Abstract: A communication system includes an optical “LAN” (50) interconnecting a plurality of information sources (16a) and sinks (22a) with a light-to-electrical converter (36a) associated with an electrical RF transmitters (32a) and an RF-to-light converter (38a) to a receiver (34a). The transmitter is coupled by way of electrical-to-light converter (46a), and the receiver is coupled by way of light-to-electrical converter (44a), and by way of a directional coupler (76a), to an end of an optical bus (74a), so that light signals representing signals to be transmitted flow in one direction, and light signals representing received signals flow in the other direction through the bus. A directional coupler (72a) at the other end of the optical bus routes the transmit light signals to a light-to-RF converter (47a) which feeds a sink or antenna (12a), and received signals from a source or antenna are routed by way of an RF-to-light converter (40a) and the directional coupler (72a) onto the optical bus (74a).

Abstract: A method for laser shock peening a surface is disclosed. A laser beam pulse from a laser apparatus is produced. The laser pulse has a cross-section taken perpendicular to the laser beam, a fluence profile across the cross-section. The pulse against an area on said surface. The fluence profile is controlled such that process induced defects are reduced.

Abstract: A communication system includes an optical “LAN” (50) interconnecting a plurality of information sources (16a) and sinks (22a) with a light-to-electrical converter (36a) associated with an electrical RF transmitters (32a) and an RF-to-light converter (38a) to a receiver (34a). The transmitter is coupled by way of electrical-to-light converter (46a), and the receiver is coupled by way of light-to-electrical converter (44a), and by way of a directional coupler (76a), to an end of an optical bus (74a), so that light signals representing signals to be transmitted flow in one direction, and light signals representing received signals flow in the other direction through the bus. A directional coupler (72a) at the other end of the optical bus routes the transmit light signals to a light-to-RF converter (47a) which feeds a sink or antenna (12a), and received signals from a source or antenna are routed by way of an RF-to-light converter (40a) and the directional coupler (72a) onto the optical bus (74a).

Abstract: A method for laser shock peening a surface is disclosed. A laser beam pulse from a laser apparatus is produced. The laser pulse has a cross-section taken perpendicular to the laser beam, a fluence profile across the cross-section. The pulse against an area on said surface. The fluence profile is controlled such that process induced defects are reduced.

Abstract: A target is laser shock peened by directing against an ablative coating thereon a laser beam pulse having a fluence, duration, and corresponding peak power effective for ablating the coating to form a plasma and shock wave therein. The plasma is confined adjacent the target to plastically deform the target by the shock wave to develop residual compressive stress therein. The pulse has a duration less than ten nanoseconds and a corresponding peak power for increasing coupling efficiency between the pulse and plasma.

Abstract: A reflective modulator (10) includes a light splitter (12) which divides light into two portions, one of which is applied to a directional coupler (14) by a first path (20), and the other of which is applied to the directional coupler (14) by way of cascaded electrooptic (e-o) modulators (18a, 18b). One port of the directional coupler (14) is terminated in a reflector (22), and the other in an absorptive termination (24). Electrical signals A and B are applied to the modulators (18a, 18b), with the result of generation of sum and difference frequencies modulating the light. The light leaves the reflective modulator (10) and is coupled to a utilization apparatus (64) by a second directional coupler (28). A further e-o modulator (26) may be coupled in the first path, for controlling the long-term average phase shift. In a particularly advantageous embodiment of the invention, the signal sources (30a, 30b) are elemental antennas of an array (30).

Abstract: A reflective modulator (10) includes a light splitter (12) which divides light into two portions, one of which is applied to a directional coupler (14) by a first path (20), and the other of which is applied to the directional coupler (14) by way of cascaded electrooptic (e-o) modulators (18a, 18b). One port of the directional coupler (14) is terminated in a reflector (22), and the other in an absorptive termination (24). Electrical signals A and B are applied to the modulators (18a, 18b), with the result of generation of sum and difference frequencies modulating the light. The light leaves the reflective modulator (10) and is coupled to a utilization apparatus (64) by a second directional coupler (28). A further e-o modulator (26) may be coupled in the first path, for controlling the long-term average phase shift. In a particularly advantageous embodiment of the invention, the signal sources (30a, 30b) are elemental antennas of an array (30).

Abstract: A method of hygroscopic optical material fabrication comprising the steps of cutting a hygroscopic optical material to generate an optical substrate of appropriate dimensions and polishing the hygroscopic optical material for appropriate surface figure or surface quality. The cutting and polishing of the hygroscopic optical material is completed while the hygroscopic optical material is isolated from aqueous contamination so as to maintain or increase the damage threshold of the hygroscopic optical material.

Abstract: A laser resonator includes a laser medium having opposite end faces inclined at Brewster's angle and disposed in optical alignment between spaced-apart and tilted first and second optical elements. A method for adjusting the optical alignment includes pumping the laser medium to produce a laser beam, and adjusting separation spacing between the two optical elements. Tilt of at least one of the optical elements is adjusted in response to any observed change in beam cross-sectional size. In an additional embodiment, the laser medium is initially positioned at about equal spacings between the first and second elements. Position of the laser medium is then adjusted, at a constant value of the separation spacing, to within a position range selected for a specific value of a ratio of intracavity peak power of circulation of the laser beam and a critical power for self-focusing to effect discrimination of mode-locked operation over continuous wave operation.

Abstract: An oven for heating a crystal for nonlinear frequency conversion of a laser beam. A grasping device resiliently grasps together the first and second sides of the crystal while allowing for generally unrestricted thermal expansion of the crystal. A heater element and a temperature sensor are each supported by the grasping device and are each in thermal contact with the crystal. A temperature controller is connected to the heater element and the temperature sensor.

Abstract: An optical modulator includes pump and signal lasers optically aligned with an optical modulator element having a nonlinear refractive index. In operation, a pulsed optical pump beam is focused inside the modulator element for obtaining oscillatory sagittal and tangential mode radii thereof. A signal beam is propagated through the focus in the modulator element at a crossing angle with the spatially modulated pump beam for phase modulation thereof. Material nonlinearity due to electronic polarization or molecular orientation provides ultrafast rise times with correspondingly high modulation bandwidth.