Abstract: A photonically-sampled electronically-quantized analog-to-digital converter generates an optical signal comprising a series of optical pulses. The optical signal is split into a first and a second optical path. The split optical signal is detected in the first path and then the detected optical signal is converted to a reference digital signal. The split optical signal in the second path is modulated with an input RF signal and a plurality of demultiplexed RF-modulated optically-sampled signals is generated from the modulated optical signal. The plurality of demultiplexed RF-modulated optically-sampled signals is then pulse broadened, detected, and converted to a plurality of sampled-RF digital signals. The reference digital signal and the plurality of sampled-RF digital signals are digital signal processed to generate a digital representation of the input RF signal.

Abstract: A linearized electro-optic modulator includes a substrate comprising a first Mach Zehnder interferometer comprising a first and second optical waveguide and a second Mach Zehnder interferometer comprising a first and a second optical waveguide. A signal electrode is positioned on the substrate to receive a modulation signal. First and second ground electrodes are positioned on the substrate and are electrically connected to ground potential. The signal electrode and the first and second ground electrodes are positioned so that an electric field generated by the signal electrode modulates both the first and second Mach Zehnder interferometers to generate a first and a second linearized modulated optical signal.

Abstract: A photonically-sampled electronically-quantized analog-to-digital converter generates an optical signal comprising a series of optical pulses. The optical signal is split into a first and a second optical path. The split optical signal is detected in the first path and then the detected optical signal is converted to a reference digital signal. The split optical signal in the second path is modulated with an input RF signal and a plurality of demultiplexed RF-modulated optically-sampled signals is generated from the modulated optical signal. The plurality of demultiplexed RF-modulated optically-sampled signals is then pulse broadened, detected, and converted to a plurality of sampled-RF digital signals. The reference digital signal and the plurality of sampled-RF digital signals are digital signal processed to generate a digital representation of the input RF signal.

Abstract: A photonically-sampled electronically-quantized analog-to-digital converter generates an optical signal comprising a series of optical pulses. The optical signal is split into a first and a second optical path. The split optical signal is detected in the first path and then the detected optical signal is converted to a reference digital signal. The split optical signal in the second path is modulated with an input RF signal and a plurality of demultiplexed RF-modulated optically-sampled signals is generated from the modulated optical signal. The plurality of demultiplexed RF-modulated optically-sampled signals is then pulse broadened, detected, and converted to a plurality of sampled-RF digital signals. The reference digital signal and the plurality of sampled-RF digital signals are digital signal processed to generate a digital representation of the input RF signal.

Abstract: A photonically-sampled electronically-quantized analog-to-digital converter generates an optical signal comprising a series of optical pulses. The optical signal is split into a first and a second optical path. The split optical signal is detected in the first path and then the detected optical signal is converted to a reference digital signal. The split optical signal in the second path is modulated with an input RF signal and a plurality of demultiplexed RF-modulated optically-sampled signals is generated from the modulated optical signal. The plurality of demultiplexed RF-modulated optically-sampled signals is then pulse broadened, detected, and converted to a plurality of sampled-RF digital signals. The reference digital signal and the plurality of sampled-RF digital signals are digital signal processed to generate a digital representation of the input RF signal.

Abstract: A linearized electro-optic modulator includes a substrate comprising a first Mach Zehnder interferometer comprising a first and second optical waveguide and a second Mach Zehnder interferometer comprising a first and a second optical waveguide. A signal electrode is positioned on the substrate to receive a modulation signal. First and second ground electrodes are positioned on the substrate and are electrically connected to ground potential. The signal electrode and the first and second ground electrodes are positioned so that an electric field generated by the signal electrode modulates both the first and second Mach Zehnder interferometers to generate a first and a second linearized modulated optical signal.

Abstract: An electro-optic push-pull modulator requiring reduced high switching voltages through combinations of device structure and operation, causing linear and quadratic electro-optic effects to add. Such combinations of device structure and operation include combinations of crystal axis orientation, waveguide structure, electrode structure, electric field biasing, operating wavelengths, and optical polarizations. By inducing linear and quadratic electro-optic effects to add, significant refractive index changes can be realized with lower switching voltages, V&pgr;. Furthermore, significant reduction in switching voltage for push-pull modulators can also be realized through combinations of device structure and operation effectively inducing solely the quadratic electro-optic effect.

Abstract: An optical modulator configured in accordance with the present invention utilizes a ridged optical waveguide substrate. The interferometric arms of the optical waveguide are formed within the substrate ridges. A dielectric material having a dielectric constant less than the dielectric constant of the substrate material is formed on the substrate in the areas surrounding the ridges. The drive signal and ground electrodes are formed above the dielectric layer and positioned such that portions of the electrodes are located adjacent to the substrate ridges (and, consequently, proximate to the waveguide arms). In one embodiment, the height of the dielectric layer is less than the height of the ridges. In another embodiment, the height of the dielectric layer is equal to the height of the ridges.

Abstract: A loaded-line optical modulator includes an optical waveguide having first and second interferometric arms, a drive signal electrode, and a plurality of loading capacitors connected to the drive signal electrode. The loading capacitors are asymmetrically configured such that the amount of modulation in the first interferometric arm differs from the amount of modulation in the second interferometric arm. The asymmetric nature of the loading capacitors generates a nonzero chirp in the modulated optical signal. Various dual-drive techniques for a loaded-line optical modulator having a plurality of drive electrodes are also disclosed.

Abstract: An electro-optic push-pull modulator requiring reduced high switching voltages through combinations of device structure and operation, causing linear and quadratic electro-optic effects to add. Such combinations of device structure and operation include combinations of crystal axis orientation, waveguide structure, electrode structure, electric field biasing, operating wavelengths, and optical polarizations. By inducing linear and quadratic electro-optic effects to add, significant refractive index changes can be realized with lower switching voltages, V&pgr;. Furthermore, significant reduction in switching voltage for push-pull modulators can also be realized through combinations of device structure and operation effectively inducing solely the quadratic electro-optic effect.

Abstract: This is an electro-optic modulator having an electro-optic substrate such as lithium niobate, an optical waveguide defined within the substrate, an electrode structure including a microwave transmission line elevated from the substrate by conductive legs. In one embodiment, a low-dielectric constant buffer layer is disposed between the substrate and the transmission line. The conductive legs extend from the transmission line to a surface of the substrate toward the waveguide, through the buffer layer. The microwave transmission line is elevated from the substrate at a distance such that the electrical propagation velocity is at a maximum. The high electrical velocity is offset by a loading capacitance introduced by the conductive legs which slows the electrical velocity down on the transmission line to match the optical velocity. Pairs of opposing conductive legs provide a strong electric field for modulating the optical signal.

Abstract: An optical link exhibiting net gain without the use of optical or electronic amplifiers. The link includes a high-power laser, a high-sensitivity external modulator for intensity modulating the laser output, an optical fiber, and photodiode detector. The electrical input port of the external modulator is impedance-matched to the output port of an electrical signal source using a transformer double-tuned circuit. The link exhibits electrical transfer efficiency (i.e., gain) proportional to the square of the optical bias power and modulator sensitivity, and much lower insertion loss than prior art links. The link can be advantageously used wherever low-insertion loss, high bandwidth, and low distortion transmission of electrical signals is required over distances up to ten kilometers.