Abstract: An electro-optical coherent light beam signal transmission system capable of transmitting signals occupying a wide bandwidth collimated beam for a substantial distance. The system has a coherent light generator modulated at a wide bandwidth and a reflecting mirror system that radiates the modulated coherent light generated in a selected direction and spreads the said coherent light into a collimated beam having a safe energy level distribution. A coherent light receiving module in alignment with the radiated coherent light beam decollimates and focusses the coherent beam on a light sensor. Subsequently the communications signal is distributed to end users through cable systems. The coherent light generator is preferably a semiconductor coherent light generating diode and includes a temperature monitoring and regulating system which maintains coherent light generator at an optimum operating temperature for peak output levels.