Four-wave mixing, as well as its induced intensity noise, is harmful to wavelength division multiplexing systems. The efficiency and the relative intensity noise of four-wave mixing are numerically simulated for the t...Four-wave mixing, as well as its induced intensity noise, is harmful to wavelength division multiplexing systems. The efficiency and the relative intensity noise of four-wave mixing are numerically simulated for the two-wave and the three-wave fiber transmissions. It is found that the efficiency decreases with the increase of both the frequency spacing and the fiber length, which can be explained using the quasi-phase-matching condition. Furthermore, the relative intensity noise decreases with the increase of frequency spacing, while it increases with the increase of fiber length, which is due to the considerable power loss of the pump light. This investigation presents a good reference for the practical application of wavelength division multiplexing systems.展开更多
Based on the frequency-domain multimode theoretical model, detailed investigations on the noise characteristic of the semiconductor ring laser （SRL） are first performed in this paper. The comprehensive nonlinear ter...Based on the frequency-domain multimode theoretical model, detailed investigations on the noise characteristic of the semiconductor ring laser （SRL） are first performed in this paper. The comprehensive nonlinear terms related to the third order nonlinear susceptibility Z3 are included in this model; the Langevin noise sources for electric field and carrier density fluctuations are also taken into account. As the injection current increases, the SRL may present several operation regimes. Remarkable and unusual low frequency noise enhancement in the form of a broad low frequency tail extending all the way to the relaxation oscillation peak is observed in any of the operation regimes of SRLs. The influences of the backscattering coefficient on the relative intensity noise （RIN） spectrum in typical operation regimes are investigated in detail.展开更多
Based on the mathematical model of quantum well laser diode(QW LDs) developed, the paper presents a relative intensity noise(RIN) model, which employs Gaussian form random noise with its average being to zero. It can ...Based on the mathematical model of quantum well laser diode(QW LDs) developed, the paper presents a relative intensity noise(RIN) model, which employs Gaussian form random noise with its average being to zero. It can be straightforwardly used to describe the effect of the noise on the performance of QW LDs. The RIN becomes notable in the frequency range of interests and therefore affects the device modulation property. The results are in good agreement of the published data. The RIN model proposed and the results can be used for purpose of device technique improvement and performance simulation of optical communication systems and networks.展开更多
Effective multiple optoelectronic feedback circuits for simultaneously suppressing low-frequency and relaxation oscillation intensity noise in a single-frequency phosphate fiber laser are demonstrated. The forward tra...Effective multiple optoelectronic feedback circuits for simultaneously suppressing low-frequency and relaxation oscillation intensity noise in a single-frequency phosphate fiber laser are demonstrated. The forward transfer function, which relates the laser output intensity to the pump modulations, is measured and analyzed. A custom two-path feedback system operating at different frequency bands is designed to adjust the pump current directly. The relative intensity noise is decreased by 20dB from 0.2 to 5kHz and over lOdB from 5 to lOkHz. The relaxation oscillation peak is suppressed by 22dB. In addition, a long term （24h） laser instability of less than 0.05% is achieved.展开更多
Relative intensity noise(RIN) and high-speed modulation characteristics are investigated for an Al Ga In As/In P hybrid square-rectangular laser(HSRL) with square side length, rectangular length, and width of 15,300, ...Relative intensity noise(RIN) and high-speed modulation characteristics are investigated for an Al Ga In As/In P hybrid square-rectangular laser(HSRL) with square side length, rectangular length, and width of 15,300, and 2 μm, respectively. Single-mode operation with side-mode suppression larger than 40 dB has been realized for the HSRL over wide variation of the injection currents. In addition, the HSRL exhibits a 3 dB modulation bandwidth of 15.5 GHz, and an RIN nearly approaches standard quantum shot-noise limit 2 hv∕P=-164 dB∕Hz at high bias currents due to the strong mode selection of the square microcavity. With the increase of the DC bias current of the Fabry–Perot section, significantly enhanced modulation bandwidth and decreased RIN are observed.Furthermore, intrinsic parameters such as resonance frequency, damping factor, and modified Schawlow–Townes linewidth are extracted from the noise spectra.展开更多
目的探讨不同物理特性实时噪声环境对视觉相关作业工效的影响。方法 40名在校大学生青年志愿者随机分为不同强度组[对照组(环境背景噪声不高于40 d BA)、65 d BA白噪声组、75 d BA白噪声组]、不同频率组[低频谱组(<500Hz)、中高频谱...目的探讨不同物理特性实时噪声环境对视觉相关作业工效的影响。方法 40名在校大学生青年志愿者随机分为不同强度组[对照组(环境背景噪声不高于40 d BA)、65 d BA白噪声组、75 d BA白噪声组]、不同频率组[低频谱组(<500Hz)、中高频谱组(500~3000 Hz),强度均为75 d BA]。使用NES-C4测试系统对各组人员的视觉相关神经行为功能进行测试。结果与对照组相比,65 d BA和75 d BA强度噪声可显著影响受试者在视觉保留、视觉反应时、曲线吻合、目标追踪、立体视觉项目的得分(P<0.05),且呈现噪声强度越高影响越大的趋势;设定75 d BA条件下,不同频率噪声对受试者视觉保留、视觉反应时间、曲线吻合、目标追踪、立体视觉各项指标的影响均未见显著差异(P>0.05)。结论作业环境中噪声强度是影响视觉相关作业工效的主要因素。展开更多
Intracavity absorption spectroscopy is a strikingly sensitive technique that has been integrated with a two-wavelength setup to develop a sensor for human breath.Various factors are considered in such a scenario,out o...Intracavity absorption spectroscopy is a strikingly sensitive technique that has been integrated with a two-wavelength setup to develop a sensor for human breath.Various factors are considered in such a scenario,out of which Relative Intensity Noise(RIN)has been exploited as an important parameter to characterize and calibrate the said setup.During the performance of an electrical based assessment arrangement which has been developed in the laboratory as an alternative to the expensive Agilent setup,the optical amplifier plays a pivotal role in its development and operation,along with other components and their significance.Therefore,the investigation and technical analysis of the amplifier in the system has been explored in detail.The algorithm developed for the automatic measurements of the system has been effectively deployed in terms of the laser’s performance.With this in perspective,a frequency dependent calibration has been pursued in depth with this scheme which enhances the sensor’s efficiency in terms of its sensitivity.In this way,our investigation helps us in a better understanding and implementation perspective of the proposed system,as the outcomes of our analysis adds to the precision and accuracy of the entire system.展开更多
Cascaded random Raman fiber lasers(CRRFLs)have been used as a new platform for designing high power and wavelength-agile laser sources.Recently,CRRFL pumped by ytterbium-doped random fiber laser(YRFL)has shown both hi...Cascaded random Raman fiber lasers(CRRFLs)have been used as a new platform for designing high power and wavelength-agile laser sources.Recently,CRRFL pumped by ytterbium-doped random fiber laser(YRFL)has shown both high power output and low relative intensity noise(RIN).Here,by using a wavelength-and bandwidth-tunable point reflector in YRFL,we experimentally investigate the impacts of YRFL on the spectral and RIN properties of the CRRFL.We verify that the bandwidth of the point reflector in YRFL determines the bandwidth and temporal stability of YRFL.It is found that with an increase in the bandwidth of the point reflector in YRFL from 0.2 nm to 1.4 nm,CRRFL with higher spectral purity and lower RIN can be achieved due to better temporal stability of YRFL pump.By broadening the point reflector’s bandwidth to 1.4 nm,the lasing power,spectral purity,and RIN of the 4th-order random lasing at 1349 nm can reach 3.03 W,96.34%,and–115.19 dB/Hz,respectively.For comparison,the spectral purity and RIN of the 4th-order random lasing with the point reflector’s bandwidth of 0.2 nm are only 91.20%and–107.99 dB/Hz,respectively.Also,we realize a wavelength widely tunable CRRFL pumped by a wavelength-tunable YRFL.This work provides a new platform for the development of ideal distributed Raman amplification pump sources based on CRRFLs with both good temporal stability and wide wavelength tunability,which is of great importance in applications of optical fiber communication and distributed sensing.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 61177073)the Open Fund of Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Provincial Higher Education Institutes+2 种基金Jinan University (Grant No. gdol201101)the Fund of Innovation of Graduate School of National University of Defense Technology(Grant No. B110703)Hunan Provincial Innovation Foundation for Postgraduate,China (Grant No. CX2011B033)
文摘Four-wave mixing, as well as its induced intensity noise, is harmful to wavelength division multiplexing systems. The efficiency and the relative intensity noise of four-wave mixing are numerically simulated for the two-wave and the three-wave fiber transmissions. It is found that the efficiency decreases with the increase of both the frequency spacing and the fiber length, which can be explained using the quasi-phase-matching condition. Furthermore, the relative intensity noise decreases with the increase of frequency spacing, while it increases with the increase of fiber length, which is due to the considerable power loss of the pump light. This investigation presents a good reference for the practical application of wavelength division multiplexing systems.
基金Project supported by the Major State Basic Research Development Program of China (Grant No.2010CB328206)
文摘Based on the frequency-domain multimode theoretical model, detailed investigations on the noise characteristic of the semiconductor ring laser （SRL） are first performed in this paper. The comprehensive nonlinear terms related to the third order nonlinear susceptibility Z3 are included in this model; the Langevin noise sources for electric field and carrier density fluctuations are also taken into account. As the injection current increases, the SRL may present several operation regimes. Remarkable and unusual low frequency noise enhancement in the form of a broad low frequency tail extending all the way to the relaxation oscillation peak is observed in any of the operation regimes of SRLs. The influences of the backscattering coefficient on the relative intensity noise （RIN） spectrum in typical operation regimes are investigated in detail.
文摘Based on the mathematical model of quantum well laser diode(QW LDs) developed, the paper presents a relative intensity noise(RIN) model, which employs Gaussian form random noise with its average being to zero. It can be straightforwardly used to describe the effect of the noise on the performance of QW LDs. The RIN becomes notable in the frequency range of interests and therefore affects the device modulation property. The results are in good agreement of the published data. The RIN model proposed and the results can be used for purpose of device technique improvement and performance simulation of optical communication systems and networks.
基金Supported by the National High-Technology Research and Development Program of China under Grant Nos 2013AA031502 and 2014AA041902the National Natural Science Foundation of China under Grant Nos 11174085,51132004,and 51302086+3 种基金the Guangdong Natural Science Foundation under Grant Nos S2011030001349 and S20120011380the China National Funds for Distinguished Young Scientists under Grant No 61325024the Science and Technology Project of Guangdong Province under Grant No 2013B090500028the’Cross and Cooperative’Science and Technology Innovation Team Project of Chinese Academy of Sciences under Grant No 2012-119
文摘Effective multiple optoelectronic feedback circuits for simultaneously suppressing low-frequency and relaxation oscillation intensity noise in a single-frequency phosphate fiber laser are demonstrated. The forward transfer function, which relates the laser output intensity to the pump modulations, is measured and analyzed. A custom two-path feedback system operating at different frequency bands is designed to adjust the pump current directly. The relative intensity noise is decreased by 20dB from 0.2 to 5kHz and over lOdB from 5 to lOkHz. The relaxation oscillation peak is suppressed by 22dB. In addition, a long term （24h） laser instability of less than 0.05% is achieved.
基金National Key R&D Program of China(2016YFB0402304)National Natural Science Foundation of China(NSFC)(61235004,61377105,61527823)
文摘Relative intensity noise(RIN) and high-speed modulation characteristics are investigated for an Al Ga In As/In P hybrid square-rectangular laser(HSRL) with square side length, rectangular length, and width of 15,300, and 2 μm, respectively. Single-mode operation with side-mode suppression larger than 40 dB has been realized for the HSRL over wide variation of the injection currents. In addition, the HSRL exhibits a 3 dB modulation bandwidth of 15.5 GHz, and an RIN nearly approaches standard quantum shot-noise limit 2 hv∕P=-164 dB∕Hz at high bias currents due to the strong mode selection of the square microcavity. With the increase of the DC bias current of the Fabry–Perot section, significantly enhanced modulation bandwidth and decreased RIN are observed.Furthermore, intrinsic parameters such as resonance frequency, damping factor, and modified Schawlow–Townes linewidth are extracted from the noise spectra.
文摘目的探讨不同物理特性实时噪声环境对视觉相关作业工效的影响。方法 40名在校大学生青年志愿者随机分为不同强度组[对照组(环境背景噪声不高于40 d BA)、65 d BA白噪声组、75 d BA白噪声组]、不同频率组[低频谱组(<500Hz)、中高频谱组(500~3000 Hz),强度均为75 d BA]。使用NES-C4测试系统对各组人员的视觉相关神经行为功能进行测试。结果与对照组相比,65 d BA和75 d BA强度噪声可显著影响受试者在视觉保留、视觉反应时、曲线吻合、目标追踪、立体视觉项目的得分(P<0.05),且呈现噪声强度越高影响越大的趋势;设定75 d BA条件下,不同频率噪声对受试者视觉保留、视觉反应时间、曲线吻合、目标追踪、立体视觉各项指标的影响均未见显著差异(P>0.05)。结论作业环境中噪声强度是影响视觉相关作业工效的主要因素。
基金This work was supported in part by the German Academic Exchange Service(Deutsche Akademische Austausch Dienst(DAAD)),and in part by the University of Kassel.
文摘Intracavity absorption spectroscopy is a strikingly sensitive technique that has been integrated with a two-wavelength setup to develop a sensor for human breath.Various factors are considered in such a scenario,out of which Relative Intensity Noise(RIN)has been exploited as an important parameter to characterize and calibrate the said setup.During the performance of an electrical based assessment arrangement which has been developed in the laboratory as an alternative to the expensive Agilent setup,the optical amplifier plays a pivotal role in its development and operation,along with other components and their significance.Therefore,the investigation and technical analysis of the amplifier in the system has been explored in detail.The algorithm developed for the automatic measurements of the system has been effectively deployed in terms of the laser’s performance.With this in perspective,a frequency dependent calibration has been pursued in depth with this scheme which enhances the sensor’s efficiency in terms of its sensitivity.In this way,our investigation helps us in a better understanding and implementation perspective of the proposed system,as the outcomes of our analysis adds to the precision and accuracy of the entire system.
基金This work is supported by the key projects of National Natural Science Foundation of China(Grant Nos.61635005 and U21A20453)the Zhejiang Lab—UESTC Joint Research Center Project(Grant No.202012KFY00562).
文摘Cascaded random Raman fiber lasers(CRRFLs)have been used as a new platform for designing high power and wavelength-agile laser sources.Recently,CRRFL pumped by ytterbium-doped random fiber laser(YRFL)has shown both high power output and low relative intensity noise(RIN).Here,by using a wavelength-and bandwidth-tunable point reflector in YRFL,we experimentally investigate the impacts of YRFL on the spectral and RIN properties of the CRRFL.We verify that the bandwidth of the point reflector in YRFL determines the bandwidth and temporal stability of YRFL.It is found that with an increase in the bandwidth of the point reflector in YRFL from 0.2 nm to 1.4 nm,CRRFL with higher spectral purity and lower RIN can be achieved due to better temporal stability of YRFL pump.By broadening the point reflector’s bandwidth to 1.4 nm,the lasing power,spectral purity,and RIN of the 4th-order random lasing at 1349 nm can reach 3.03 W,96.34%,and–115.19 dB/Hz,respectively.For comparison,the spectral purity and RIN of the 4th-order random lasing with the point reflector’s bandwidth of 0.2 nm are only 91.20%and–107.99 dB/Hz,respectively.Also,we realize a wavelength widely tunable CRRFL pumped by a wavelength-tunable YRFL.This work provides a new platform for the development of ideal distributed Raman amplification pump sources based on CRRFLs with both good temporal stability and wide wavelength tunability,which is of great importance in applications of optical fiber communication and distributed sensing.
