Fiber optic dye amplifier

摘要

A fiber optic amplifier as disclosed, comprised of a fiber optic, monomode waveguide which has a core and cladding. Part of the cladding over a predetermined region is removed and replaced by an active medium capable of absorbing light energy at a first wavelength and emitting light energy at a second wavelength. The active medium is a lasing dye which has an index of refraction adjusted to be slightly less than the index of refraction of the fiber core. The amount of cladding which is removed is adjusted such that a predetermined amount of penetration of the evanescent field from a pump light signal coupled into an end of the fiber penetrates the active medium. A probe signal to be amplified causes stimulated emission from the excited dye molecules by penetration of its evanescent field into the dye in the region where the cladding is removed. In the preferred embodiment a recirculating pump is used to circulate dye through a cavity which is placed over the portion of the fiber where the cladding is removed. The dye molecules in contact with the surface caused by removal of the cladding are continually changed. A temperature control unit maintains the temperature of the dye such that its index of refraction remains tuned to an amount just less than the index of refraction of the core.