Welcome to Visidyne!

Visidyne, Inc. - Developer of SAMNET, NORSE, and the MicroRanger ^TM

(SAMNET data archives are located here: ftp://ftp.visidyne.com/Samnet/)

Visidyne Inc. is a broad-based R&D company that specializes in E O sensor hardware and software. 

SAM is Visidyne's new, ground-based sensor that simultaneously measures the optical depth (OD) of clouds and the forward scattering (FS) properties of their particles.

NORSE is the DoD standard nuclear optical/radar effects code.

MicroRanger^TM is a non-contact laser ranger /vibrometer.

Visidyne Inc. (VI) was established in 1969. Its expertise was in atmospheric sciences (theoretical modeling and laboratory and field measurements) and in modeling optical and infrared nuclear weapons effects. In 1991, VI acquired the senior technical staff of the nuclear group of Physical Research, Inc. that increased the atmospheric modeling capability and provided expertise in nuclear effects on radar systems. In 1997 Visidyne gained extensive laser remote sensing through merger with PhotoMetrics, Inc. Today Visidyne’s focus is on Electro-optics and Atmospheric Measurements and Modeling but it retains its involvement in the nuclear weapons effects modeling for the Defense Threat Reduction Agency.

The Corporation is headquartered in Burlington, MA with facilities in Santa Barbara CA, Huntsville AL, and Anacortes WA. Visidyne has an experienced management team that includes Drs Jack Carpenter, AT Stair, and Gil Davidson. Visidyne is privately held with about 50 employees. Over 70% of staff is technical including 13 PhDs. Numerous patents have been issued to its scientists and engineers and assigned to Visidyne.

         Visidyne’s Research & Development activities are focused around core competencies in application of optical sensing and measurement technology and remote characterization of atmospheric phenomena. These efforts serve both government and commercial markets. Two main areas are optical metrology and engineering and sensor development include the following expertise:

Optical metrology

• Atmospheric modeling (cloud transmission and scattering phenomena, cloud thermal and solar scatter radiance, polarization effects)

• Remote sensing (satellite, balloons, aircraft, and ground platforms)

• Space physics (satellite sensors and orbital mechanics)

• Nuclear and atmospheric effects (infrared and visible emissions and ionization concentrations)

 

Engineering design and sensor development

• Electro-optical systems and sensors (ground, airborne, balloon and satellite platforms)

• Space-based sensors (visible and infrared push brooms, multi-color imagers, and polarization sensors)

•  Precision stabilized balloon borne pointing and tracking systems and payloads

• Optically based measurements (magnetic, mechanical, and optical sensors)

Many sensors and applications that Visidyne Inc. has developed are based on the unique optical phase measurement techniques that Visidyne has perfected that allows for a precision of one part per billion in the comparative phase between two or more electromagnetic signals.

Below is a brief description of the representative VI projects and products.

***********************************************************

Optical Phase Measurements

Monocular 3-D Imaging

A

monocular imager that is capable of generating 3-D imaging at the sub-millimeter level has been invented and is under development by Visidyne as a prototype for a NASA optical hazard landing system. The underlying patented technologies provide for a system of medium and high-powered, infrared systems that illuminate a scene with intensity modulated light at frequencies up to 10 MHz.  This yields an image of the scene and provides a time/distance scale that a specialized CCD chip converts the received backscatter light into a base band signal to generate range and intensity values for each pixel. In addition a 1.2Kw illuminator was designed and built for hi-power, long-range illumination. 

Applications: Landing system, industrial inspection, medical applications, facial recognition, identification of military targets for kinetic hit-to-kill interceptors and targets under difficult conditions of low contrast, partially obscured, and/or behind foliage.

 

MicroRanger™ and MicroVibrometer

M

icroRanger™ is a patented precision non-contact distance and vibration measurement instrument. It uses intensity modulated laser light to measure displacements with micrometer precision at kilohertz bandwidths up to tens of meters from the probe depending upon the level of laser illumination.

Based on this technology, a laser-motion-tracking-system that measures displacements with micron precision was developed to enable linear motion analysis of a wide variety of objects. As a stand-alone instrument it can either be incorporated into an application or carried between measurement locations. As a motion study tool it can be connected to a PC for high-speed data collection.

Applications: Wide industrial and scientific use where precision displacement measurements are required, for example for extended structures in space, for satellite constellation station keeping, or for remotely monitoring the vibrational characteristics of large structures such as bridges.

Hyper Dense Wavelength Multiplexing (HDWM)

HDWM expands the use of available fiberoptic cable by multiplexing any of the existing multi-color channels by a factor of as much as two orders of magnitude.  Since the HDWM system is highly linear there is no crosstalk between these channels and this allows for a much more efficient use of the cables already installed in metropolitan areas.

    The underlying technology of this approach makes use of phase modulation as contrasted to intensity modulation.  The attributes of this technological approach are that it decreases the noise figure, increases the available bandwidth, reduces the distortion of amplification, and is not subject to crosstalk between the channels.  The approach uses an optical phase diversity receiver

 

Applications: This technology is appropriate for both DoD and commercial applications.  For DoD platforms it provides distribution of sensor/control data, redundant fiber links to and from multiple locations, and chip-scale hyper-dense frequency division multiplexing.  The technology is flexible and permits mixed analog and digital signals without interference.  It allows programmable signal-to-noise/bandwidth and bit rate/bandwidth products. The channels are available fulltime and require no time-division multiplexing.

    For the metropolitan-area fiber-optic distribution networks, even though there are already many multi-color channels, there will be a need to increase the number of discrete channels as the usage demands increase.  The high-fidelity nature of this approach will increase each optical channel's usage and will permit as much as a hundred-fold increase in the aggregate data rate in each of the existing channels.

    A patent protecting this technology has been issued and a proof of concept has been demonstrated by a recognized organization.

Photonic A to D Converter

T

his technology is a continuation of Visidyne’s efforts in the application of optical phase encoding and detection to the problem of digitizing and transporting wideband analog signals. Contemporary schemes generally encode data by modulating the intensity of an optical beam in a fiber.  Visidyne has demonstrated that by modulating the phase of the optical carrier, rather than its intensity, both greater channel capacity, more gigabits-per-second, and greater linearity can be achieved.  By adding a photonic process in front of conventional electronic analog-to-digital converters, the resolution of present day and future electronic ADCs can be improved by a factor from 2 to 3 bits at any sample rate, with similar reductions in inter-modulation distortions.  Since this Photonic Front-End can be remote from the electronic digitizer, connected to the data destination by a pair of optical fibers, it can be used as a high-bandwidth data link as well.  The hardware at the data source is electrically passive and potentially very compact and rugged making it ideal for applications such as transport of RF signals from remote antennas with high fidelity and low distortion.  There is also an inherent tolerance to a severe radiation environment.

Applications: Fiber optics and RF communications.

 

Photonic Clock

The most common options for precision clocks are quartz crystal oscillators in the form of Oven Controlled Crystal Oscillators (OCXOs) that use a high quality mechanical resonator, the quartz crystal element, to stabilize the frequency of an oscillator and atomic clocks that use a hyperfine transition in an excited gas, e.g., Cs or Rb to stabilize a frequency.  OCXOs can have excellent short-term stability.  Long-term stability is limited due to aging effects such as out-gassing and de-crystallization changing the crystal resonance frequency. Atomic clocks have relatively poor short-term stability due to the complex electronic chain required, but have the best long-term stability. 

Visidyne has developed a Photonic clock that can achieve the best capabilities of both, the excellent short-term stability of a high performance crystal clock along with a long-term stability approaching that of an atomic clock.  While the underlying principles of the Photonic clocks are not new, the technologies to implement them are recent and their use novel, including such Photonic elements as low power, energy efficient, vertical cavity surface emitting laser (VCEL) diodes, low loss single mode optical fiber having minimal mass even in substantial lengths, and fast optical detectors. 

Visidyne has demonstrated a Photonic clock consisting of diode laser, optical delay line and detector/receiver that are used to design RF oscillators at 2 to 10 Ghz, with less phase noise in a smaller footprint and at lower power consumption than existing, all electronic designs.

Applications: digital electronics, GPS, better cell phone technology with better RF throughput.

***********************************************************

Cloud Characterization for Remote Sensing

SAMNET Sensor

S

AMNET is a unique, patent-pending instrument complex that measures the radiance of the solar disk and the associated aureole resulting from the passage of solar radiation through atmospheric aerosols and clouds. The radiance of the solar disk measures the cloud optical depth. This is one of the two most important optical measures of cloud radiative effects.  The aureole measurements made simultaneously by the SAMNET sensor yields information on the Forward Scattering of the sunlight that is defined by the ice/water composition of the cloud along the line of sight and, as such, SAMNET is important for understanding cloud transmissive effects as well as particle size and ice content of cirriform clouds. SAMNET is accompanied by a sophisticated modeling software package that provides characterization of atmospheric conditions.

Applications: Remote sensing, cloud characterization, weather and climate studies.

***********************************************************

High Altitude Balloon Payloads

In the late 1970s, Visidyne began a period of involvement in high-altitude balloon-borne payload programs. Payloads were designed for staring at Earth infrared backgrounds, measuring various atmospheric parameters with lidar systems, and tracking rocket launch plumes.

More recently, Visidyne designed a platform for the Navy Research Laboratory's HARBOR-MIST program in which an imaging system was flown to 100,000 feet using a 5 million cubic foot balloon.  A requirement for these measurements was to maintain pointing accuracy of 1 arcsec/sec for three minutes using rate-integrating gyros.  Pointing range was 360 degrees continuous azimuth, +/- 75 degrees elevation and +/- 10 degrees roll.  Payload capacity of up to 500 pounds can be accommodated by our existing platform.

 

 

Instrumentation & Systems Developed by Visidyne

Space Instrumentation X-Ray Instrumentation Space Particle Imager for Space Debris Measurements Rocketborne Bremsstrahlung X-Ray Detector MSX Xenon Lamp Particulate Monitor X-Ray Microscope Optics MSX Krypton Lamp Radiometer Water Vapor Monitor X-Ray Telescope Optics     Lidar Systems Particle Instrumentation Portable Eye Safe Targeting/Tracking Lidar Rocketborne Retarding Potential Analyzers for Measurements of Vehicle Potentials Balloonborne Multiwavelength Incoherent Lidar - (ABLE) Rocketborne Electrostatic Analyzers for Measurements of Artificial and Natural Aurora Balloonborne Coherent CO2 Lidar Rocketborne Electron Accelerators for Upper Atmospheric Excitation Sounding Rocket Lidar System Alpha Detectors     Infrared Instrumentation Vapor Releases Balloonborne LWIR Radiometer System Water Vapor Release Module SWIR Imager and Interferometer for Groundbased STS Plume Measurements Uranium Vapor Release Module Airborne Target Discrimination Imager for Optical Clutter Suppression Groundbased Background Optical Suppression Dual Beam SWIR Interferometer System Balloon Payloads Airborne SWIR Scanning Imager Balloonborne Payload System for Precise Pointing of IR Sensors - BAMM Balloonborne Lidar for Atmospheric Rayleigh, Mie and Raman Measurements - ABLE I, II, III Visible Instrumentation Balloonborne Payloads with Precision Pointing and Tracking for UV-Visible Sensors – KESTREL Rocketborne Visible Spectrometers for Measurements of Artificial Aurora Balloonborne CO2 Coherent Lidar Rocketborne Photometers for Measurements of Artificial and Natural Aurora   Rocketborne Scanning Photometer for  Measurements of Artificial Aurora       VUV/UV Instrumentation   Rocketborne UV Spectrometers for Measurements of Artificial and Natural Aurora   Rocketborne UV Photometers for Measurements of Artificial and Natural Aurora   Rocketborne and Laboratory VUV Photoelectron Spectrometers   Rocketborne VUV Image Scanner   Rocketborne VUV Ionization Detector   Rocketborne VUV Photometers

***********************************************************

 

Computer Code Development Code Customer Description NucSim DTRA Computes RF and IR operability in a nuclear disturbed environment   VECTR   USN   Spatial and Spectral Tracking of ENVAR Signals   ENVAR USN Signal Association Using Envelope Coherence   HiSEMM USASSDC Simulation-Level Nuclear Environments for Infrared and Radar Sensors   ATHENA DNA Heated Gas Emissivities and Opacities   SSGM NRL/DNA Strategic Scene Generation Model   IRSim DNA Simulator for Nuclear Scene Generation   PEM DNA Phenomenology Engagement Module – A Fast NORSE Derivative   NORSE DNA Nuclear Optical and Radar Systems Effects Code   ROSCOE DNA/USAF Radar and Optical Systems Code   NADIR DNA/USAF Nuclear-Induced IR Emissions Code for Air Force Systems   DND NASA/USAF Prediction of Polyatomic, Elevated Temperature and Pressure, Line Positions and Strengths   VOSEC ATSA System Evaluation of Effects of IR Backgrounds and Clutter   VERAA ATSA Updated Version of TACTIR   TACTIR USAF Nuclear Burst Emission Seen Through the Atmosphere for Tactical Applications   SLAM DNA Visible and Nuclear Induced Emission Code   HIRAM USAF Non-equilibrium Atmospheric Limb IR Emission Code   SIM USAF/IBM Satellite System Simulation Code   SIMDRV USAF Nuclear Simulation Code for Use in Satellite System Predictions   FASCODE I USAF First Version of High Resolution, Line-by-Line Atmospheric Transmission and Emission Code   LOWTRAN I DNA/USAF First Version of the Standard Lower Resolution Atmospheric Transmission Code (Part of OPTIR)   OPTIR DNA/USAF First Optical/Infrared Nuclear Prediction Code