Sierra Monolithics Inc. had a chip market all to itself at 40 Gbit/s, but the company is going to have to deal with more competition as the 100 Gbit/s generation comes along. The privately held company is trying to get a headstart, at least, having announced its SerDes chips yesterday. And that's why CoreOptics Inc. -- an optical subsystems vendor -- came out last June with its own 40 Gbit/s SerDes.