Tokyo Institute of Technology · Engineering
Professor Nobuhiko Nishiyama's research lab specializes in advanced photonic integration technologies, focusing on the development of high-performance vertical-cavity surface-emitting lasers (VCSELs) and InP-based thin-film membrane platforms. The lab pioneers novel materials and nanostructures—such as AlGaInAs DBRs, oxide-confined VCSELs, and heterogeneously integrated InP/Si hybrid substrates—to enable ultracompact, energy-efficient, and high-speed photonic devices. Key research directions include monolithic integration of active and passive components, polarization control in VCSELs, and room-temperature heterogeneous bonding for silicon photonics. The lab's work aims to overcome bottlenecks in datacom, telecom, and optical interconnects by advancing materials growth, device design, and integration techniques.
Figures are computed from collected data and may differ slightly.
1.3- and 1.55- <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$mu$</tex> m vertical-cavity surface-emitting lasers (VCSELs) on InP have been realized. High-reflectivity AlGaInAs–InP lattice matched distributed Bragg reflectors (DBRs) were grown on InP substrates. 1.7 (for 1.3 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$mu$</tex> m) and 2.0 (for 1.55 <tex xmlns:mml="http://www.w3.org/1998/Math/Math
High efficiency continuous-wave operation of 1.53 µm vertical cavity surface emitting lasers (VCSELs) with buried tunnel junction grown by metal organic chemical vapour deposition (MOCVD) has been demonstrated. Devices show a high differential quantum efficiency of 46% and a singlemode power of 1 mW. Minimum threshold current and voltage are 0.45 mA and 1.3 V at room temperature, respectively for devices of 5 µm diameter.
Abstract Recently a novel photonic integration technology, based on a thin InP-based membrane, is emerging. This technology offers monolithic integration of active and passive functions in a sub-micron thick membrane. The enhanced optical confinement in the membrane results in ultracompact active and passive devices. The membrane also enables approaches to converge with electronics. It has shown high potential in breaking the speed, energy and density bottlenecks in conventional photonic integra
We have demonstrated an oxide confinement polarization controlled vertical-cavity surface-emitting laser (VCSEL) grown on a GaAs [311]B substrate. The polarization state was well controlled along the [2~33] crystal direction due to an anisotropic gain in the [311]B plane. We fabricated a small oxide aperture VCSEL with a threshold of 260 /spl mu/A and realized single-transverse mode and single-polarization operation for the first time. The sidemode suppression ratio (SMSR) was 35 dB and the orth
We propose a novel vertical-cavity surface emitting laser (VCSEL) with Al(Ga)As multi-oxide layer (MOX) structure for the purpose of enlarging window aperture maintaining single transverse mode operation. We have fabricated an InGaAs-GaAs VCSEL with the proposed MOX structure formed on GaAs (311)B substrate. We have performed a numerical simulation to investigate single-mode behavior of the proposed structure and showed a possibility of single-mode VCSEL's with a large active area. We have fabri
Abstract Heterogeneous wafer bonding of InP/Si at room temperature is studied using surface-activated bonding (SAB) technology. To minimize the degradation of optical property while maintaining enough bonding strength, various bonding conditions including gas species of fast atom beam (FAB) were examined. The results show that a bonding strength of over 0.5 MPa can be obtained with less degradation of photoluminescence (PL) property of InP/Si hybrid wafer by combining Xe and Ar gases for FAB. Us
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