Limits of Performance of a Nd3+-Doped Fiber Amplifier at 1.3 μm

Abstract

There has been a continuing interest in developing fiber amplifiers for the 1.3 μm window which is used for most optical communications traffic. Neodymium-doped fibers remain potential candidates for this function despite the problem of excited state absorption (ESA) near 1.3 μm which can lead to loss rather than gain, particularly at shorter wavelengths [1]. The effects of ESA are known to be a function of glass composition: Aluminum/phosphorus-doped silica [2-4] and phosphate glass [5] exhibit gain at shorter wavelengths than Ge-doped silica, and fluorozirconate glass has provided gain at wavelengths as short as 1.32 μm [6-9]. Despite these results, the practicality of Nd3+-doped fiber amplifiers is still in question. We have addressed this issue by constructing a fiber amplifier model which exploits the availability of measured cross sections for a wide variety of Nd3+-doped glasses.