Softbank Corp. said Monday it will start offering a fiber-optic Internet connection service this month, posing another challenge to industry giant NTT Corp., a dominant player in the field.

Three years ago, Softbank challenged NTT by launching the Yahoo BB asymmetrical digital subscriber line service, and has been credited with bringing down the country's broadband access prices to among the cheapest in the world.

"We will beat the NTT group in ADSL and fiber-optics services combined," Softbank Chief Executive Masayoshi Son told a news conference.

The Internal Affairs and Communications Ministry said there were about 1.6 million users of fiber-optic services in Japan as of the end of August.

Compared with ADSL, which uses exiting telephone lines, the fiber-optics network boasts much faster connection speeds -- up to 100 megabits per second.

The NTT group has been dominant in the fiber-optics field. Other service providers include KDDI Corp. and utilities, including Tokyo Electric Power Co. Their Internet connection services are known as fiber-to-the-home (FTTH) services.

NTT East and NTT West, regional operators of the telecom behemoth, had a combined 1.16 million FTTH users as of the end of August.

Son hopes to capture the market as it did with ADSL. Softbank has about 4.42 million subscribers to its ADSL service. NTT East and West have a combined 4.66 million.

But the new service unveiled Monday does not have the price impact of Softbank's ADSL launch three years ago.

The monthly fee for the Yahoo BB fiber-optic service for individual home use is priced at 7,234 yen, including consumption tax. While direct comparison with rivals is difficult due to varying options, Softbank's prices remain unimpressive.

Son said the company will offer various discounts during promotional campaigns.