Research

Membrane photonic circuits

An introduction of photonic integrated circuits (PICs) for on-chip interconnects is considered as a promising solution to replace global electrical wiring on Si-LSIs. For this purpose we have proposed the concept of a membrane PIC composed of InP-based photonic platform with a membrane structure (high-index-contrast waveguide with the thickness of around 200 nm) bonded on Si or SOI substrate using a benzocyclobutene (BCB) adhesive wafer bonding method. The high index contrast (HIC) waveguide structure which enables ultra-small and highly integrated optical circuits is very attractive for realization of low power dissipation photonic devices. Recently, lateral current injection (LCI)lasers with thin core layers have been demonstrated as an application for current injection structure. As a results, very low threshold lasing of optically and also electrically pumped membrane DFB laser have been obtained. With these technologies, we are also engaged in membrane based photodetectors, modulators and waveguides to realize photonic integrated circuits on membrane platform.

Si/III-V Hybrid integration

In recent years, with the rapid increasing of internet traffic, researches are being done to produce large-scale Optical Integrated Circuit possessing high efficient and high capacity optical routing tool. AS an approach, to manufacture optically active devices like optical source and amplifier using III-V semiconductors on Si platform ‘III-V/Si Hybrid Integration process’ is available. Si is a transparent and low-loss medium within communication wavelength band and small-size optical circuit can be manufactured using Si, it is possible to do large-scale integration by CMOS process at low cost. As III-V group semiconductors like InP are direct-bandgap semiconductors, it is possible to realize optical devices using III-V semiconductors which will be difficult to realize using indirect-bandgap Si. In this group, we emphasize on the characteristics of each InP optical source and Si optical waveguides and use their combined structure to realize multi-function optical integrated circuit which is difficult to realize with only InP or Si.

Heterogeneous Integration

Under Construction

Metamaterial devices

Optical metamaterials offer new opportunities for innovation in the field of electromagnetic parameter design, such as the design of permittivity ε and permeability µ. The major focus of attention is to create artificial materials with unique ε-µ values that cannot be observed in any existing media and to take advantage of these expanded parameters for better control of electromagnetic waves. Recent progress in optical metamaterials has allowed researchers to move material properties away from the non-magnetic line µ = 1 and has opened the third quadrant of the parameter space (i.e., ε<0 and simultaneously µ<0), which was previously inaccessible. One of the next trends is to think of metamaterials as devices, where the structuring of metal and the hybridization with functional agents brings new functionality. Especially, introducing optical metamaterials into actual photonic devices poses an exciting challenge. Much effort has been expended in the development of advanced optical applications using the concept of metamaterials. In our laboratory, we demonstrate InP-based optical devices combined with metamaterials to show the possibility of permeability control on the semiconductor-based photonics platform.

LiDAR

Under Construction

Grid-Free WDM with Multipul Wavelength Laser/h2>

Under Construction

Topological Photonic Circuits

Under Construction/p>

Nishiyama Laboratory
Quantum Nanoelectronics Research Core, Tokyo Institute of Technology

7F, S9-1, 2-12-1 O-okayama, Meguro-ku Tokyo 152-8552, Japan +81-3-5734-2555 ee.e titechnishiyama

Nishiyama lab. Student's room : South Bldg. 9 #701, #706, #707 | Measurement room : South Bldg. 9 #604, #502, #201 |
Clean room : South Bldg. 9 #202, B1F Exposure house | Research Laboratory of Ultra-High Speed Electronics