Multiple Quantum Well (MQW) materials and devices have been designed and demonstrated to have large optical nonlinearities which are suitable for use in ultrafast optical TDMA interconnects at 1.3 μm. The MQW materials consist of GaAlInAs wells and AlInAs barriers grown lattice-matched to a semi-insulating InP substrate by molecular beam epitaxy. The MQW samples exhibited large absorption changes at 1.3 μm due to bandfilling and exchange effects. The carrier saturation densities near the heavy-hole exciton peak were similar to those for GaAs/AlGaAs MQWs. The large optical nonlinearities near 1.3 μm were used to demonstrate an all-optical, high-contrast asymmetric reflection modulator suitable for performing all-optical time-division demultiplexing at low pump intensities. The modulator consists of an asymmetric Fabry-Perot etalon which utilizes a nonlinear MQW spacer. The modulator exhibited an on/off contrast ratio of greater than 1000:1 and an insertion loss of 2.2 dB at a pump intensity of 30 kW/cm2. The recovery of the modulator is shown to decay with a time-constant of 725 ps.