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ABSTRACT: We have numerically demonstrated an efficient mode multiplexer which can tailor the input field patterns by using a phase controller and a mode coupler formed by four single-mode fibers (SMFs). By connecting the mode multiplexer to a multimode fiber (MMF), two orthogonal higher-order modes of the MMF can be simultaneously excited to form two communication channels. The simulated results show that very low modal interference between the two excited modes can be achieved by using the proposed mode multiplexer. We have also discussed the effect of the distance and size of the SMFs in the mode coupler on the performance of the proposed mode multiplexer.
Optics Express 06/2011; 19(13):12673-8. · 3.59 Impact Factor
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ABSTRACT: A novel light-controllable long-period fiber grating (LPFG) is demonstrated by making use of a PCF infiltrated with a photoresponsive liquid crystal (LC) mixture consisting of nematic LC molecules and light-sensitive 4-methoxyazobenzene (4MAB). With the aid of the photo-induced isomerization of 4MAB, the refractive index of the LC mixture can be modulated and the periodic index perturbation along the fiber can be achieved by exposing the PCF to a blue laser through a mask. The resonance wavelength and dip depth of the LPFG can be controlled by using different blue-laser irradiation time, numbers of period, and 4MAB concentrations. In addition, the photo-induced LPFG is erasable under green-laser illumination.
Optics Express 03/2011; 19(7):6756-61. · 3.59 Impact Factor
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ABSTRACT: We report the modal interference in the PCF spliced to two core-size mismatched SMFs. Clear interference patterns can be observed and the relation between the fringe period and the length of the PCF is discussed.
OptoeElectronics and Communications Conference (OECC), 2010 15th; 08/2010
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ABSTRACT: A simple dielectric hollow-tube has been experimentally demonstrated at terahertz range for bio-molecular layer sensing based on the anti-resonant reflecting wave-guidance mechanism. We experimentally study the dependence of thin-film detection sensitivity on the optical geometrical parameters of tubes, different thicknesses and tube wall refractive indices, and on different resonant frequencies. A polypropylene hollow-tube with optimized sensitivity of 0.003 mm/μm is used to sense a subwavelength-thick (λ/225) carboxypolymethylene molecular overlayer on the tube's inner surface, and the minimum detectable quantity of molecules could be down to 1.22 picomole/mm(2). A double-layered Fabry-Pérot model is proposed for calculating the overlayer thicknesses, which agrees well with the experimental results.
Optics Express 08/2010; 18(18):19353-60. · 3.59 Impact Factor
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ABSTRACT: We have theoretically investigated the propagation properties of two kinds of selectively liquid-filled PCFs. For internally liquid-filled PCFs, the outer air-hole layers function as the second cladding to reduce the penetration of the light field while the inner liquid-hole layers can still induce the tunable PBG effect. The complementary structures, externally liquid-filled PCFs, can be used in long-period fiber gratings to decrease the utilization of the lossy liquids and remain single-mode operation for the existence of the inner air-hole layers. The confinement losses of both selectively liquid-filled PCFs are shown to be efficiently reduced due to the outer or inner air-hole layers, which is quite useful for further applications.
Optics Express 06/2009; 17(11):8729-34. · 3.59 Impact Factor
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ABSTRACT: We have theoretically investigated the dispersion characteristics of dispersion compensating fibers based on dual-core liquid-filled PCFs. A very high negative chromatic dispersion value D = -19000 ps/(nm-km) can be achieved at 1.55-microm wavelength by an appropriate design. By varying the geometry of the PCF and the index of the filling liquid, the phase-matching wavelength and dispersion values are shown to be well tuned to desired values. The proposed structure also demonstrates good tunable properties with operation temperature for optical communication systems.
Optics Express 04/2008; 16(7):4443-51. · 3.59 Impact Factor
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ABSTRACT: Dispersion compensating fibers based on dual-core liquid-filled PCFs are proposed. The dispersion characteristics of the proposed structure are investigated. A very high negative chromatic dispersion value D = –19000 ps/(nm-km) can be achieved at 1.55-µm wavelength by an appropriate design. By varying the geometry of the PCF and the index of the filling liquid, the phase-matching wavelength and dispersion values are shown to be well tuned to desired values.
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ABSTRACT: We have theoretically investigated the birefringence and loss properties of the selectively liquid-filled photonic crystal fibers with the liquid asymmetrically infiltrated into one-line air holes along x-axis. A high birefringence value B = 1.74 × 10−3 can be achieved at λ = 1.55 μm. By varying the index of the infiltrating liquid, the birefringence values are shown to be well tuned. In addition, the confinement losses can be efficiently reduced by diminishing the number of liquid holes, which is quite useful for optical devices.
Optics Communications.
