Nagoya University · Engineering
Professor Hiroshi Hasegawa's research lab specializes in advanced optical communication systems and photonic technologies, with a strong focus on next-generation optical networking, reservoir computing, and high-capacity optical transmission. The lab explores innovative architectures such as spatial channel networks, elastic optical networks, and hybrid reservoir computing systems to enhance network flexibility, spectrum efficiency, and computational performance. Key research directions include all-optical signal processing, photonic machine learning, and the development of energy-efficient, scalable optical infrastructure for future communication networks. The lab also investigates fundamental physical phenomena in semiconductor materials, such as strain-induced band structure changes, to support next-generation optoelectronic devices.
Figures are computed from collected data and may differ slightly.
The valence band structure in silicon single crystals subjected to an external uniaxial stress is investigated. The cyclotron resonance line for holes in such crystals is predicted to display a significant shift with increasing stress, if the split band populated with holes is associated with the quantum number ${M}_{J}=\ifmmode\pm\else\textpm\fi{}\frac{1}{2}$. This strain-induced shift is characterized by the following properties: (a) Its magnitude is of the order of 10% of the frequency for st
Photonic reservoir computing has been intensively investigated to solve machine learning tasks effectively. A simple learning procedure of output weights is used for reservoir computing. However, the lack of training of input-node and inter-node connection weights limits the performance of reservoir computing. The use of multiple reservoirs can be a solution to overcome this limitation of reservoir computing. In this study, we investigate parallel and deep configurations of delay-based all-optic
We propose a novel network architecture that exploits coarse granular routing while add/drop operations are done at wavelength granularity. For the proposal, we introduce a node architecture and a network design algorithm. Numerical results demonstrate that the proposed architecture’s performance approaches that of single-layer optical path networks while substantially reducing hardware scale.
A spatial channel network (SCN) was recently proposed toward the forthcoming spatial division multiplexing (SDM) era, in which the optical layer is explicitly evolved to the hierarchical SDM and wavelength division multiplexing layers, and an optical node is decoupled into a spatial cross-connect (SXC) and wavelength cross-connect to achieve an ultrahigh-capacity optical network in a highly economical manner. In this paper, we report feasibility demonstrations of an evolution scenario regarding
Elastic optical networks (EONs) are able to provide high spectrum utilization efficiency due to flexibility in resource assignment. In translucent EONs, by employing regenerators and using advanced modulation formats for transmission, spectrum efficiency can be further improved. Survivability is regarded as an important aspect of EONs, and p-cycle protection is considered to be an attractive scheme due to its fast restoration and high protection efficiency. In this paper, we propose methods for
The erosive burning effects in a small test motor loaded with highly aluminized practical composite propellants have been investigated in detail by using an X-ray absorption diagnostics to measure the propellant local regression. The motor was specially designed to have two propellant slabs and was called as DSM (Double Slab Motor). Significant erosive burning was forced to occur in the motor for several combustion pressure levels and ranges of mass flux in the port. A new simple correlative equ
A novel coarse granular routing scheme for elastic optical networks is proposed in this paper, together with a node architecture and a network design algorithm. The proposed scheme allows any combination of optical paths to be routed together, and each bundle of paths, named waveband, is routed as an entity. The flexibility in bundled paths differentiates the proposed routing scheme from optical path hierarchies proposed so far and is especially appropriate for elastic optical path networks in w
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