||Recently, with the escalating demands for optical communications, the need for bandwidth in optical communication network has increased. The technology fiber fabrication opens the possibility for fiber bandwidth form 1.3 to 1.6μm. Cr4+:YAG double-clad crystal fiber (DCF) grown by the co-drawing laser-heated pedestal growth method has a strong spontaneous emission spectrum from 1.3 to 1.6μm. Such fiber is therefore, eminently suitable for optical coherence tomography (OCT), broadband optical amplifier, amplifier spontaneous emission (ASE) light source, and tunable solid-state laser applications.|
In this thesis, multilayer dielectric thin films were directly deposited by E-gun coating onto the end faces of the Cr4+:YAG DCF. To improve thin-film quality, we can increase transmittance of laser output, and to design for the high power laser. For broadband optical amplifier in dual-pump and double-pass scheme, a 2.8-dB gross gain, a 1.6-dB insertion loss, and a 1.2-dB net gain at 1.4-μm signal wavelength have been successfully developed with HR coating onto one of the Cr4+:YAG DCF end faces.