Engineers at AFO Research (Glendale, CA) have developed a series of fluorophosphate glasses based on the so-called MBBA (magnesium fluoride, barium fluoride, barium metaphosphate, and aluminum metaphosphate) system; doped with erbium, the glasses are intended for use in broadband compact optical fibers, compact waveguide amplifiers, and compact fiber lasers. Tests at the University of California, Irvine, showed that the glasses exhibit a spectroscopic quality factor Q of 1.62, higher than other commercially available optical glasses; for example, Q for BK20 is 1.56, for ZBLAN is 1.54, for phosphate glass is 1.34, and for FP20 is 0.99. (A measurement of the quality of spectroscopic transitions of rare-earth ions, Q is the ratio of two parameters determined from a fit of theoretical free-ion oscillator strengths to experimental spectral optical-absorption measurements).
Strong emission bands were observed at 1536 nm with effective bandwidths of 91 nm-the widest of any commercial laser glass, according to Ashot Margaryan, chief operating officer of AFO Research. The high Q factor will enable the size of fiber lasers and amplifiers to be reduced while improving their performance, he says. Contact Margaryan at [email protected]