Kenichi Iga

Spot size dependence of filtering characteristics in dielectric multilayer filters for WDM applications

We investigated filtering characteristics of dielectric filters for use in wavelength division multiplexing systems by employing an improved transfer matrix method. It is pointed out that the spotsize should be larger than 3mm for 25Ghz channel spacing. The spot size of input Gaussian beam is very critical affecting the performance.

Highly strained GaInAs/GaAs QW for 1.2 /spl mu/m surface emitting lasers

We discuss a possibility of high performance VCSELs emitting at 1.2 /spl mu/m wavelength for high speed single mode fiber datacom. Good temperature characteristics of highly strained GaInAs-GaAs QW edge emitting lasers are demonstrated under heatsink-free cw operations.

1.1-1.2 /spl mu/m multiple-wavelength vertical cavity surface emitting laser array with highly strained GaInAs/GaAs QWs on patterned substrate

We demonstrated a single-mode multiple wavelength VCSEL array with highly strained GaInAs/GaAs QWs on a patterned GaAs substrate in the new wavelength band of 1.1-1.2 /spl mu/m. The emission wavelength of a 16-channel array ranges from 1116 nm to 1154 nm. By using this technique, the wavelength span of the multi-wavelength GaInAs/GaAs VCSEL can be expanded and we can expect a wideband WDM-LAN using the VCSEL array.

Hollow optical waveguide with thin film coating for micromachined photonic integrated circuits

We propose a novel hollow optical waveguide with thin film coating for temperature insensitive photonic devices. Low-loss and polarization insensitive propagation characteristics are predicted. We fabricated a hollow waveguide with metal coated walls on GaAs substrate. The propagation loss was 2.6 dB/cm and 7.3 dB/cm for TE and TM modes, respectively.

Low bias voltage dry etching of InP by inductively coupled plasma (ICP) using SiCl/sub 4//Ar

We report on anisotropic and smooth etching of InP by low bias voltage ICP using SiCl/sub 4/-Ar at high substrate temperature. We used an inductively coupled plasma (ICP) scanning electron microscope (SEM) photograph of circular array patterns of InP. The etching mask was a negative-type electron beam resist SAL601.

Heavy p-type carbon doping to AlAs for InP based optoelectronic devices

We propose a novel C auto-doping method for AlAs grown by MOCVD using trimethylaluminum (TMAI) and tertiarybutylarsine (TBAs) and applying C heavily doped AlAs films as p-type doped layers in InP material systems. Some new device applications are also proposed. We proposed an auto-doping technique which enables to control doping level by only changing the V-III ratio. To investigate doping conditions, we grew AlAs on GaAs substrates by MOCVD.

Carrier lifetime measurement of long wavelength GaInNAs lasers

We investigated the dependence of the carrier lifetime of GaInNAs lasers on the nitrogen composition. Carrier lifetime reduction partly contributes to high thresholds of GaInNAs lasers, but other origins such as compositional fluctuations should be considered and avoided.