Thin layers of AlAs and GaAs, grown by molecular beam epitaxy (MBE), are used to simulate the properties of Al x Ga 1-x As. These AlAs-GaAs superlattices (SL's) are used as cladding layers (instead of Al x Ga 1-x As) in heterostructure lasers capable of room-temperature operation. It is thus possible to obtain laser diodes which are composed only of the binary compounds GaAs and AlAs. The all-binary lasers are compared to conventional Al x Ga 1-x As-GaAs double-heterostructure (DH) lasers grown and fabricated under similar conditions.