An optical communication system is provided which includes an optical signal transmitter which communicates high bandwidth, high power frequencies. The optical signal transmitter includes a high efficiency/high power optical source such as an optical magnetron or a phased array source of electromagnetic radiation, and a modulator element. The modulator element may be within a resonance cavity of the high efficiency/high power optical source (intra cavity) or external to the cavity (extra cavity). The modulator element serves to modulate output radiation of the high efficiency/high power optical source to produce a modulated high frequency optical signal which may be transmitted through the air. The optical signal transmitter is particularly useful in providing the last mile connection between cable service operators and end users.