The Performance of Acoustic-Optical $Q$-switched Mode-Locking 1.34 $mu$m Nd:GdVO$_{4}$ Laser

A diode-end-pumped $Q$ -switched mode-locking $hbox{Nd:GdVO}_{4}$ laser operating at 1.34 $mu{hbox {m}}$ with an acousto-optical (AO) Q-switch in a compact V-type cavity was realized in our experiment for the first time. When the AO Q-switch repetition rate was 10 kHz, the maximum average output power of 750 mW and the pulse energy of 75 $muhbox{J}$ were obtained at the maximum incident pump power of 9 W. The mode-locking modulation depth of about 100% was obtained at certain pump power over the threshold. The mode-locked pulse inside in the $Q$-switched pulse had a repetition rate of 341 MHz, and its average pulsewidth was estimated to be about 350 ps. A developed rate equation model for the $Q$ -switched and mode-locked lasers with an AO Q-switch were proposed by using the hyperbolic secant functional methods. The results of numerical calculations of the rate equations were in good agreement with the experimental results.      

Plasmon-Waveguide Interband Cascade Lasers Near 7.5 $mu$ m

Broad-area plasmon-waveguide interband cascade lasers with emission wavelengths near 7.5 mu m were demonstrated at temperatures up to 121 K in continuous-wave mode. Their threshold current densities and voltages varied from 72 A/cm² and 2.1 V at 84 K to 400 A/cm² and 2.7 V at 121 K, showing very efficient use of bias voltage (e.g., voltage efficiency of about 90% at 84 K) at this long wavelength. These plasmon-waveguide lasers also operated in pulsed mode at temperatures up to 165 K with emission wavelengths near 7.6 mum and threshold current density of 1100 A/cm².     

Extended Continuous Tuning of a Single-Frequency Diode-Pumped Vertical-External-Cavity Surface-Emitting Laser at 2.3 $mu$m

We report on single-frequency operation and wide mode-hop-free tuning range of a diode laser-pumped vertical- external-cavity surface-emitting semiconductor laser producing up to 3 mW around 2.3 $mu$m. An optically stable external cavity of only 1.4 mm is formed using a concave dielectric mirror of 2-mm radius. The maximum continuous tuning is about 500 GHz wide, obtained by a synchronized ramp of external cavity length and of the gain medium temperature. We used this tunable source to record a direct absorption spectrum of methane, which is found to match well a simulated spectrum from the HITRAN (high-resolution transmission molecular absorption database http://www.cfa.harvard.edu/hitran) database.      

A 24 GHz Amplitude Monopulse Comparator in 0.13 $mu$m CMOS

This letter presents the design and implementation of a wideband 24 GHz amplitude monopulse comparator in 0.13 $mu$m CMOS technology. The circuit results in 9.6 dB gain in the sum channel at 24 GHz with a 3-dB bandwidth of 23.0–25.2 GHz, and a sum/difference ratio of $> 25$ dB at 20–26 GHz. The measured input P1 dB is ${-}14.4$ dBm at 24 GHz. The chip is only 0.55$,times,$ 0.50 mm$^{2}$ (without pads) and consumes 44 mA from a 1.5 V supply, including the input active baluns and the differential to single-ended output stages (28 mA without the input and output stages). To our knowledge, this is the first demonstration of a high performance mm-wave CMOS monopulse comparator RFIC.      

A K-Band High-Gain Down-Conversion Mixer in 0.18 $mu$m CMOS Technology

A high gain CMOS down conversion mixer with a gain enhancement technique is presented. This technique includes negative resistance generation, parasitic capacitance cancellation and current-injection. These are implemented with an additional circuitry. This mixer has a conversion gain of 9.12 dB, input 1 dB compression point of -11 dBm at 24 GHz, while consuming 16.2 mW from 1.8 V supply. Between 22 and 26 GHz, the LO-to-RF and RF-to-LO isolations are better than 35 dB and 26 dB, respectively.     

High-Q Slow-Wave Coplanar Transmission Lines on 0.35 $mu$m CMOS Process

In this letter, experimental results and trends for shielded coplanar waveguide transmission lines (S-CPW) implemented in a 0.35 $mu$m CMOS technology are provided. Because of the introduction of floating strips below the CPW transmission line, high effective dielectric permittivity and quality factor are obtained. Three different geometries of S-CPW transmission lines are characterized. For the best geometry, the measured effective dielectric permittivity reaches 48, leading to a very high slow-wave factor and high miniaturization. In addition, measurements demonstrate a quality factor ranging from 20 to 40 between 10 and 40 GHz, demonstrating state-of-the-art results for transmission lines realized in a low-cost CMOS standard technology.      

A Wideband PLL-Based G/FSK Transmitter in 0.18 $mu$m CMOS

A wideband phase-locked loop (PLL)-based G/FSK transmitter (TX) architecture is presented in this paper. In the proposed TX, the G/FSK data is applied outside the loop; hence, the data rate is not constrained by the PLL bandwidth. In addition, the PLL remains locked all the time, preventing the carrier frequency from drifting. In this architecture, the G/FSK modulation signal is generated from a proposed Sigma-Delta modulated Phase Rotator $(SigmaDelta{hbox{-PR}})$. By properly combining the multi-phase signals from the PLL output, the $SigmaDelta{hbox{-PR}}$ effectively operates as a fractional frequency divider, which can synthesize modulation signals with fine-resolution frequencies. The proposed $SigmaDelta{hbox{-PR}}$ adopts the input signal as the phase transition trigger, facilitating a glitch-free operation. The impact of the $SigmaDelta{hbox{-PR}}$ on the TX output noise is also analyzed in this paper. The proposed TX with the $SigmaDelta{hbox{-PR}}$ is digitally programmable and can generate various G/FSK signals for different applications. Fabricated in a 0.18 $muhbox{m}$ CMOS technology, the proposed TX draws 6.3 mA from a 1.4 V supply, and delivers an output power of $-$11 dBm. With a maximum data rate of 6 Mb/s, the TX achieves an energy efficiency of 1.5 nJ/bit.      

A 0.6 V Low-Power Wide-Range Delay-Locked Loop in 0.18 $mu$m CMOS

In this letter, a delay-locked loop (DLL) suitable for low-power and low-voltage operations is presented. To overcome the performance limitations, such as a restricted locking range and elevated output jitters, a novel voltage-controlled delay cell and a phase/frequency detector with a start controller are employed in the proposed DLL. Using a standard 0.18 mum CMOS process, the fabricated circuit exhibits a locking range from 85 to 550 MHz. The measured peak-to-peak and rms jitters at 550 MHz are 25.6 and 3.8 ps, respectively. Operated at a supply voltage of 0.6 V, the power consumption of the DLL circuit varies from 2.4 to 4.2 mW within the entire locking range.     

A 5.6 GHz Low Power Balanced VCO in 0.18 $mu$m CMOS

A 5.6 GHz balanced voltage-controlled oscillator (VCO) is designed and implemented in a 0.18 mum CMOS 1P6M process. It consists of two single-ended complementary Colpitts LC-tank VCOs coupled by two pairs of varactors. At the supply voltage of 1.2 V, the output phase noise of the VCO is -119.13 dBc/Hz at 1MHz offset frequency from the carrier frequency of 5.6 GHz, and the figure of merit is -190.29 dBc/Hz. Total VCO core power consumption is 2.4 mW. Tuning range is about 600 MHz, from 5.36 to 5.96 GHz, while the control voltage was tuned from 0 to 1.2 V.     

A Slew Controlled LVDS Output Driver Circuit in 0.18 $mu$m CMOS Technology

This article presents a power-efficient low-voltage differential signaling (LVDS) output driver circuit. The proposed approach helps to reduce the total input capacitance of the LVDS driver circuit and hence relaxes the tradeoffs in designing a low-power pre-driver stage. A slew control technique has also been introduced to reduce the impedance mismatch effect between the output driver circuit and the line. The pre-driver stage shows a total input capacitance of 50 fF and also controls the voltage swing and common-mode voltage at the input of the LVDS driver output stage. This makes the operation at low supply voltages using a conventional 0.18 $muhbox{m}$ CMOS technology feasible. The output driver circuit consumes 4.5 mA while driving an external 100 $Omega $ resistor with an output voltage swing of $V_{OD} = $400 mV, achieving a normalized power dissipation of 3.42 mW/Gbps. The area of the LVDS driver circuit is 0.067 ${hbox{mm}}^{2}$ and the measured output jitter is $sigma _{rms} = $4.5 ps. Measurements show that the proposed LVDS driver can be used at frequencies as high as 2.5 Gbps where the speed will be limited by the load $RC$ time constant.      

A 51 to 65 GHz Low-Power Bulk-Driven Mixer Using 0.13 $mu$m CMOS Technology

A low-voltage and low-power down-conversion bulk-driven mixer using standard 0.13 $mu$ m CMOS technology is presented in this letter. To work on a low supply voltage and low power consumption applications while maintaining reasonable performance, the bulk-driven technique is selected in this V-band mixer design. The mixer has a conversion gain of $0 pm 1.5$ dB from 51 to 65 GHz with low supply voltage of 1 V and low power consumption of 3 mW. To our knowledge, the MMIC is the highest frequency CMOS bulk-driven mixer to date with good conversion gain and low power consumption among the recently published active mixers around 60 GHz.      

A 1.8 V 900 $mu$ W 4.5 GHz VCO and Prescaler in 0.18 $mu$m CMOS Using Charge-Recycling Technique

This letter presents a charge-recycling VCO and divider in 0.18 $mu$m CMOS technology. The power consumption of the proposed circuit is significantly reduced by stacking the low-voltage divider on the top of the low-voltage VCO, and hence, the VCO reuses the current from the divider. To enhance the reliability of the proposed circuit under supply voltage variation, transistor sharing and adaptive body-biasing techniques are employed. It allows the proposed circuit to operate down to 1.45 V of supply voltage without degrading the FoM. Experimental results show that the proposed circuit achieves 900 $mu$W of power consumption and ${-}184$ dBc/Hz of FoM at 1.8 V.      

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.      

Bipolar Cascade Superluminescent Diodes at the 1.04-$mu$m Wavelength Regime

In this study, we investigate the performance of GaAs-based bipolar cascade superluminescent diodes with different cavity lengths. The device operates around the important bio-optical therapeutic 1.04- $muhbox{m}$ wavelength window. The introduction of tunnel junctions tends to minimize the nonuniform carrier distribution between distinct multiple quantum-wells (QWs), which is a problem in conventional SLDs, whose electroluminescent spectra are governed by the center wavelength of QWs near the p-side. Our devices exhibit nice electrical characteristics of low leakage current and overcome the limitation of nonuniform carrier distribution, thereby presenting a promising prospect for the near infrared white-light sources.      

Modal Gain of 2.4- $mu$m InGaAsSb–AlGaAsSb Complex-Coupled Distributed-Feedback Lasers

High-resolution spectroscopy was used to examine gain characteristics of Cr-grating complex-coupled distributed-feedback (DFB) lasers near 2.4 $mu$m. The single-mode lasers contain InGaAsSb–AlGaAsSb active regions grown by molecular beam epitaxy on GaSb. Modal gain was extracted from the measured amplified spontaneous emission spectra and compared with reference Fabry–PÉrot lasers. The material gain is similar in both cases, having a value near 1300 cm$^{-1}$, while the internal losses are quite different. The DFBs have an additional loss, approximately equal to the lateral Cr grating coupling coefficient. This indicates a fundamental performance limitation for complex-coupled DFBs.      

A 2.4-GHz Resistive Feedback LNA in 0.13-$mu$m CMOS

A $g_{m}$-boosted resistive feedback low-noise amplifier (LNA) using a series inductor matching network and its application to a 2.4 GHz LNA is presented. While keeping the advantage of easy and reliable input matching of a resistive feedback topology, it takes an extra advantage of $g_{m}$ -boosting as in inductively degenerated topology. The gain of the LNA increases by the $Q$ -factor of the series RLC input network, and its noise figure (NF) is reduced by a similar factor. By exploiting the $g_{m}$-boosting property, the proposed fully integrated LNA achieves a noise figure of 2.0 dB, S21 of 24 dB, and IIP3 of ${- 11}~ hbox{dBm}$ while consuming 2.6 mW from a 1.2 V supply, and occupies 0.6 ${hbox {mm}}^{2}$ in 0.13-$mu{hbox {m}}$ CMOS, which provides the best figure of merit. This paper also includes an LNA of the same topology with an external input matching network which has an NF of 1.2 dB.      

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 $^{circ }hbox{C}$.      

Analytical Model of $I$– $V$ Characteristics of Arbitrarily Shallow p-n Junctions

For the first time, an analytical model of arbitrarily shallow p-n junctions is presented. Depending on the junction depth, electrical characteristics of ultrashallow p-n junctions can vary from the characteristics of standard Schottky diodes to standard deep p-n junctions. This model successfully unifies the standard Schottky and p-n diode expressions. In the crossover region, where the shallow doping region can be totally depleted, electrical characteristics phenomenologically substantially different from typical diode characteristics are predicted. These predictions and the accuracy of the presented model are evaluated by comparison with the MEDICI simulations. Furthermore, ultrashallow $hbox{n}^{+}$-p diodes were fabricated, and the anomalous behavior in the crossover regime was experimentally observed.      

0.13 $mu$ m SiGe BiCMOS Technology Fully Dedicated to mm-Wave Applications

This paper presents a complete 0.13$,muhbox{m}$ SiGe BiCMOS technology fully dedicated to millimeter-wave applications, including a high-speed (230/280 GHz ${rm f}_{rm T}/{rm f}_{rm MAX}$) and medium voltage SiGe HBT, thick-copper back-end designed for high performance transmission lines and inductors, 2 $hbox{fF}/muhbox{m}^{2}$ high-linearity MIM capacitor and complementary double gate oxide MOS transistors. Details are given on HBT integration, reliability and models as well as on back-end devices models.      

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.