Zuhua Zhu

Wafer bonding technology and its optoelectronic applications

This paper describes the wafer bonding technology and its applications to optoelectronic devices and circuits. It shows that the wafer bonding technology can create new device structures with unique characteristics and can form integrated optoelectronic circuits containing optical, electronic and micro-mechanical devices.

Wafer bonding technology and its applications in optoelectronic devices

The new optoelectronic integrated technology--wafer bonding is described. The results of wafer bonding and applications in several new types of optoelectronic devices are presented.

Long wavelength VCSELs using AlAs/GaAs mirrors and strain-compensated quantum wells

We present a 1.53 /spl mu/m strain-compensated MQW VCSEL using wafer-fused AlAs/GaAs DBR mirrors. Under room temperature pulsed pumping, we measured excellent dynamic single mode characteristics, a low threshold current of 10 mA, and a linewidth of less than 0.1 nm.

NaCl:OH− color center laser modelocked by a novel bonded saturable Bragg reflector

Abstract We present the design and modelocking results of a novel saturable Bragg reflector constructed from separate Bragg stack and quantum well semiconductor wafers, bonded by the technique of atomic rearrangement. This device was used to modelock a NaCl:OH− color center laser, producing 200 fs pulses in the 1.60 μm range. The laser is self-starting, requires no dedicated dispersion compensating optics, and maintains a highly stable, nearly transform limited output pulse train with up to 500 mW average output power.

Surface-micromachined tunable resonant cavity LED using wafer bonding

Surface micromachining and wafer bonding techniques have been integrated to fabricate a dual-use resonant cavity tunable LED/photodetector operating at 1.5 micrometers . The device has a tuning range of 75 nm, and a spectral linewidth of 4 nm, with an extinction ratio of greater than 20 dB throughout the tuning range. The device has potential applications in WDM networks and optical interconnects due to the small physical size, beam profile, and wafer-scale fabrication and testing possibilities. A GaAs/AlAs distributed Bragg reflector (DBR) is integrated with an InGaAsP strain-compensated multiple quantum well gain medium using wafer bonding. The InGaAsP material with a central wavelength of 1.52 micrometers is grown lattice-matched on an InP substrate. After wafer bonding, the InP substrate is removed, leaving the active layers on the GaAs-based mirror and substrate. The top DBR mirror of the resonant cavity is formed using surface micromachining techniques. The mirror consists of a 4 5 pair S1/S1O2 DBR and a T1/W support and contact layer. These materials are deposited on a sacrificial polymide layer above the InP-based gain medium. The polymide is selectively etched to release the membrane, creating an air gap between the top mirror and the epitaxial layers. When a voltage is applied between these two layers, the membrane is deflected towards the substrates, changing the Fabry-Perot cavity length, and causing a corresponding change in the resonance wavelength of the device. The device functions as a resonant cavity photodetector by reverse biasing the multiple quantum well region. The absorption bandwidth and wavelength running are identical to the emission characteristics of the same device when used as an LED.

Long wavelength VCSELs using wafer-fused GaAs/AlAs Bragg mirror and strain-compensated quantum wells

We have employed two innovative technologies, strain-compensated multiple quantum wells and material bonding, to demonstrate low threshold and dynamic single mode 1.5 /spl mu/m vertical cavity surface emitting (VCSEL) lasers.

New optical readout technique for ultra-high capacity information storage using microelectromechanical tips

Ultra-high capacity information storage is a goal pursued by many researchers in the fields of optical computation and optical signal processing. We present for the first time a new optical technique combining electro-optic probing and micromechanical tips to perform the readout and writing for an ultra-high capacity memory. Potentially, this technique could achieve a storage density of 1 Terabit/cm/sup 2/.