Tapered fiber liquid crystal hybrid broad band device

This paper presents the results of design, manufacturing and characterization of a hybrid broad band filter based on taper technology and liquid crystalline structure using a standard single mode fiber. A liquid crystal mixture, denoted 1550*, was designed for the electrically driven modulation of an electromagnetic wave at visible range. The main reason for using a biconical optical fiber taper as a core is surrounding it by a liquid crystalline medium providing the possibility to control an effective refractive index of fiber cladding. Two kinds of rubbing, orientation parallel and orthogonal to the taper axis, were applied. The performance of a tuned cladding was studied at electric field and temperature domains. The induced reorientation of liquid crystal molecules was measured at a broad wavelength range, between 500 and 1200 nm. All fabricated tunable broad band filter devices exhibit internal losses lower than 0.5 dB. (paper)