title: Strong resonance and a highly compact longperiod grating in a large-mode-area photonic crystal fiber.
abstract: A strong resonance and extremely short length long-period grating (LPG) has been fabricated in a large-mode-area photonic crystal fiber (PCF) by use of a CO2 laser heat source. We believe that such a longperiod grating in pure silica PCF is the first example of a point-by-point technique. The fabrication method is simple and repeatable. The resulting LPG has been developed with eight periodic collapses within a 2.8-mmlong period of the fiber, which gives the strong resonance of core-cladding mode coupling. The lowest mode of LP01 is at a 1529.2-nm wavelength with a full width at half-maximum of ~0.7 nm and a resonance strength of -31.5 dB. The principal advantages of this LPG are that (1) it is temperature insensitive and stable, (2) the device is compact when it is packaged, and (3) it provides practical, low-cost all-fiber filters and PCF-based devices for optical fiber communications and sensing systems.
authors.forename: Yinian
authors.initials: Y
authors.lastname: Zhu
authors.forename: Ping
authors.initials: P
authors.lastname: Shum
authors.forename: Hin-Joo
authors.initials: HJ
authors.lastname: Chong
authors.forename: M
authors.initials: M
authors.lastname: Rao
authors.forename: Chao
authors.initials: C
authors.lastname: Lu