Transcript Purpose of the activities are

Status and experiences with oil-filled
Pressure Balanced backbone (VEOCII)
5/7 July 2010, KM3NeT meeting at Nikhef - Mar van der Hoek et.al.
electronic department
Realization of a prototype section length of 210 m of
Vertical Electro-Optical Cable *
Purpose of the activities are:
•To review design aspect of Nikhef’s concept of a Pressure Balanced Oil Filled (PBOF)
Vertical Electro-Optical Cable (VEOC)
•To experience practical aspects during assembly of a prototype VEOC-length
•To produce a prototype section for performance testing in a pressure tank
•To perform subsequent deployment experiments in a sea-environment
•To optimize next generation PBOF-VEOC designs and the assembly thereof.
* Fibers and copper wires were inserted into the HDPE sections by Baas Research and
Development BV, a Dutch company specialized in the field of fibers and photonics.
After completion, Baas R&D also performed the optical measurements on the fibers.
5/7 July 2010, KM3NeT meeting at Nikhef - Mar van der Hoek et.al.
electronic department
Prototype VEOC assembly
The VEOCII cable assembly according to Nikhef’s Pressure Balanced Oil Filled (PBOF) hybrid
cable concept consists of:
7 sections of 6 mm OD (transparent) HDPE tube each 30 m long, being coupled with T-fittings.
The HDPE tubes are inserted with:
- 2 copper wires
- a pre-assembled bundle of fiber consisting of:
-1 multimode 50/125 μm ‘Monitoring Fiber’, having an optimized coating for
response to pressure and microbending
- 12 single mode fibres G.652 (zero dispersion wavelength @ 1310 nm)
To detect effects of the VEOC-concept on the fiber’s optical properties there is chosen
not to use a bend resistant fiber type for the single mode fibers
.
5/7 July 2010, KM3NeT meeting at Nikhef - Mar van der Hoek et.al.
electronic department
Geometry of the VEOCIIa assembly
Ports for oil filling after insertion of fibers and copper wires
30 m
30 m
210 m
5/7 July 2010, KM3NeT meeting at Nikhef - Mar van der Hoek et.al.
electronic department
Schematic Assembly for first run
Copper wire
Pre-assembled fiber bundle
Fiber/ copper wires pulled-in
and fed-through by hand *
Tube #1
Tube #2
Copper wire
Tube #7
Pull-in rope
* This procedure was chosen for a quick start and learning from the first production run only.
For follow-up VEOC-assemblies, optimized apparatus will be used, being designed on the
experiences during the (now completed) first-trial!
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5/7 July 2010, KM3NeT meeting at Nikhef - Mar van der Hoek et.al.
electronic department
Testing of fibers before and after insertion into tube …
Conventional OTDR (C-OTDR) based measurement of distributed
optical attenuation:
SM fibers @ 1550 nm
MM fiber @ 850 nm
Ready for next
completion level…
Brillouin OTDR (B-OTDR) -based
measurement of strain distribution in SM fibers
5/7 July 2010, KM3NeT meeting at Nikhef - Mar van der Hoek et.al.
electronic department
Example of a measuring result for a single mode fiber
SINGLE MODE FIBER- RED COATED
OTDR MEASUREMENT @ 1550 nm
MEASURED BEFORE
MEASURED AFTER
INSERTION INTO TUBE
INSERTION INTO TUBE
5/7 July 2010, KM3NeT meeting at Nikhef - Mar van der Hoek et.al.
electronic department
Example of a measuring result for the multimode fiber
MULTIMODE 50/125 µm ‘MONITOR’ FIBER –TRANSPARENT COATED
OTDR MEASUREMENT @ 850 nm
MEASURED BEFORE
MEASURED AFTER
INSERTION INTO TUBE
INSERTION INTO TUBE
5/7 July 2010, KM3NeT meeting at Nikhef - Mar van der Hoek et.al.
electronic department
In-bundle over length of
Multimode fiber wrt
singlemode fibers
Reel with pre-assembled bundle of 12
single mode and 1 multimode fiber.
Fibers are kept in a bundle by a helix-wire.
5/7 July 2010, KM3NeT meeting at Nikhef - Mar van der Hoek et.al.
electronic department
Some first results…
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13 Optical fibers and 2 copper wires were successfully integrated into a 6 mm OD HDPE tube.
A total length of 210 m VEOC was produced, consisting of 7 sections of 30 m length HDPE tube,
connected by T-fittings for subsequent oil filling
A pre-assembled set of 12 single mode fibers and 1 multimode fiber was combined with 2
copper wires and pulled-in per 30 m section of HDPE tube
For the single mode fibers, the optical attenuation @ 1550 nm did not change significantly
For the multimode fiber with optimized bend-and pressure sensitivity the optical attenuation @
850 nm did not change significantly Note: optical attenuation will measured again after oil filling
C-OTDR measurements were carried out to record the distributed strain in each optical fiber. At
first sight, no significant changes in the strain distribution were observed. However, the B-OTDR
records will be analyzed in detail in the coming weeks
During assembly a differential length of the monitoring (multimode) fiber with respect to the
single mode fibers was observed. This required extra attention for ‘streamlining’ during fiber
feed-in and during closing of the HDPE sections at the T-couplings between the VEOC sections.
(This aspect will be relaxed when using a breakout box for storage of extra c.q. differential
length of the fibers in the final design of the VEOC.
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Assembly of the VEOCIIa showed up till now the validity and potential of the PBOF concept
• Improvements for ease of production of next VEOC-assembly runs are defined
5/7 July 2010, KM3NeT meeting at Nikhef - Mar van der Hoek et.al.
electronic department
Oil filling of the HDPE tubes: schematic
5/7 July 2010, KM3NeT meeting at Nikhef - Mar van der Hoek et.al.
electronic department
Oil filling of the HDPE tubes: equipment view
Mechanical Design
1) Oil Filling port to Manifold
2) System Filling Port
3) Pneumatic Connection 5 Bar Air Pressure
4)Vacuum Port (Oil Suction)
Air
Oil
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4
Control Panel
Oil Tanks 2 x 12.7 Liter
5/7 July 2010, KM3NeT meeting at Nikhef - Mar van der Hoek et.al.
electronic department
Next steps
According to Nikhef’s current planning the following next steps are foreseen:
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Assembly of penetrators at both ends of the assembly, for feedthrough of optical fibers and
copper wires. Assembly will be done by an external company
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Oil filling of the HDPE tubes. This will be done at Nikhef, using the special designed equipment.
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Additional measurements of the optical fiber characteristics after filling and at ambient pressure:
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Optical attenuation
Polarization Mode Dispersion (PMD)
TBD
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Testing of the VEOCII a assembly under 600 bar pressure in a water tank. During these tests
the optical attenuation and PMD of the fibers will be monitored from outside the tank. Alos the
electrical characteristics of the copper wires will be tested.
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Deployment tests of the VEOCIIa assembly. During these measurements the optical fibers will
be monitored using stand-alone optical measuring equipment housed in e.g. an OM.
5/7 July 2010, KM3NeT meeting at Nikhef - Mar van der Hoek et.al.
electronic department
The prototype VEOCIIa sub-assembly is on display at the Main Hall…
5/7 July 2010, KM3NeT meeting at Nikhef - Mar van der Hoek et.al.
electronic department