Cable system operators and their equipment vendors are exploring 100 gigabit per second upgrades for their networks despite research showing a flattening of bandwidth demand growth over the past two years.

United States-based optical networking vendor Xtera said overnight that its 100G technology — which was first commercially utilised on the repeatered Gulf Bridge International cable — is now generally available.

Xtera said it has conducted several 100G field trials on regional and trans-oceanic cables around the world, as well as simulated optical transmission surveys to determine the maximum system capacity a subsea cable can support.

In the Pacific, Telstra Global and Infinera have trialled 100G over a dedicated fibre pair on segment 5 of the Asia-America Gateway (AAG) cable system.

The segment spans 4200 kilometres and connects San Luis Obispo in California to Oahu, Hawaii.

Infinera deployed its DTN-X platform with a prototype super-channel line card, and 500Gbit/s photonic integrated circuits.

Last week, network operator Pacnet announced that it is planning this year to deploy 100G technology on its East Asia Crossing - City to City (EAC-C2C) cable that connects seven Asian countries with a total span of 36,800 kilometres.

The EAC-C2C currently utilises 10Gbit/s optical transport. Pacnet did not disclose its equipment supplier for the 100G upgrade.

While cable operators are upgrading the capacity of their systems, global bandwidth demand has levelled off over the past two years, Telegeography analyst Tim Stronge told the Pacific Telecommunications Council 13 conference in Hawaii.

Commsday reported that Stronge's forecasts show that bandwidth demand growth currently sits at below 40 percent per year.

He sais it's been "easing off steadily for the past two years" and believes it will drop to around 30 percent in a few years time.

Stronge expects demand to pick up again from 2015, with 36 percent growth forecast.