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Kawasaki, Japan

Yasuoka N.,Fujitsu Limited | Ebe H.,Fujitsu Limited | Kawaguchi K.,Fujitsu Limited | Ekawa M.,Fujitsu Limited | And 5 more authors.
Journal of Lightwave Technology | Year: 2012

A polarization-insensitive quantum dot semiconductor optical amplifiers (QD-SOAs) have been studied for use in future optical communication systems. A part of our work shows that the optical polarization property in QDs depends on both their aspect ratio and strain. To control these two parameters, we propose the use of strain-controlled columnar QDs (SC-CQDs), which exhibit a high aspect ratio and have strain-controlled side barriers for polarization-insensitive operation in the 1.5-μ m wavelength band. QD-SOAs with these optimized SC-CQDs demonstrated polarization-insensitive characteristics. They showed a gain of 8.0 dB with polarization dependence of the gain as low as 0.4 dB, -3-dB saturation output power of 18.5 dBm at a wavelength of 1550 nm, and error-free amplification at a bit rate of 40 Gbit/s. © 2006 IEEE.

QD Laser Inc. and University of Tokyo | Date: 2014-04-25

The present invention is an image projection device that includes: a light source 12 that emits a laser beam 34; a scanning mirror 14 that two-dimensionally scans the laser beam 34 emitted from the light source 12; and a projection mirror 24 that projects scanned light onto a retina 26 of an eyeball 22 of a user to project an image onto the retina 26, the scanned light being composed of the laser beam 34 that has been scanned by the scanning mirror 14, wherein the laser beam 34 emitted from the light source 12 is scanned by using a part of an operating range of the scanning mirror 14.

Watanabe K.,University of Tokyo | Akiyama T.,QD Laser Inc. | Yokoyama Y.,QD Laser Inc. | Takemasa K.,QD Laser Inc. | And 7 more authors.
Journal of Crystal Growth | Year: 2013

We have progressed the growth procedure for high-density highly-uniform In(Ga)As/GaAs quantum dots (QDs) by using molecular beam epitaxy and have demonstrated high-gain 1.06-μm QD lasers for consumer electronics. The structural and optical properties of QD crystals have been improved by optimizing the growth temperature, employing InGaAs QDs in place of InAs QDs, and utilizing a height-limiting growth method, which is called the Indium-flush procedure. Lasers containing ten-layer height-limited InGaAs QDs provided a net modal gain as high as 60 cm-1, which is one of the largest values for InAs/GaAs QD lasers. These results will promise the development of optoelectronic devices with high-density multiply-stacked QDs in the 1-μm band. © 2013 Elsevier B.V. All rights reserved.

Kageyama T.,Institute for Nano Quantum Information ElectronicsThe University of Tokyo4 6 1 KomabaMeguro ku | Watanabe K.,Institute of Industrial ScienceThe University of Tokyo4 6 1 KomabaMeguro ku | Vo Q.H.,Institute of Industrial ScienceThe University of Tokyo4 6 1 KomabaMeguro ku | Takemasa K.,QD Laser Inc. | And 3 more authors.
Physica Status Solidi (A) Applications and Materials Science | Year: 2016

The strain-compensation (SC) technique to reduce the accumulation of strain is a promising approach to increase the design flexibility as well as the performance of quantum dot (QD) lasers. Here we have studied the application of tensile-strained ultra-thin GaP layers into multiple stacked InAs/GaAs QD grown by MBE. XRD analysis shows the controllability of the average strain in multiple-stacked QD active layer, revealing a reduction in accumulated strain. Fabricated QD laser diodes including thinner QD active layers realized by SC technology show a narrower vertical far-field angle and an increased small signal modulation bandwidth without loss of gain. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

QD Laser Inc. | Date: 2015-08-10

Radiotelephony sets; computers; mobile computers; portable computers; cellular phones; smartphones; computer peripheral devices; peripheral device for radiotelephony sets; wearable computers; wearable radiotelephony sets; wearable cellular phones; wearable smartphones; wearable peripheral devices for computers; wearable peripheral devices for radiotelephony sets; wearable peripheral devices for cellular phones; wearable peripheral devices for smartphones; wearable visual display units; head-mounted displays; visual display units for displaying retinal image; wearable visual display units for displaying retinal image; wearable visual display units for displaying retinal image with camera; 3D spectacles; spectacles. Eye testing machines and apparatus; auxiliary medical devices; devices for examination of the visual field; auxiliary medical devices with camera for displaying retinal image; devices for examination of the visual field for displaying retinal image.

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