First Mile Access Networks and Enabling Technologies

Transmitters: Lasers

Lasers are used as optical sources for emitting modulated data into an optical fiber. Lasers have a distinct property whereby they can emit a narrow beam of light having a small optical spectrum (line width), while having a high-output optical power (a concentrated beam of photons of approximately the same phase and frequency). A laser is a semiconductor device (for optical purposes at least, although different forms of lasers do exist) whose operation is governed by the population inversion condition. The population inversion condition specifies the numeric superiority in volume of the electrons in the excited state (formed by absorption of energy by normal state electrons) over the electrons in the ground state in a semiconductor ...