Date of download: 6/17/2016 Copyright © 2016 SPIE. All rights reserved. Cross section of a triangular-lattice dual-core PCF coupler with d=1μm, Λ=2μm, and dc=0.6μm. Figure Legend: From: Improving triangular-lattice photonic-crystal-fiber couplers by introducing geometric nonuniformities Opt. Eng. 2007;46(9): doi: /

Date of download: 6/17/2016 Copyright © 2016 SPIE. All rights reserved. Coupling length versus hole diameter for different hole spacings with dc=0.6μm at λ=1.55μm. Error bars are only shown for the curve Λ=2μm. Figure Legend: From: Improving triangular-lattice photonic-crystal-fiber couplers by introducing geometric nonuniformities Opt. Eng. 2007;46(9): doi: /

Date of download: 6/17/2016 Copyright © 2016 SPIE. All rights reserved. Power transfer along the PCF coupler at λ=1.55μm with d=0.9μm, Λ=3μm, and dc=0.6μm. Figure Legend: From: Improving triangular-lattice photonic-crystal-fiber couplers by introducing geometric nonuniformities Opt. Eng. 2007;46(9): doi: /

Date of download: 6/17/2016 Copyright © 2016 SPIE. All rights reserved. Coupling efficiency versus hole spacing for different air-hole diameters with dc=0.6μm at λ=1.55μm. Figure Legend: From: Improving triangular-lattice photonic-crystal-fiber couplers by introducing geometric nonuniformities Opt. Eng. 2007;46(9): doi: /

Date of download: 6/17/2016 Copyright © 2016 SPIE. All rights reserved. Coupling length versus central hole size for different air-hole diameters with Λ=2.5μm at λ=1.55μm. Figure Legend: From: Improving triangular-lattice photonic-crystal-fiber couplers by introducing geometric nonuniformities Opt. Eng. 2007;46(9): doi: /

Date of download: 6/17/2016 Copyright © 2016 SPIE. All rights reserved. Coupling length versus hole spacing Λ for different values of e=dy∕dx, with d=dc=dx=1μm at λ=1.55μm. (a) Only the first corona of holes is elliptical; (b) all the holes are elliptical. Figure Legend: From: Improving triangular-lattice photonic-crystal-fiber couplers by introducing geometric nonuniformities Opt. Eng. 2007;46(9): doi: /

Date of download: 6/17/2016 Copyright © 2016 SPIE. All rights reserved. Cross-sectional view of the field distribution for Λ=1.6, with d=dc=dx=1μm at λ=1.55μm: (a) e=1, L=260μm; (b) e=1.6, L=100μm; (c) e=2.5, L=81μm. Figure Legend: From: Improving triangular-lattice photonic-crystal-fiber couplers by introducing geometric nonuniformities Opt. Eng. 2007;46(9): doi: /

Date of download: 6/17/2016 Copyright © 2016 SPIE. All rights reserved. Coupling length versus wavelength for different locations of the central air hole (r=0.2μm, θ=0, π∕4, π∕2). Here d=1.2μm, dc=0.6μm, and Λ=2.5μm. Figure Legend: From: Improving triangular-lattice photonic-crystal-fiber couplers by introducing geometric nonuniformities Opt. Eng. 2007;46(9): doi: /

Date of download: 6/17/2016 Copyright © 2016 SPIE. All rights reserved. (a) Coupling length versus central hole diameter dc. (b) Normalized power transfer versus propagation length (d=1.2μm, Λ=2.5μm, and dc=0.5μm). Figure Legend: From: Improving triangular-lattice photonic-crystal-fiber couplers by introducing geometric nonuniformities Opt. Eng. 2007;46(9): doi: /

Date of download: 6/17/2016 Copyright © 2016 SPIE. All rights reserved. Coupling length versus air-hole spacing. Solid and dashed curves show the coupling lengths for x-polarized and y-polarized modes, respectively. Figure Legend: From: Improving triangular-lattice photonic-crystal-fiber couplers by introducing geometric nonuniformities Opt. Eng. 2007;46(9): doi: /