title: Multiple-beam interference patterns in optical fiber generated with ultrafast pulses and a phase mask.
abstract: We compare the cladding patterns present in grating structures fabricated with an ultrafast laser and a phase mask with a cw beam interference model. We find that the observed patterns agree well with the model results for picosecond pulses; however, for femtosecond pulses, we show that the full bandwidth and the pulsed nature of the sources must be considered because the pattern can be affected by group-velocity walk-off. An interesting consequence of order walk-off is the possibility of pure two-beam interference generation with a phase mask in the femtosecond pulse regime.
authors.affiliation: Communications Research Centre Canada, 3701 Carling Avenue, P.O. Box 11490, Station H, Ottawa, Ontario, Canada K2H 8S2. christopher.smelser@crc.ca
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Smelser
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Mihailov
authors.forename: Dan
authors.initials: D
authors.lastname: Grobnic
authors.forename: Ping
authors.initials: P
authors.lastname: Lu
authors.forename: Robert B
authors.initials: RB
authors.lastname: Walker
authors.forename: Huimin
authors.initials: H
authors.lastname: Ding
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Dai