title: Structural long period gratings made by drilling micro-holes in photonic crystal fibers with a femtosecond infrared laser.
abstract: We present a new method for fabricating structural long-period gratings (LPGs) in photonic-crystal fibers (PCFs). The method is based on periodically drilling holes into the PCF cladding along the length of the fiber by use of a focused femtosecond infrared laser. A very short LPG with only 9 periods and a grating length of < 4 mm exhibited resonance strength of over 20 dB and a polarization dependent loss of 25 dB. The high resonance strength is attributed to the strong modulated mode-field profile caused by the significant perturbation of the fiber geometry. The mechanism of LPG formation is discussed based on coupled local-mode theory.
authors.affiliation: Department of Electrical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon,Hong Kong, PR China.
authors.forename: Shujing
authors.initials: S
authors.lastname: Liu
authors.forename: Long
authors.initials: L
authors.lastname: Jin
authors.forename: Wei
authors.initials: W
authors.lastname: Jin
authors.forename: Dongning
authors.initials: D
authors.lastname: Wang
authors.forename: Changrui
authors.initials: C
authors.lastname: Liao
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D007834:Lasers; D017785:Photons; D012031:Refractometry / Q000295:instrumentation*