A thin, large, high-definition television screen employs optical waveguides. Light (32) flows through waveguides (28) arranged, in parallel, across a substrate (64). Light from a source (44) is coupled into the waveguides using a Graded Index (GRIN) microlens array (56). Taps (37) direct light out and make it visible at different locations along the length of the waveguides. Long interaction length (8) taps with deflectors (10) are introduced which enable many waveguides to be placed side-by-side and still maintain high screen resolutions. Polymers, both electro-optic and non-electro-optic, are used in one embodiment as a waveguide building material. However, acousto-optic, thermo-optic (86) and magneto-optic effects may also be used with other materials such as glass and silicon dioxide. This display can be economically produced by forming a flexible waveguide ribbon (62) which integrates multiple waveguides (1), intensity modulators (40) and taps (38) into a single unit. Waveguide manufacturing techniques based on thermo-poling, photolocking, extruding, preform fiber-drawing, and laser milling are also discussed.

Optical waveguide display system

Methods and systems for providing multimedia telecommunication services to multimedia workstations communicating with a multimedia central office which includes a digital switch complex coupled to a public digital telephone network, and at least one twisted pair transceiver coupled to at least one twisted pair link in a telephone loop plant. The multimedia central office further includes at least one switch complex operatively associated with the digital switch complex and the at least one twisted pair transceiver. The multimedia central office is capable of transceiving signals with multimedia workstations interfaced to the public digital telephone network, and with multimedia workstations interfaced to the at least one twisted pair link in the telephone loop plant. The signals which are transceived include audio signals, video signals, and digital data signals used in providing the multimedia telecommunication services.

Methods and systems for multimedia communications via public telephone networks

A power converter nearly losslessly delivers energy and recovers energy from capacitors associated with controlled rectifiers in a secondary winding circuit, each controlled rectifier having a parallel uncontrolled rectifier. First and second primary switches in series with first and second primary windings, respectively, are turned on for a fixed duty cycle, each for approximately one half of the switching cycle. Switched transition times are short relative to the on-state and off-state times of the controlled rectifiers. The control inputs to the controlled rectifiers are cross-coupled from opposite secondary transformer windings.

High efficiency power converter

The present invention provides high power linear amplification of an amplitude and/or phase modulated signal using multiple saturated (or if desired, unsaturated) amplifiers (4) driven by an appropriate set of switched (5), and/or phase modulated (6) constant amplitude signals derived from the input signal. The present invention combines three amplitude reconstruction techniques and implements the amplitude reconstruction modulator (11) digitally.

Amplification using amplitude reconstruction of amplitude and/or angle modulated carrier

A logic signal isolator comprising a transformer having a primary winding and a secondary winding; a transmitter circuit which drives said primary winding in response to a received logic signal, such that in response to a first type of edge in the logic signal, a signal of a first predetermined type is supplied to the primary winding and in response to a second type of edge in the logic signal, a signal of a second predetermined type is supplied to said primary winding, the primary winding and the transmitter being referenced to a first ground; and the secondary winding being referenced to a second ground which is galvanically isolated from the first ground and said secondary winding supplying to a receiver circuit signals received in correspondence to the signals provided to the primary winding, the receiver reconstructing the received logic signal from the received signals.

Signal isolators using micro-transformers

A self-oscillating power converter utilizes a MOSFET power transistor switch with its output electrode coupled to a tuned network that operatively limits the voltage waveform across the power switch to periodic unipolar pulses. The transistor switch may be operated at a high radio frequency so that its drain to gate interelectrode capacitance is sufficient to comprise the sole oscillatory sustaining feedback path of the converter. A reactive network which is inductive at the operating frequency couples the gate to source electrodes of the transistor switch and includes a variable capacitance as a means of adjusting the overall reactance, and hence the converter's switching frequency in order to provide voltage regulation. A resonant rectifier includes a tuned circuit to shape the voltage waveform across the rectifying diodes as a time inverse of the power switch waveform.

Self-oscillating high frequency power converter

Arc-cosine phase modulation is achieved by transforming the baseband signal with a tanh -1 transformation function, by modulating a carrier signal with a quadrature sum of two exponential signals related to the inverse hyperbolic tangent signal, and by hard limiting and filtering the modulated signal.

Arc-cosine phase modulators

Disclosed is a ground isolating circuit adapted for construction on a single integrated circuit surface. The circuit comprises a microwave oscillator responsive to an applied data signal, a planar transformer for coupling the microwave signals generated by the oscillator, and a detector for rectifying the coupled, ground isolated microwave signal.

Integrated solid state isolator circuit

The hysteresis effect produced by a saturable absorber disposed within a resonant cavity is utilized in a bistable optical circuit. Use in an optical memory and optical data-processing system is contemplated.

Bistable optical circuit using saturable absorber within a resonant cavity

Modulation distortion due to phase modulation error in an interferometer type modulator is minimized by extracting a portion of the phase modulated carrier frequency signals in the two branches of the interferometer and sensing the resulting amplitude modulation in an auxiliary interferometer circuit. The modulation signal is compared with the input modulation signal and a weighted error signal is formed. The latter is then used to impress an error correcting phase modulation on the carrier frequency signals.

Harold Seidel

Papers

Self-oscillating high frequency power converter

Arc-cosine phase modulators

Integrated solid state isolator circuit

Bistable optical circuit using saturable absorber within a resonant cavity

Feedforward error correction in interferometer modulators