Narrow-band-mode converting Fabry-Perot output coupler for fiber lasers

Summary form only given. Tilted Bragg gratings have been demonstrated to be efficient mode converters in two-mode fibers. A pair of tilted Bragg gratings in a two-mode section of a single-mode fiber can be written in a way to become a nonreflecting narrow-band transmission filter. The latter device behaves like an ordinary Fabry-Perot with one exception: light is only reflected in the LP/sub 11/ mode and therefore not guided by the adjacent single-mode fiber. In this paper we present a Fabry-Perot device where mode conversion (LP/sub 01/-LP/sub 11/) is accompanied by mode reflection. The result is a narrow-band transmission and reflection at resonance used as an output coupler for fiber lasers.