Xian-Jie Li

An 850 nm wavelength monolithic integrated photoreceiver with a single-power-supplied transimpedance amplifier based on GaAs PHEMT technology

An 850 nm wavelength monolithic integrated photoreceiver with a novel single-power-supplied transimpedance amplifier is reported based on 0.8 /spl mu/m depleted GaAs PHEMT technology. The IC consists of an MSM photodetector and a transimpedance amplifier with a 50 ohm-matched differential output. The MSM PD on the chip shows a dark current of 2.0 nA as well as a responsivity of 0.30 A/W under a bias of 3.5 V. The TIA shows a transimpedance gain of more than 58 dB/spl Omega/ with a -3 dB bandwidth of 2.0 GHz. Opening eye diagrams are demonstrated at bit-rates of 1.25 Gbit/s and 2.5 Gbit/s under a +5 V supply.

AlGaAs/InGaAs PHEMT preamplifier for optical communication systems

The design, fabrication and characteristics of a AlGaAs/InGaAs PHEMT monolithic transimpedance preamplifier is described. The PHEMT material used here is based on /spl delta/-doped carrier supplying layer and GaAs/AlGaAs superlattice buffer. The transconductance and output conductance of a 1 /spl mu/m-gate PHEMT is 250 mS/mm and 8mS/mm respectively with threshold voltage of -1.2 v, the maximum saturation current density is 235 mS/mm. On-wafer network analysis with HP8510 network analyzer shows its cut-off frequency of 21 GHz and maximum oscillation frequency of 40 GHz. Transimpedance preamplifier its measured maximum transimpedance gain of 51.4 dB/spl Omega/ with -3 dB bandwidth no less than 5.05 GHz. The input equivalent-noise current density is 13 PA//spl radic/Hz.

Design and performance of transimpedance amplifier and cascadable amplifier with AlGaAs/GaAs HBTs

The design and performance of transimpedance amplifier and cascade amplifier of different bandwidths with AlGaAs/GaAs HBTs were described. A transimpedance amplifier with 2.5 Gbit/s bit rate as well as two cascadable amplifiers with 3 GHz and 10 GHz bandwidth were achieved.

A divide-by-2 static frequency divider with AlGaAs/GaAs HBTs technology

A divide-by-2 Static frequency divider using AlGaAs/GaAs heterojunction bipolar transistors (HBTs) was described based on a master-slave D flip-flops. For a HBT with a 3.5/spl times/8 /spl mu/m/sup 2/ emitter had a DC current gain of 30. The unity current gain cutoff frequency (F/sub t/) and the maximum oscillation frequency (F/sub max/) of the HBTs were extrapolated to about 40 GHz. The IC was tested from DC to 8 GHz and demonstrated proper function under a supply voltage of -7 V to -8 V.

Optoelectronic integrated single power source MSM/HEMT photoreceivers

ABSTRACT A monolithic integrated photoreceiver for 1 .55-urn wavelength fiber-optic receivers has been designed and fabricated with one amplifier stage, two stages of source follower and a feedback resistance structure. The optoelectronic integrated circuit (OEIC) receiver cornbines an InGaAs MSM photodetector with InP-based InAlAs/InGaAs HEMT. The receiver demonstrates a transrnitting bit rate of 2.5Gb/s with a transirnpedance of 58 ) dB. While operating at 2.SGbit/s, the chip consumes 160mW at a single +5V supply voltage.Keyword: Photoreceiver, InGaAs MSM photodetector, InAlAs/InGaAs HEMT, OEIC 1 INTRODUCTION High-speed photoreceivers are required of very-large-capacity optical transmission systems. An optoelectronic receiver,which usually consists of a photodetector and a transirnpedance (TZ) amplifier, is used to convert the optical signalsinto electrical signals in the front end of optical fiber communication. Therefore, a high-speed TZ amplifier plays a keycomponent in the design of optoelectronic integrated circuits1.Photoelectric monolithic integrated circuits have small volume, high yield and low parasitic effects. Moreover theydispense with subsequent assembling packaging procedure and assembling packaging cost, and eliminate influences of

Self-organized (553)BIn0.15Ga0.85As/GaAs quantum-wire field-effect transistors

Extremely uniform and high-density In0.15Ga0.85As/GaAs quantum wires (QWRs) were naturally formed on a (553)B-oriented GaAs substrate by molecular-beam epitaxy. The density of the QWRs is as high as 4.0×105 cm−1. The strong photoluminescence peak at λ=868 nm from the (553)B QWRs shows a large polarization anisotropy [p=(I∥−I⊥)/(I∥+I⊥)=0.22] and a very small full width at half maximum of 9.2 meV at 12 K. Based on the modulation-doped (553)B QWR structure, self-organized QWR field-effect transistors were fabricated (the channel along the QWRs’ direction). The devices demonstrate very good saturation characteristics and pinch-off behavior at room temperature. A maximum transconductance (gm) of 135 mS/mm is measured for 2 μm gate-length devices.

10 Gb/s InAlAs/InGaAs HEMT transimpedance preamplifiers

Design, fabrication and characteristics of a 10 Gb/s InAlAs/InGaAs HEMT monolithic transimpedance preamplifier are described. Maximum transconductance of 450 mS/mm, cutoff frequency f/sub T/ of 48 GHz and maximum oscillation frequency f/sub max/ of 55 GHz for a device with gate-length of 0.8 /spl mu/m have been obtained. For the preamplifier, transimpedance gain and bandwidth are 47.5 dB/spl Omega/ and 7.2 GHz respectively, the input equivalent noise density is 15.8 PA//spl radic/Hz.

InP-based monolithic integration of 1.55-μm MQW laser diode and HBT driver circuit

An improved fabrication process and related experiment results of an InP-based monolithic integrated transmitter OEIC with a 1.55 micrometers MQW laser diode (LD) and an InP/InGaAs heterojunction bipolar transistors (HBT) driver circuit are presented. The epitaxial structure of the laser and driver circuits were continuously grown on semi- insulating Fe-doped InP substrate by a metal-organic chemical vapor deposition system using a vertically integration. HCL, H3PO4/H2O2 and HBr/HNO3 solution system were involved as selective or nonelective wet chemical etching respectively for the epitaxies of InP, InGaAs and InGaPAs. Both a nearly-standard contact photolithography depending on a two-step exposure technique and an electrical connection related to smoothly wet chemical etching profile of InP and InGaP in the crystal direction of (01-1) were developed in the process. The laser diode with a 3-um-wide ridge waveguide forming by a double- groove process self-aligned to the metal contact of P-type region showed an average threshold current as low as about 10mA. The HBT with a 120-nm-thick base layer performed a DC current gain of about 60-70 and an emitter-collector breakdown voltage of up to 4-5V. A clear eye diagram of the monolithic transmitter under a pulsed operation with 622Mbit/s bitrate nonreturn-to-zero pseudorandom code was obtained.