Google is one of six companies in a new consortium called Unity that is building a new undersea cable to boost internet capacity between the United States and Asia.

The fibre-optic cable will run between Chikura, off the coast of Tokyo, and Los Angeles. Construction of the cable is expected to cost $300 million and will begin immediately, the companies said. It should be available for use in the first quarter of 2010.

Other companies involved include Bharti Airtel, Global Transit, KDDI, Pacnet and SingTel. The group plans to allow ownership and management of individual fiber pairs within the cable.

The cable is expected to increase Trans-Pacific capacity by about 20 per cent, adding as much as 7.68Tbits per second of bandwidth.

Rumours of Google's involvement in a new undersea cable surfaced last year, but Google didn't confirm its plans at the time. Speculators have also suggested that Google bought a significant amount of "dark fibre" on the cheap after telecommunications companies overbuilt years ago, but Google has said little about its activities in this area.

This won’t be the first time Google has become involved in a telecommunications project. The search giant entered the ongoing US Federal Communications Commission auction for wireless spectrum, which will allow spectrum winners to build mobile-phone networks. It’s unclear whether Google is still participating in the auction because the FCC is not revealing the names of bidders who are active in it.