Low-Threshold 1.3-$mu$m GaInNAs Quantum-Well Lasers Using Quaternary-Barrier Structures

GaInNAs quaternary-barrier structures, where indium is incorporated to achieve the lattice-matched condition, have been employed for 1.3-m GaInNAs-GaAs single- (SQW) and triple-quantum-well (TQW) lasers. Compared to a GaNAs ternary-barrier structure, photoluminescence results from the quaternary-barrier sample show improved optical properties. Threshold current densities have been achieved with the lowest values of 150 and 529 A/cm² for GaInNAs SQW and TQW lasers at room temperature, respectively.     

Optical Absorption Glucose Measurements Using 2.3-$mu$m Vertical-Cavity Semiconductor Lasers

Continuous glucose monitoring has been shown to help diabetes mellitus patients stabilize their glucose levels, leading to improved patient health. One promising technique for monitoring blood glucose concentration is to use optical absorption spectroscopy. This letter proposes the use of thermally tunable 2.3-mum vertical-cavity surface-emitting lasers to obtain blood absorption spectra. The partial least squares technique is used to determine the glucose concentration from the spectra obtained in aqueous glucose solutions.     

Self-Oscillation Free 0.35 $mu$ m Si/SiGe BiCMOS X-Band Digital Frequency Divider

This letter reports a digital master-slave D-type register divide-by-512 frequency divider designed in a 0.35 Si/SiGe BiCMOS technology. The 600times1200 mum² circuit operates up to 9.5 GHz dissipating 120 mW. Self-oscillations are avoided by the use of a radio frequency carrier detector that controls the bias of the last six registers.     

A 24-GHz Transmitter With On-Chip Dipole Antenna in 0.13-$mu$m CMOS

A fully integrated dual-conversion transmitter chain with an on-chip dipole antenna and an integer-N synthesizer operating in the 24-GHz Instrument, Scientific and Medical (ISM) band was fabricated in 0.13-mum CMOS. The choice of 24-GHz operation enables the integration of a 4-mm long antenna on chip. The transmitter chain can support data rate of 100 Mb/s. It provides 6-dBm output power to a 100-Omega load at 22.4 GHz with 152-mW power dissipation including that of a frequency synthesizer. At this output power level, the dual conversion architecture can mitigate the VCO pulling even when an antenna and a power amplifier are integrated on the same substrate as the VCO. The out-of-band emissions due to the modulation side lobes and image have been sufficiently suppressed. The stray emissions of local oscillator can also be reduced using circuit techniques. The signal from the transmitter has been picked up 95 meters away with a horn antenna, which suggests that wireless communications between a single chip radio and a base station 100 meters away is possible.     

High Characteristic Temperature of Highly Stacked Quantum-Dot Laser for 1.55-$mu$ m Band

We fabricated broad-area laser diodes comprising 30-layer stacks of InAs quantum dots (QDs) by using strain compensation. The devices exhibited ground-state lasing at 1529 nm in pulsed mode with a high characteristic temperature of 113 K around room temperature (20 $^{circ}hbox{C}$–80 $^{circ}hbox{C}$). Ground-state lasing was achieved because of the high QD density afforded by strain compensation.      

Quantum-Dot Semiconductor Optical Amplifiers With Polarization-Independent Gains in 1.5-$mu$ m Wavelength Bands

We have demonstrated a polarization-independent gain in semiconductor optical amplifiers that have columnar quantum dots surrounded by strained side barriers in 1.5-$mu$ m wavelength bands. We obtained a polarization-dependent gain of 0.5 dB with a gain of 10 dB and a saturation output power of 18 dBm at a wavelength of 1.55 $mu$ m.      

Analysis and Design of an Efficient Irreversible Energy Recovery Logic in 0.18-$mu$m CMOS

This paper presents the design and experimental evaluation of a new type of irreversible energy recovery logic (ERL) families called complementary energy path adiabatic logic (CEPAL). It inherits the advantages of quasi-static ERL (QSERL) family, but is with improved driving ability and circuit robustness. The proposed logic style features no hold phase compared to its QSERL counterpart under the same operation conditions; thereupon no feedback keeper is required so that considerable improvements in area and power overheads can be achieved. Moreover, its throughput becomes twice as high as that of QSERL when their frequencies of power clocks (PCs) are identical. Results on the impact of variation on CEPAL are provided. Comparison between CEPAL and other known low-power logic style achieving iso-performance, namely, subthreshold logic is also given. In order to demonstrate workability of the newly developed circuit, an 8-bit shift register, designed in the proposed techniques, has been fabricated in a TSMC 0.18- $mu$m CMOS process. Both simulation and measurement results verify the functionality of such a logic, making it suitable for implementing energy-aware and performance-efficient very-large scale integration (VLSI) circuitry.      

3-GHz Silicon Photodiodes Integrated in a 0.18-$mu$m CMOS Technology

A new PIN photodiode (PD) structure with deep n-well (DNW) fabricated in an epitaxial substrate complementary metal–oxide–semiconductor (epi-CMOS) process is presented. The DNW buried inside the epitaxial layer intensifies the electric field deep inside the epi-layer significantly, and helps the electrons generated inside the epi-layer to drift faster to the cathode. Therefore, this new structure reduces the carrier transit time and enhances the PD bandwidth. A PD with an area of $70times 70 mu$m $^{2}$ fabricated in a 0.18- $mu$m epi-CMOS achieves 3-dB bandwidth of 3.1 GHz in the small signal and 2.6 GHz in the large signal, both with a 15-V bias voltage and 850-nm optical illumination. The responsivity is measured 0.14 A/W, corresponding to a quantum efficiency of 20%, at low bias. The responsivity increases to 0.4 A/W or 58% quantum efficiency at 16.2-V bias in the avalanche mode.      

1.3-$mu$ m VCSEL Transmission Performance up to 12.5 Gb/s for Metro Access Networks

We experimentally demonstrate 1.33-$mu$m vertical- cavity surface-emitting laser characterization (linewidth and chirp measurements) and very good propagation performances at multi-Gb/s in single-mode-fiber transmission. Error-free measurements are presented both for 10.3 Gb/s over 40 km and for 12.5 Gb/s over 20 km at different operating temperatures.      

High-Performance 1.55-$mu$ m Superluminescent Diode With Butt-Coupled Spot-Size Converter

We report the design and fabrication of a novel 1.55-m spot-size converter superluminescent diode (SLD) for optical access networks. The active section of SLD was fabricated by using a planar buried heterostructure to adopt the double-waveguide-core structure for low-threshold and high-output power operation at a low injection current. A ridge-based passive waveguide was employed for an efficient coupling to a planar lightwave circuit. The threshold current was as low as 14 mA, and the maximum output power was as high as 28 mW with ripple less than 3 dB at an injection current of 200 mA.     

2-$mu$ m Mode-Locked Semiconductor Disk Laser Synchronously Pumped Using an Amplified Diode Laser

We report a mode-locked antimonide-based semiconductor disk laser operating at 2 $mu$m, synchronously pumped with a pulsed source incorporating a 1.57- $mu$m diode laser, a lithium niobate intensity modulator, and an erbium-doped fiber amplifier. The method for producing the pump signal utilizes commercially available telecom components and allows for convenient selection of the mode-locking harmonics. When compared with configurations based on mode-locked pump sources, the generation of pump pulses using amplitude modulation and digital data technology is simple and offers the possibility to actively lock the optical pulses to a stable clock.      

A 100-kHz to 20-MHz Reconfigurable Power-Linearity Optimized $G_m$–$C$ Biquad in 0.13-$mu$ m CMOS

Fully reconfigurable transceivers are required to answer the low-power high flexibility demand of future mobile applications. This paper presents a fully reconfigurable G_m-C biquadratic low-pass filter which offers a large range of both frequency and performance flexibility. First, a design approach is proposed focusing on linearity properties by extending Volterra analysis from circuit to architectural level in order to optimize the filters performance. Secondly, a novel switching technique is discussed that allows a bandwidth tuning over more than two orders of magnitude starting from 100 kHz up to 20 MHz and which uses only gate transistor capacitance. Fundamental to this technique is that the power consumption can be traded with the desired performance. Furthermore, the quality factor, noise level and linearity are all programmable over a very wide range. The biquad is processed in a 0.13-mum CMOS technology and operates at different supply voltages down to less than 0.8 V. For a 1.2-V supply, the filter consumes between 103 muA (100 kHz) and 11.85 mA (20 MHz) for a low noise setting around 25 to 35 muVrms integrated over the filter bandwidth achieving an third-order intermodulation intercept point of 10 dBVp.     

All-Silicon 1.55-$mu$m High-Resolution Photon Counting and Timing

We investigate the performances at 1.55- $mu{hbox{m}}$ wavelength of silicon single photon avalanche diodes (SPADs), demonstrating their suitable applicability in laser characterizations and ultra-sensitive autocorrelation measurements. We investigate the photon detection efficiency and the two-photon absorption process of both lightly doped thick SPADs and heavily doped thin SPADs. Finally, we report the accurate pulse-shape characterization of a 1.55- $mu{hbox{m}}$ pulsed laser by means of a thin silicon SPAD that exploits the best intrinsic time resolution of 25 ps with wide dynamic range and low measurement time.      

2.7-$mu$ m GaSb-Based Diode Lasers With Quinary Waveguide

Type-I double-quantum-well (QW) GaSb-based diode lasers operating at 2.7 $mu hbox{m}$ with room-temperature continuous-wave (CW) output power of 600 mW and peak power-conversion efficiency of 10% were designed and fabricated. The devices employed 470-nm-wide AlGaInAsSb waveguide optimized for improved device differential gain. CW threshold current density about 100 $hbox{A}/hbox{cm}^{2}$ per QW and slope efficiency of 150 mW/A were demonstrated at 16 $^{circ }hbox{C}$.      

Rate Equations for 1.3-$mu$ m Dots-Under-a-Well and Dots-in-a-Well Self-Assembled InAs–GaAs Quantum-Dot Lasers

A rate-equation model, in which three discrete quantum-dot (QD) energy levels are assumed and all possible relaxation paths and carrier transport in the GaAs barrier are considered, is presented to analyze the steady-state performance of 1.3 mum undoped and doped dots-under-a-well (DUW) and dots-in-a-well (DWELL) InAs-GaAs QD lasers. DWELL QD lasers have higher saturation value of QD level occupation probabilities and characteristic temperature (T₀) than that of DUW QD lasers due to the improvement of hole confinement. The p-doped QD laser shows lower threshold current density than n-doped QD laser at the same threshold condition, and the T₀ of n-doped DWELL laser is higher than that of p-doped DWELL laser at room temperature. Optimized QD layer number of DUW and DWELL QD lasers with different QD density is discussed     

Low-Threshold Strained Quantum-Well GaSb-Based Lasers Emitting in the 2.5- to 2.7-$mu$ m Wavelength Range

GaInAsSb–GaSb strained quantum-well (QW) ridge waveguide diode lasers emitting in the wavelength range from 2.51 to 2.72 $ mu{hbox {m}}$ have been grown by molecular beam epitaxy. The devices show ultralow threshold current densities of 44 $hbox{A}/{hbox {cm}}^{2}$ (${L}rightarrow infty $) for a single QW device at 2.51 $ mu{hbox {m}}$, which is the lowest reported value in continuous-wave operation near room temperature (15 $^{circ}hbox{C}$) at this wavelength. The devices have an internal loss of 3 ${hbox {cm}}^{-1}$ and a characteristic temperature of 42 K. By using broader QWs, wavelengths up to 2.72 $mu{hbox {m}}$ could be achieved.      

A 0.6-V Dynamic Biasing Filter With 89-dB Dynamic Range in 0.18-$mu$ m CMOS

This paper presents a 100-kHz fifth-order Chebychev low-pass filter (LPF) using the proposed dynamic biasing (DB) technique which enables wide dynamic range under a low-supply voltage. The change of state variables in the internal nodes of the filter can be corrected by using a novel simplified scheme, avoiding the output transient owing to dynamic biasing. The filter, including an automatic frequency tuning system based on the voltage-controlled-filter (VCF) architecture and voltage reference circuit, is fabricated in a 0.18-mum standard CMOS technology with a 0.5-V threshold voltage and consumes 443 muW from a power supply of 0.6 V. The output noise and the in-band IIP₃ are 575 pA_rms and 219 muA, respectively. The filter achieves a dynamic range of 89 dB.     

Ultra-Low-Voltage 20-GHz Frequency Dividers Using Transformer Feedback in 0.18-$mu$ m CMOS Process

This paper presents the design and analysis of ultra- low-voltage (ULV) high-frequency dividers using transformer feedback. Specifically, a differential-input differential-output injection-locked (IL) divider topology with transformer feedback and a wideband transformer-coupled (TC) divider with quadrature outputs are demonstrated, both of which can operate well at supply voltages as low as the device's threshold voltages. Fabricated in a standard 0.18-mum CMOS process, the ULV-IL divider measures an input frequency range from 16.1 GHz to 20 GHz while consuming a total power from 2.75 mW to 4.35 mW at 0.5 V supply, and the TC-divider measures an input frequency range of 27.8% from 15.1 GHz to 20 GHz with IQ sideband rejection of - 31 dBc while consuming power from 11.4 mW to 13.6 mW at 0.6 V supply.     

Experimental Study of the Lasing Modes of 1.3-$mu$m Highly Strained InGaAs–GaAs Quantum-Well Oxide-Confined VCSELs

We present an experimental study of the main modes involved in the emission properties of InGaAs–GaAs quantum-well oxide-confined long wavelength vertical-cavity surface-emitting lasers. Lasing properties are dominated by the so-called “oxide modes” and by aperture modes, respectively, for small and large driving currents. We present complementary investigations of the laser emission including far-field angular distribution and spectroscopic near-field optical microscopy to a better understanding of the nature of the “oxide modes.”      

Lifetime of Combined $k$-out-of-$n$ , and Consecutive $k_{c}$ -out-of-$n$ Systems

A combined k-out-of-n:F(G) & consecutive k_c -out-of-n :F(G) system fails (functions) iff at least k components fail (function), or at least fcc consecutive components fail (function). Explicit formulas are given for the lifetime distribution of these combined systems whenever the lifetimes of components are exchangeable, and have an absolutely continuous joint distribution. The lifetime distributions of the aforementioned systems are represented as a linear combination of distributions of order statistics by using the concept of Samaniego's signature. Formulas for the mean lifetimes are given. Some numerical results are also presented.