| AVS 60th International Symposium and Exhibition | |
| Nanometer-scale Science and Technology | Monday Sessions |
| Session NS+BI+EM-MoM |
| Session: | Nanophotonics and Plasmonics |
| Presenter: | P. Stenberg, University of Eastern Finland |
| Authors: | P. Stenberg, University of Eastern Finland M. Roussey, University of Eastern Finland S. Honkanen, University of Eastern Finland M. Kuittinen, University of Eastern Finland |
| Correspondent: | Click to Email |
Research related to Silicon photonics is a topic of high interest in the photonics community. Demands in the field of all optical signal processing are driving research and industry towards faster and more efficient devices and processes. The interest against Silicon is not merely because of the optical characteristics of the material but also because the fabrication of Silicon photonic devices can be adapted to the existing production lines enabling cost efficient mass fabrication.
Our study is focused on a Silicon photonic nanodevice called Merged Photonic Crystal Slot Waveguide (MPCSW), in which features of photonic crystals (PhC) and slot waveguides are compiling, by taking advantage of the slow light effect in the PhC [1] and the field confinement in the slot region [2]. We propose to create the PhC by directly patterning the rails of the slot waveguide. The device is designed on a Silicon on insulator (SOI) substrate and it is coated with amorphous TiO2 by Atomic Layer Deposition (ALD) technique to fill the structure with optically interesting nonlinear material.
We have studied the possibility to use the device as a band pass filter in near infrared region. The MPCSW structure is designed by using three dimensional Finite Difference Time Domain (3D-FDTD) method to create a photonic band gap (PBG) and a transmission peak appearing in the center of it.
For easier coupling, the input and output waveguides are 3 µm wide and are tapered to nano-waveguides. Coupling from a nano-waveguide to a slot waveguide is made by using an adiabatic coupler to reduce the conversion loss. The adiabatic couplers and nano-to-micro tapers are at both ends of the fabricated waveguide structure. The MPCSW is placed in the middle of the waveguide structure and it contains 10 periods of photonic crystal on both sides of the cavity. The whole device is embedded in conformally coated amorphous TiO2.
In our presentation we show results concerning simulation and characterization. In simulation we introduce normalized transmission spectra as a function of the fill factor, the cavity length and the period. Also the group index corresponding to the transmission spectra for the same parameters is presented. The fabrication of the structure is discussed where electron beam lithography, plasma etching and ALD techniques are used. Finally we propose possibilities to use the device in nonlinear guided-wave optics by taking advantages of the slow light effect in the PhC and the field confinement in the slot region when the structure is filled with a nonlinear material.
[1] M. Roussey, J. Opt. Soc. Am. B, 24, 1416-1422, (2007)
[2] A. Säynätjoki, Optics Express, 17, 21066-21075, (2009)