device design but also the excellent suitability of the material system AlGaInAs/InP. Advantages and restrictions are discussed in this paper. Transmission experiments with single-mode VCSELs at 1.55 mum show error-free data transmission at modulation frequencies up to 10 Gbit/s. At 1.68 and 1.80 mum, gas sensing experiments detecting methane and water, respectively, could be successfully performed. (C) 2002 Elsevier Science B.V. All rights reserved.