Estimation of random errors for lidar based on noise scale factor

Estimation of random errors, which are due to shot noise of photomultiplier tube(PMT) or avalanche photodiode(APD) detectors, is very necessary in lidar observation. Due to the Poisson distribution of incident electrons, there still exists a proportional relationship between standard deviation and square root of its mean value. Based on this relationship,noise scale factor(NSF) is introduced into the estimation, which only needs a single data sample. This method overcomes the distractions of atmospheric fluctuations during calculation of random errors. The results show that this method is feasible and reliable.

A novel noise optimization technique for inductively degenerated CMOS LNA

This paper proposes a novel noise optimization technique.The technique gives analytical formulae for the noise performance of inductively degenerated CMOS low noise amplifier（LNA）circuits with an ideal gate inductor for a fixed bias voltage and nonideal gate inductor for a fixed power dissipation,respectively,by mathematical analysis and reasonable approximation methods.LNA circuits with required noise figure can be designed effectively and rapidly just by using hand calculations of the proposed formulae.We design a 1.8 GHz LNA in a TSMC 0.25 μm CMOS process.The measured results show a noise figure of 1.6 dB with a forward gain of 14.4 dB at a power consumption of 5 mW,demonstrating that the designed LNA circuits can achieve low noise figure levels at low power dissipation.

Comparative studies of silicon photomultipliers and traditional vacuum photomultiplier tubes

Silicon photomultipliers （SiPMs） are a new generation of semiconductor-based photon counting devices with the merits of low weight, low power consumption and low voltage operation, promising to meet the needs of space particle physics experiments. In this paper, comparative studies of SiPMs and traditional vacuum photomultiplier tubes （PMTs） have been performed regarding the basic properties of dark currents, dark counts and excess noise factors. The intrinsic optical erosstalk effect of SiPMs was evaluated.

Position dependent circuit model for thin avalanche photodiodes

This paper presents a circuit model for thin avalanche photodiodes （APDs）. In this model, the nonuniformity of the electric filed in the multiplication region is modeled using a stepwise method. The model also tries to take the effects of carrier＇s position dependent properties, like carder＇s dead length and the history of carder＇s previous ionization into account by developing an effective electric field in the multiplication region. The output photocurrent and multiplication gain obtained from the proposed model for different lengths of the multi- plication region achieve a good agreement in comparison with available experimental data. In addition, calculated excess noise factor reveals the model ability for noise and sensitivity analysis.