An extremely short long-period grating (LPG) with strong resonance has been developed in a large-mode-area photonic crystal fiber (PCF) by use of the heat source of a CO2 laser. We believe that such a LPG in pure silica PCF is the first example to be obtained with the point-by-point technique. The fabrication method is simple and repeatable. The resulting LPG has 8 periods, written by a CO2 laser, within a 2.8-mm length of fiber, which yields a deep notch of core–cladding mode coupling of -31.5 dB at the telecommunication wavelength of 1529.2 nm, with a FWHM of ~0.7 nm. The principal advantages of this LPG are that it is practical, cost effective, and compact.
© 2003 Optical Society of America
(060.2280) Fiber optics and optical communications : Fiber design and fabrication
(060.2300) Fiber optics and optical communications : Fiber measurements
(060.2310) Fiber optics and optical communications : Fiber optics
(230.4000) Optical devices : Microstructure fabrication
Yinian Zhu, Ping Shum, Joo-Hin Chong, M. K. Rao, and Chao Lu, "Deep-notch, ultracompact long-period grating in a large-mode-area photonic crystal fiber," Opt. Lett. 28, 2467-2469 (2003)