ALD high-k layer grating couplers for single and double slot on-chip SOI photonics

作者：Naiini Maziar M^*; Henkel Christoph; Mahn Gunnar B; Ostling Mikael

来源：Solid-State Electronics, 2012, 74: 58-63.

DOI：10.1016/j.sse.2012.04.012

• Integrated photonics
• Grating couplers
• High-k thin films
• Slot waveguides
• Fabrication and characterization

State of the art grating couplers for horizontal single and double slot waveguides are presented; in these devices the input signal is transmitted from a single mode optical fiber to silicon on insulator slot waveguide. In the waveguides, atomic layer deposited (ALD) high-k dielectrics form the low refractive index slot. It is demonstrated that a fully etched design combined with precision of ALD result in highly reproducible devices with theoretical efficiency variations less than 1%. Devices have a peak calculated coupling efficiency of 24% at 1.55 mu m. In order to achieve an optimal design, optical properties of high-k films are studied by spectroscopic ellipsometry. Measured refractive indices show variations from reference values, originated from film variation in densities. Chips with a test slot material are fabricated and the optical efficiency of the couplers is characterized. The maximum measured coupling efficiency of the couplers is 18.5%.

• 出版日期2012-8