GaAs-based devices including dilute nitride lasers are potential light sources for future optical fibre communication systems at the wavelength of 1.3 mm. We present the results on optimisation of the growth conditions of long-wavelength GaAs-based lasers. The samples grown by the molecular beam epitaxy with quantum well active regions consisted of strain-compensating layers and strain-mediating layers were characterised by photoluminescence and double crystal X-ray diffraction methods. The optical properties were very much affected by a choice of growth conditions, details of the quantum wells, and post-growth thermal treatment. This presentation will outline the development of GaAs-based long-wavelength VCSEL's and summarize the research and prospects in this field.