STURBRIDGE, Mass., July 19 -- SpecTran Corp. announced that it is being bought by Lucent Technologies for about $99 million. SpecTran, a manufacturer of optical fiber, employs approximately 400 at its Sturbridge plant, and another 120 at its plant in Avon, Conn. Lucent is expected to pay about $64 million for SpecTran stock, at $9 per share, and to assume $35 million in SpecTran debts.Charles B. Harrison, SpecTran's president and CEO, says the company regards this sale as a positive move. Despite growing sales at SpecTran over the last several quarters, Harrison said, the company's heavy debt load has prevented necessary capital investments. SpecTran's board decided that Lucent, one of 34 possible candidates for the buyout, represented the best alternative for the company's shareholders, employees and communities, Harrison continued. The transaction, which is scheduled to commence Wednesday, should be completed by September 30.