Amplification Effect on Rayleigh Scattering and SBS in 25 km Distributed Fiber Raman Amplifier

The amplification effect on stimulated Brillouin scattering （SBS） and Rayleigh scattering in the backward pumped G652 fibers Raman amplifier have been researched. The signal source is a tunable narrow spectral bandwidth （〈10 MHz） ECL laser and is pumped by the tunable power 1427.2 nm fiber Raman laser. The Rayleigh scattering lines are amplified by fiber Raman amplifier, and Stokes stimulated Brillouin scattering lines are amplified by fiber Raman amplifier and fiber Brillouin amplifier. The SBS lines total gain is a production of the gain of Raman and the gain of Brillouin amplifier. In experiment, the gain of SBS is about 42 dB and the saturation gain of 25 Ion G652 backward FRA is about 25 dB, so the gain of fiber Brillouin amplifier is about 17 dB.     

应用于2.4GHz无线传感网的超低功耗射频接收前端设计

This paper presents the design of an ultralow power receiver front-end designed for a wireless sensor network （WSN） in a 0.18 μm CMOS process. The author designs two front-ends working in the saturation region and the subthreshold region respectively. The front-ends contain a two-stage cross-coupling cascaded common-gate （CG） LNA and a quadrature Gilbert IQ mixer. The measured conversion gain is variable with high gain at 24 dB and low gain at 7 dB for the saturation one, and high gain at 22 dB and low gain at 5 dB for the subthreshold one. The noise figure （NF） at high gain mode is 5.1 dB and 6.3 dB for each. The input 1 dB compression point （IPldB） at low gain mode is about -6 dBm and -3 dBm for each. The front-ends consume about 2.1 mA current from 1.8 V power supply for the saturation one and 1.3 mA current for the subthreshold one. The measured results show that, comparing with the power consumption saving, it is worth making sacrifices on the performance for using the subthreshold technology.     

A CMOS variable gain LNA for UWB receivers

A CMOS variable gain low noise amplifier(LNA) is presented for 4.2-4.8 GHz ultra-wideband application in accordance with Chinese standard.The design method for the wideband input matching is presented and the low noise performance of the LNA is illustrated.A three-bit digital programmable gain control circuit is exploited to achieve variable gain.The design was implemented in 0.13-μm RF CMOS process,and the die occupies an area of 0.9 mm~2 with ESD pads.Totally the circuit draws 18 mA DC current from 1.2 V DC supply,the LNA exhibits minimum noise figure of 2.3 dB,S(1,1) less than -9 dB and S(2,2) less than -10 dB.The maximum and the minimum power gains are 28.5 dB and 16 dB respectively.The tuning step of the gain is about 4 dB with four steps in all.Also the input 1 dB compression point is -10 dBm and input third order intercept point(IIP3) is -2 dBm.     

A S-BAND 2.5 MW HIGH POWER BROADBAND KLYSTRON

In this paper,the design considerations of a high-efficiency high-gain broadband klystron aredescribed.Its buncher has been studied by using small signal gain and large signal efficiencyprograms.With small gain greater than 50dB,the buncher bandwidths of 10% and 10—15% can beobtained for 7 and 8 cavity klystrons respectively.The design methods and measured results ofoutput circuits of two types are introduced.The bandwidths of the filter type and the overlappingmode two gap cavity output circuits are about 7.5—10% and 10—12% respectively.Two types ofS-band broadband klystrons with the two respective output circuits described are constructed andtested,and the one with the former output circuit has 1dB equi-drive bandwidth of 7.5% with anefficiency of 38% and a gain of 43 dB,while the other with the later output circuit has 1dB equi-drive bandwidth of 10%.Their output power is greater than 2.5 MW.     

Design and optimization of a 2.4 GHz RF front-end with an on-chip balun

A 2.4 GHz low-power,low-noise and highly linear receiver front-end with a low noise amplifier(LNA) and balun optimization is presented.Direct conversion architecture is employed for this front-end.The on-chip balun is designed for single-to-differential conversion between the LNA and the down-conversion mixer,and is optimized for the best noise performance of the front-end.The circuit is implemented with 0.35μm SiGe BiCMOS technology.The front-end has three gain steps for maximization of the input dynamic range.The overall maximum gain is about 36 dB.The double-sideband noise figure is 3.8 dB in high gain mode and the input referred third-order intercept point is 12.5 dBm in low gain mode.The down-conversion mixer has a tunable parallel R-C load at the output and an emitter follower is used as the output stage for testing purposes.The total front-end dissipation is 33 mW under a 2.85 V supply and occupies a 0.66 mm~2 die size.     

Design of Si—bipolar Monolithic Main Amplifier IC for Optical Fiber Receivers

A broadband amplifer with transadmittance and transimpedance stages is designed and two types of improved AGC amplifiers are developed on the base of theory study.Making use of the basic amplifier cells.a main amplifier IC for optical-fiber receivers is deliberated.By computer simulating the performances of the designed main amplifier meet the necessity of high gain and wide dynamic range.They are maximum voltage gain of 42 dB,ths bandwidth of 730 MHz,the input signal(Vp-0)range from 5 mV to 1V,the output amplitude about 1V,the dynamic range of 46 dB.The designed circuit containing no inductance and large caacitance will be convenient for realizing integration.A monolithic integrated design of 622Mb/s main amplifier is completed.     

Dual-band RF receiver for GPS-L1 and compass-B1 in a 55-nm CMOS

A fully integrated dual-band RF receiver with a low-IF architecture is designed and implemented for GPS-L 1 and Compass-Bl in a 55-nm CMOS process. The receiver incorporates two independent IF channels with 2 or 4 MHz bandwidth to receive dual-band signals around 1.57 GHz respectively. By implementing a flexible frequency plan, the RF front-end and frequency synthesizer are shared for the dual-band operation to save power consumption and chip area, as well as avoiding LO crosstalk. A digital automatic gain control （AGC） loop is utilized to improve the receiver＇s robustness by optimizing the conversion gain of the analog-to-digital converter （ADC）. While drawing about 20 mA per channel from a 1.2 V supply, this RF receiver achieves a minimum noise figure （NF） of about 1.8 dB, an image rejection （IMR） of more than 35 dB, a maximum voltage gain of about 122 dB, a gain dynamic range of 82 dB, and an maximum input-referred 1 dB compression point of about -36.5 dBm with an active die area of 1.5 × 1.4 mm2 for the whole chip.     

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.     

Research on optimizing the noise figure of low noise amplifier method via bias and frequency

In this paper,we present the design of an integrated low noise amplifier(LNA)for wireless local area network(WLAN)applications in the 5.15-5.825 GHz range using a SiGe BiCMOS technology.A novel method that can determine both the optimum bias point and the frequency point for achieving the minimum noise figure is put forward.The method can be used to determine the optimum impedance over a relevant wider operating frequency range.The results show that this kind of optimizing method is more suitable for the WLAN circuits design.The LNA gain is optimized and the noise figure(NF)is reduced.This method can also achieve the noise match and power match simultaneously.This proposal is applied on designing a LNA for IEEE 802.11a WLAN.The LNA exhibits a power gain large than 16 dB from 5.15 to 5.825 GHz range.The noise figure is lower than 2 dB.The OIP3 is 8 dBm.Also the LNA is matched to 50 Ω input impedance with 6 mA DC current for differential design.     

可重构双频段低噪声放大器的设计和实现

A reconfigurable dual-band LNA is presented. The LNA employs switching capacitors and circuit in to realize the dual-band operation. These methodologies are used to design and implement a reconfigurable LNA for IMT-A and UWB application. The LNA is implemented using TSMC-0.13 μm CMOS technology. Measured performance shows an input matching of better than -13.5 dB, a voltage gain of 18-22.8 dB, with an NF of 4.3-4.7 dB in the band of 3.4-3.6 GHz, and an input matching of better than -9.7 dB, a voltage gain of 14.7-22.4 dB, and with an NF of 3.7-4.9 dB in the band of 4.2-4.8 GHz. According to the measure results, the proposed LNA achieves dual-band operation, and it proves the feasibility of the proposed topology.     

Gain and noise figure spectrum control algorithm for fiber Raman amplifiers

In this letter, a fiber Raman amplifier (FRA) design method enabling the simultaneous control of the gain and noise figure (NF) spectra, is proposed. By constructing the FRA with predetermined target forward/backward gain spectra, the spectral error function of NF is calculated, to determine the pump power combination satisfying both the targeting gain and NF spectra. The FRA gain/NF design within 0.1 dB of accuracy is demonstrated for various shapes of target spectra.     

Threshold level and gain of forward stimulated Brillouin scattering in a forward pumped s-band discrete DCF fibers Raman amplifier

Recently,with fast developing of extra-capacity of fi-ber communication experi mental systems ,dense wave-length division multiplexing (DWDM) technology hasbeen adopted widely[1-3].Now,1300 nmband and 1550nmband have been connected with each other to be a…     

反向泵浦光纤拉曼放大器的实现与传输实验

文章设计并实现了C L波段4泵浦光纤拉曼放大器(FRA),讨论了泵浦驱动电路的设计及掺铒光纤放大器(EDFA)与FRA 150 km混合传输的传输性能.实验结果表明,驱动电路可以稳定可靠地工作,当拉曼放大器的增益＜5 dB时,信号的误码性能不会得到显著提高.实验结果可为EDFA与FRA混合传输系统中增益的配置提供参考.     

DCF光纤拉曼放大器的实验研究

DCF(dispersion compensating fibre)光纤具有较高的拉曼增益系数,利用这一点可以用较短长度的DCF光纤制成分立式的光纤拉曼放大器,作为传输线路上的损耗补偿.本文在测量并计算了DCF光纤的拉曼增益系数的基础上,对分立式的DCF放大器的开关增益和噪声指数进行了测量和分析,并将分立式FRA和分布式FRA在开关增益和噪声指数方面做了比较。介绍了用不同的测量方法所造成的实验结果的差异.实验结果表明,放大介质为5 km的DCF光纤所构成的放大器,在抽运功率为800 mW的条件下,最大增益可达14.77dB,3 dB带宽为35 nm,满足作为损耗补偿的要求.     

Simultaneous amplification of wavelength-division-multiplexed signals by a highly efficient fibre Raman amplifier pumped by high-power semiconductor lasers

We describe the first operation of a high-power semiconductor-laser pumped fibre Raman amplifier (FRA) using high-Raman-gain optical fibre in the 1.5?m region. A high optical gain of 5 dB for 60mW of pump power is obtained. We have also achieved simultaneous amplification of wavelength-division-multiplexed signals by the FRA.     

光纤拉曼放大器

主要讨论了光纤拉曼放大器的原理、历史、现状和前景，同时分析了它的设计原则、增益均衡的各种方法，给出了拉曼放大器的仿真模型。最后讨论了放大器基本特性对系统性能的影响。     

宽带平坦增益光纤喇曼放大器最新进展

在整个工作波段内具有较好的增益平坦度是对应用在波分复用光纤通信系统中的光纤喇曼放大器的一个基本要求.在光纤喇曼放大器的数学模型的基础上分析了实现其平坦增益的几种方法,然后对宽带平坦增益光纤喇曼放大器的最新进展进行了综合评述,最后对其发展进行了展望.     

多泵浦喇曼放大器简化模型设计及泵浦优化

对多泵浦光纤喇曼放大器(FRA)功率传输方程进行了合理简化,得到密集波分复用系统(DWDM)信号合成喇曼增益的数学模型,分析了受激喇曼散射(SRS)对信号喇曼增益的影响。并在该简化模型基础上介绍了一种对泵浦波长分布和输入功率进行优化计算的方法,实现了超宽带平坦的喇曼增益谱,为多泵浦FRA在DWDM系统中的应用提供了有价值的参考。     

新型增益平坦光纤喇曼放大器的研究

利用光子转换理论的前向受激喇曼散射(SRS)耦合方程,结合多波长泵浦和光纤级联两种方法,提出了一种新型的具有平坦增益的宽带光纤喇曼放大器(FRA).采用数值解法对100信道的波分复用(WDM)系统进行了仿真,得到了宽带增益平坦的功率输出,为光纤喇曼放大器(FRA)增益平坦化提供了一种新的实现方法.