Characterization and fabrication of rare-earth doped amplifying fibers based on atomic layer deposition

Nano-Rare Earth Doped Fibers (NREDFs) have shown great application for optical fiber amplifiers, fiber lasers and sensors. The rapid development of fiber communication systems has a higher requirement on the NREDFs. Atomic layer deposition (ALD) is a chemical vapor deposition technique based on the sequential use of self-terminating gas-solid reactions. As a film deposition technique, ALD is known for its effective material utilization at low temperatures, accuracy thickness control, excellent step coverage, good uniformity and adhesion, good conformability. In this paper, ALD was used to fabricate high concentration alumina-erbium co-doped amplifying fibers. Based on Modified Chemical Vapor Deposition (MCVD) and ALD, using nanomaterials as a dopant, the alumina-erbium co-doped amplifying fibers were fabricated. The main advantages of this novel method include good uniformity, high dispersibility, and high doping concentration. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) images and X-ray energy dispersive spectroscopy (EDS) showed the physical and chemical features of the deposited film upon a porous silica soot layer. Photoluminescence (PL) and absorption spectra were used to characterize the optical properties. The fibers have high gain, low noise, high power and are independent of polarization, which make them desirable for fiber devices.