Output level required for a given distance depends on ambient lightning, even if you use a modulated IR carrier direct sunlight will just about completely saturate an IR transistor, a well designed photo diode detector might do better but not sure by how much. Fluorescent lights can interfere with signals as well. Wavelength is mostly irrelevant. Build one and experiment with it, they're not difficult to make.
Standard IR remote controls work more then 10m, and use simple three pin receiver IC's. It's normal to pulse the emitter LED at 1A or so using a carrier frequency of about 38KHz.