ALLENTOWN, Pa., Aug. 10 -- Agere Systems Inc. said that former parent Lucent Technologies Inc. has agreed to buy almost $3 billion worth of its products over the next three years. The company said in documents filed with the US Securities and Exchange Commission that Lucent will buy at least $800 million of Agere products from Feb. 1, 2001 through Jan. 31, 2002, and at least $1 billion in each of the two years after that. The agreement allows Lucent to carry over portions of the yearly purchase commitments during the first two years, according to the filing.