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Search Publications by: David A. Howe (Assoc)

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Displaying 51 - 75 of 125

Cancellation of Vibration-Induced Phase Noise in Optical Fibers

November 15, 2008
Author(s)
Archita Hati, Craig W. Nelson, Jennifer A. Taylor, David A. Howe
Vibration causes mechanical distortions in fiber-optic transmission lines that induce phase fluctuations. A scheme is described which enables electronic cancellation of vibration-induced phase noise in an optical fiber wound on a spool. We report 20 dB or

Relative Intensity Noise Suppression for Photonic Links

September 15, 2008
Author(s)
Craig Nelson, Archita Hati, David A. Howe
We propose and experimentally demonstrate a novel technique to reduce laser relative intensity noise (RIN). A RIN suppression servo is usually implemented by inserting an intensity modulator in the optical path and controlling measured light intensity with

Handbook of Frequency Stability Analysis

July 1, 2008
Author(s)
William Riley, David A. Howe
This handbook, which can be used as both a tutorial and a reference, describes practical techniques for frequency stability analysis. It covers the definitions of frequency stability, measuring systems and data formats, pre-processing steps, analysis tools

Vibration-induced PM noise measurements of a rigid optical fiber spool

May 19, 2008
Author(s)
Jennifer A. Taylor, Craig W. Nelson, Archita Hati, Neil Ashby, David A. Howe
The opto-electronic oscillator (OEO) has emerged in recent years as an excellent low-noise source that rivals the best RF oscillators over broad offset frequencies. The main sources of noise in an OEO are the laser and RF modulator, photo detector, loop

The Role of Phase Noise Research and Metrology

February 19, 2008
Author(s)
David A. Howe
The oscillating, or repeating, signal that is the basis for constructing all signals is a voltage that exactly follows simple periodic sine and cosine functions of time. The synthesis of such signals, using an oscillator coupled with a ¿frequency

Active Vibration-induced PM Noise Control in Optical Fibers: Preliminary Studies

May 29, 2007
Author(s)
David A. Howe, Archita Hati, Craig Nelson, Jennifer A. Taylor, Neil Ashby
Vibration causes mechanical distortions in fiber-optic transmission lines that induce time (phase) fluctuations. RF systems are increasingly using optical fibers in various ways and must occasionally operate in environments with acoustic and structure-born

Further Examination of the Injection-Locked Dual Optoelectronic Oscillator

May 29, 2007
Author(s)
Kai Hudek, Archita Hati, W Zhou, David A. Howe, Craig W. Nelson
Optoelectronic oscillators (OEO), utilizing the low loss nature of optical links, can generate oscillations with very high Q values. The long delay line used in the oscillator can, however, support many modes of oscillation. Mode spacing is inversely

Microwave Optoelectronic Oscillator with Optical Gain

May 29, 2007
Author(s)
Craig W. Nelson, Archita Hati, David A. Howe, W Zhou
Optoelectronic oscillators (OEO) are unique compared to radio-frequency (RF) oscillators in that they do not fundamentally require a RF gain element in order to satisfy the amplitude threshold condition for oscillation. All the energy required for

Microwave optoelectronic oscillator with optical gain

May 29, 2007
Author(s)
Craig Nelson, Archita Hati, David A. Howe, W Zhou
Optoelectronic oscillators (OEO) are unique compared to radio-frequency (RF) oscillators in that they do not fundamentally require a RF gain element in order to satisfy the amplitude threshold condition for oscillation. All the energy required for

Optical Fiber Vibration and Acceleration Model

May 29, 2007
Author(s)
Neil Ashby, David A. Howe, Jennifer A. Taylor, Archita Hati, Craig W. Nelson
We derive expressions for the group velocities of transverse electric and transverse magnetic electromagnetic waves in a stretched single-mode fiber. Stretching can occur either as a result of temperature changes of the spool on which the fiber is wound

Phase Noise of X-band Oscillator and Amplifier Technologies Compared

May 29, 2007
Author(s)
David A. Howe, Archita Hati
We compare best-in-class phase noise of different technologies of oscillators and amplifiers at X-band. Results are presented based on recent measurements at NIST. In particular, comparisons are made between mature technologies of multiplied quartz

Preliminary study on the vibration sensitivity performance of microwave components

May 29, 2007
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe, Neil Ashby, Jennifer A. Taylor, Kai Hudek, C. Hay, David Seidel, D. Eliyahu
Vibration sensitivity is an important specification for oscillators on mobile systems, Unmanned Aerial Vehicles (UAVs) etc. These systems must provide superior performance when subject to severe environmental conditions. Electronic oscillators often can

TheoH and Allan Deviation as Power-Law Noise Estimators

February 1, 2007
Author(s)
Jennifer A. Taylor, David A. Howe
A spectral interpretation using the frequency response of the Allan Variance is used to determine slopes of f α noise, commonly called ''power-law noise.'' This paper shows that TheoH provides significantly better determination of f α noise slopes at long

Merits of PM Noise Measurement over Noise Figure: A Study at Microwave Frequencies

October 1, 2006
Author(s)
Archita Hati, David A. Howe, Fred L. Walls, D. Walker
This paper addresses two issues: (i) it compares the usefulness of phase-modulation (PM) noise measurements vs. noise figure (NF) measurements in characterizing the merit of an amplifier, and (ii) it reconciles a general misunderstanding in using ¿174 dBc

Comparison of AM noise in commercial amplifiers and oscillators at X-band

June 5, 2006
Author(s)
Archita Hati, David A. Howe, Craig Nelson
In this paper we discuss the importance of amplitude modulated (AM) noise. AM noise is often neglected and considered as a minor problem. However, AM noise can become very important in high performance systems that require ultra-low phase modulated (PM)

Low Phase Noise Amplifier and Oscillator using Feed-Forward Technique at 10 GHz

June 5, 2006
Author(s)
Archita Hati, Craig Nelson, David A. Howe
We discuss the performance of a feed-forward amplifier (FFA) at 10 GHz. The feed-forward method is primarily used to suppress intermodulation distortion in amplifiers to suppress up-converted near-DC noise. The main amplifier in this configuration is a low

Relativity and Timing in X-ray Pulsar Navigation

June 5, 2006
Author(s)
Neil Ashby, David A. Howe
XNAV is a technology demonstration that will use photons from X-ray pulsars for navigation and spacecraft attitude determination. This paper summarizes relativistic effects in the context of XNAV. It also characterizes the primary task in the time domain

TheoH Bias-removal Method

June 5, 2006
Author(s)
David A. Howe, Jennifer A. Taylor, Tiffany Tassett
A version of Theo1 variance, called TheoBR variance (BR for ''bias-removed'' relative to the Allan variance), is constructed. This relative bias correction is applied over a range of the longest-recommended Allan tau values for a given data run. The oH

Comparison of AM Noise in Commercial Amplifiers and Oscillators at X-Band

June 1, 2006
Author(s)
Archita Hati, David A. Howe, Craig W. Nelson
In this paper we discuss the importance of amplitude-modulated (AM) noise. AM noise is often neglected and considered a s a minor problem. However, AM noise can become very important in high performance systems that require ultra-low phase-modultaed (PM)