Phase and group modal birefringence of an index-guiding photonic crystal fibre with helical air holes
ABSTRACT In this paper, we propose a novel photonic crystal fibre (PCF) with high phase birefringence and very low group birefringence. It is composed of a solid silica core and a cladding with helix-pattern air holes. Using a full-vector finite-element method, we study the phase and group modal birefringence of such PCF at various air-hole sizes, pitches and wavelengths. Owing to this innovative structure of air holes, a high phase to group modal birefringence rate is obtained. Its phase modal birefringence is as large as 10−4 magnitude; however, the group modal birefringence of this PCF is at 10−7–10−6. The phase birefringence is 2 orders of magnitude larger than group birefringence over a broad wavelength span, which means that the light with different polarization and effective index has almost a same group velocity. As a result, the group modal birefringence that closely relates to the polarization modal dispersion is negligible.
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ABSTRACT: A selectable infiltrating large hollow core photonic band-gap fiber is fabricated with simple arc discharge technique. The offset, discharge duration, arc current and discharge times are optimized for selected sealing side air-holes but leave the central large air-hole partially open. The collapse length of the PCF is shortened by increasing the number of discharges and offset with discharge duration and arc current kept at a relatively low level. Light with the wavelength located at the photonic band-gap can still propagate while the central hollow air-hole is infiltrated with a kind of oil with refractive index of 1.30. The selectable infiltrating large hollow core photonic band-gap fiber has potential application for implementing novel lasers, sensors and tunable optoelectronic devices.Chinese Science Bulletin 07/2012; 58(21). DOI:10.1007/s11434-012-5549-5 · 1.37 Impact Factor
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ABSTRACT: We experimentally and theoretically study nonlinear light propagation in a rotating waveguide array. We show that noninertial effects can lead to mode conversion, enhanced transport, and vector (gap) soliton formation. Experimentally, we directly observe these dynamics, both within and between bands, by recording intensity in position space and power spectra in momentum space. The results are fundamental to all rotating nonlinear lattices and hold potential for a variety of twisted photonic devices.Physical Review A 04/2009; 79(4). DOI:10.1103/PhysRevA.79.041804 · 2.99 Impact Factor
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ABSTRACT: By adjusting the polarisation state of the pump at 805 nm parallel to slow (x) and fast (y) axes of the highly birefringent photonic crystal fibre with zero dispersion wavelengths 790 nm and 750 nm, this paper demonstrates the efficient polarisation-sensitive four wave mixing involved in pump, anti-Stokes and Stokes signals and soliton self-frequency shift effects induced by the phase-matching between red-shifted solitons and blue-shifted dispersive waves. If the reduction of coupling efficiency to the circular pump laser mode or other circular fibres due to asymmetry of the core is neglected, more than 98% of the total input power is kept in a single linear polarisation. Controlled dispersion characteristic of the doublet of fundamental guided-modes results in achieving light field strongly confined in principal axes of photonic crystal fibre, and enhancing the corresponding nonlinear-optical process through the remarkable nonlinear birefringence.Chinese Physics B 07/2010; 19(7):074218. DOI:10.1088/1674-1056/19/7/074218 · 1.39 Impact Factor