An external guided wave optical modulator which provides the combination of high bandwidth, low insertion loss, and linearity is being developed. Researchers are designing, fabricating, and testing a novel multiple quantum well electroabsorption modulator. It operates at an optical wavelength of 1300 nm, at microwave frequencies in excess of 40 GHz, with an insertion loss of less than 3dB, a signal-to-noise ratio of at least 40dB, a composite triple beat dynarnic range of at least 55dB, and a two-tone spurious free dynamic range of at least 80dB. The multiple quantum well layer consists of indium gallium arsenide phosphide wells with indium phosphide barriers. The modulator design is small, lightweight, and rugged.Commercial Applications:Commercial applications include telecommunications and cable television transmitters and repeater, phased array antenna fiber optic links, satellite microwave dish remoting, and high bit rate local area networks and wide area networks.