We demonstrated two-dimensional beam steering by using VCSEL-based slow-light waveguide array with large angular dispersion of 1.8°/nm, which showed potential to achieve resolution point of over 10,000 dots. We obtained chip gain of 18.4 dB.
In this study, we have demonstrated vertical and smooth inductively coupled plasma (ICP) dry etching of InP and GaAs using either solid iodine or ICl 3 powder as gas sources at a low process temperature of 90 °C. We prepared solid iodine crystal and ICl 3 powder in the ICP etching chamber as etching gas sources in a process chamber. Iodine or chlorine gases were supplied with a high vapor pressure from the solid source into the process chamber. Vertical and smooth etching was realized under a condition of low temperature and low bias RF power. We believe that solid iodine- and ICl 3 powder-ICP etching are very simple and useful processes for InP- and GaAs-based device fabrication with a resist mask.
An ultra-compact (<;55μm) and low-voltage (Vpp=500mV) electro-absorption modulator was demonstrated based on a Bragg reflector waveguide. The miniature device offers 3dB-bandwidth over 13GHz, showing a prospect of ultra-low power-consumption below 100fJ/bit thanks to its low-voltage swing.
We propose and demonstrate a novel tunable planar air-core Fabry–Perot resonator for tunable wavelength filters based on hollow waveguides. The resonator consists of two circular grating mirrors and an air cavity based on a slab hollow waveguide, and light is confined three-dimensionally in the air-core cavity. Changing the air-core thickness of the hollow waveguide enables us to achieve a large propagation constant change on the order of 10%, which would be useful for widely tunable filtering applications. We fabricate two kinds of planar air-core resonators with 1-mm-long and λ/4-long air-cavities, respectively. We evaluate its grating mirror reflectivity and demonstrate tunable filter applications. The footprint of the fabricated λ/4 air-cavity resonator is only 0.1 mm2 and the resonator exhibits a quality factor of 3220 and 9 nm wavelength tunability of resonant cavity modes.
Some lasing characteristics of index-guided InGaAs-GaAlAs vertical-cavity surface-emitting lasers (VCSEL's) with a native oxide confinement structure, which produced a low threshold current of 70 μA, are presented. It was found that nonradiative recombination was reduced and the estimated surface recombination velocity was almost negligible. The oxidation process was uniform to produce low threshold devices while the oxidation rate was dependent on the doping or composition of DBR's.
We analyze and improve the crosstalk between adjacent output-ports in Bragg reflector waveguides array-based wavelength selective switching. Crosstalk below -23 dB is obtained in a 200-port waveguide array with a pitch of only 30 μm.
We demonstrate the microfabrication of Si by KOH wet etching using a mask pattern amorphized by an ion beam as an etching mask.An electron cyclotron resonance ion shower system was used as an ion beam source of 100 to 1000 eV energy.We succeeded in fabricating an etching mask that can etch a Si (110) substrate wafer to a depth of 3.7 µm by amorphizing the Si surface at an ion energy of 400 eV.In addition, we made microfluidic devices and single-cell isolation chips using the proposed microfabrication technique.We believe that the proposed technique will be useful for the microfabrication of Si-based microfluidic devices and biochips.
