This letter discusses an experimental demonstration of 10-Gb/s packet-by-packet burst-mode optical 3R regeneration in an optical-label switching router. A monolithically integrated Mach-Zehnder interferometer with semiconductor optical amplifiers provides the all-optical 2R regeneration. Synchronous modulation with the use of Fabry-Pe/spl acute/rot filter-based clock recovery performs the burst-mode retiming function necessary for 3R regeneration. The clock recovery works successfully despite a clock phase discontinuity between adjacent packets. The optical 3R regenerator shows bit-error rates below 1/spl times/10/sup -10/ and sensitivity variations less than 1.5 dB over a wide range of guard times from 3 to 1000 ns.