Method and apparatus for obtaining a simplified electro-optical signal coupling system

摘要

A laser signal coupling device one embodiment of which comprises a transmitter where a laser diode is coupled to a single mode fiber optic cable through the use of a lens whose position relative the diode is kept constant but whose length is adjusted to obtain a beam waist for the focused beam at some predefined point such as inside the end of the fiber optic cable. Such a positioning of the beam waist can increase the yield by reducing the effect of alignment variations in axial, radial and angular directions as well as reduce noise from fiber end surface reflections. The same concept may be used to accurately focus signaling received from an optic cable, in a surface of a signal detector. Further, the concept may be used for focusing between optic cable of different types such as converting from multi-mode to single-mode fiber optic cable.