Highly Nonlinear and Birefringent Spiral Photonic Crystal Fiber

<table>Birefringence versus wavelength for fixed ellipticity ratios of 1.4, 1.5, 1.6, and 1.7 with fundamental <svg height="11.175" id="M25" style="vertical-align:-0.0pt" version="1.1" viewbox="0 0 13.5875 11.175" width="13.5875" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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l-110 215q-26 51 -44 63t-72 17l6 28h250l-6 -28l-27 -4q-30 -5 -35 -10t3 -27q17 -43 95 -190q70 78 154 185q15 21 10 29.5t-33 12.5l-30 4l5 28h236z" id="x1D44B"></path></g>
</svg> and <svg height="11.175" id="M26" style="vertical-align:-0.0pt" version="1.1" viewbox="0 0 11.6625 11.175" width="11.6625" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,-0,0,-.017,.062,11.113)"><path d="M667 650l-9 -28q-53 -5 -76 -17t-64 -59q-51 -61 -175 -225q-21 -29 -27 -55l-27 -136q-13 -65 -0.5 -80t83.5 -22l-7 -28h-280l8 28q64 4 81 19t30 83l25 128q6 35 -7 65l-98 231q-17 41 -32.5 52t-68.5 16l8 28h252l-6 -28l-40 -4q-27 -3 -33 -12.5t2 -31.5
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</svg> polarization modes.</table>

Advances in OptoElectronics

Highly Nonlinear and Birefringent Spiral Photonic Crystal Fiber

Figure 4