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Fiber Optic Cable Configurations

By on July 27, 2023 in connectors, Displacement Sensor, Fiber Optic Vacuum Passthru, Fiberoptic Sensors, FO cables

Philtec Fiber Optic sensors can make displacement measurements inside of mechanisms, machinery and vacuum chambers. To gain access to the measurement locations, Fiber Optic cables may be connectorized for the probe tips to be separated from the electronics. In some complex applications, more than one joint may be required for the installation and removal of the sensor systems. An illustration shows sensor configurations with as many as four parts that have been made and are available for some of Philtec’s sensor products. Contact our application engineering team to see if one of these systems can work for you…sales@philtec.com

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Long Length Fiberoptic Cables

By on February 5, 2020 in 90° Probes, Displacement Sensor, Fiber Optic Vacuum Passthru, Fiberoptic Sensors, Magnetic Fields, Non-Contact Sensing, Quartz Fibers

PROBLEM
Quartz fibers have excellent transmission over long lengths, but they are very expensive and usually cost prohibitive. A recent customer asked for a model D171 sensor with 45 meter length for displacement measurements in vacuum and high magnetic field.

SOLUTION
A 3-piece cost saving system was devised where only nineteen 200µm quartz fibers were used to illuminate 10% of the model D171 probe area.
Part A – Two Ø 1000 µm Hard Clad Silica Fibers, 20 m long in air
Part B – Two Ø 1000 µm Bundles of Ø 200µm Silica/Silica (Quartz) Fibers, 24.5m long in vacuum
Part C – Ø 4320 µm D171 Glass Fibers, 0.5 m long in Vacuum

Part A has two Ø1000µm fibers at the connector interface:

1000 µm HCS Fiber

Part B Ø1000 µm fiber bundles each have 19 fibers at the connector interface:

one transmits light and one returns reflected light.

Part B transmit fibers were randomly mixed with Part C glass fibers. Although Part B fibers illuminated just 10% of Part C fibers, this D171 sensor calibrated to an acceptable 70 mm displacement range. And therefore, the system cost was much lower than it would otherwise have been if all of the D171 fibers had been illuminated by quartz fibers.

Model D171 has several thousand 50µm glass fibers in a 4320µm diameter bundle.
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Sensors for Space Telescope Lens Testing

By on May 23, 2019 in Cryogenic environments, Displacement Sensor, Fiber Optic Vacuum Passthru, Fiberoptic Sensors, multiplexing sensors, Non-Contact Sensing, Quality Control, space cryogenics, Space Telescope Lens

The Euclid Satellite project a good example of Philtec’s sensors being used with excellent results in cryogenic conditions. A technical paper published in 2012  shows Philtec’s high precision sensors were successfully used at 150°K to verify the distortion of lens holders to be <1 micron,  well within the project requirements.

This month Philtec has again delivered sensor systems for space telescope lens distortion measurements. These are 2-channel fiber optic displacement sensor systems designed for 3.2 mm operation in vacuum.

2-Channel Displacement Sensor with BvF120 Vacuum Passthru Assembly

Seven 2-channel sensor systems were delivered with the following options:

  • Multi-Channel Vacuum Passthru Assembly in 120 mm Custom Flange
  • SS Interlok Cable Jacket in Vacuum
  • 6m Total Fiberoptic Cable Length (1.5 in air, 4.5 in vacuum)
  • Low CTE Invar Tips

The fiber optic cables are trifurcated for connection to the vacuum passthru (one transmit bundle and two receivers). With 14 sensor channels x 3 legs each, 42 vacuum ports were required. Each BvF120 has 16 ports, and therefore three BvF120 assemblies were used to pass all channels.

Multi-Channel Vacuum Passthru Assembly

REFERENCE

‘Test Results of High-Precision Large Cryogenic Lens Holders’, 2012, Proceedings of the SPIE Publication “Modern Technologies in Space- and Ground-based Telescopes and Instrumentation II”.

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