Electrically and mechanically induced long period gratings in liquid crystal photonic bandgap fibers

Technical University of Denmark, Lyngby, Capital Region, Denmark
Optics Express (Impact Factor: 3.49). 07/2007; 15(13):7901-12. DOI: 10.1364/OE.15.007901
Source: PubMed


We demonstrate electrically and mechanically induced long period gratings (LPGs) in a photonic crystal fiber (PCF) filled with a high-index liquid crystal. The presence of the liquid crystal changes the guiding properties of the fiber from an index guiding fiber to a photonic bandgap guiding fiber - a so called liquid crystal photonic bandgap (LCPBG) fiber. Both the strength and resonance wavelength of the gratings are highly tunable. By adjusting the amplitude of the applied electric field, the grating strength can be tuned and by changing the temperature, the resonance wavelength can be tuned as well. Numerical calculations of the higher order modes of the fiber cladding are presented, allowing the resonance wavelengths to be calculated. A high polarization dependent loss of the induced gratings is also observed.


Available from: Jesper Laegsgaard, Jan 06, 2016
Fig. 1.
Danny Noordegraaf, Lara Scolari, Jesper Lægsgaard, Lars Rindorf, Thomas Tanggaard Alkeskjold, "Electrically and mechanically induced long period gratings in liquid crystal photonic
bandgap fibers," Opt. Express 15, 7901-7912 (2007);
Image ©2007 Optical Society of America and may be used for noncommercial purposes only. Report a copyright concern regarding this image.
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    • "Since the attributes of LCs can be tuned easily by applying external stimuli, the transmission characteristics of PLCFs can be simply manipulated in thermal2345678910111213, electric [2,4,9,11,1415161718192021, or optical [3,19,21,22] fields. PLCFs have great potential for practical applications, including long-period gratings [16,22], polarimeters [17], and filters [18]. Mach et al. demonstrated thermal control of the transmission power of a microstructure optical fiber [23]. "
    [Show abstract] [Hide abstract] ABSTRACT: This work demonstrates a multi-stable variable optical attenuator (VOA) that is fabricated by infiltrating a photonic crystal fiber (PCF) with a liquid crystal (LC) gel. Varying the cooling rate or biasing the electric field during gelation yields various degrees of scattering. Therefore, LC gel-filled PCFs with various transmittances can be realized. At a wavelength of 1550 nm, an attenuation rate of −33.4 dB/cm is obtained at a cooling rate of 30°C/min and a biasing voltage of 400 V during gelation. The proposed all-in-fiber VOA exhibits tunable attenuation and multiple stable states at room temperature.
    Full-text · Article · Aug 2014 · Applied Optics
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    • "A lot of researches have been made to study the production of sensor based on PCF filled with fluid. Birefringence tunable optical devices based on sleeve type of PCF selective filling polymer were researched by Noordegraaf et al. [9]. In document [10], it introduced that the continuous tuning birefringence was realized by applied transverse voltage on the PCF filled by liquid crystal. "
    [Show abstract] [Hide abstract] ABSTRACT: In this study, the photonic crystal fiber (PCF) air holes were filled with a kind of new functional material—magnetic fluid (MF) is presented. According to the sensitive characteristics of MF's refractive index versus temperature and magnetic field, the loss characteristic of the PCF filled with MF caused by temperature/magnetic field were analyzed theoretically by finite element method. It could be concluded that when the surrounding temperature rises from 37.5 to 80°C, the PCF loss sensitivity is about −0.167 dB/°C; when the external magnetic field rises from 20 to 300 Oe, the PCF loss sensitivity is about 0.042 dB/Oe. Besides, experiment was also carried out to verify the aforementioned results. With the same external condition, the loss sensitivity of temperature is about −0.167 dB/°C and loss sensitivity of magnetic field is about 0.046 dB/Oe. The results indicated that theoretical calculation basically agrees with the experimental verification, by which a new method and new thought for temperature and magnetic field measurement is provided. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:831–834, 2014
    Full-text · Article · Apr 2014 · Microwave and Optical Technology Letters
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    • "The introduction of the LC or RIF provides additional degree of freedom for designing novel in-fiber devices. For example, the polarization properties can be thermally tuned through the filled LC, resulting in high polarization dependent loss [32]. The LPG in a fluid-filled PCF has a high thermal tuning coefficient of up to –1.58 nm/℃, which is due to the large thermo-optic coefficients of fluid [33]. "
    [Show abstract] [Hide abstract] ABSTRACT: The authors review the recent advances in fabricating long-period gratings (LPGs) in photonic crystal fibers (PCFs). The novel light-guiding properties of the PCFs allow the demonstration of novel sensors and devices based on such LPGs. The sensitivity of these PCF LPGs to temperature, strain and refractive index is discussed and compared with LPGs made on conventional single-mode fibers. In-fiber devices such as tunable band rejection filters, Mach-Zehnder interferometers are discussed. KeywordsPhotonic crystal fiber–long-period grating–optical fiber sensor
    Preview · Article · Mar 2012 · Photonic Sensors
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