Symmetric waveguides written in Er/sup 3+/-doped B/sub 2/O/sub 3/-based glass using femtosecond laser pulses

Single-mode channel waveguides are fabricated in Er/sup 3+/-doped Bi/sub 2/O/sub 3/-based glass using femtosecond laser pulses at 800 nm. A waveguide with circular transverse profile is demonstrated without using any beam shaping technique.