Power Coupling Efficiency Enhancement in Multimode Step-Index Fiber Using Refractive and Diffractive Microlenses

<table>Power coupling efficiency <svg height="9.875" id="M204" style="vertical-align:-2.29482pt" version="1.1" viewbox="0 0 7.9375 9.875" width="7.9375" xmlns="http://www.w3.org/2000/svg">
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</svg> is shown as a function of beam wavelength <svg height="10.8125" id="M205" style="vertical-align:-0.20064pt" version="1.1" viewbox="0 0 8.5749998 10.8125" width="8.5749998" xmlns="http://www.w3.org/2000/svg">
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</svg> for two different beam spot sizes at the beam waist. The fibre parameters are <svg height="14.7875" id="M206" style="vertical-align:-3.13504pt" version="1.1" viewbox="0 0 60.724998 14.7875" width="60.724998" xmlns="http://www.w3.org/2000/svg">
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<tspan style="font-size: 12.50px; " x="21.405136" y="0">4</tspan>
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</svg>, <svg height="11.45" id="M207" style="vertical-align:-0.23827pt" version="1.1" viewbox="0 0 50.287498 11.45" width="50.287498" xmlns="http://www.w3.org/2000/svg">
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<g transform="translate(72,-62.84)">
<text transform="matrix(1,0,0,-1,-71.95,63.12)">
<tspan style="font-size: 12.50px; " x="0" y="0">Δ</tspan>
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<tspan style="font-size: 12.50px; " x="24.530886" y="0">1</tspan>
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</svg> and <svg height="11.1" id="M208" style="vertical-align:-0.17555pt" version="1.1" viewbox="0 0 69.150002 11.1" width="69.150002" xmlns="http://www.w3.org/2000/svg">
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<tspan style="font-size: 12.50px; " x="0" y="0">N</tspan>
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<tspan style="font-size: 12.50px; " x="39.584499" y="0">.</tspan>
<tspan style="font-size: 12.50px; " x="42.710247" y="0">2</tspan>
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International Journal of Optics

fig9

Figure 9

Figure 9: Power Coupling Efficiency Enhancement in Multimode Step-Index Fiber Using Refractive and Diffractive Microlenses 