Abstract: An electroabsorptive modulator (EAM) for providing RF modulation of optical inputs signals. The EAM is formed as a semiconductor waveguide on a semiconductor substrate with an optical input port and an optical output port and electrical contacts for connection to the RF input. The configuration of the waveguide portion of the EAM is optimized to provide a modal match with the particular optical device to which the EAM is to be connected, for example, an optical fiber. By optimizing the modal match between the EAM and the optical device to which the EAM is connected, the optical insertion losses are minimized thereby improving the overall performance of the optical system. The device is formed from a plurality of quantum wells selected to compensate for the increased mode field dimensions.

Abstract: A semiconductor laser is formed with an array of a small number (two to ten) antiguide elements each containing a portion of the active region of the semiconductor laser. Interelement structures between the antiguide elements are formed to have a relatively high interelement loss coefficient (at least 100 cm.sup.-1), providing excellent discrimination between the resonant in-phase mode and the unwanted nonresonant modes. Lateral reflectors may be utilized at the edge of the array to reflect light back to the array, but are not necessary when the antiguide elements are sufficiently wide and the effective index step between the antiguide elements and interelement structures is sufficiently large. Because only a relatively small number (10 or less) of antiguide elements are utilized, fabrication tolerances are relatively large and practical devices may be produced with satisfactory yields.

Abstract: A high-power semiconductor laser diode that employs a lateral antiresonant reflecting optical waveguide for generating a single-mode laser beam having an aperture spot size on the order of 4 to 8 microns. The lateral antiresonant reflecting optical waveguide is a negative-index waveguide or antiguide that operates in an antiresonance condition for the fundamental lateral mode, but not for the higher-order lateral modes. Consequently, the fundamental lateral mode is reflected by the lateral waveguide while the higher-order lateral modes are allowed to leak out. This provides strong discrimination between the fundamental lateral mode and the higher-order lateral modes in order to generate a single-mode laser beam having a large aperture spot size. The lateral waveguide also provides good lateral mode stability due to the large negative step in the waveguide index of refraction.