Abstract
A diode-pumped relative gain of 2 dB at 1.55 μm wavelength based on evanescent excitation using a highly Er 3+ -doped laser glass over side-polished fiber was demonstrated for the first time. The pump efficiency can be highly improved with a blazed grating to achieve ultra-low-noise fiber amplifiers and upconversion fiber lasers. © 2005 Optical Society of America.