Abstract:
A waveguide assembly for a use with, for example, a microwave receiver. The waveguide assembly includes: a waveguide; a tapered structure disposed within the waveguide, the tapered structure tapering in thickness from a first end with a zero height to a second end where the tapered structure has a height which nearly fills, but does not completely fill, the waveguide, to thereby define a modulator receiving space between the tapered structure and an adjacent wall of said waveguide. The second end of the tapered structure is preferably disposed adjacent an open circuited end of the waveguide. An electro-optic modulator is disposed on a dielectric substrate, the dielectric substrate being disposed at least partially within the modulator receiving space and the electro-optic modulator being disposed so that it is located, in use, at an antinode of a standing wave of the waveguide assembly.
Abstract:
A waveguide of radio frequency electromagnetic fields is multi-furcated into a plurality of radio frequency waveguide sections, each radio frequency waveguide section having an optoelectronic modulator electrically coupled to it. Each optoelectronic modulator has an optical waveguide disposed therein such that, in use, light traveling in the optical waveguides of the optoelectronic modulators travels in a direction orthogonal with respect to the direction the radio frequency electromagnetic field travels in the radio frequency waveguide sections. The plurality of radio frequency waveguide sections are fed from a common source of said radio frequency energy. In some embodiments, each radio frequency waveguide section has a dielectric material having a length and/or a dielectric constant selected such that a relative time delay of the radio frequency energy propagating in the radio frequency waveguide sections accommodates for a time delay of the light traveling from one optoelectronic modulator to a next optoelectronic modulator of a series connection of multiple optoelectronic modulators.
Abstract:
The invention is a Demodulator for an Optical Analog Pulse Position Modulated signal suitable for inclusion in receivers for Free Space Optical communication systems. In one embodiment the Demodulator may use the pulse position modulated optical information signal and the clock signal with different wavelengths. By proper biasing of a Semiconductor Optical Amplifier and selection of wavelengths for the information signal and the clock signal, the performance of the Demodulator is made insensitive to noise in the received signals.
Abstract:
A PPM transmitter includes an optical clock generator for generating equally-spaced optical pulses with a sampling period T; an encoder for transforming an incoming waveform U(t) into a linear combination V(t) of U(t) and a delayed output V(t−kT) according to a rule V(t)=U(t)+aV(t−kT), where k is a positive integer, V(t) is voltage generated by the encoder and a is a coefficient; and an optical delay generator for delaying optical pulses generated by the optical clock generator in proportion to the voltage V(t), such that Δtn=bV(t), where b is another coefficient and where Δtn is the amount of delay imposed by the optical delay generator. The PPM transmitter functions with a PPM receiver for communicating data without the need to transmit or otherwise provide a clock signal. The PPM receiver decodes an original series of the delayed optical pulses Q(t) and a second series Q(t−ckT) delayed by ckT where c is a coefficient.
Abstract:
The present invention is a programmable and latching retro-reflective construct suitable for use as an optical label in an optical labeling system. The invention contains retro-reflective structures such as lens beads, corner cubes or other retro-reflecting type structures. The retro-reflective construct further comprises a wavelength selective, programmable and latching reflecting structure located at the reflecting surfaces of the retro-reflective structures. The optical construct can optionally contain additional optical filtering structures. Methods for fabricating the invention are also described.
Abstract:
This invention provides a versatile unit cell as well as programmable and reconfigurable optical signal processors (such as optical-domain RF filters) that are constructed from arrays of those unit cells interconnected by optical waveguides. Each unit cell comprises an optical microdisk, an optical phase shifter, and at least one input/output optical waveguide, wherein the microdisk and the phase shifter are both optically connected to a common waveguide.
Abstract:
In one of the embodiments, a dark channel array is provided which includes gain channels, each configured to emit an output beam from an output surface and to have a light wave propagating therethrough. It further includes a dark channel configured to emit an output beam from the output surface of the dark channel array and to have a light wave propagating in the dark channel, such that output beams from the plurality of gain channels are coherently coupled in phase with each other. The dark channel array is configured such that the dark channel captures a portion of the output beam from at least two of the plurality of gain channels by radiant coupling.
Abstract:
A method and apparatus for modulating an RF signal. The RF signal is supplied to a grating modulator having a grating, and light of at least a first wavelength is supplied as a first optical carrier to the grating modulator. The first carrier light is modulated by the grating modulator, wherein the first wavelength of the first carrier coincides with a null in the third derivative of a transmittance spectrum of the grating. Optionally, light of at an additional, second wavelength as a second optical carrier, is supplied to the grating modulator which modulates the second carrier light. The second wavelength of the second carrier coincides with another null, but different than the first mentioned null, in the third derivative of a transmittance spectrum of the grating.
Abstract:
The present invention relates to a laser transmitter capable of being configured to transmit one of a plurality of wavelengths. Specifically, the laser transmitter may be reconfigured using the resonance passbands of a tunable microresonator coupled with a fixed grating.
Abstract:
In one embodiment, a dark channel array is provided which includes gain channels, each gain channel being configured to emit an output beam, and which includes a dark channel configured to cause output beams from the gain channels to be coherently couple in phase with each other.