The singlemode Si-photonic wire waveguide allows sharp bends,which significantly expands the design flexibility of optical devices and circuits. Here, the suppression of the polarization crosstalk at a sharp bend will be an important issue, since a large crosstalk affects the performance of devices and circuits. In this study, the three-dimensional (3-D) finite-difference time-domain (FDTD) simulation showed that the crosstalk at a 90°-bend with a radius of 0.35-1.75 µm is less than -25 dB at a wavelength of 1.55 µm. In the experiment,the crosstalk from TE-like to TM-like polarization was evaluated to be -13 dB to -10 dB. This large value was explained by a small tilt of waveguide sidewalls, which seriously increased the crosstalk. In addition, it was found in the calculation that some combinations of bends increase or decrease the crosstalk, and that a U-shape bend is the most effective for the suppression of the crosstalk.
© 2004 IEEE
Atsushi Sakai, Tatsuhiko Fukazawa, and Toshihiko Baba, "Estimation of Polarization Crosstalk at a Micro-Bend in Si-Photonic Wire Waveguide," J. Lightwave Technol. 22, 520- (2004)