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This paper presents a 43-Gb/s clock and data recovery (CDR) optoelectronic integrated circuit (OEIC) that consists of a 43-GHz heterojunction phototransistor (HPT) oscillator as an optoelectronic clock recovery circuit and a 40-Gb/s-class heterojunction bipolar transistor (HBT) decision circuit. The layer and fabrication process of the HPT and HBT are fully compatible, and the HPT has a photocoupling window in the emitter electrode for optical access from the top. When the HPT is directly illuminated, the HPT oscillator successfully extracts a 43-GHz electrical clock signal from a 43-Gb/s optical data stream by itself. The OEIC regenerates the data signal input into the HBT decision circuit by using the electrical clock signal optoelectronically extracted by the HPT oscillator. The CDR OEIC achieves error-free operation for a 231-1 PRBS data signal. The power dissipation of the OEIC is only 0.79 W, which is less than half that of a fully electrical 40-Gb/s-class CDR IC. This is the first successful demonstration of HPT-based OEICs integrated with HBT digital circuits operating at such a high bit rate. [ABSTRACT FROM PUBLISHER]

An ultra‐broadband 6 bit digital‐to‐analogue converter (DAC) has been designed and fabricated in InP‐HBT technology. The DAC IC includes six 2:1 MUXs and thus operates with a half‐rate clock. The DAC module is equipped with 1 mm connectors for its analogue output to ensure broadband characteristics. The measured analogue output bandwidth (BW) is >40 GHz. Four‐level pulse amplitude modulation signals with clear eye openings were measured at symbol rates of up to 75 GBd. This MUX‐DAC module has the widest BW of any previously reported DACs and is suitable for high‐symbol‐rate optical transmitters. [ABSTRACT FROM AUTHOR]

A suitable emitter structure for the fabrication of InP/InAlGaAs/GaAsSb double heterojunction bipolar transistors (DHBTs) with a passivation ledge is reported. With a composite emitter structure consisting of an InP and thin InAlGaAs, a passivation ledge can be easily fabricated by wet etching. A high current gain of 117 is obtained even for a 0.25 μm emitter DHBT with a base sheet resistance of about 1100 Ω/sq. The fabricated HBT also exhibits an fmax of more than 330 GHz while maintaining a breakdown voltage of more than 9 V. [ABSTRACT FROM AUTHOR]

We demonstrate a new configuration for an optoelectronic self-injection-locked (SIL) oscillator, where a part of the electrical output signal is self-injected after passing through a long optical delay line for output phase-noise reduction. The SIL oscillator consists of an electrical free-running oscillator and a long optical feedback loop. For the compact and low cost configuration, the free-running oscillator is realized with an InP HPT-based monolithic oscillator and electrical-to-optical conversion is carried out by two low-speed and low-cost laser diodes. With this new configuration, we achieve more than 55-dB phase-noise reduction at 10-kHz frequency offset from the center frequency of about 10.8 GHz by injecting 8-dBm optical signals without using any high-speed optoelectronic components. [ABSTRACT FROM PUBLISHER]

A 30-GHz optically injection-locked self-oscillating optoelectronic mixer (OIL-SOM) is implemented with a high-performance InP-InGaAs heterojunction phototransistor. The subharmonic conversion efficiency and phase noise characteristics of OIL-SOM are investigated and used for analyzing OIL-SOM-based 60-GHz radio-over-fiber downlink data transmission performance. The OIL-SOM characteristics provide lower and upper boundaries for the input optical local oscillation (LO) power range within which the link performance does not significantly depend on input optical LO power [ABSTRACT FROM PUBLISHER]

We demonstrate 60-GHz band bidirectional radio-on-fiber (RoF) links based on InP-InGaAs heterojunction phototransistor (HPT) optoelectronic mixers. They employ remote up/down conversion scheme with optical local oscillator signals distributed from the central office and intermediate frequency (IF) fiber transmission for both up- and down-links. Since frequency up/down conversions and photodetection are carried out by a single HPT optoelectronic mixer, base station architecture is greatly simplified. In order to validate its feasibility, both up- and down-link RoF transmissions of 16 quadrature amplitude modulator data are successfully demonstrated at 60-GHz band using 1.25-GHz IF for down-link and 2.0-GHz IF for up-link. [ABSTRACT FROM PUBLISHER]

We demonstrate an optically injection-locked self-oscillating optoelectronic mixer (OIL-SOM) for radio-on-fiber downlink applications. OIL-SOM is based on a monolithic oscillator containing an InP-InGaAs heterojunction phototransistor (HPT). The oscillator is OIL by remotely delivered optical local oscillator (LO) signals, and provides low phase-noise and high-power electrical LO signals. In addition, the HPT in this oscillator can simultaneously perform optoelectronic mixing, in which optically transmitted intermediate frequency signals are up-converted to the desired radio-frequency band with high conversion efficiency. With these, OIL-SOM can make base station architecture simple in radio-on-fiber downlink systems. [ABSTRACT FROM PUBLISHER]

A 100 GHz electrical clock signal was successfully recovered from a 100 Gbit/s RZ optical data stream using direct optical injection locking of a 100 GHz InP/InGaAs HPT oscillator. This is believed to be the highest clock frequency ever recovered using transistor-based ICs and the first report of 100 Gbit/s operation for transistor-based OEICs. [ABSTRACT FROM AUTHOR]

A new circuit configuration for an emitter-coupled logic (ECL) gate that can reduce propagation delay time has been demonstrated. Nineteen- stage ring oscillators were fabricated using InP/InGaAs double-hetero- junction bipolar transistors (DHBTs) with cutoff frequency fr and maximum oscillation frequency f[SUBmax] of about 232 and 360 GHz, respectively, to evaluate the speed performance of the proposed ECL gate. The minimum propagation delay is 3.21 ps/gate. The proposed ECL gate is about 8% faster than the conventional ECL gate. [ABSTRACT FROM AUTHOR]

An InP HBT 1:4 demultiplexer lC with a multiphase clock architecture is described that reduces the number of circuit elements and power consumption while maintaining operating speed. The IC operated at 50 Gbit/s with 1.17 W power consumption at a supply voltage of -4.5 V. Compared to an IC with a conventional tree-type architecture using the same InP HBTs, the power consumption is less than half while the operating speed of 50 Gbit/s is maintained. [ABSTRACT FROM AUTHOR]

An ECL gate delay of 3.48 ps/stage in a 19-stage conventional ring oscillator fabricated in an over-300 GHz ƒ[subT]/ ƒ[submax] InP DHBT technology has been demonstrated. This is the first report (to the authors' knowledge) of sub-4 ps ECL gate delay. Large collector current density contributes to the very short gate delay. [ABSTRACT FROM AUTHOR]

A low-power 16:1 multiplexer (MUX) IC using undoped-emitter InP/InGaAs heterojunction bipolar transistors (HBTs) has been successfully designed and fabricated. To minimise power consumption, the collector current density of each HBT was optimised taking into account the required operating speed and the number of fan-outs. Up to 47 Gbit/s error-free operation was confirmed with low power consumption of about 3.2W. These results demonstrate that InP/inGaAs HBT technology is attractive for fabricating over 40 Gbit/s, low-power medium-scale-integration (MSI) circuits. [ABSTRACT FROM AUTHOR]

Background: Older patients with lung cancer tend to have significant coexisting diseases and less aggressive treatment is often advisable.Objective: To investigate the clinicopathological features of lung cancer in patients aged 80 years and over.Methods: The medical records of 966 patients with lung cancer between 1976 and 1999 were reviewed retrospectively.Results: There were 56 (5.8%) patients 80 years old or over. Thirty-nine (70%) were male, and 22 (39%) patients had poor performance status (2-4). Some of the patients had a medical history of cardiovascular disease (n = 23; 41%), cerebrovascular disease (n = 5; 9%), diabetes mellitus (n = 11; 20%), or malignant disease (n = 8; 14%). Twenty-one (35%) patients were diagnosed as having surgically resectable disease and 20 patients underwent radiotherapy, but 25 patients only received supportive care because of concomitant illnesses. Only 9 and 2 patients, respectively, had chemotherapy and surgery. There was no statistical difference in the survival rate of the two groups of patients receiving radiotherapy or supportive care.Conclusion: Adequate palliative care to provide prolonged quality survival is an appropriate primary goal of therapy for lung cancer in the octogenarian until less invasive treatments are developed. [ABSTRACT FROM AUTHOR]

Demonstrates the abnormal redistribution of zinc in indium phosphide/indium gallium arsenide heterojunction bipolar transistor (HBT) structures. Function of the n[sup +] doped subcollector; Importance of base layer width control for excellent HBT performance; Use of secondary-ion mass spectrometry to determine epilayer atomic concentration profiles.

Examines high performance zinc (Zn)-doped-base indium phosphide (InP)/In gallium arsenide (GaAs) double-heterojunction bipolar transistors (DHBT) grown by metalorganic vapor phase epitaxy. Prerequisite for high-performance HBT; Growth of the InP/InGaAs DHBT; Characteristic of the microwave performance of the DHBT.

Fabricates a double-heterostructure bipolar transistor using InP and InGaAs materials. Pair doping at the heterointerface; Capability of suppressing collector current blocking; Use of metalorganic chemical vapor deposition; Electron transport properties of the InP collector.

0.25 μm emitter InP/InGaAs double heterojunction bipolar transistors (DHBTs) are presented that simultaneously exhibit a high collector current density (Jc) of more than 3 mA/μm2 and high breakdown voltage (BVCEO) of 12 V. The DHBTs consist of a 30 nm-thick InGaAs base, 250 nm-thick InGaAs/InAlGaAs/InP collector and 150 nm-thick n-doped InP field buffer. Since the doping level of the InP field buffer is relatively high, only the InGaAs/InAlGaAs/InP collector is depleted at low VCE. Thus, the DHBTs can provide ft = 173 GHz and fmax = 470 GHz at Jc = 3.5 mA/μm2. On the other hand, at a high VCE, both the InGaAs/InAlGaAs/InP collector and InP field buffer are depleted. Therefore, the effective depletion thickness increases, which results in a BVCEO of 12 V. These results indicate that the use of the InP field buffer provides both high-speed performance and high BVCEO. [ABSTRACT FROM AUTHOR]

A high-speed low-power decision circuit using InP/InGaAs double- heterojunction bipolar transistors (DIIBTs) has been successfully designed and fabricated. The DIIBTs exhibit a cutoff frequency fr and maximum oscillation frequency fmax of 232 and 360GHz, respectively, at a collector current density of 2.5 mA/μm2. To boost the operating speed, a novel-master slave D-type flip-flop (MS-DFF) was used. Up to 90 Gbit/s operation was achieved with low power consumption of 0.5 W. These results demonstrate that InP-based DHBTs are attractive for making ultra-high-performance ICs for future optical communications systems operating at bit rates of 100 Gbit/s or more. [ABSTRACT FROM AUTHOR]

An 80 GHz electrical clock signal was successfully recovered from an 80 Gbit=s RZ optical data stream using direct optical injection locking of an 80 GHz InP=InGaAs HPT oscillator. The measured rms jitter is less than 0.31 ps for 2 [sup 31] 1 PRBS data signal. This is the first demonstration of the electrical clock extraction at such a high frequency using optical injection locking of an electrical oscillator. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports on carbon (C) doping in InGaAsSb grown on (001) InP substrates by the metalorganic chemical vapor depositions (MOCVD) method using carbontetrabromide (CBr4). The influence of the CBr4 flow rate on the relationships between InGaAsSb alloy compositions and the molar flow ratio of III–V-atom precursors was investigated in C-doped InGaAsSb films. We found that there is nonlinear dependence of the solid In content on the molar flow ratio of group-III precursors for C-doped InGaAsSb. Thermodynamic calculations of the reactions in the InGaAsSb growth process reveal that the characteristic nonlinear dependence is due to the etching reactions of group-III elements with hydrogen bromide, which is generated by CBr4 decomposition. The solid Sb content of both undoped and C-doped InGaAsSb films decreases with increasing molar flow ratio of In precursors due to the preferential incorporations of InAs in In-rich antimonide compounds. On the basis of the obtained knowledge, we have succeeded in growing C-doped InGaAsSb film with a high hole concentration of over 1.0×1019 cm−3, which is useful for the base layer of InP-based heterojunction bipolar transistors. As in C-doped GaAsSb, the effect of hydrogen passivation of C-acceptors in C-doped InGaAsSb is almost negligible. [Copyright &y& Elsevier]