title: On the use of the Type I and II scheme for classifying ultrafast laser direct-write photonics.
abstract: The use of the Type I and Type II scheme, first introduced and used by fiber Bragg grating researchers, has recently been adopted by the ultrafast laser direct-write photonics community to classify the physical geometry of waveguides written into glasses and crystals. This has created confusion between the fiber Bragg grating and direct-write photonics community. Here we propose a return to the original basis of the classification based on the characteristics of the material modification rather than the physical geometry of the waveguide.
authors.forename: Simon
authors.initials: S
authors.lastname: Gross
authors.forename: Mykhaylo
authors.initials: M
authors.lastname: Dubov
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Withford