A 1.55-μm laser array monolithically integrated with an MMI combiner

The monolithic integration of four 1.55-μm range InGaAsP/InP distributed feedback lasers with a 4×1 multimode-interference(MMI) optical combiner using the varied width ridge method is proposed and demonstrated. The average output power is 1.5 mW when the current of LD is 100 mA and the threshold current is 30-35 mA at 25℃.The lasing wavelength is 1.55-μm range and 40 dB sidemode suppression ratio is obtained.The four channels can operate separately or simultaneously.     

A 1.65μm three-section distributed Bragg reflector （DBR） laser for CH4 gas sensors

A 1.65-μm three-section distributed Bragg reflector(DBR) laser for CH4 gas sensors is reported.The DBR laser has a wide tunable range covering the R3 and R4 methane absorption line manifolds.The wavelength tunability properties,temperature stability and laser linewidth are characterized and analyzed.Several advantages were demonstrated compared with traditional DFB lasers in harmonic detection.     

An asymmetric broad waveguide structure for a 0.98-μm high-conversion-efficiency diode laser

A novel asymmetric broad waveguide diode laser structure was designed for high power conversion efficiency (PCE). The internal quantum efficiency, the series resistance, and the thermal resistance were theoretically optimized. The series resistance and the thermal resistance were greatly decreased by optimizing the thickness of the P-waveguide and the P-cladding layers. The internal quantum efficiency was increased by introducing a novel strain-compensated GaAs0.9P0.1/InGaAs quantum well. Experimentally, a single 1-cm bar with 20% fill factor and 900 μm cavity length was mounted P-side down on a microchannel-cooled heatsink, and a peak PCE of 60% is obtained at 26.3-W continuous wave output power. The results prove that this novel asymmetric waveguide structure design is an efficient approach to improve the PCE.     

An asymmetric broad waveguide structure for a 0.98-μm high-conversion-efficiency diode laser

A novel asymmetric broad waveguide diode laser structure was designed for high power conversion efficiency（PCE）.The internal quantum efficiency,the series resistance,and the thermal resistance were theoretically optimized.The series resistance and the thermal resistance were greatly decreased by optimizing the thickness of the P-waveguide and the P-cladding layers.The internal quantum efficiency was increased by introducing a novel strain-compensated GaAs0.9P0.1/InGaAs quantum well.Experimentally,a single 1-cm bar with 20% fill factor and 900 μm cavity length was mounted P-side down on a microchannel-cooled heatsink,and a peak PCE of 60% is obtained at 26.3-W continuous wave output power.The results prove that this novel asymmetric waveguide structure design is an efficient approach to improve the PCE.     

1.3μm Superluminescence Diode with Butterfly Package for Fiber Gyroscope

Superluminescence diode(SLD) modules with wide spectrum characteristics are required in fiber gyroscopes.A 1.3μm butterfly packaged superluminescence diode with the spectrum widt over 30 nm is reported and recent advances in process of SLD is described in the paper.The SLD modules have been applied to fiber gyroscopes.     

A 700 MHz laser radar receiver realized in 0.18 μm HV-CMOS

This study presents a CMOS receiver chip realized in 0.18 µm High-Voltage CMOS (HV-CMOS) technology and intended for high precision pulsed time-of-flight laser range finding utilizing high-energy sub-ns laser pulses. The IC chip includes a trans-impedance preamplifier, a post-amplifier and a timing comparator. Timing discrimination is based on leading edge detection and the trailing edge is also discriminated for measuring the width of the pulse. The transimpedance of the channel is 25 kΩ, the uncompensated walk error is 470 ps in the dynamic range of 1:21,000 and the input referred equivalent noise current 450 nA (rms).     

A 0.35μm CMOS Mixer for 2.45-GHz RFID Application

A RF mixer with both low noise and high linearity is designed,operating at 2.45-GHz ISM band for RFID application.The designed mixer uses an optimal input matching network and the carefully chosen sizes of transistors,also with the appropriate bias point,to improve the noise figure(NF).Also,with a resonant LC loop as the current source and a parallel PMOS-resistor as the load,the mixer has a high linearity.The post simulation results show that the single side- band noise figure of 8.57 dB,conversion gain of 10.02 dB,input 1-dB compression point(P-1dB)of-8.33 dBm,and input third-order intercept point(IIP3)of 5.35 dBm.     

A 0.18μm CMOS inductorless complementary-noise-canceling-LNA for TV tuner applications

This paper presents an inductorless complementary-noise-canceling LNA(CNCLNA) for TV tuners.The CNCLNA exploits single-to-differential topology,which consists of a common gate stage and a common source stage. The complementary topology can save power and improve the noise figure.Linearity is also enhanced by employing a multiple gated transistors technique.The chip is implemented in SMIC 0.18μm CMOS technology.Measurement shows that the proposed CNCLNA achieves 13.5-16 dB voltage gain from 50 to 860 MHz,...     

A 0.18μm CMOS fluorescent detector system for bio-sensing application

A CMOS fluorescent detector system for biological experiment is presented. This system integrates a CMOS compatible photodiode, a capacitive trans-impedance amplifier （CTIA）, and a 12 bit pipelined analog-to- digital converter （ADC）, and is implemented in a 0.18μm standard CMOS process. Some special techniques, such as a ＂contact imaging＂ detecting method, pseudo-differential architecture, dummy photodiodes, and a T-type reset switch, are adopted to achieve low-level sensing application. Experiment results show that the Nwell/Psub photodiode with CTIA pixel achieves a sensitivity of 0.1 A/W at 515 nm and a dark current of 300 fA with 300 mV reverse biased voltage. The maximum differential and integral nonlinearity of the designed ADC are 0.8 LSB and 3 LSB, respectively. With an integrating time of 50 ms, this system is sensitive to the fluorescence emitted by the fluorescein solution with concentration as low as 20 ng/mL and can generate 7 fA photocurrent. This chip occupies 3 mm^2 and consumes 37 mW.     

Fabrication of four-channel DFB laser array using nanoimprint technology for 1.3μm CWDM systems

Four-channel monolithically integrated index-coupled distributed-feedback laser array has been fabricated using nanoimprint technology for 1.3 m CWDM system.Selective lasing wavelength with 20 nm wavelength space is obtained.The present results show that the nanoimprint technology is mature and reliable in the fabrication of DFB laser array.     

Active Mixers for Direct Conversion Receivers with 0.35-μm BiCMOS

In this paper, the design requirements of different mixers for direct conversion receivers are discussed. Special attention has been paid into the detection of amplitude-modulated RF signal envelope. Three active mixers have been implemented to investigate the discussed requirements by using a 0.35-m, 25-GHz BiCMOS technology. The same process allows an objective comparison between the different topologies. The mixers are designed for a single 2.7 V supply, and specified for low power consumption. Different topologies are compared by their spurious free dynamic ranges (SFDR) with respect to their individual power consumption. Also, their performance were measured at different LO power levels and supply voltages. The results show insignificant differences between the topologies in low voltage applications.     

A 0.18μm CMOS Gilbert low noise mixer with noise cancellation

正This paper presents a broadband Gilbert low noise mixer implemented with noise cancellation technique operating between 10 MHz and 0.9 GHz.The Gilbert mixer is known for its perfect port isolation and bad noise performance.The noise cancellation technique of LNA can be applied here to have a better NF.The chip is implemented in SMIC 0.18μm CMOS technology.Measurement shows that the proposed low noise mixer has a 13.7-19.5 dB voltage gain from 10 MHz to 0.9 GHz,an average noise figure of 5 dB and a minimum value of 4.3 dB.The core area is 0.6 x 0.45 mm~2.     

A 5.2 GHz low-voltage low-noise amplifier with 0.35 μm CMOS technology

A low-voltage CMOS low-noise amplifier (LNA) architecture is presented. We have used a TSMC 0.35?µm CMOS high-frequency model to design a fully integrated 1?V, 5.2?GHz two-stage CMOS low-noise amplifier for RF front-end applications. No off-chip element is needed and a conventional common-source with feedback technology is used in this circuit. The first stage of the LNA is the common-source with feedback structure and the output stage is a buffer which increases the gain somewhat. An interstage negative-impedance circuit is added between the two stages of the LNA to further enhance the overall gain and thus upgrade its performance. Mainly because of the finite Q of the inductor, the negative-impedance circuit used in this interstage can cancel the losses in the first-stage inductor load. The input and output matching network is matched to approximately 50?Ω. The simulation results show that the amplifier provides a gain of 9.48?dB, a noise figure of 4.08?dB, and draws 13.4?mW from a 1?V supply. The S11 and S22 are both lower than ?15?dB.     

A 0.18μm CMOS single-inductor single-stage quadrature frontend for GNSS receiver

This paper presents an improved merged architecture for a low-IF GNSS receiver frontend,where the bias current and functions are reused in a stacked quadrature LNA-mixer-VCO.Only a single spiral inductor is implemented for the LC resonator and an extra 1/2 frequency divider is added as the quadrature LO signal generator. The details of the design are presented.The gain plan and noise figure are discussed.The phase noise,quadrature accuracy and power consumption are improved.The test chip is fabricated though a 0.18μm RF CMOS process. The measured noise figure is 5.4 dB on average,with a gain of 43 dB and a IIP3 of-39 dBm.The measured phase noise is better than -105 dBc/Hz at 1 MHz offset.The total power consumption is 19.8 mW with a 1.8 V supply. The experimental results satisfy the requirements for GNSS applications.     

AlGaN/GaN HEMTs with 0.2μm V-gate recesses for X-band application

正AlGaN/GaN HEMTs with 0.2μm V-gate recesses were developed.The 0.2μm recess lengths were shrunk from the 0.6μm designed gate footprint length after isotropic SiN deposition and anisotropic recessed gate dry etching.The AlGaN/GaN HEMTs with 0.2μm V-gate recesses on sapphire substrates exhibited a current gain cutoff frequency f_t of 35 GHz and a maximum frequency of oscillation f_(max) of 60 GHz.At 10 GHz frequency and 20 V drain bias,the V-gate recess devices exhibited an output power density of 4.44 W/mm with the associated power added efficiency as high as 49%.     

A 3.1-4.8 GHz transmitter with a high frequency divider in 0.18μm CMOS for OFDM-UWB

A fully integrated low power RF transmitter for a WiMedia 3.1-4.8 GHz multiband orthogonal frequency division multiplexing ultra-wideband system is presented. With a separate transconductance stage, the quadrature up-conversion modulator achieves high linearity with low supply voltage. The co-design of different resonant frequencies of the modulator and the differential to single （D2S） converter ensures in-band gain flatness. By means of a series inductor peaking technique, the D2S converter obtains 9 dB more gain without extra power consumption. A divided-by-2 divider is used for carrier signal generation. The measurement results show an output power between -10.7 and -3.1 dBm with 7.6 dB control range, an OIP3 up to 12 dBm, a sideband rejection of 35 dBc and a carrier rejection of 30 dBc. The ESD protected chip is fabricated in the Jazz 0.18μm RF CMOS process with an area of 1.74 mm^2 and only consumes 32 mA current （at 1.8 V） including the test associated parts.     

掺铒a-Si:H,O薄膜1.54μm光致发光和微结构

采用等离子化学气相淀积方法,改变SiH4和N2O的流量比制备含有不同氧浓度的a-Si：H,O薄膜.用离子注入方法掺入铒,经300一935℃快速热退火,在波长1.54μm处观察到很强的室温光致发光.氧的加入可以大大提高铒离子的发光强度,并且发光强度随氧含量的变化有一个类似于高斯曲线的分布关系,不是单调地随氧含量的增加而增强.研究了掺铒a-Si:H,O薄膜和微结构,讨论了发光强度与薄膜微结构的关系.