The maker of optical switches, scheduled to enter testing soon, received investments from the likes of Williams Communications and the venture capital unit of Tyco International. The cash infusion brings Tenor's total financing to more than $120 million since November of 1998.
Tenor is among a cavalcade of start-ups scrambling to build optical-based equipment for service providers looking to upgrade existing networks or build new schemes based on speedy fiber optics.
Tenor makes a switching device for fiber-optic networks that lets a communications service provider develop and connect a new service more efficiently to a customer, such as a high-speed private connection for a business.
Other new investors include Amerindo Investment Advisors, BancBoston Ventures, Charter Growth Capital and Morgan Stanley Dean Witter, among others.
Amber Networks, a start-up maker of optical routing devices, closed $90 million in third-round funding last month.