Abstract: There is provided a super luminescent light emitting device comprising a semiconductor body including a central region and two opposing end regions extending a predetermined distance from the end faces. A gain guiding linear strip of material adjacent to a side of the active region extends between the end faces and is inclined along its longitudinal axis at a predetermined angle relative to a direction normal to at least one of the end faces. An optical beam path of the device has an optical axis of symmetry extending between the end faces parallel to the longitudinal axis of the strip. The beam path has end lateral boundaries at each of the end regions whose lateral carrier and optical confinement is determined by the gain guiding strip to allow light reflected at the end faces to be refracted out of the optical beam path.

Abstract: A low coherence light-emitting device comprises a semiconductor body with a pair of end faces, The device contains an optical beam path which has an axis of symmetry extending between the end faces. At least one of the end faces is inclined at an angle which is nonperpendicular to the optical axis and the tangent of this angle is greater than or equal to the width of the beam path divided by the length of the body between the end faces. The device may be made by forming at least one of the end faces such that the end face is inclined at an angle relative to a plane perpendicular to the optical axis. The tangent of the angle is greater than or equal to the width of the optical path divided by the length of the body between the end faces.

Abstract: A low coherence light emitting device comprises a semiconductor body with pair of opposed end faces. The device contains a current confining structure which forms an effective optical beam path between the end faces. The current confining structure is inclined at an angle relative to the direction perpendicular to at least one of the end faces. The tangent of this angle is greater than or equal to the effective optical beam path divided by the length of the body between the end faces. The structure thereby forms a device in which off-axis reflection is obtained at at least one of the device's end faces.

Abstract: An optical coupling system comprises a radiation emitting device and a radiation receiver. The radiation emitting device has an emitting end face and emits radiation having an optical axis of symmetry which is inclined at an output angle relative to the direction perpendicular to the emitting end face. The radiation receiver has a receiving axis and a receiving end face which is inclined at a wedge angle relative to a plane perpendicular to the receiving axis and the receiving end face is positioned adjacent the emitting device. The receiving end face may be first inclined at the wedge angle such that the optical axis of incident radiation is inclined at an angle relative to the normal of the receiving end face. The receiver is then positioned such that the receiving axis is inclined at a receiving angle relative to the normal of the receiving end face such that the radiation propagates about in the direction of the receiving axis.

Abstract: An optical system comprises a low coherence light-emitting device and a mirror. The mirror is positioned adjacent an end face of the device such that light emitted from the end face may be redirected back into the device. Radiation having low coherence, which is emitted from an opposing end face, is amplified greatly due to the radiation which reenters the device.

Abstract: A cutterhead assembly suitable for forming a topographic signal representative pattern in a recording media, such as a disc substrate, is constructed having a base member, a piezoelectric element and a cutting stylus. The piezoelectric element in this structure is asymmetrically assembled to the base member to reduce phase modulation of the recorded signal which would otherwise occur from the transverse motion of the stylus during the cutting operation.

Abstract: Piezoelectric video disc recording cutterheads have small and intricate geometries that make it difficult to compute or measure their mechanical characteristics, especially during the recording process. A monitoring circuit, for use during recording, for monitoring and measuring the mechanical characteristics of a recording cutterhead takes the form of a bridge network. The motional charge or motional current, which are related to the mechanical characteristics of the cutterhead, is measured by means of the bridge network. One branch of the bridge is arranged to include the piezoelectric cutterhead, the other branch comprises a variable capacitor which is adjusted to compensate for the shunt capacitance of the equivalent electrical circuit of the cutterhead. When the variable capacitance is properly adjusted the combination of the currents through the bridge network provides a signal representative of the displacement characteristics of the cutterhead.

Abstract: A system for measuring shoe length of a stylus adapted to track a path along a surface of a video disc comprises positioning the tip of the stylus adjacent the surface of a substrate having a signal therein for effecting capacitive variations between the stylus and the substrate, and measuring the capacitive variations between the stylus and the substrate while they are oriented in a first position to obtain a first signal. The stylus is then tilted an angle of .theta. degrees relative to the substrate, whereby the stylus and substrate are oriented in a second position relative to each other. The capacitive variations are measured while the stylus and substrate are oriented in the second position to obtain a second signal. The first signal is then compared with the second signal to obtain a difference signal proportional to the shoe length of the stylus.

Abstract: The fabrication of ultrasonic-wave lenses and prisms using low-surface tension (poor adhesion) polyalkene sheet (such as polyethylene) as an impedance-matching quarter-wave anti-reflective layer is made possible by the use of certain very low surface-tension cements.

Abstract: Disclosed is a random phase diffuser which is inserted between a transducer and an insonification subject in accoustical imaging. The diffuser is comprised of an array of lossless elements which cause sound emitted by the transducer to be passed through and emitted with a phase value of 0.degree. or 180.degree.. Additionally disclosed is the combination of a random phase diffuser with a wedge coupling feature for increasing insonification efficiency.