QUEBEC CITY, Aug. 24 -- EXFO Electro-Optical Engineering Inc. has agreed to purchase Avantas Networks Corp. in a cash and share deal valued at $93 million, extending its portfolio of testing devices for fiber optic networks.
   EXFO said it will pay $36 million in cash plus approximately 4.4 million of its shares to buy the Montreal-based start-up company of 100 employees. The total value of the deal includes $28 million of Avantas' cash on hand, for a net price of $65 million, EXFO said. The deal is backed by both boards and is expected to close by the end of the first quarter of fiscal 2002.