NEW YORK, May 30 -- Lucent Technologies Inc. is reportedly seeking to acquire Chromatis Networks Inc. of Herndon, Va. Sources say Lucent is offering #&36;5.5-billion in stock for the privately held optical network technology company. Industry analysts say that a deal with Chromatis will keep Lucent in step with industry competitors who have already made large acquisitions of optical networking companies, such as Nortel Networks Corp. and Cisco Systems Inc.   Chromatis creates systems that consolidate data and voice communications from within large corporations or among several smaller businesses -- that information is then transmitted within cities across high-capacity fiber optic networks.