ALMA correlator fiber optic patch panel info

Documentation

• ALMA-54.10.02.00-0007-B-PR: Proper use for AOS Fiber Optic Patch Panel Procedure (local .doc   local PDF)

Photos

Judging from the photos below, each of the three "ALMA-x" rack contains 8 rows of 8 connector module units (cassettes) = 64, and 64*3racks = 192 units, plus 1 row with one or 2 units each, total = 196 units. Each connector has all 8 fibers terminated. The ACA rack has 3 rows of 8 units = 24 units, plus 1 row with one unit, total = 25 units. There are 22 ACA pads and 170 12m pads, for a total of 192 pads. Quoting from the ACAS documentation:

• • "The external cables are terminated directly at the rear of the ALMA-B/ACA Patch Panel Racks. In order to allow the simultaneous correlation of the scientific data generated by the ACA antennas in the ALMA-B correlator and in the ACA correlator, the DTS signals coming from the ACA stations are optically split and routed to both the ACA Patch Panel and the ALMA-B Patch Panel. The splitters are located in the ACA Patch Panel Rack. The other signals (LO and M&C) are not split."
• 
• The photos above suggests that there is enough room in this room for a second patch panel devoted to the WSU's use of the spare fiber from each antenna?

WSU needs

• Will need rack space in current AOS patch panel room for EDFAs to use when antennas are on distant pads, EDFA is 1 inch wide (by 4U) per signal
• CLOA was built for 80 antennas. Plan is to plumb that many through to OSF.
• The HIL has taken up some space since these photos were taken. Christophe will ask BE group to take new photo, and measure available spare size for racks.
• Will need short cables to go from the new WSU/EDFA rack to go to the termination point of the new ~200-core AOS-OSF fiber. Where is that termination point of the current 48-core fiber?
• What is needed at OSF?
  • straight connection to AT ingest, which requires an interface card from 400G to 100G multimode.
  • 2 spare racks have been set aside in correlator design/budget (40 racks total, standard 19 inch) which could hold these cards (35 per rack), which CJ thinks is enough for 66 antennas.
  • Additional cooling is a concern. 12kW has been assumed in correlator proposal.
  • Additional rack(s?) needed for upgraded ACAS
  • Only yearly maintenance envisioned to clean fibers, check power levels, like the CLOA room
  • Will need termination point of 200-fiber cable elsewhere, coiling up the unused ones, and allowing the 80 to continue to the correlator room.
  • What is power usage of all telecommunication system?

Location

• at AOS: taken from ICD Between: HIL Simulation Environment And: Infrastructure (local PDF)
  
• at OSF: taken from same document above
  
• at OSF: taken from OSF Fibre Management Rack Technical Specification
  

Diagrams

• AOS Technical Building Drawings (30MB) (local PDF)
• ICD baseline correlator to Site (local PDF)
• for PM antenna signal path: taken from ACA Spectrometer Subsystem Design Description on EDM (local PDF)
  
• overall: taken from ALMA BACK END FIBER OPTIC PATCH PANEL FOR AOS TECHNICAL BUILDING Specification (local PDF)
  

CAI mapping

• old wikipage
• new confluence site (requires permission)
• How to use the ACA correlator

-- ToddHunter - 2021-10-19