PHOTONIC CRYSTAL WAVEGUIDE BIOSENSOR

The hollow core photonic crystal waveguide biosensor is designed and described.The biosensor was tested in experiments for artificial sweetener identifcation in drinks.The photonic crystal waveguide biosensor has a high sensitivity to the optical properties of liquids flling up the hollow core.The compactness,good integration ability to different optical systems and compatibility for use in industrial settings make such biosensor very promnising for v arious biomedical applicat ions.

Polarization characteristics of chiral photonic crystal fibers with an elliptical hollow core

The theoretical study of dielectric-chiral photonic crystal fiber （PCF） with an elliptical hollow core is presented. The band structure of chiral photonic crystal （PhC） is calculated by using a modified plane-wave expansion （PWE） method. By examining the out-of-plane photonic bandgaps （PBGs） of chiral PhC, a kind of chiral PCF with a hollow core is designed and their eigenstates are calculated. The distributions of mode field and polarization state are demonstrated, and how the structural asymmetry of the core together with the chirality in the background affects the modal polarization is discussed. The dependences of birefringence on chirality for different ellipticities of core are investigated.

Benzene Shape Photonic Crystal Fiber Based Plasma Sensor： Design and Analysis

A novel benzene core photonic crystal fiber （BC-PCF） is proposed for plasma sensing applications. The proposed BC-PCF parameters have been tuned to gain high sensitivity, high numerical aperture （NA）, and low confinement loss, and modality over the extensive variety of 0.7 μm to 1.9μm wavelength. The explored results for the ideal structure have exhibited the high sensitivity up to 77.84% and negligible confinement loss of 7.9×10^-3dB/m at 1.3μm wavelength. The V-barometer remains under 2.405 over the whole working wavelength. So the proposed BC-PCF is a single mode fiber, which advances the long partition correspondence applications. Furthermore, high numerical aperture （NA） makes the fiber potential candidate in medical imaging applications. The plan of the sensor is to find out the creative potential outcomes in sensing applications.

Intermodal interference based refractive index sensor employing elliptical core photonic crystal fiber

A refractive index(RI)sensor based on elliptical core photonic crystal fiber(EC-PCF)has been proposed.The asymmetric elliptical core introduces the polarization-dependent characteristics of the fiber core modes.The performances of intermodal interference between the intrinsic polarization fiber core modes are investigated by contrast in two interferometers based on the Mach-Zehnder(M-Z)and Sagnac interference model.In addition,the RI sensing characteristics of the two interferometers are studied by successively filling the three layers air holes closest to the elliptical core in the cladding.The results show that the M-Z interference between LP_(01)and LP_(11)mode in the same polarized direction is featured with the incremental RI sensing sensitivity as the decreasing interference length,and the infilled scope around the elliptical core has a weak correlation with the RI sensing sensitivity.Due to the high birefringence of LP11 mode,the Sagnac interferometer has better RI sensing performance,the maximum RI sensing sensitivity of 12000 nm/RIU is achieved under the innermost one layer air holes infilled with RI matching liquid of RI=1.39 at the pre-setting EC-PCF length of 12 cm,which is two orders of magnitude higher than the M-Z interferometer with the same fiber length.The series of theoretical optimized analysis would provide guidance for the applications in the field of biochemical sensing.

Enhancement of the Sensitivity of Gas Sensor Based on Microstructure Optical Fiber

This paper proposes the design and characterization of microstructure optical fiber for gas sensing applications. The aim is to detect toxic and colorless gases over a wide transmission band covering 0.80 gm to 2.00gm wavelength. Numerical investigation is carried out by using the finite element method （FEM）. The numerical study shows that sensitivity of the proposed sensor is moderately increased by introducing four non-circular holes around the defected core of photonic crystal fiber and the confinement loss is also reduced. Furthermore, we confirm that increasing the diameter of central air core and size of the non-circular holes can improve the relative sensitivity and the confinement loss is reduced by increasing the diameter of air holes in the cladding. The enhancement of the relative sensitivity is more than 27.58% （0.1323 to 0.1688） at the wavelength 2=1.33gm that is the absorption line of methane （CH4） and hydrogen fluoride （HF） gases. The confinement loss of the fiber is 1.765x 10-8dB/m.