A low-noise, high-SNR balanced homodyne detector for the bright squeezed state measurement in 1–100 kHz range

We report a low-noise, high-signal-to-noise-ratio(SNR) balanced homodyne detector based on the standard transimpedance amplifier circuit and the inductance and capacitance combination for the measurement of the bright squeezed state in the range from 1 kHz to 100 kHz. A capacitance is mounted at the input end of the AC branch to prevent the DC photocurrent from entering the AC branch and avoid AC branch saturation. By adding a switch at the DC branch,the DC branch can be flexibly turned on and off on different occasions. When the switch is on, the DC output provides a monitor signal for laser beam alignment. When the switch is off, the electronic noise of the AC branch is greatly reduced at audio-frequency band due to immunity to the impedance of the DC branch, hence the SNR of the AC branch is significantly improved. As a result, the electronic noise of the AC branch is close to -125 dBm, and the maximum SNR of the AC branch is 48 dB with the incident power of 8 mW in the range from 1 kHz to 100 kHz. The developed photodetector paves a path for measuring the bright squeezed state at audio-frequency band.

LOW-FREQUENCY LOW-NOISE CIRCUITS DESIGN USING AN E_n-I_n MODEL

In view of the limitations of a Rn-Gn model in the low frequency range and the defects of an En-In model in common use now, this paper builds a complete En-In model according to the theory of random harmonic. The parameters for the low-noise design such as the equivalent input noisy voltage Ens, the optimum source impedance Zsopt and the minimum noise figure Fmin can be calculated accurately by using this En-In model because it considers the coherence between the noise sources fully. Moreover, this paper points out that it will cause the maximum 30% miscalculation when neglecting the effects of the correlation coefficient 7. Using the series-series circuits as an example, this paper discusses the methods for the En-In noise analysis of electronic circuits preliminarily and demonstrates its correctness through the comparison between the simulated and measured results of the minimum noise figure Fmin of a single current series negative feedback circuit.

A Low-Noise Readout Circuit for Gyroscopes

In order to suppress the noise of gyroscopes,the method based on lock-in amplifier and capacitor matching of the low-noise readout circuit is proposed. Firstly,the principle to suppress the noise by lock-in amplifier is analyzed,and the noise model of front end is proposed. Secondly,the noise optimization for the charge amplifier is presented according to the noise model of front end. Finally,a readout circuit is constructed by this approach. The measurement results show that the parasitic capacitance of front end is 18 p F,and the noise at resonant frequency( 4 k Hz) is 133 n V / Hz1 / 2,and the overall bias stability is 30° /h,and the noise level is 0. 003° /( s·Hz1 / 2). The noise of the gyroscope with the low-noise readout by this method is suppressed effectively.

Design of a Low-Noise Front-End Readout CSP-Shaper System for CZT Detectors

This paper describes a low-noise front-end readout circuit for CZT detectors based on TSMC 0.35 um mixed-single CMOS technology;mainly analyzes the noise model of the detector-preamplifier and presents the low-noise circuit schematic of charge sensitive preamplifier and shaper. Considering the parasitical influences, the circuit and layout-design are optimized to reduce noise. The preliminary simulation results show that, the equivalent noise charge (ENC) is 74 e﹣ (rms), noise slope is 9 e﹣/pF, power consumption is 2 mW, and non-linearity

Low-Noise Amplification, Detection and Spectroscopy of Ultra-Cold Systems in RF Cavities

The design and development of a cryogenic Ultra-Low-Noise Signal Amplification (ULNA) and detection system for spectroscopy of ultra-cold systems are reported here for the operation in the 0.5 - 4 GHz spectrum of frequencies (the “L” and “S” microwave bands). The design is suitable for weak RF signal detection and spectroscopy from ultra-cold systems confined in cryogenic RF cavities, as entailed in a number of physics, physical chemistry and analytical chemistry applications, such as NMR/NQR/EPR and microwave spectroscopy, Paul traps, Bose-Einstein Condensates (BEC’s) and cavity Quantum Electrodynamics (cQED). Using a generic Low-Noise Amplifier (LNA) architecture for a GaAs enhancement mode High-Electron Mobility FET device, our design has especially been devised for scientific applications where ultra-low-noise amplification systems are sought to amplify and detect weak RF signals under various conditions and environments, including cryogenic temperatures, with the least possible noise susceptibility. The amplifier offers a 16 dB gain and a 0.8 dB noise figure at 2.5 GHz, while operating at room temperature, which can improve significantly at low temperatures. Both dc and RF outputs are provided by the amplifier to integrate it in a closed-loop or continuous-wave spectroscopy system or connect it to a variety of instruments, a factor which is lacking in commercial LNA devices. Following the amplification stage, the RF signal detection is carried out with the help of a post-amplifier and detection system based upon a set of Zero-Bias Schottky Barrier Diodes (ZBD’s) and a high-precision ultra-low noise jFET operational amplifier. The scheme offers unique benefits of sensitive detection and very-low noise amplification for measuring extremely weak on-resonance signals with substantial low- noise response and excellent stability while eliminating complicated and expensive heterodyne schemes. The LNA stage is fully capable to be a part of low-temperature experiments while being operated in cryogenic conditions down to about 500 mK.

Low-noise 1.3 μm InAs/GaAs quantum dot laser monolithically grown on silicon

We report low-noise, high-performance single transverse mode 1.3 μm InAs/GaAs quantum dot lasers monolithically grown on silicon(Si) using molecular beam epitaxy. The fabricated narrow-ridge-waveguide Fabry–Perot(FP) lasers have achieved a room-temperature continuous-wave(CW) threshold current of 12.5 mA and high CW temperature tolerance up to 90°C. An ultra-low relative intensity noise of less than-150 dB∕Hz is measured in the 4–16 GHz range. Using this low-noise Si-based laser, we then demonstrate 25.6 Gb/s data transmission over13.5 km SMF-28. These low-cost FP laser devices are promising candidates to provide cost-effective solutions for use in uncooled Si photonics transmitters in inter/hyper data centers and metropolitan data links.

Nonlinearity-tailored fiber laser technology for low-noise, ultra-wideband tunable femtosecond light generation

The emission wavelength of a laser is physically predetermined by the gain medium used. Consequently, arbitrary wavelength generation is a fundamental challenge in the science of light. Present solutions include optical parametric generation, requiring complex optical setups and spectrally sliced supercontinuum, taking advantage of a simpler fiber technology: a fixed-wavelength pump laser pulse is converted into a spectrally very broadband output, from which the required resulting wavelength is then optically filtered. Unfortunately, this process is associated with an inherently poor noise figure, which often precludes many realistic applications of such supercontinuum sources. Here, we show that by adding only one passive optical element—a tapered photonic crystal fiber—to a fixed-wavelength femtosecond laser, one can in a very simple manner resonantly convert the laser emission wavelength into an ultra-wide and continuous range of desired wavelengths, with very low inherent noise, and without mechanical realignment of the laser. This is achieved by exploiting the double interplay of nonlinearity and chirp in the laser source and chirp and phase matching in the tapered fiber. As a first demonstration of this simple and inexpensive technology, we present a femtosecond fiber laser continuously tunable across the entire red–green–blue spectral range.

A single-to-differential low-noise amplifier with low differential output imbalance

This paper presents a single-ended input differential output low-noise amplifier intended for GPS applications. We propose a method to reduce the gain/amplitude and phase imbalance of a differential output exploiting the inductive coupling of a transformer or center-tapped differential inductor.A detailed analysis of the theory of imbalance reduction,as well as a discussion on the principle of choosing the dimensions of a transformer,are given.An LNA has been implemented using TSMC 0.18μm technology with ESD-protected.Measurement on board shows a voltage gain of 24.6 dB at 1.575 GHz and a noise figure of 3.2 dB.The gain imbalance is below 0.2 dB and phase imbalance is less than 2 degrees.The LNA consumes 5.2 mA from a 1.8 V supply.

Design and performances of a low-noise and radiation-hardened readout ASIC for CdZnTe detectors

In this paper,we present the design and performances of a low-noise and radiation-hardened front-end readout application specific integrated circuit（ASIC） dedicated to CdZnTe detectors for a hard X-ray imager in space applications.The readout channel is comprised of a charge sensitive amplifier,a CR-RC shaping amplifier,an analog output buffer,a fast shaper,and a discriminator.An 8-channel prototype ASIC is designed and fabricated in TSMC 0.35-μm mixed-signal CMOS technology,the die size of the prototype chip is 2.2×2.2 mm^2.The input energy range is from 5 to 350 keV.For this 8-channel prototype ASIC,the measured electrical characteristics are as follows：the overall gain of the readout channel is 210 V/pC,the linearity error is less than 2%,the crosstalk is less than 0.36%,The equivalent noise charge of a typical channel is 52.9 e^- at zero farad plus 8.2 e^- per picofarad,and the power consumption is less than 2.4 mW/channel.Through the measurement together with a CdZnTe detector,the energy resolution is 5.9%at the 59.5-keV line under the irradiation of the radioactive source ^（241）Am.The radiation effect experiments show that the proposed ASIC can resist the total ionization dose（TID） irradiation of higher than200 krad（Si）.

A Multi-Section Quantum-Dot Semiconductor Optical Amplifier for Ultrabroad-Band Gain-Flattened Low-Noise Amplification

We propose an ultrabroad-band 1R regenerator utilizing a multi-section quantum-dot semiconductor optical amplifier. Due to the reduced electron states, quantum dot is beneficial in broadening the gain spectrum and lowering the noise figure. Combining this with a multi-section structure drastically improves the gain equality among the different bound states, leading to an increase in the maximum output power and an improvement of the noise figure.

A CMOS variable gain low-noise amplifier with ESD protection for 5 GHz applications

This paper presents a variable gain low-noise amplifier（VG-LNA） for 5 GHz applications.The effect of the input parasitic capacitance on the inductively degenerated common source LNA＇s input impedance is analyzed in detail.A new ESD and LNA co-design method was proposed to achieve good performance.In addition,by using a simple feedback loop at the second stage of the LNA,continuous gain control is realized.The measurement results of the proposed VG-LNA exhibit 25 dB（-3.3 dB to 21.7 dB） variable gain range,2.8 dB noise figure at the maximum gain and 1 dBm IIP3 at the minimum gain,while the DC power consumption is 9.9 mW under a 1.8 V supply voltage.

A9.8-30.1GHzCMOSlow-noise amplifier with a 3.2-dB noise figure using inductor-and transformer-based gm-boosting techniques

A 9.8–30.1 GHz CMOS low-noise amplifier(LNA)with a 3.2-dB minimum noise figure(NF)is presented.At the architecture level,a topology based on common-gate(CG)cascading with a common-source(CS)amplifier is proposed for simultaneous wideband input matching and relatively high gain.At the circuit level,multiple techniques are proposed to improve LNA performance.First,in the CG stage,loading effect is properly used instead of the conventional feedback technique,to enable simultaneous impedance and noise matching.Second,based on in-depth theoretical analysis,the inductor-and transformer-based gm-boosting techniques are employed for the CG and CS stages,respectively,to enhance the gain and reduce power consumption.Third,the floating-body method,which was originally proposed to lower NF in CS amplifiers,is adopted in the CG stage to further reduce NF.Fabricated in a 65-nm CMOS technology,the LNA chip occupies an area of only 0.2 mm^(2)and measures a maximum power gain of 10.9 dB with−3 dB bandwidth from 9.8 to 30.1 GHz.The NF exhibits a minimum value of 3.2 dB at 15 GHz and is below 5.7 dB across the entire bandwidth.The LNA consumes 15.6 mW from a 1.2-V supply.

A 65-nm low-noise low-costΣ△modulator for audio applications

This paper introduces a low-noise low-costΣA modulator for digital audio analog-to-digital conversion. By adopting a low-noise large-output swing operation amplifier,not only is the flicker noise greatly inhibited,but also the power consumption is reduced.Also the area cost is relatively small.The modulator was implemented in a SMIC standard 65-nm CMOS process.Measurement results show it can achieve 96 dB peak signal-to-noise plus distortion ratio（SNDR） and 105 dB dynamic range（DR） over the 22.05-kHz audio band and occupies 0.16 mm^2. The power consumption of the proposed modulator is 4.9 mW from a 2.5 V power supply,which is suitable for high-performance,low-cost audio codec applications.

Design and analysis of a UWB low-noise amplifier in the 0.18μm CMOS process

An ultra-wideband （3.1-10.6 GHz） low-noise amplifier using the 0.18μm CMOS process is presented. It employs a wideband filter for impedance matching. The current-reused technique is adopted to lower the power consumption. The noise contributions of the second-order and third-order Chebyshev fliers for input matching are analyzed and compared in detail. The measured power gain is 12.4-14.5 dB within the bandwidth. NF ranged from 4.2 to 5.4 dB in 3.1-10.6 GHz. Good input matching is achieved over the entire bandwidth. The test chip consumes 9 mW （without output buffer for measurement） with a 1.8 V power supply and occupies 0.88 mm^2.

Low-noise and highly stable optical fiber temperature sensor using modified pulse-reference-based compensation technique

We modify the pulse-reference-based compensation technique and propose a low-noise and highly stable optical fiber temperature sensor based on a zinc telluride film-coated fiber tip. The system noise is measured to be 0.0005 dB, which makes it possible for the detection of the minor reflectivity change of the film at different temperatures. The temperature sensitivity is 0.0034 d B/℃, so the resolution can achieve 0.2℃. The maximum difference of the temperature output values of the sensor at 20℃ at different points in time is 0.39℃. The low cost, ultra-small size, high stability, and good repeatability of the sensor make it a promising temperature sensing device for practical application.

Link Budget and Enhanced Communication Distance for Ambient Internet of Things

Backscatter communications will play an important role in connecting everything for beyond 5G(B5G)and 6G systems.One open challenge for backscatter communications is that the signals suffer a round-trip path loss so that the communication distance is short.In this paper,we first calculate the communication distance upper bounds for both uplink and downlink by measuring the tag sensitivity and reflection coefficient.It is found that the activation voltage of the envelope detection diode of the downlink tag is the main factor limiting the back-scatter communication distance.Based on this analysis,we then propose to implement a low-noise amplifier(LNA)module before the envelope detection at the tag to enhance the incident signal strength.Our experimental results on the hardware platform show that our method can increase the downlink communication range by nearly 20 m.

An Yb-fiber frequency comb phase-locked to microwave standard and optical reference

We present a fully stabilized Yb-fiber frequency comb locked to a microwave standard and an optical reference separately. The carrier-envelope offset frequency is generated by a standard f–2f interferometer with 40 dB signal-tonoise ratio. The offset frequency and the repetition rate are stabilized simultaneously to the radio frequency reference for more than 30 hours, and the fractional Allan deviation of the comb is the same as the microwave standard of 10^(-12) at 1 s.Alternatively, the comb is locked to an ultra-stable optical reference at 972 nm using an intracavity electro-optic modulator,exhibiting a residual integrated phase noise of 458 mrad(1 Hz–10 MHz) and an in-loop tracking stability of 1.77× 10^(-18) at 1 s, which is significantly raised by six orders comparing to the case locked to the microwave frequency standard.

A CMOS 3.1 - 10.6 GHz UWB LNA Employing Modified Derivative Superposition Method

Low noise amplifier (LNA) performs as the initial amplification block in the receive path in a radio frequency (RF) receiver. In this work an ultra-wideband 3.1 10.6-GHz LNA is discussed. By using the proposed circuits for RF CMOS LNA and design methodology, the noise from the device is decreased across the ultra wide band (UWB) band. The measured noise figure is 2.66 3 dB over 3.1 10.6-GHz, while the power gain is 14 ± 0.8 dB. It consumes 23.7 mW from a 1.8 V supply. The input and output return losses (S11 & S22) are less than –11 dB over the UWB band. By using the modified derivative superposition method, the third-order intercept point IIP3 is improved noticeably. The complete circuit is based on the 0.18 μm standard RFCMOS technology and simulated with Hspice simulator.

A gain-flatness optimization solution for feedback technology of wideband low noise amplifiers

The S parameter expression of high-frequency models of the high electron mobility transistors (HEMTs) with basic feedback structure,especially the transmission gain S 21,is presented and analyzed.In addition,an improved feedback structure and its theory are proposed and demonstrated,in order to obtain a better gain-flatness through the mutual interaction between the series inductor and the parallel capacitor in the feedback loop.The optimization solution for the feedback amplifier can eliminate the negative impacts on transmission gain S 21 caused by things such as resonance peaks.Furthermore,our theory covers the shortage of conventional feedback amplifiers,to some extent.A wideband low-noise amplifier (LNA) with the improved feedback tech-nology is designed based on HEMT.The transmission gain is about 20 dB with the gain variation of 1.2 dB from 100 MHz to 6 GHz.The noise figure is lower than 2.8 dB in the whole band and the amplifier is unconditionally stable.

A low power dual-band multi-mode RF front-end for GNSS applications

A CMOS dual-band multi-mode RF front-end for the global navigation satellite system receivers of all GPS,Bei-Dou,Galileo and Glonass systems is presented.It consists of a reconfigurable low noise amplifier（LNA）,a broadband active balun,a high linearity mixer and a bandgap reference（BGR） circuit.The effect of the input parasitic capacitance on the input impedance of the inductively degenerated common source LNA is analyzed in detail.By using two different LC networks at the input port and the switched capacitor at the output port,the LNA can work at two different frequency bands（1.2 GHz and 1.5 GHz） under low power consumption.The active balun uses a hybrid-connection structure to achieve high bandwidth.The mixer uses the multiple gated transistors technique to acquire a high linearity under low power consumption but does not deteriorate other performances.The measurement results of the proposed front-end achieve a noise figure of 2.1/2.0 dB,a gain of 33.9/33.8 dB and an input 1-dB compression point of 0/1 dBm at 1227.6/1575.42 MHz.The power consumption is about 16 mW under a 1.8 V power supply.