An APF (All-Pass Filter) delay module in which eight single-ring resonators are serially cascaded is designed and fabricated. The polymer waveguide used for the realization of the APF delay module is a buried structure whose core width and height are 1.5μm. The core and cladding index are 1.51 and 1.378, respectively, which corresponds to the relative index difference of 8%. In order to use a thermo-optic effect of polymer materials, electrodes are evaporated above the ring resonator to provide heating currents. The time delay is measured to be about 50 ps when 2 rings are in resonance, and about 105 ps and 150 ps, respectively, when 4 and 6 rings of APF are in resonance, respectively. When all of 8 rings are in resonance, the delay is measured to be about 200 ps.
2. Vestergaard Hau, L., S. E. Harris, Z. Dutton, C. H. Behroozi, "Light speed reduction to 17 metres per second in an ultracold atomic gas," Nature, Vol. 397, 594, 1999.
3. Bajcsy, M., A. S. Zibrov, and M. D. Lukin, "Stationary pulses of light in an atomic medium," Nature, Vol. 426, 638, 2003.
4. Okawachi, Y., M. S. Bigelow, J. E. Sharping, Z. Zhu, A. Schweinsberg, D. J. Gauthier, R. W. Boyd, and A. L. Gaeta, "Tunable all-optical delays via Brillouin slow light in an optical fiber," Phys. Rev. Lett., Vol. 94, 153902, 2005.
5. Song, K. Y. and K. Hotate, "25 GHz bandwidth Brillouin slow light in optical fibers," Opt. Lett., Vol. 32, 217, 2007.
6. Camacho, R. M., M. V. Pack, J. C. Howell, A. Schweinsberg, and R. W. Boyd, "Wide-bandwidth, tunable, multiple-pulse-width optical delays using slow light in cesium vapor," Phys. Rev. Lett., Vol. 98, 153601, 2007.
7. Zuang, L., C. G. H. Roelo?zen, R. G. Heideman, A. Borreman, A. Meijerink, and W. van Etten, "Single-chip ring resonator-based 1 x 8 optical beam forming network in CMOS-compatible waveguide technology," IEEE Photon. Technol. Lett., Vol. 19, 1130-1132, 2007.
8. Rasras, M. S., et al., "Integrated resonance-enhanced variable optical delay lines," IEEE Photon. Technol. Lett., Vol. 17, 834-836, 2005.
9. Madsen, C. K. and G. Lenz, "Optical all-pass filters for phase response design with applications for dispersion compensation," IEEE Photon. Technol. Lett., Vol. 10, 994-996, 1998.
10. Khurgin, J. B., "Optical buffers based on slow light in electromagnetically induced transparent media and coupled esonator structures: Comparative analysis," J. Opt. Soc. Am. B, Vol. 22, 1062, 2005.
11. Ghulinyan, M., M. Galli, C. Toninelli, J. Bertolotti, S. Gottardo, F. Marabelli, D. Wiersma, L. Pavesi, and L. Andreani, "Wide-band transmission of non-distorted slow waves in one-dimensional optical superlattices," Appl. Phys. Lett., Vol. 88, 241103, 2006.
12. Lee, D., T. Lee, J. Park, S. Kim, and Y. Chung, "Widely tunable double-ring-resonator add/drop filter," Korean J. Opt. Photon. (HankookKwanghakHoeji), Vol. 18, 216-220, 2007.
13. Kwon, O., J. Kim, and Y. Chung, "Design and fabrication of variable optical signal delay line based on polymer coupled ring resonators," Korean J. Opt. Photon. (HankookKwanghakHoeji), Vol. 22, 256-261, 2011.
14. Poon, J. K. S., J. Scheuer, and A. Yariv, "Wavelength-selective reflector based on a circular array of coupled microring resonators," IEEE Photon. Technol. Lett., Vol. 16, 1331-1333, 2004.
15. Poon, J. K. S. , J. Scheuer, S. Mookherjea, G. T. Paloczi, Y. Huang, and A. Yariv, "Matrix analysis of microring coupled-resonator optical waveguides," Opt. Express, Vol. 12, 90-103, 2004.
16. Yariv, A., Y. Xu, R. K. Lee, and A. Scherer, "Coupled-resonator optical waveguide: A proposal and analysis," Opt. Lett., Vol. 24, 711-713, 1999.
17. Morichetti, F., A. Melloni, C. Canavesi, F. Persia, M. Martinelli, and M. Sorel, "Tunable slow-wave optical delay-lines," Slow and Fast Light, MB2, Washington DC, 2006.
18. Poon, J. K. S., L. Zhu, G. A. De Rose, and A. Yariv, "Transmission and group delay of micro ring coupled resonator," Opt. Lett., Vol. 31, 456, 2006.
19. Morichetti, F., A. Melloni, A. Breda, A. Canciamilla, C. Ferrari, and M. Martinelli, "A reconfigurable architecture for continuously variable optical slow-wave delay lines," Opt. Express, Vol. 15, 17273-17282, 2007.
20. Melloni, A., F. Morichetti, and M. Martinelli, "Linear and nonlinear pulse propagation in coupled resonator slow-wave optical structures," Opt. Quantum Electron., Vol. 35, 365-379, 2003.
21. Reynolds, A. L., U. Peschel, F. Lederer, P. J. Roberts, T. F. Krauss, and P. J. I. De Maagt, "Coupled defects in photonic crystals," IEEE Trans. Microwave Theory Tech., Vol. 49, 1860, 2001.
22. Xia, F., L. Sekaric, and Y. Vlasov, "Ultracompact optical buffers on a silicon chip," Nature Photonics, Vol. 1, 65-71, 2007.