Coupling technique for LED or laser to fibre - has optical transformer in form of horn reflector and sheathed core fibre with rotational symmetry

摘要

The optical coupling method permits a light emitting diode or laser beam source to be connected with an optical fibre by the use of an optical transformer. A horn shaped reflector may be used to convert a rectangular profile light source to a circular profile. The reflector may be used as a device to produce a lobe with a circular cross-section to connect with from a cylinder a cylindrical fibre or may produce an elliptical section profile to connect from the rectangular form. For a laser coupling the relevant equations are of the type dx. sin (psi)X 2 a no square root 2. delta. f; dy. sin (psi)y 2 a no square root 2. delta. f. Where dx. dy are the aperture coordinates, 2a is the diameter of the optical fibre, no is the refractive index, (psi)x, y are the aperture angles and delta. f. is the refractive index differential ratio.