Research

Last missing component for Si Photonics...

Si laser diodes are expected to revolutionize the way we communicate within a tiny Si chip: from electrical to optical interconnections. On-chip optical interconnection will provide ultra-fast clock distribution among multi-core processors with low power consumptions and ultimately realize the on-chip data centre that integrates optical networks between cores and solid-state-disks.

Si photonics is making disruptive innovation replacing Cu based electrical interconnections with optical interconnections. Si photonics has advantages over the conventional III-V compound semiconductor based legacy technologies in terms of low cost, low power, and high integration capabilities. Recently, almost all optical components have been developed in Si Photonics like high speed modulators, detectors, low loss waveguide, and so on. However, the light source made on Si is the last missing component to realize the full monolithic integration. There are several practical solutions to integrate III-V lasers by wafer bonding or hybrid integration. But, Si based lasers are ideal to achieve the photonics and electronics convergence on a Si chip.

Si Quantum Well Light-Emitting Diode

How to overcome the in-direct band gap...

Quantum Confinement

Compatible with Carrier Injection

According to our first-principle calculations, we can expect direct recombination in ultra-thin Si Quantum-Well by conduction band valley projections. We have confirmed strong photo-luminescence from Si QW (001) with thickness down to or less than 1.0 nm (5 atomic layers). It was difficult to accommodate the compatibility between quantum confinements and carrier injections. To achieve it, we employed lateral carrier injections suitable for Si processes, and fabricated a Si QW Light-Emitting-Diode (LED) with Si3N4 optical waveguide.

Si Quantum Well Membrane LED fabricated by state-of-the-art Si CMOS & MEMS processes

We are developing toward the first

Si Quantum Well Laser Diodes.

Stimulated emissions observed exclusively at the waveguide edge, but still below lasing threshold...

Collaborators:

Prof. Y. Arakawa, Prof. S. Iwamoto, Dr. S. Kako (University of Tokyo).

Drs. T. Ido, Y. Suwa, K. Tani, K. Oda, M. Sagawa, J. Kasai, (PETRA, PECST, Hitachi), T. Okumura, M. Takahashi, E. Nomoto, T. Mine, Y. Lee, H. Arimoto,

N.Sakuma, D. Hisamoto, H. Uchiyama, J. Yamamoto, T. Sakamizu,

S. Kimura, T. Sugawara, and M. Aoki, and more engineering support staffs (Hitachi).