Short-length andbroadbandmismatchedopticalcouplerswithtapered Hamming functionforC-andL-band

摘要

Mismatched opticalcouplerswithvariablewidthsofwaveguidetaperedbyHammingfunctionarenumerically investigatedinthedemandofshort-length,broadband,andlowcrosstalk.Weusedglobalsearchalgorithmandbeam propagationmethodtoseekoptimalstructureparametersofcouplingwaveguide.Thecouplerlengthis3.6mmwithin the C+L-band(1.53–1.61 mm) forvariablewidthsofwaveguideatcrosstalklevelof 35 dB.Comparisonwith constant widthofwaveguide,theconstantwidthofwaveguidehasacouplerlengthof4.4mmandcanonlyachieve 20 dBofcrosstalkwithintheC-band(1.53–1.565 mm). Obviously,thewaveguidewithvariablewidthshasthe advantageoverconstantwidthforthedemandofshort-length,bandwidth,andlow-crosstalk.