Ultracompact polarization converter with a dual subwavelength trench built in a silicon-on-insulator waveguide

Optics Letters (Impact Factor: 3.18). 01/2012; 37:365-367.

ABSTRACT The design and fabrication of an ultracompact silicon-on-insulator polarization converter is reported. The polarization conversion with an extinction ratio of 16 dB is achieved for a conversion length of only 10 μm. Polarization rotation is achieved by inducing a vertical asymmetry by forming in the waveguide core two subwavelength trenches of different depths. By taking advantage of the calibrated reactive ion etch lag, the two depths are implemented using a single mask and etching process. The measured converter loss is −0.7  dB and the 3 dB bandwidth is 26 nm.

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