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Search Publications by: Tasshi Dennis (Fed)

Displaying 26 - 50 of 84

A novel solar simulator based on a super-continuum laser

June 3, 2012

Author(s)

Tasshi Dennis, John B. Schlager, Hao-Chih Yuan, Qi Wang, Daniel Friedman

The design and operation of a novel solar simulator based on a high-power, super-continuum fiber laser is described in this work. The simulator features a multi-sun irradiance with continuous spectral coverage from the visible to the infrared. By use of a

Producing known complex modulation signals for calibration of optical modulation analyzers

March 4, 2012

Author(s)

Tasshi Dennis, Bernd Nebendahl

A family of optical modulation signals with known properties was generated using three phase-locked lasers for calibration of the complex measurement plane. Patterns predicted from first principles were measured with a real-time optical modulation analyzer

High-Accuracy Photoreceiver Frequency Response Measurements at 1.55 um by Use of a Heterodyne Phase-Locked Loop

September 29, 2011

Author(s)

Tasshi Dennis, Paul D. Hale

We demonstrate a high-accuracy heterodyne measurement system for characterizing the magnitude of the frequency response of high-speed 1.55 µm photoreceivers from 2 MHz to greater than 50 GHz. At measurement frequencies below 2 GHz, we employ a phase-locked

Multimode Fiber Launch Study: Estimating the Impact on Measurements of Delay

August 1, 2010

Author(s)

Tasshi Dennis

The purpose of this study was to evaluate measurement uncertainties introduced into time delay calibrations of multimode fiber reference spools. While the principles described are generally applicable, the results could be different for other types of

Dual-rate linear optical sampling for remote monitoring of complex modulation formats

June 2, 2010

Author(s)

Tasshi Dennis, Paul A. Williams

We demonstrate linear optical sampling using simultaneous pulsed and CW local oscillators to enable phase tracking of a data modulated carrier. The technique enables the direct measurement of remotely received signals with low phase noise.

Chirp characterization of external modulators with finite extinction ratio using linear optical sampling

May 1, 2010

Author(s)

Tasshi Dennis, Paul A. Williams

We demonstrate a network monitoring technique for the frequency chirping of external modulators based on linear optical sampling. We present α parameter waveforms of digital data modulation from simultaneously measured amplitude and phase. Digital data

Direct measurement of vector polarization-mode dispersion from repeated random data by use of linear optical sampling

March 1, 2010

Author(s)

Paul A. Williams, Tasshi Dennis

Polarization-dependent optical sampling techniques measure the complex electric field, allowing one to monitor the degrading effects of a communication channel. Here we show the ability to extract the polarization-mode dispersion of the transmission

Full PMD vector measured directly from modulated data using linear optical sampling

July 15, 2009

Author(s)

Paul A. Williams, Tasshi Dennis

We demonstrate a new technique to monitor the polarization-mode dispersion in a fiber communication channel by analyzing the modulated data at the fiber output measured with Polarization-Sensitive Linear Optical Sampling (PS-LOS).

Polarization-sensitive linear optical sampling for characterization of polarization-multiplexed QPSK

March 20, 2009

Author(s)

Paul A. Williams, Tasshi Dennis, Ian R. Coddington, Nathan R. Newbury

We describe polarization-sensitive phase-referenced linear optical sampling for measuring polarization, amplitude, and phase of a high speed optical waveform. With a single measurement, we simultaneously measure both orthogonal polarization channels of 2

Word-synchronous linear optical sampling of 40 Gb/s QPSK signals

March 20, 2009

Author(s)

Tasshi Dennis, Paul A. Williams, Ian R. Coddington, Nathan R. Newbury

We demonstrate word-synchronous measurements of QPSK format 40 Gb/s PRBS signals using linear optical sampling with a precision time-base, which allows us to average waveforms and distinguish between signal distortion and noise in eye diagrams.

Coherent measurements with fiber-laser frequency combs

February 2, 2009

Author(s)

Nathan R. Newbury, Ian R. Coddington, Tasshi Dennis, William C. Swann, Paul A. Williams

The coherent and broad spectral output of fiber-laser frequency combs can be exploited for a variety of high-resolution measurements outside of conventional frequency metrology. We will discuss recent measurements in spectroscopy, ranging, and

Vector characterization of high-speed components using linear optical sampling with milliradian resolution

December 1, 2008

Author(s)

Paul A. Williams, Tasshi Dennis, Ian R. Coddington, William C. Swann, Nathan R. Newbury

We demonstrate linear optical sampling measurements optimized for characterization of the signals produced by optical components. By sampling the optical electric field before and after the component, we isolate the full vector field (phase and amplitude)

Analyzing quantitative light scattering spectra of phantoms measured with optical coherence tomography

March 1, 2008

Author(s)

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