Probability Distributions.- Linear Models for Regression.- Linear Models for Classification.- Neural Networks.- Kernel Methods.- Sparse Kernel Machines.- Graphical Models.- Mixture Models and EM.- Approximate Inference.- Sampling Methods.- Continuous Latent Variables.- Sequential Data.- Combining Models.

Pattern Recognition and Machine Learning

Electro-optic modulators translate high-speed electronic signals into the optical domain and are critical components in modern telecommunication networks1,2 and microwave-photonic systems3,4. They are also expected to be building blocks for emerging applications such as quantum photonics5,6 and non-reciprocal optics7,8. All of these applications require chip-scale electro-optic modulators that operate at voltages compatible with complementary metal–oxide–semiconductor (CMOS) technology, have ultra-high electro-optic bandwidths and feature very low optical losses. Integrated modulator platforms based on materials such as silicon, indium phosphide or polymers have not yet been able to meet these requirements simultaneously because of the intrinsic limitations of the materials used. On the other hand, lithium niobate electro-optic modulators, the workhorse of the optoelectronic industry for decades9, have been challenging to integrate on-chip because of difficulties in microstructuring lithium niobate. The current generation of lithium niobate modulators are bulky, expensive, limited in bandwidth and require high drive voltages, and thus are unable to reach the full potential of the material. Here we overcome these limitations and demonstrate monolithically integrated lithium niobate electro-optic modulators that feature a CMOS-compatible drive voltage, support data rates up to 210 gigabits per second and show an on-chip optical loss of less than 0.5 decibels. We achieve this by engineering the microwave and photonic circuits to achieve high electro-optical efficiencies, ultra-low optical losses and group-velocity matching simultaneously. Our scalable modulator devices could provide cost-effective, low-power and ultra-high-speed solutions for next-generation optical communication networks and microwave photonic systems. Furthermore, our approach could lead to large-scale ultra-low-loss photonic circuits that are reconfigurable on a picosecond timescale, enabling a wide range of quantum and classical applications5,10,11 including feed-forward photonic quantum computation. Chip-scale lithium niobate electro-optic modulators that rapidly convert electrical to optical signals and use CMOS-compatible voltages could prove useful in optical communication networks, microwave photonic systems and photonic computation.

Integrated lithium niobate electro-optic modulators operating at CMOS-compatible voltages

CRYSTALLINE MATERIALS Introduction Physical Properties Optical Properties Mechanical Properties Thermal Properties Magnetooptic Properties Electrooptic Properties Elastooptic Properties Nonlinear Optical Properties GLASSES Introduction Commercial Optical Glasses Specialty Optical Glasses Fused Silica Fluoride Glasses Chalcogenide Glasses Magnetooptic Properties Electrooptic Properties Elastooptic Properties Nonlinear Optical Properties Special Glasses POLYMERIC MATERIALS Optical Plastics Index of Refraction Nonlinear Optical Properties Thermal Properties Engineering Data METALS Physical Properties of Selected Metals Optical Properties Mechanical Properties Thermal Properties Mirror Substrate Materials LIQUIDS Introduction Water Physical Properties of Selected Liquids Index of Refraction Nonlinear Optical Properties Magnetooptic Properties Commercial Optical Liquids GASES Introduction Physical Properties of Selected Gases Index of Refraction Nonlinear Optical Properties Magnetooptic Properties Atomic Resonance Filters APPENDICES Safe Handling of Optical Materials Abbreviations, Acronyms, and Mineralogical or Common Names for Optical Materials Abbreviations for Methods of Preparing Optical Materials and Thin Films Fundamental Physical Constants Units and Conversion Factors

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Handbook of Optical Materials

Dark optical solitons: physics and applications

The absolute scale of the second-order nonlinear-optical coefficients of several important nonlinear-optical materials has been obtained with improved accuracy. Second-harmonic generation, parametric fluorescence, and difference-frequency generation measurements have been made at several wavelengths in the near-infrared region. The second-harmonic generation measurement was performed at the fundamental wavelengths of 1.548, 1.533, 1.313, 1.064, and 0.852 µm. The materials measured included congruent LiNbO3,1%MgO:LiNbO3,5%MgO:LiNbO3,LiTaO3,KNbO3,KTiOPO4,KH2PO4, quartz, GaAs, GaP, α-ZnS, CdS, ZnSe, and CdTe. We made the parametric fluorescence measurement to determine the nonlinear-optical coefficients of congruent LiNbO3 and 5%MgO:LiNbO3 at pump wavelengths of 0.532 and 0.488 µm. We made the difference-frequency generation measurement for congruent LiNbO3 at a pump wavelength of 0.532 µm. The second-harmonic generation, parametric fluorescence, and difference-frequency generation measurements yielded consistent data on the nonlinear-optical coefficients of the materials. We found that many of the currently accepted standard values are overestimated because of neglect of the multiple-reflection effect in (nearly) plane-parallel-plate samples. The dispersion of the nonlinear-optical coefficients showed that Miller’s Δ is barely constant over the wavelength range measured and thus that Miller’s rule is not so good as other methods for wavelength scaling of the nonlinear-optical coefficients.

Absolute scale of second-order nonlinear-optical coefficients

Photonic systems are being deployed today using advances in fiber communications and the convergence of optical-wireless. This talk explores extending this convergence to our military's communications & sensor systems through the development of photonic-based coherent frequency converting technologies operating throughout the RF and millimeter wave spectrum.

The convergence of microwave photonic and optical wireless systems with military communication and sensor systems

A communications device includes a transmitter device having an optical source to generate an optical carrier signal, and a first modulator coupled to the optical source and to modulate the optical carrier signal with a radio frequency (RF) input signal, and an optical waveguide coupled to the transmitter device. The communications device includes a receiver device coupled to the optical waveguide and including a second modulator to further modulate the modulated optical carrier signal with a local oscillator (LO) signal, a frequency modulation-phase modulation (FM-PM) discriminator coupled to the second modulator and to convert the modulated optical carrier signal to an intensity modulated optical carrier signal based upon the LO signal, and an optical-to-electrical converter coupled to the FM-PM discriminator and to generate an intermediate frequency (IF) signal based upon the intensity modulated optical carrier signal.

Communications device with discriminator for generating intermediate frequency signal and related methods

A phase modulated (PM) microwave photonic link (MPL) with linearity improvement is presented. The link demodulates the PM using a phase discriminator based on a dynamically tunable, integrated, sixth-order optical lattice filter in planar lightwave circuit (PLC) technology. The linearity of the demodulation process is optimized by using electrical spectrum monitoring and a feedback algorithm to automatically choose the filter coefficients. For a 2 GHz modulation frequency, the link achieves a 6.7 dB improvement in the third-order output intercept point (OIP3) for intermodulation distortion (IMD) over a Mach-Zehnder interferometer (MZI).

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Dynamic linearity improvement of phase and frequency modulated microwave photonic links using optical lattice filter discriminators

A tunable Radio Frequency (RF) filter device includes a tunable optical source generating an optical carrier signal, and a modulator coupled to the tunable optical source and modulating the optical carrier signal with an RF input signal The tunable RF filter device may include first and second optical waveguide paths coupled to the modulator and having first and second dispersion slopes of opposite sign from each other, one or more of the first and second optical waveguide paths comprising an optical splitter and combiner pair therein, and an optical-to-electrical converter coupled to the first and second optical waveguide paths and generating an RF output signal with a frequency notch therein based upon the tunable optical source

Tunable RF filter device using optical waveguide paths with splitter and combiner pairs and related methods

A phased antenna array includes a plurality of electro-optic (EO) circuits. Each EO circuit has a digital-to-analog converter (DAC) configured to receive a baseband signal, and an optical source comprising an opto-electronic oscillator configured to generate an optical signal. Each EO circuit also has an EO modulator coupled downstream of the DAC and to the optical source and configured to modulate an optical carrier signal based upon the baseband signal and the optical signal, and an optical combiner coupled downstream of the EO modulator and coupled to the optical source. In addition, there are a plurality of antenna circuits spaced apart from the plurality of EO circuits, each antenna circuit comprising at least one photodiode and an antenna element coupled thereto. Moreover, a plurality of optical fibers couple the plurality of EO circuits to the plurality of antenna circuits.

Phased antenna array including a plurality of electro-optical circuits having an optical source with an opto-electronic oscillator and associated methods

Richard DeSalvo

Papers

The convergence of microwave photonic and optical wireless systems with military communication and sensor systems

Communications device with discriminator for generating intermediate frequency signal and related methods

Dynamic linearity improvement of phase and frequency modulated microwave photonic links using optical lattice filter discriminators

Tunable RF filter device using optical waveguide paths with splitter and combiner pairs and related methods

Phased antenna array including a plurality of electro-optical circuits having an optical source with an opto-electronic oscillator and associated methods