期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
Influences of quantum noises on direct-modulated properties of 1.3-μm InGaAsP/InP laser diodes
1
作者 王俊 马骁宇 +2 位作者 白一鸣 曹力 吴大进 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第9期2125-2129,共5页
Due to the zero dispersion point at 1.3μm in optical fibres, 1.3-μm InGaAsP/InP laser diodes have become main light sources in fibre communication systems recently. Influences of quantum noises on direct-modulated p... Due to the zero dispersion point at 1.3μm in optical fibres, 1.3-μm InGaAsP/InP laser diodes have become main light sources in fibre communication systems recently. Influences of quantum noises on direct-modulated properties of single-mode 1.3-μm InGaAsP/InP laser diodes are investigated in this article. Considering the carrier and photon noises and the cross-correlation between the two noises, the power spectrum of the photon density and the signal-to-noise ratio (SNR) of the direct-modulated single-mode laser system are calculated using the linear approximation method. We find that the stochastic resonance (SR) always appears in the dependence of the SNR on the bias current density, and is strongly affected by the cross-correlation coefficient between the carrier and photon noises, the frequency of modulation signal, and the photon lifetime in the laser cavity. Hence, it is promising to use the SR mechanism to enhance the SNR of direct-modulated InGaAsP/InP laser diodes and improve the quality of optical fibre communication systems. 展开更多
关键词 InGaAsP/InP laser diodes carrier noise photon noise linear approximation method
原文传递
Noise analysis of grating-based x-ray differential phase-contrast imaging with angular signal radiography
2
作者 Wali Faiz 鲍园 +5 位作者 高昆 吴朝 卫晨希 昝贵彬 朱佩平 田扬超 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第4期138-143,共6页
X-ray phase-contrast imaging is one of the novel techniques,and has potential to enhance image quality and provide the details of inner structures nondestructively.In this work,we investigate quantitatively signal-to-... X-ray phase-contrast imaging is one of the novel techniques,and has potential to enhance image quality and provide the details of inner structures nondestructively.In this work,we investigate quantitatively signal-to-noise ratio(SNR) of grating-based x-ray phase contrast imaging(GBPCI) system by employing angular signal radiography(ASR).Moreover,photon statistics and mechanical error that is a major source of noise are investigated in detail.Results show the dependence of SNR on the system parameters and the effects on the extracted absorption,refraction and scattering images.Our conclusions can be used to optimize the system design for upcoming practical applications in the areas such as material science and biomedical imaging. 展开更多
关键词 angular signal radiography signal-to-noise ratio photon statistical noise mechanical error
原文传递
Performance comparison of ghost imaging versus conventional imaging in photon shot noise cases 被引量:3
3
作者 Zijie Li Qing Zhao Wenlin Gong 《Chinese Optics Letters》 SCIE EI CAS CSCD 2020年第7期40-44,共5页
The performances of ghost imaging and conventional imaging in photon shot noise cases are investigated. We define an imaging signal-to-noise ratio called SNRtranwhere only the object’s transmission region is used to ... The performances of ghost imaging and conventional imaging in photon shot noise cases are investigated. We define an imaging signal-to-noise ratio called SNRtranwhere only the object’s transmission region is used to evaluate the imaging quality and it can be applied to ghost imaging(GI) with any random pattern. Both the values SNRtran GIof GI and SNRtran CIof conventional imaging in photon shot noise cases are deduced from a simple statistical analysis. The analytical results, which are backed up by numerical simulations, demonstrate that the value SNRtran GIis related to the ratio between the object’s transmission area Aoand the number density of photons illuminating the object plane Io, which is similar to the theoretical results based on the first principle of GI with a Gaussian speckle field deduced by B. I. Erkmen and J. H. Shapiro [in Adv. Opt. Photonics 2, 405–450(2010)]. In addition, we also show that the value SNRtran CIwill be larger than SNRtran GIwhen Ao is beyond a threshold value. 展开更多
关键词 ghost imaging photon shot noise signal-to-noise ratio SPECKLE
原文传递
An approach to obtain the pinch-off voltage of 4-T pixel in CMOS image sensor
4
作者 李斌桥 于俊庭 +1 位作者 徐江涛 于平平 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2010年第7期53-56,共4页
An approach to obtain the pinch-off voltage of 4-T pixel in CMOS image sensor is presented.This new approach is based on the assumption that the photon shot noise in image signal is impacted by a potential well struct... An approach to obtain the pinch-off voltage of 4-T pixel in CMOS image sensor is presented.This new approach is based on the assumption that the photon shot noise in image signal is impacted by a potential well structure change of pixel.Experimental results show the measured pinch-off voltage is consistent with theoretical prediction.This technique provides an experimental method to assist the optimization of pixel design in both the photodiode structure and fabrication process for the 4-T CMOS image sensor. 展开更多
关键词 pinch-off voltage CMOS image sensor photon shot noise pixel design
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部