Compact broadband polarizer based on shallowly-etched silicon-on-insulator ridge optical waveguides - eScholarship (2010)

Compact broadband polarizer based on shallowly-etched silicon-on-insulator ridge optical waveguides Daoxin Dai, * Zhi Wang, Nick Julian and John E. Bowers University of California Santa Barbara, ECE Department, Santa Barbara, CA 93106, USA dxdai@ece.ucsb.edu Abstract: A new way to make broadband polarizers on silicon-on-insulator (SOI) waveguides is proposed, analyzed and characterized. The characteristics of the eigenmodes in a shallowly-etched SOI ridge optical waveguide are analyzed by using a full-vectorial finite-different method (FV-FDM) mode solver. The theoretical calculation shows that the loss of TE fundamental mode could be made very low while at the same time the TM fundamental mode has very large leakage loss, which is strongly dependent on the trench width. The leakage loss of the TM fundamental mode changes quasi-periodically as the trench width w tr varies. The formula of the period ∆w tr is given. By utilizing the huge polarization dependent loss of this kind of waveguide, a compact and simple optical polarizer based on a straight waveguide was demonstrated. The polarizer is fabricated on a 700nm-thick SOI wafer and then characterized by using a free-space optical system. The measured extinction ratio is as high as 25dB over a 100nm wavelength range for a 1mm-long polarizer. ©2010 Optical Society of America OCIS codes: (230.7390) Waveguides, planar; (230.5440) Polarization-sensitive devices. References and links Y. Kokubun, and S. Asakawa, “ARROW-type polarizer utilizing form birefringence in multilayer first cladding,” IEEE Photon. Technol. Lett. 5(12), 1418–1420 (1993). L. Pierantoni, A. Massaro, and T. Rozzi, “Accurate modeling of TE/TM propagation and losses of integrated optical polarizer,” IEEE Trans. Microw. Theory Tech. 53(6), 1856–1862 (2005). M. A. Duguay, Y. Kokubun, T. L. Koch, and L. Pfeiffer, “Antiresonant reflecting optical waveguides in Si0 2 -Si multilayer structures,” Appl. Phys. Lett. 49(1), 13–15 (1986). T. Yamazaki, J. Yamauchi, and H. Nakano, “A branch-type TE/TM wave splitter using a light-guiding metal line,” J. Lightwave Technol. 25(3), 922–928 (2007). L. Z. Sun, and G. L. Yip, “Analysis of metal-clad optical waveguide polarizers by the vector beam propagation method,” Appl. Opt. 33(6), 1047–1050 (1994). G. Y. Li, and A. S. Xu, “Analysis of the TE-pass or TM-pass metal-clad polarizer with a resonant buffer layer,” J. Lightwave Technol. 26(10), 1234–1241 (2008). R. Wan, F. Liu, X. Tang, Y. Huang, and J. Peng, “Vertical coupling between short range surface plasmon polariton mode and dielectric waveguide mode,” Appl. Phys. Lett. 94(14), 141104 (2009). R.-C. Twu, C.-C. Huang, and W.-S. Wang, “TE-pass Zn-diffused liNbO 3 waveguide polarizer,” Microw. Opt. Technol. Lett. 48(11), 2312–2314 (2006). Y. Cui, Q. Wu, E. Schonbrun, M. Tinker, J.-B. Lee, and W. Park, “Silicon-based 2-D slab photonic crystal tm polarizer at telecommunication wavelength,” IEEE Photon. Technol. Lett. 20(8), 641–643 (2008). A. d’Alessandro, B. Bellini, D. Donisi, R. Beccherelli, and R. Asquini, “Nematic Liquid Crystal Optical Channel Waveguides on Silicon,” IEEE J. Quantum Electron. 42(10), 1084–1090 (2006). D. Liang, and J. E. Bowers, “Recent progress in lasers on silicon,” Nat. Photonics 4(8), 511–517 (2010). Q. Wang, and S. T. Ho, “Ultracompact TM-pass silicon nanophotonic waveguide polarizer and design,” IEEE J. Photon. 2(1), 49–56 (2010). A. A. Oliner, S. T. Peng, T. I. Hsu, and A. Sanchez, “Guidance and leakage properties of a class of open dielectric waveguides: Part II-New physical effects,” IEEE Trans. Microw. Theory Tech. 29(9), 855–869 (1981). K. Ogusu, “Optical strip waveguide: a detailed analysis including leaky modes,” J. Opt. Soc. Am. 73(3), 353– M. A. Webster, R. M. Pafchek, A. Mitchell, and T. L. Koch, “Width dependence of inherent tm-mode lateral leakage loss in silicon-on-insulator ridge waveguides,” IEEE Photon. Technol. Lett. 19(6), 429–431 (2007). #136369 - $15.00 USD Received 11 Oct 2010; revised 16 Nov 2010; accepted 23 Nov 2010; published 14 Dec 2010 (C) 2010 OSA 20 December 2010 / Vol. 18, No. 26 / OPTICS EXPRESS 27404