An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
We demonstrate a technique for optical performance monitoring by simultaneously identifying optical signal-to-noise ratio (OSNR), chromatic dispersion (CD), and polarization-mode dispersion (PMD) using artificial neural networks trained with parameters
The fundamental starting point for the analysis of all two-state waveforms is the determination of the low- and highstate levels. This is a two-step process. First, the data are grouped into points belonging to each state, and second, the value of each
Ian R. Coddington, William C. Swann, Nathan R. Newbury
A stabilized frequency comb provides a broadband array of highly resolved comb lines. Using a multiheterodyne technique, we measure the amplitude and phase of every comb line, allowing for massively parallel, high-resolution optical sampling.
Edward F. Kelley, Karl Lang, Louis D. Silverstein, Michael H. Brill
A standard methodology exists for estimating the flux from front projection displays by sampling the projected illuminance of a white source signal. With the advent and use of white projection primaries, a dramatic increase in flux can be achieved over the
Measurement of a small black area on a white electronic display screen is often accompanied by serious contamination from veiling glare in the detector. The black measurement can be thousands of percent in error. Character-stroke-contrast or small-area
We developed artificial neural network models to simultaneously identify three separate impairments that can degrade optical channels, namely optical signal-to-noise ratio, chromatic dispersion, and polarization mode dispersion. The neural networks were
Xiaoyu X. Li, Thomas Scott, Christopher L. Cromer, Joshua A. Hadler
For the past ten years, NIST has used high-reflectivity, optical choppers as beamsplitters and attenuators when calibrating the absolute responsivity and response linearity of detectors used with high-power CW lasers. The chopper-based technique has
Reflection measurements are critical to the evaluation of display performance under ambient illumination conditions. Various hemispherical reflection methods are evaluated for their suitability and robustness across display technologies. The standard
Shellee D. Dyer, Martin J. Stevens, Burm Baek, Sae Woo Nam
We demonstrate an all-fiber photon pair source with the highest coincidence-to-accidental ratio (CAR) reported to date in the fiber optic telecom C-band.
Jeffrey A. Jargon, Xiaoxia Wu, Louis Christen, Scott Nuccio, Omer F. Yilmaz, Loukas Paraschis, Yannick K. Lize, Alan Willner
We experimentally demonstrate a monitoring technique for determining misalignment between the in-phase/ quadrature (I/Q) data streams and between the data and pulse carving in an 80 Gb/s serial-type return-to-zero differential quadrature phase-shift-keying
Nathan R. Newbury, Paul A. Williams, William C. Swann
We have recently demonstrated the coherent transfer of an optical signal over a 251 km link of optical fiber by use of the standard Doppler-cancellation approach to remove the effects of the fiber-link noise. The fundamental limit to the frequency
Charles Dietlein, Jon E. Bjarnason, Erich N. Grossman, Zoya Popovic
Conventional material measurements of transmission and reflection in the millimeter-wave and terahertz frequency range do not differentiate between scattering and absorption, grouping effects from both mechanisms together into 'loss'. Accurate knowledge of
Tasshi Dennis, Shellee D. Dyer, Andrew Dienstfrey, Gurpreet Singh, Paul Rice
We demonstrate the ability of multiple forms of optical coherence tomography (OCT) in the frequency domain to quantitatively size scatterers. Combined with a variety of distinct phantoms, we gain insight into the measurement uncertainties associated with
We discuss the true definitions of specular and diffuse reflection. Many people think that diffuse reflection is Lambertian reflection. Such is not the case. Lambertian is a special type of diffuse reflection, and the often-used equations for Lambertian
We report the first direct comparison of relative carrier mobilities in semiconducting organic polymer films measured using non-contact optical pump terahertz probe spectroscopy to those reported in electrical device studies. Relative transient signal
Katie Hurst, Richard K. Ahrenkiel, Steve W. Johnston, Anne Dillon, Lara Roberson, John H. Lehman
The photoconductive recombination lifetimes of carbon nanotube (CNT) thin films as a function of wavelength are measured by resonant-coupled photoconductive decay (RCPCD) method (1). The carrier recombination lifetime is a fundamental property of carbon
Eric Gansen, Mary A. Rowe, M. Greene, Danna Rosenberg, Todd E. Harvey, Mark Su, Sae Woo Nam, Richard P. Mirin
Detectors capable of resolving the number of photons in a pulse of light are important components for the advancement of quantum information technologies. We demonstrate photon-number discrimination using a novel single-photon detector that utilizes a
John H. Lehman, Tom Campbell, Anne Dillon, Roop Mahajan
Quantitative, systematic and reproducible metrology of carbon nanotubes is paramount to the fundamental understanding of these promising nanomaterials. Moreover, development of novel techniques which extend the current arsenal of nanotools is also
Anindita Saha, Hongye Liang, Aldo Badano, Edward F. Kelley
We report on the characterization of two novel probes for measuring display color without contamination from other screen areas or off-normal emissions. The probes are characterized using a scanning slit method and a moving laser and LED arrangement. The
Trade magazine discussion of the need for better sunlight-readability measurement methods based upon ambient contrast measurements. Diffuse reflectance measurements and directed illumination measurements are combined and scaled to daylight levels to
Optical properties are important for determining fundamental characteristics of carbon single-walled nanotube (SWNT) samples including purity, chirality, and tube diameter. Previously, we have estimated the volume fraction of metallic versus semiconducting
Martin J. Stevens, Robert Hadfield, Robert E. Schwall, Sae Woo Nam, Richard P. Mirin
We report the observation of photon antibunching from a single, self-assembled InGaAs quantum dot (QD) at temperatures up to 135 K. The second-order intensity correlation, g(2)(0), is less than 0.260 ± 0.024 for temperatures up to 100 K. At 120 K, g(2)(0)
Display performance under ambient conditions is as important for display characterization as are darkroom measurements. We review ambient-contrast measurements and the design and use of sampling spheres rather than large integrating spheres for making
Greens function (GF) modeling defects may take effect only if the GF as well as its various integrals over a line, a surface and/or a small volume can be efficiently evaluated. The GF itself is needed in modeling a point defect while the integrals needed