Coherent Inc. of Santa Clara, Calif., has formed a joint venture with Fiber Optics Network Solutions Corp. of Northboro, Mass., to develop a high-power broadband transmission product line for cost-effective cable TV and high-speed Internet access. The move marks Coherent's first foray into the telecommunications market. The venture, CFX Communications Systems, plans to launch products that can provide analog and digital transmissions supporting hybrid fiber coax networks and fiber-to-the-home systems. During the past 21/2 years, Fiber Optics Network Solutions has invested in prototyping a linearized broadband transmission product line.