Fluorescence characterization and gain studies on a dye-doped graded index polymer optical-fiber preform

• Published in: Optics and laser technology 2008-07, Vol.40 (5), p.687-691
• Main Authors: Kailasnath, M., Sreejaya, T.S., Kumar, Rajesh, Vallabhan, C.P.G., Nampoori, V.P.N., Radhakrishnan, P.
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; Fabrication. Testing and measurement of fiber parameters; Fiber optics; Fundamental areas of phenomenology (including applications); Graded index (GI); Gradient-index (grin) devices; Interfacial gel polymerization; Optical elements, devices, and systems; Optics; Physics; Preform
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/j.optlastec.2007.10.015

Preparation of an appropriate optical-fiber preform is vital for the fabrication of graded-index polymer optical fibers (GIPOF), which are considered to be a good choice for providing inexpensive high bandwidth data links, for local area networks and telecommunication applications. Recent development of the interfacial gel polymerization technique has caused a dramatic reduction in the total attenuation in GIPOF, and this is one of the potential methods to prepare fiber preforms for the fabrication of dye-doped polymer-fiber amplifiers. In this paper, the preparation of a dye-doped graded-index poly(methyl methacrylate) (PMMA) rod by the interfacial gel polymerization method using a PMMA tube is reported. An organic compound of high-refractive index, viz., diphenyl phthalate (DPP), was used to obtain a graded-index distribution, and Rhodamine B (Rh B), was used to dope the PMMA rod. The refractive index profile of the rod was measured using an interferometric technique and the index exponent was estimated. The single pass gain of the rod was measured at a pump wavelength of 532 nm. The extent of doping of the Rh B in the preform was studied by axially exciting a thin slice of the rod with white light and measuring the spatial variation of the fluorescence intensity across the sample.