Fiber amplification in the 940-nm water vapor absorption band using the /sup 4/F/sub 3/2/ /sup 4/I/sub 9/2/ transition in Nd

The measurement of atmospheric water vapor in the 940-nm absorption band may be accomplished using fiber amplifiers based on the /sup 4/F/sub 3/2//spl rarr//sup 4/I/sub 9/2/ transition in Nd. We report initial experimental results on the effects codopants have on the characteristics of this transition in Nd-doped fiber, and present modeled and experimental results of a fiber amplifier. To our knowledge, this is the first reported fiber amplifier employing this transition.