SAN JOSE, Calif., Sept. 10 -- Optical Networks Inc. has raised an additional $15 million in its third major round of venture investment, increasing its total financing to date to $50 million. The company plans to put the funds toward field trials of its all-optical metro networking solution, Dynamic Transport System, to be conducted in the US and abroad in the fourth quarter of 1999. Optical Networks expects the first revenue shipments of this system to take place in the first quarter of 2000.The leader and newest investor in this most recent round of financing was Fidelity Ventures, the venture capital branch of Fidelity Investments, which provided $7.5 million. Repeat investors included Canaan Partners; Invesco; Chase Capital; Kleiner Perkins Caufield & Byers; Silver Creek Technology Investors; Mohr, Davidow Ventures; and Sumitomo.