Fumio Koyama

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We propose a novel design for multi-wavelength arrays of vertical cavity surface-emitting lasers (VCSELs) using high-contrast gratings (HCGs) as top mirrors. A range of VCSEL cavity wavelengths in excess of 100 nm is predicted by modifying only the period and duty-cycle of the high-contrast gratings, while leaving the epitaxial layer thickness unchanged.(More)
We demonstrate a metal nano-aperture GaAs vertical cavity surface emitting laser (VCSEL) for sub-wavelength optical near-filed probing, which exhibits the strong plasmon enhancement of both optical near-fields and voltage signals with forming a metal nano-particle in the nano-aperture. The threshold current is as low as 300microA, which shows a potential of(More)
We demonstrate single-mode fiber transmission distance enhancement up to 120 km of a directly-modulated injection-locked VCSEL modulated by a 10Gb/s NRZ signal. Injection locking induced data pattern inversion of the VCSEL causes adjustable chirp, which greatly extends reach. Both experiments and simulations are shown to explain this phenomenon.
UNLABELLED Using a self-imaged diffraction coupled model in a Talbot cavity for vertical cavity surface emitting laser arrays, the effect of self-imaged reflections on the lasing threshold of a finite 2-D array was investigated. Array size and the ratio defined by the element diameter/element spacing were found to affect the effective reflectivity as seen(More)
A tunable Bragg reflector based on a 3D hollow waveguide (HWG) has been proposed. Ultrawide tuning ranges of 152 nm and 164 nm, respectively, in Bragg wavelengths of TE and TM modes of the Bragg reflector have been presented experimentally. With a 3D hat-shaped HWG, a giant birefringence of 0.012 has been demonstrated that can be varied with a variable air(More)
Robust and tolerant single-transverse-mode photonic crystal GaInAs vertical-cavity surface-emitting lasers are fabricated and investigated. Triangular lattice patterns of rectangular air holes of various etch-depths are introduced in the top mirror. The stable single-transversemode operation is observed with a large margin of allowance in the etch depth (t(More)
We present the modeling and the experimental result of a micro-machined VCSEL with a thermally actuated semiconductor/SiO<sub>2</sub> cantilever structure. The modeling result shows a giant wavelength-temperature dependence of over 3.5 nm/K. The fabricated device exhibits a temperature dependence of 0.79 nm/K, which is 10 times larger than that of(More)