Katsu Okamoto

 

CTO AiDi Corporation

Email: katsu@okamoto-lab.com

 

Optical fibers, PLCs (planar lightwave circuits) and InP PICs (photonic integrated circuits) are fundamental building blocks of optical communication systems such as wavelength division multiplexing (WDM), time division multiplexing (TDM), code division multiplexing (CDM) systems, and fiber-to-the-home (FTTH) access networks. The most prominent feature of the planar waveguide device is its simple and well defined waveguide structure. This allows us to fabricate functional devices such as arrayed-waveguide gratings (AWGs), reconfigurable optical add/drop multiplexers (ROADMs), wavelength selective switches (WSSs), and etc.

Planar waveguide devices are widely regarded as the best hope to meet rapidly growing bandwidth requirements while similarly reducing cost per bit. Benefits of photonic integration come mainly from (1) small size by eliminating fiber connections, (2) high reliability and (3) stability of the spatial/temporal interference circuits. The third is specific to photonic devices and is not applicable to electronics circuits.

Silicon photonics is now a technical focus, because it potentially offers an entirely new generation of ultra-compact and low-cost photonic integrated circuits. By integrating fundamental building blocks (such as lasers, modulators, multi/demultiplexer, and detectors) on a single silicon substrate, one could produce a silicon photonics chip that has both electronic and photonics functionalities.

The lecture will describe fundamental principles of fibers and waveguides, numerical analysis/design technique such as BPM, and review state-of-the-art fiber and PLC technologies such as photonic crystal fibers, AWGs, and silicon photonics etc.

 

1. Optical waveguides
2. Optical fibers
3. Nonlinear optical effects in fibers
4. Beam propagation method
5. Principle of AWG and functional PLC devices
6. Silicon photonics

 

Katsunari Okamoto received the B.S., M.S., and Ph.D. degrees in electronics engineering from Tokyo University, Tokyo, Japan, in 1972, 1974, and 1977, respectively. He joined Nippon Telegraph and Telephone Corporation (NTT), Japan, in 1977, and was engaged in the research on transmission characteristics of fibers and fiber-optic components. He proposed for the first time the dispersion-flattened fiber (DFF) and succeeded in fabrication of DFF that had chromatic dispersion less than +/-1 ps/km/nm over a wide spectral range. Since 1990, he has been working on the analysis and synthesis of guided-wave devices, the computer-aided-design (CAD) and fabrication of silica-based planar lightwave circuits (PLCs) at NTT Photonics Laboratories. He developed a CAD tool based on the beam propagation method and a FEM waveguide and stress analyses. The design tool for arrayed-waveguide grating (AWG) filter is widely utilized in NTT Photonics Laboratory and its subsidiary company (NEL). He is well-known for developing various kinds of AWGs and integrated-optic reconfigurable add/drop multiplexers. AWGs are now widely used in the commercial WDM systems. From 2006 to 2008, he was a Professor of Electrical and Computer Engineering at the University of California at Davis (UC Davis). His research at UC Davis includes passive and active photonics devices for high-performance all optical networks. He is currently the CTO of AiDi Corporation, Japan.

Dr. Okamoto is a Fellow of the Institute of Electrical and Electronics Engineers (IEEE). He has published more than 240 papers in technical journals and international conferences. He authored and co-authored 8 books including “Fundamentals of Optical Waveguides” (Elsevier).