Quantum amplifier having passive core and active cladding providing signal gain by interaction of evanescent-wave components of signal and pump beams propagating along the core

摘要

An optical amplifier particularly for use in a high data-rate fibre- optics communication link utilizing a body of a dielectric substance transparent to signal light of a given band of wavelengths and transparent also to pumping light of a different band of wavelengths, a smooth continuous surface along the length of the body having as amplifying component a layer of laser material adhered contiguous to the surface. Both signal light and pumping light are introduced into an end face of the body, which may be a passive dielectric fibre core such as glass, or a passive dielectric slab with parallel side walls, utilising mode order converting holograms. By the phenomenon of penetration by light of both frequencies within a thin layer of the adhered material as the light beams undergo multiple total internal reflections at the interface between the body and the laser material, atoms of active material, e.g. Nd.sup..sup.+ 3 or organic dye molecules in the laser medium are optically pumped to a higher energy level, and fluoresce and are stimulated by the evanescent-wave component of the signal light to coherently emit light in a band of wavelengths correlated with the signal band of wavelengths. The amplified signal light is delivered from the other end face, and is launched through further hologram devices in a transmission mode into a succeeding fibre or slab of the link.