Noriaki Kaida

Analysis of GaInAsP Surfaces by Contact-Angle Measurement for Wafer Direct Bonding with Garnet Crystals

GaInAsP surfaces with various treatments were analyzed by contact-angle measurement for wafer direct bonding between GaInAsP and garnet crystals. The contact angle of a water droplet was measured to estimate the hydrophilicity of the wafer surfaces. The most hydrophilic surface was obtained after an O2 plasma activation process. Direct bonding was successfully achieved between GaInAsP activated by O2 plasma and garnet crystals.

Direct Bonding between Quaternary Compound Semiconductor and Garnet Crystals for Integrated Optical Isolator

An integrated optical isolator employing a nonreciprocal phase shift is very attractive because it does not need phase matching. We have investigated a novel configuration of the integrated optical isolator, employing the nonreciprocal phase shift, in which the magnetooptic waveguide has a magnetic garnet/GaInAsP/InP structure. The wafer direct bonding technique is necessary to realize this structure. The direct bonding between quaternary III–V compound semiconductors and garnet crystals was experimentally studied. The bonding was achieved by chemical treatment and subsequent heat treatment at temperatures ranging from 110 to 330°C. Cross-sectional scanning electron microscope (SEM) images indicated that there were no gaps between the two wafers in contact.

Wafer surface treatment for bonding GaInAsP and magnetooptic garnet

GaInAsP surfaces were investigated by contact angle measurement to estimate their hydrophilicity for completing wafer direct bonding with magnetooptic garnet. Wafer direct bonding was successfully achieved between O/sub 2/ plasma activated GaInAsP and garnet crystals. This technique has been applied with the aim of integrating a laser diode and an optical isolator.

Coupling characteristics of three-guide tapered coupler for integrated optical isolator with semiconductor guiding layer

The characteristics of the three-guide tapered coupler for an integrated optical isolator with a semiconductor guiding layer (GaInAsP) were experimentally studied. By the experiment for measuring power branching ratio, the unbalance of the ratio smaller than 2% was confirmed for wavelengths ranging between 1.50 and 1.58 /spl mu/m. The coupling to the central waveguide occurred when two light waves in the side waveguides were in phase. No output was coupled to the central waveguide when they were 180/spl deg/ out of phase. The isolation of more than 17dB will be achieved when the coupler is employed in the isolator.

Contact angle measurement of GaInAsP surfaces for wafer direct bonding with garnet crystals

GaInAsP surfaces were investigated by contact angle measurement of a water droplet to estimate their hydrophilicity. The most hydrophilic surface of GaInAsP was obtained by the O/sub 2/ plasma activation process. Wafer direct bonding was successfully achieved between O/sub 2/ plasma activated GaInAsP and garnet crystals.

Wafer surface treatment for integrating laser diode and optical isolator by direct bonding

GaInAsP surfaces were investigated by contact angle measurement to estimate their hydrophilicity for completing wafer direct bonding. Wafer direct bonding was successfully achieved between O/sub 2/ plasma activated GaInAsP and garnet crystals.

First multi-mode interference devices fabricated by metal-organic vapor phase diffusion enhanced selective area epitaxy

For the first time multi-mode interference (MMI) power splitters have been fabricated by selective area growth, using our novel metal-organic vapor phase diffusion enhanced selective area epitaxy (MOVE/sup 2/) process which features extremely wide-range in-plane bandgap control and high design flexibility and therefore is very suitable for photonic integration. Excess losses as low as 2 dB have been obtained for MMI power splitters with smooth and sufficiently flat waveguide structures including S-bends.