Communication Infrastructure Upgrade on Mauna Kea


The communications infrastructure on Mauna Kea is in need of upgrading to provide adequate service to existing and planned facilities on Mauna Kea, in particular the Smithsonian Submillimeter Array (SMA). The upgrade include replacing the four fiber optic cables currently serving CFHT, IRTF, KECK, and Subaru with a single fiber sheath, replacing the GTE Hawaiian Tel Cu cable and adding a GTE Hawaiian Tel fiber optic cable.

The improvements described in this report affect Gemini, CFHT, IRTF, KECK, Subaru, Smithsonian, CSO, and JCMT and will focus on an effective use of the two 4-inch conduits running between HH-16 by CFHT and HH-23 by KECK.


Currently there are two 4-inch communications conduits extending along the northern route from the Summit Communications Room that serve CFHT, IRTF, and KECK. CSO and JCMT are currently served along the southern route. Four 4-inch conduits have been installed from HH-23 near KECK to HH-25 near Subaru. As part of the Gemini project, new communications conduits consisting of four 4-inch conduits will be laid between the Summit Communications Room and HH-16 by CFHT.

Currently, one of the conduits along the northern route contains a 200 pair GTE Hawaiian Tel Cu cable for telephone service and the other conduit holds up to four fiber optic cables. The fiber optic cables are currently used in the Summit Communications Network operated by the Institute for Astronomy. Both of these conduits are congested preventing any additional pull of cables without prior removal of existing cable(s).


The basic communication requirements for each facility on Mauna Kea include

  1. GTE Hawaiian Tel Cu cables for telephone (voice) connection (25+ pairs/facility)
  2. GTE Hawaiian Tel fiber optic cables for high bandwidth wide area connection (new)
  3. UH fiber optic cables for local area network around the summit and Hale Pohaku (minimum 6 pairs of fibers/facility)

GTE Hawaiian Tel currently does not have fiber optic access to any of the facilities.

Proposed Plan

The current plan calls for supplying the communication needs to Gemini, CFHT, IRTF, KECK, Subaru, SMA, JCMT, and CSO through the northern route.

The project is expected to be completed in two phases. The first phase is planned to coincide with the infrastructure upgrade that the Gemini Project has planned between the Summit Communications Room and CFHT. The second phase will commence once the conduits between Subaru and CSO have been installed as part of the SMA Infrastructure improvement.


During Phase I, the four separate fiber optic cables currently serving CFHT, IRTF, KECK, and Subaru will be replaced by a single sheath of fiber optic cable containing up to 16 bundles of 6 pair fiber optic cable (or 32 bundles of 3 pair fiber optic cable, depending on the vendor) for a total of 192 fibers. The diameter of the 192 fiber cable is approximately 1". Each facility will be allocated up to 12 pairs of fiber optic cables, tripling their current capacity. The fiber optic cable will be field spliced at hand holes near each facility to fibers leading to the patch panels in each facility. The main fiber optic cable will terminate near KECK (or Subaru, if ready) with the unused fibers un-terminated.

GTE Hawaiian Tel will pull an additional bundle of fiber and replace their 200 pair Cu cable at the same time.

One 4-inch conduit can hold either three 1 1/4" subducts or one 200 pair Cu cable and two 1 1/4" subducts. The 96 pair fiber optic cable will be pulled through a subduct. There are three possibilities for using the two 4-inch conduits; which one is best requires further analysis. The possibilities are:

  1. IfA fiber (f) in one conduit, and GTE fiber (F) and Cu cable (Cu) in the other conduit. This option physically separates the UH and GTE cables. This option prevents an upgrade of the Cu cable without disrupting fiber optic based service offered by GTE.
  2. The IfA and GTE fiber share a conduit. The GTE Cu cable resides in the other. The configuration allows for an upgrade of the Cu service without interruption of fiber based services.
  3. The IfA and GTE cables all share one conduit. leaving the second conduit free for future expansion.

Proposed Implementation Procedure

In order to minimize duplication of effort during the communication infrastructure upgrade, some of the work must be coordinated with the communication conduit work performed by Gemini. The proposed implementation schedule is (work closely related to the Gemini project is in bold face)

  1. GTE Hawaiian Tel (HawTel) lays temporary Cu service between CFHT and KECK/Subaru.
  2. Gemini pulls Cu cable between the Summit Communications Room and CFHT.
  3. HawTel splices the temporary Cu cable to the new Cu cable and IRTF, KECK, and Subaru.
  4. HawTel removes old Cu trunk between CFHT and KECK and pulls two subducts and a new Cu cable or three subducts into the empty conduit (A).
  5. Contractor/HawTel pulls in new UH fiber from Summit Communications Room to CFHT
  6. Continues pulling that same fiber optic cable, without splicing at CFHT, all the way to KECK (or Subaru, if ready) through a subduct in Conduit A
  7. Fibers leading to the patch panels of CFHT, IRTF, and KECK will be spliced to the new UH fiber sheath.
  8. The FDDI ring will be reconnected using the new fibers.
  9. The old UH fiber optic cables will be removed from the conduit (B).
  10. HawTel will pull in the remaining cables though Conduit B, if necessary.
  11. Cu service will be switched from the temporary service to the new buried Cu cable.

It is important that the first 6 steps be closely coordinated with the Gemini Infrastructure work. HawTel should be ready to switch over the Cu service to the temporary cable when Gemini has completed step 2. Similarly, steps 5 and 6 should be coordinated closely.

Phase II

During Phase II, fiber optic cables for UH and HawTel, as well as the HawTel Cu cable will be pulled from KECK/Subaru to the SMA, JCMT, and CSO. These cables will be spliced to the respective existing cables from Phase I near KECK/Subaru.