We present a novel optical amplitude regenerator based on blue-chirp spectral slicing using a semiconductor optical amplifier (SOA). The combination of blue-chirp spectral slicing and gain competition in the SOA has a unique input/output (I/O) power-transfer function, which is controlled by the power of an input data signal injected into the SOA. The I/O power-transfer function provides selective amplitude-level regeneration of either the mark or space level of the input data signal. In this paper, we experimentally investigate the transfer function and the regeneration effect using a quantum-dot semiconductor optical amplifier. The results show that the regenerator has unique regeneration effect, specialized for either the mark or space level of a 10-Gbit/s on-off keying signal.