In this report we present all-optical switches and modulators based on the intersubband transition in semiconductor quantum wells. The use of InGaAs/AlAsSb coupled double quantum well structures is proposed to facilitate intersubband transitions in the optical-communication band, and to reduce the intersubband absorption recovery time from several picoseconds to a few hundred femtoseconds by utilizing enhanced electron-phonon scattering. Subpicosecond all-optical gating and modulation in coupled double quantum wells are observed using pump-probe experiments at optical-communication wavelengths. The results indicate that the intersubband transition in this structure is very useful for ultrafast all-optical switching devices.