1. Integrated High Order Filters in AlGaAs Waveguides with up to Eight Side-Coupled Racetrack Microresonators Rajiv Iyer ‡, Francesca Pozzi †, Marc Sorel †, Zhenshan Yang ‡, Philip Chak ‡, John Sipe ‡, Stewart Aitchison ‡ ‡ Department of Electrical and Computer Engineering, Department of Physics, University of Toronto, Toronto, Canada † Department of Electronics & Electrical Engineering, University of Glasgow, Glasgow, UK

2. Overview Microrings and SCISSORs Microrings and SCISSORs SCISSOR modeling SCISSOR modeling Design and Fabrication of 8 ring AlGaAs SCISSOR Design and Fabrication of 8 ring AlGaAs SCISSOR Experimental Results Experimental Results Summary Summary

3. Microresonators as Filters

4. SCISSOR Structures Side-Coupled-Integrated-Spaced-Sequence- Of-Resonators Side-Coupled-Integrated-Spaced-Sequence- Of-Resonators Have been proposed for: high-order filtering, optical logic, and slow light Have been proposed for: high-order filtering, optical logic, and slow light

5. Racetrack SCISSOR

6. SCISSOR Modeling   L r zz

7. Waveguide Design Spatial modal profiles computed using Full-vectorial finite- difference analysis n eff @ 1550 nm = 2.975 StraightCurved

8. Experimental Setup

9. Results for 8 ring SCISSOR 8 ring SCISSOR 8 ring SCISSOR 20.7 micron ring-to-ring separation 20.7 micron ring-to-ring separation 165 nm coupling gap 165 nm coupling gap Loss parameter = 3.8 cm -1 Loss parameter = 3.8 cm -1  2 = 0.15  0.13  2 = 0.15  0.13 n eff = 2.975  2.967 n eff = 2.975  2.967 TM 0 performed significantly better than TE 0 TM 0 performed significantly better than TE 0 Simulation time ~ 2 seconds

10. Summary Our Hamiltonian formulation of coupled mode equations is a fast and useful design tool to model high-index contrast structures Our Hamiltonian formulation of coupled mode equations is a fast and useful design tool to model high-index contrast structures We fabricated an 8-ring SCISSOR structure in AlGaAs We fabricated an 8-ring SCISSOR structure in AlGaAs Next steps… Next steps… Decrease losses in the device Demonstrate slow light behavior and nonlinear effects THANK YOU

11. Integrated High Order Filters in AlGaAs Waveguides with up to Eight Side-Coupled Racetrack Microresonators Rajiv Iyer, Francesca Pozzi, Marc Sorel, Zhenshan Yang, Philip Chak, John Sipe, Stewart Aitchison rajiv.iyer@utoronto.ca

12. References [1] V. Van, et. al, “Optical signal processing using nonlinear semiconductor microring resonators,” IEEE Journal of Selected Topics in Quantum Electronics, Vol. 8, No. 3, 705-713, (2002). [2]Hryniewicz, et. al, “Higher Order Filter Response in Coupled Microring Resonators,” Phot. Tech. Lett., Vol. 12, No. 3, (2000). [3] S. Pereira, P. Chak and J. E. Sipe, “All-optical AND gate by use of a Kerr nonlinear microresonator structure”, Opt. Lett., Vol. 28, No. 6, 444-446 (2003). [4] J. E. Heebner, R. W. Boyd, Q-Han Park, “SCISSOR Solitons and other novel propagation effects in microresonator-modified waveguides,” JOSA B, Vol. 19, No. 4, 722-731 (2002). [5] R. Grover, V. Van, T.A. Ibrahim, P.P. Absil, L.C. Calhoun, F.G. Johnson, J.V. Hryniewicz, P.-T. Ho, “Parallel-Cascaded Semiconductor Microring Resonators for High-Order and Wide-FSR Filters,” Jour. Light. Tech, Vol. 20, No. 5, 900-905 (2002). [6]M.F. Yanik, S. Fan, “Stopping light all optically,” Phys. Rev. Lett. 92, 083901, (2004). [7] P. Chak, R. Iyer, J. S. Aitchison, and J. E. Sipe, “Hamiltonian formulation of coupled- mode theory in waveguide structures,” submitted to Phys. Rev. E. (2005). [8] MODE Solutions software package from Lumerical Solutions Inc. Suite 660 - 789 West Pender Street, Vancouver, British Columbia, Canada, V6C 1H2.. www.lumerical.com. www.lumerical.com

13. For the RING gap, For the RING gap, the v g  0 and GVD  min at band edge Slowing and stopping light possible Slowing and stopping light possible III-V SCISSOR structures are difficult to fabricate due to sub-micron feature sizes III-V SCISSOR structures are difficult to fabricate due to sub-micron feature sizes