title: Optically controllable side-polished fiber attenuator with photoresponsive liquid crystal overlay.
abstract: This study presents an optically controllable fiber-optic attenuator consisting of side-polished fiber (SPF) with a photoresponsive liquid crystal (LC) overlay operating in the telecommunication wavelength. Attenuation is controlled by a photochemical-induced phase transition of photoresponsive LC, which modulates the evanescent field leaked from the polished area. Before optical field illumination, the photoresponsive LCs are in the light-scattering state and attenuation is high. During photoirradiation, the formation of cis-azobenzene LC disrupts the nematic host and generates a light-transparent state in which the optical loss of the SPF attenuator decreases. The photoinduced tuning range is 15 dB at an environmental temperature of 45 degrees C, and a repeatable and reversible tuning is observed with a response time of less than 5 s. The proposed all-optical controllable attenuator has potential use as an optical signal modulator in an all-fiber telecommunication system.
authors.affiliation: Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, Nantou, Taiwan. kshsiao@ncnu.edu.tw
authors.forename: Vincent K S
authors.initials: VK
authors.lastname: Hsiao
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.forename: Zhe
authors.initials: Z
authors.lastname: Chen
authors.forename: Peng-Chun
authors.initials: PC
authors.lastname: Peng
authors.forename: Jieyuan
authors.initials: J
authors.lastname: Tang
mesh_terms: D005336:Fiber Optic Technology / Q000295:instrumentation*; D007909:Lenses; D008027:Light; D050866:Liquid Crystals / Q000737:chemistry* / Q000528:radiation effects; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation; D013685:Telecommunications / Q000295:instrumentation*