A power scalable thulium-doped fiber-amplifier-based supercontinuum (SC) laser covering the shortwave infrared region from 2 to 2.5 μm is demonstrated. The SC laser has an average power up to 25.7 W and a spectral density of >12 dBm/nm. Power scalability of the laser is proven by showing that the SC laser maintains a nearly constant spectral output, beam quality (M(2) measurements), and output ...

In tasks requiring sustained attention, human alertness varies on a minute time scale. This can have serious consequences in occupations ranging from air traac control to monitoring of nuclear power plants. Changes in the electroencephalographic (EEG) power spectrum accompany these uctuations in the level of alertness, as assessed by measuring simultaneous changes in EEG and performance on an a...

Signals consisting of a sequence of pulses show that inherent origin of the 1/f noise is a Brownian fluctuation of the average interevent time between subsequent pulses of the pulse sequence. In this paper we generalize the model of interevent time to reproduce a variety of self-affine time series exhibiting power spectral density S(f) scaling as a power of the frequency f. Furthermore, we anal...

Signals consisting of a sequence of pulses show that inherent origin of the 1/f noise is a Brownian fluctuation of the average interevent time between subsequent pulses of the pulse sequence. In this paper we generalize the model of interevent time to reproduce the variety of self-affine time series exhibiting power spectral density S(f) scaling as a power of the frequency f . Furthermore, we a...

With this study we analyze the fluctuations of an electronic heat current across a molecular wire. The wire is composed of a single energy level, which connects two leads that are held at different temperatures. By use of the Green function method we derive an explicit expression for the power spectral density of the emerging heat noise. This result assumes a form that is quite distinct from th...

This paper discusses on power spectral density (PSD) characteristics which are extracted from three-dimensional (3D) electroencephalogram (EEG) models. The EEG signal recording was conducted on 150 healthy subjects. Development of 3D EEG models involves pre-processing of raw EEG signals and construction of spectrogram images. Then, the values of maximum PSD were extracted as features from the m...

Measurement of the power spectral density of (stochastic) Brownian fluctuations of micro- and nano-devices is used frequently to gain insight into their mechanistic properties. Noise is always present in these measurements and can directly influence any parameter estimation obtained through a least-squares analysis. Importantly, measurements of the spectral density of stationary random signals,...

1 In a conventional communication system with a turbo decoder, the received signal strength is measured at the receiver front end, but not the noise-power spectral density. Hence, the accuracy of the estimated bit energy-to-noise-spectral-density ratio can be poor, which degrades the turbo decoder. This paper presents an efficient iterative code-division multiple-access direct-sequence system t...

In this paper, power spectral analysis of deterministic multiscale chaotic dynamical system is presented. The system is obtained by coupling two versions of the well-known Lorenz (1963) model with distinct time scales that differ by a certain time-scale factor. This system is commonly used for exploring various aspects of atmospheric and climate dynamics, and also for estimating the computation...