1. Some developing ideas on Seafloor cabling and copper/fibreoptic split points where this talks builds and borrows from the work of VENUS, MARS, NEPTUNE and NEMO, particularly that of F. Ameli, M. Musumeci, M. Sedita
G. Hallewell
Centre de Physique des Particules de Marseille
KM3NeT Work Packages Meeting, Paris, Feb 23-24, 2009

2. Background:  Electro –optic wet mateable connectors for intermediate (~500V) voltages (Ocean Design Hybrid Mark 2 type) have been the most unreliable component in ANTARES  Ocean Design is sole source of electro-optic WM connectors: try to replace this technology with something cheaper, with multiple sources (competition)  Alcatel is having trouble with a 10KV electric-only WM connector for its deep sea nodes (NEPTUNE, NEMO) Try to develop a strategy to use copper backbone from OMs, down vertical drops and across the seafloor to secondary junction boxes

3. An early NEMO (2003?) geometry idea for redundant ring and star cabling

4. OTHER IDEAS - VENUS: Generalized Observatory Configuration: hook ring & spurs to science packages
Platform R
Backbone cable
Junction Box
Node BU
Shore Terminal R R
Repeaters
Science
Platform R
Shore Terminal R
Science
Platform
Node BU R
Junction Box R R
Junction Box BU
Here is a generalized configuration for an underwater observatory consisting of a single backbone cable loop between two shore terminals.
The terminals provide power to energize the cable, terminate the communications links to/from the underwater nodes, and provide a connection to land based networks.
The terminals may be located at a single site or some distance apart to provide geographic diversity.
Network nodes are connected to the backbone cable by means of underwater branching units (BUs) and spur cables, which may be from 5 to 25 km in length. The BUs provide power switching capability and routing of optical data channels to the nodes. The nodes distribute communications and power to a series of science platforms and secondary nodes via extension cables. All cables into a node have connectors to allow nodes to be removed for maintenance.
Depending on the network design, optical amplifiers in underwater housings (repeaters) may be used to boost the communications signals along the backbone cable.
Both repeatered and “unrepeatered” designs will be considered here.
The dotted blue line indicates the boundary of the system being considered. Because repair times for shore station equipment are short, the contribution to unavailability is negligible.
Junction Box R BU
Spur cable
Branching Units
Node
Node
Junction Box
Junction Box
Science
Platform
Junction Box

6. OTHER IDEAS - NEPTUNE: Very long deep water network

7. A Junction Box approach could be based on VENUS/NEPTUNE node technology
Penetrator MEOC
cable entry into node
(see UJ bend limiter)

8. Example of a completed UNIVERSAL JOINT
cable repair box with internal cable anchorage
and external bend limiters

9. UVic VENUS
October 2007

10. Node internal cylinder structure
Fibre splices CTA MVC
Interconnections within Alcatel Node:
HV and optics separated:
10KV W.M. connector still a problem
HV conn CTA MVC
Cable termination assembly
uses UJ (Universal Joint)
penetrator etc.

11. Node internal cylinder structure
Pre-Qualified (i.e. warrantied) MVC
(Medium voltage converter: 10kV  400V
uses C6F14 fluorinert as cooling medium (electronics completely immersed)
Fibre splices CTA MVC
HV conn CTA MVC
It would make sense to consider adding an MVC cylinder ‘ante-chamber’
in which the HV connector could be dry-mate,
the cylinder deck-filled with C6F14 –an excellent dielectric

12. UNDER DISCUSSION ONLY Node internal cylinder structure
Pre-Qualified (i.e. warrantied) MVC
(Medium voltage converter: 10kV  400V
uses C6F14 fluorinert as cooling medium (electronics completely immersed)
Fibre splices CTA MVC
HV conn CTA MVC
Threaded rod extensions
might allow fitting of an
Antechamber (cylinder+
penetrator flange)
UNDER DISCUSSION ONLY

13. Node insertion into TRF, MARS

14. Example: standard single conductor and multi-fibre branching unit
Universal Joint Technology (penetrators) might allow us to build a scalable sea floor JB-linked infrastructure without intermediate WM HV connectors
Example: standard single conductor and multi-fibre branching unit

15. MORE ON BRANCHING UNITS
BU’s can be very sophisticated
with F/O commanded power switching
A B.C, AB+C, BA.C, BA+B, CB.A, CB+A
Also colour dependent fibre drops
All this can get very expensive ~ 1M€ per B.U.
But simpler passive configurations are possible ~ 300k€ / B.U.

16. Possible (Cu) star & (fibre) hook ring geometry
Fibres + high voltage
circulate between JBs
(sea electrodes (HV)
near each JB)
One or two MEOCS
Ring of Neptune/NEMO-like JBs with
internal fibreoptic drops, DWDM and
multi-Cu to fibre conversion.
400V DC multiple generation from 7-10kV DC.
Circulating electro-optic MEOC between JBs linked by penetrators

17. MEOC Penetrator connection between between JBs
Ring of external identical Neptune-like JBs with internal fibreoptic drops, DWDM & 370V DC multiple generation to power lines in star config.
MEOC Penetrator connection between between JBs
(Voltage converter cylinders with two antechambers)
MEOCS to shore

18. Maybe simpler to deploy with multiple BU’s
MEOC to shore
All spurs have a length ~ 2x water depth for individual JB retrieval
MEOC to shore

19. Better optical budget + one less BJ
but more difficult to deploy…
MEOCs to shore

20. Consideration of copper radial (star) connections
Consideration of copper radial (star) connections to circumferential junction boxes  (Ocean Design Hybrid Mark 2 type) have been the most unreliable component in ANTARES  Ocean Design is sole source of electro-optic WM connectors: Tests with copper backbone cable are quite encouraging…

21. From Fabrizio Ameli’s talk at VLVnT08…

23. One of several electric only WM connectors: GISMA Series 80

24. Tests with copper backbone cable
Tests with copper backbone cable are quite encouraging…  Can several hundred Mb/s be transmitted over ~ 500m across seafloor (DU divided into several descending copper backbones, each for a ‘sector’?  Ocean Design is sole source of electro-optic WM connectors: but there are many mfrs (~10?) of WM electric-only connectors – even subconn connectors (a la ANATRES OMs) could be a possibility Electrical pulse reforming at DU anchor should be possible, for retransmission a further ~ 500m: Questions: how many conductors to transmit data to JBs from each DU anchor?

25. Summary. Some ideas on independently-liftable ring of identical
Summary Some ideas on independently-liftable ring of identical junction boxes linked to each other in a redundant fibre + power ring using standard deep sea electro-optic cable with penetrator technology such as used in Universal Joint ing Possible solution to Alcatel HV intranode HV cable connection problem using MVC cylinder extension ‘ante-chamber’ & fluorinert ® dielectric fluid filling Possibilities for copper transmission across sea floor with base-of-line reformed electrical pulses. Multi 100 Mb/s probably within reach of TP cables and connectors