This book presents the concepts, technologies and design techniques for devices and systems based... more This book presents the concepts, technologies and design techniques for devices and systems based on the electro-optic effect in lithium niobate. The objective of the book is to bridge from the theory of photonics and electro-optics, which is nicely covered in several textbooks, to the practice of EO device design and application, for which one typically has to refer to the technical literature. While formalism is used where appropriate, the emphasis is on practical analysis using modern modeling tools.
The book is divided into three major sections: materials, devices, and applications. The first section explains the fundamental physics that gives rise to the electro-optic effect, classes of electro-optic materials, electro-optic properties of lithium niobate, and the physics and uses of ferroelectric domain inversion. The differences among the available types of lithium niobate crystals (congruent vs. stoichiometric, magnesium-doped) are discussed, and the production of thin films by crystal ion slicing is introduced.
Part 2 explains the principles of operation, performance measures and design considerations for the most common types of electro-optic devices: beam deflectors, intensity and phase modulators, including quasi-phased matched devices. A chapter on the potential and challenges of photonic crystal fabrication in lithium niobate is also included.
Part 3 deals with the most important applications of lithium niobate electro-optic devices in microwave photonics, sensing, signal processing, and data transmission. The final chapter introduces the burgeoning area of optical and quantum frequency conversion using periodically poled lithium niobate.
An integrated electro-optic electric field sensor probe for measurement of near-surface electric ... more An integrated electro-optic electric field sensor probe for measurement of near-surface electric fields from 20 mV/m to 30 kV/m, and from low audio to VHF frequencies was demonstrated. The sensor has a single-fiber geometry to enable measurements with high spatial resolution in the near field. One dimensional electric field profile measurements were performed with millimeter spatial resolution. The dynamic range of the sensor system exceeded 100 dB in a 1 Hz bandwidth, with a minimum detectable field of 20 mV/m/root-Hz at 100 MHz, and a 1 dB compression field greater than 30 kV/m.
... James E. Toney Penn State University Electro-Optics Center 222 Northpointe Blvd, Freeport, PA... more ... James E. Toney Penn State University Electro-Optics Center 222 Northpointe Blvd, Freeport, PA 16229, jtoney@eoc.psu.edu ... parallel to the z-axis is shown in Figure 4. Whether the line is taken along the center of the crystal (blue), near the edge of the anode (green) or closer to ...
Optical Sensors and Sensing Congress (ES, FTS, HISE, Sensors), 2019
The response of Mach Zehnder Interferometer (MZI) electric field sensors is strongly dependent on... more The response of Mach Zehnder Interferometer (MZI) electric field sensors is strongly dependent on the operating point. Techniques to compensate for sensor drift include correcting the measurement based on received optical power or harmonic analysis.
Designers of electro-optic modulators and related devices often use separate tools to study the o... more Designers of electro-optic modulators and related devices often use separate tools to study the optical and electrical portions of the device. The flexibility of Comsol Multiphysics makes it possible to construct unified models of EO phenomena including realistic waveguide profiles and anisotropic material properties. We demonstrate the use of the RF Module to compute both RF and optical waveguide modes and calculate the velocity mismatch and overlap efficiency between them. Realistic index profiles for diffused waveguides are computed using the Transport of Diluted Species physics mode with anisotropic diffusion coefficients.
While Comsol Multiphysics has great flexibility for modeling photonic devices, the computational ... more While Comsol Multiphysics has great flexibility for modeling photonic devices, the computational demands of the general finite element method make it most suitable for small devices, on the order of a few microns in extent. Many integrated optical devices are much larger, having lengths of hundreds of microns or millimeters. A beam propagation method (BPM), which applies some simplifying assumptions that enable the use of a coarser grid or mesh, is commonly used to simulate larger devices. In this paper we present an implementation of a BPM-like method in Comsol Multiphysics and demonstrate its application to several common photonic devices.
Optical frequency conversion based on nonlinear optical interactions in periodically poled lithiu... more Optical frequency conversion based on nonlinear optical interactions in periodically poled lithium niobate (PPLN) is finding widespread application in the burgeoning field of quantum information processing. Second harmonic generation in PPLN can be used to convert between the 700 800 nm wavelength band where single-photon emitters and detectors are most effective and the 1550 nm band for minimum transmission loss over optical fiber. Spontaneous parametric down-conversion (SPDC) in PPLN can be used to generate polarization-entangled photon pairs for quantum key distribution and other applications. Design of PPLN waveguide-based devices for quantum frequency conversion (QFC) requires highly accurate calculation of the waveguide dispersion relation in order to determine the proper poling period, Λ, from the relation (for SHG): Λ= 1/(n_2/λ_2 -(2n_1)/λ_1 ) Where λ_1 and λ_2 are the fundamental and harmonic wavelengths and n_1 and n_2 are the corresponding effective mode indices. In contr...
All-dielectric optical fiber coupled photonic probes offer many key benefits for electric field s... more All-dielectric optical fiber coupled photonic probes offer many key benefits for electric field sensing. Benefits include ultra-high bandwidth from near DC to 100's of GHz, high spatial resolution on order of millimeters, and minimal perturbation of the measured field. Active remote biasing of such photonic probes is critical to maintain sensitivity and dynamic range performance over practical environmental test conditions. The challenge is in implementing active bias control without the use of field perturbing electric wires. In this paper, a commercially available power over fiber (PoF) component has been successfully used to control the bias of a lithium niobate Mach Zehnder interferometer (MZI) electric field sensor. Bias compensation over the entire Vpi characteristic of the sensor was demonstrated, completely mitigating any bias drift effects. Keywords–photonic electric field sensor; bias control; power over fiber; Mach Zehnder Interferometer; lithium niobate
—An integrated electro-optic electric field sensor probe for measurement of near-surface electric... more —An integrated electro-optic electric field sensor probe for measurement of near-surface electric fields from 20 mV/m to 30 kV/m, and from low audio to VHF frequencies was demonstrated. The sensor has a single-fiber geometry to enable measurements with high spatial resolution in the near field. One dimensional electric field profile measurements were performed with millimeter spatial resolution. The dynamic range of the sensor system exceeded 100 dB in a 1 Hz bandwidth, with a minimum detectable field of 20 mV/m/root-Hz at 100 MHz, and a 1 dB compression field greater than 30 kV/m.
ABSTRACT An electro-optic, solid-state electric field sensor system for noncontact detection of e... more ABSTRACT An electro-optic, solid-state electric field sensor system for noncontact detection of energized objects at power frequency (60 Hz) was investigated. In laboratory testing, the sensor system was found to have a minimum detectable field amplitude of 4 ${rm mV}/{rm m}/{rm Hz}^{1/2}$, which was further reduced by a factor of 2 through vector averaging over 20 cycles. In an experimental setup emulating the realistic scenario of an energized conducting structure (such as a street light or metal fence post), the detection of a 1-m object energized at 1 VAC at a distance of 2 m was demonstrated.
Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications VI, 2013
ABSTRACT This paper reports on the development of thin film lithium niobate (TFLN™) electro-optic... more ABSTRACT This paper reports on the development of thin film lithium niobate (TFLN™) electro-optic devices at SRICO. TFLN™ is formed on various substrates using a layer transfer process called crystal ion slicing. In the ion slicing process, light ions such as helium and hydrogen are implanted at a depth in a bulk seed wafer as determined by the implant energy. After wafer bonding to a suitable handle substrate, the implanted seed wafer is separated (sliced) at the implant depth using a wet etching or thermal splitting step. After annealing and polishing of the slice surface, the transferred film is bulk quality, retaining all the favorable properties of the bulk seed crystal. Ion slicing technology opens up a vast design space to produce lithium niobate electro-optic devices that were not possible using bulk substrates or physically deposited films. For broadband electro-optic modulation, TFLN™ is formed on RF friendly substrates to achieve impedance matched operation at up to 100 GHz or more. For narrowband RF filtering functions, a quasi-phase matched modulator is presented that incorporates domain engineering to implement periodic inversion of electro-optic phase. The thinness of the ferroelectric films makes it possible to in situ program the domains, and thus the filter response, using only few tens of applied volts. A planar poled prism optical beam steering device is also presented that is suitable for optically switched true time delay architectures. Commercial applications of the TFLN™ device technologies include high bandwidth fiber optic links, cellular antenna remoting, photonic microwave signal processing, optical switching and phased arrayed radar.
This book presents the concepts, technologies and design techniques for devices and systems based... more This book presents the concepts, technologies and design techniques for devices and systems based on the electro-optic effect in lithium niobate. The objective of the book is to bridge from the theory of photonics and electro-optics, which is nicely covered in several textbooks, to the practice of EO device design and application, for which one typically has to refer to the technical literature. While formalism is used where appropriate, the emphasis is on practical analysis using modern modeling tools.
The book is divided into three major sections: materials, devices, and applications. The first section explains the fundamental physics that gives rise to the electro-optic effect, classes of electro-optic materials, electro-optic properties of lithium niobate, and the physics and uses of ferroelectric domain inversion. The differences among the available types of lithium niobate crystals (congruent vs. stoichiometric, magnesium-doped) are discussed, and the production of thin films by crystal ion slicing is introduced.
Part 2 explains the principles of operation, performance measures and design considerations for the most common types of electro-optic devices: beam deflectors, intensity and phase modulators, including quasi-phased matched devices. A chapter on the potential and challenges of photonic crystal fabrication in lithium niobate is also included.
Part 3 deals with the most important applications of lithium niobate electro-optic devices in microwave photonics, sensing, signal processing, and data transmission. The final chapter introduces the burgeoning area of optical and quantum frequency conversion using periodically poled lithium niobate.
An integrated electro-optic electric field sensor probe for measurement of near-surface electric ... more An integrated electro-optic electric field sensor probe for measurement of near-surface electric fields from 20 mV/m to 30 kV/m, and from low audio to VHF frequencies was demonstrated. The sensor has a single-fiber geometry to enable measurements with high spatial resolution in the near field. One dimensional electric field profile measurements were performed with millimeter spatial resolution. The dynamic range of the sensor system exceeded 100 dB in a 1 Hz bandwidth, with a minimum detectable field of 20 mV/m/root-Hz at 100 MHz, and a 1 dB compression field greater than 30 kV/m.
... James E. Toney Penn State University Electro-Optics Center 222 Northpointe Blvd, Freeport, PA... more ... James E. Toney Penn State University Electro-Optics Center 222 Northpointe Blvd, Freeport, PA 16229, jtoney@eoc.psu.edu ... parallel to the z-axis is shown in Figure 4. Whether the line is taken along the center of the crystal (blue), near the edge of the anode (green) or closer to ...
Optical Sensors and Sensing Congress (ES, FTS, HISE, Sensors), 2019
The response of Mach Zehnder Interferometer (MZI) electric field sensors is strongly dependent on... more The response of Mach Zehnder Interferometer (MZI) electric field sensors is strongly dependent on the operating point. Techniques to compensate for sensor drift include correcting the measurement based on received optical power or harmonic analysis.
Designers of electro-optic modulators and related devices often use separate tools to study the o... more Designers of electro-optic modulators and related devices often use separate tools to study the optical and electrical portions of the device. The flexibility of Comsol Multiphysics makes it possible to construct unified models of EO phenomena including realistic waveguide profiles and anisotropic material properties. We demonstrate the use of the RF Module to compute both RF and optical waveguide modes and calculate the velocity mismatch and overlap efficiency between them. Realistic index profiles for diffused waveguides are computed using the Transport of Diluted Species physics mode with anisotropic diffusion coefficients.
While Comsol Multiphysics has great flexibility for modeling photonic devices, the computational ... more While Comsol Multiphysics has great flexibility for modeling photonic devices, the computational demands of the general finite element method make it most suitable for small devices, on the order of a few microns in extent. Many integrated optical devices are much larger, having lengths of hundreds of microns or millimeters. A beam propagation method (BPM), which applies some simplifying assumptions that enable the use of a coarser grid or mesh, is commonly used to simulate larger devices. In this paper we present an implementation of a BPM-like method in Comsol Multiphysics and demonstrate its application to several common photonic devices.
Optical frequency conversion based on nonlinear optical interactions in periodically poled lithiu... more Optical frequency conversion based on nonlinear optical interactions in periodically poled lithium niobate (PPLN) is finding widespread application in the burgeoning field of quantum information processing. Second harmonic generation in PPLN can be used to convert between the 700 800 nm wavelength band where single-photon emitters and detectors are most effective and the 1550 nm band for minimum transmission loss over optical fiber. Spontaneous parametric down-conversion (SPDC) in PPLN can be used to generate polarization-entangled photon pairs for quantum key distribution and other applications. Design of PPLN waveguide-based devices for quantum frequency conversion (QFC) requires highly accurate calculation of the waveguide dispersion relation in order to determine the proper poling period, Λ, from the relation (for SHG): Λ= 1/(n_2/λ_2 -(2n_1)/λ_1 ) Where λ_1 and λ_2 are the fundamental and harmonic wavelengths and n_1 and n_2 are the corresponding effective mode indices. In contr...
All-dielectric optical fiber coupled photonic probes offer many key benefits for electric field s... more All-dielectric optical fiber coupled photonic probes offer many key benefits for electric field sensing. Benefits include ultra-high bandwidth from near DC to 100's of GHz, high spatial resolution on order of millimeters, and minimal perturbation of the measured field. Active remote biasing of such photonic probes is critical to maintain sensitivity and dynamic range performance over practical environmental test conditions. The challenge is in implementing active bias control without the use of field perturbing electric wires. In this paper, a commercially available power over fiber (PoF) component has been successfully used to control the bias of a lithium niobate Mach Zehnder interferometer (MZI) electric field sensor. Bias compensation over the entire Vpi characteristic of the sensor was demonstrated, completely mitigating any bias drift effects. Keywords–photonic electric field sensor; bias control; power over fiber; Mach Zehnder Interferometer; lithium niobate
—An integrated electro-optic electric field sensor probe for measurement of near-surface electric... more —An integrated electro-optic electric field sensor probe for measurement of near-surface electric fields from 20 mV/m to 30 kV/m, and from low audio to VHF frequencies was demonstrated. The sensor has a single-fiber geometry to enable measurements with high spatial resolution in the near field. One dimensional electric field profile measurements were performed with millimeter spatial resolution. The dynamic range of the sensor system exceeded 100 dB in a 1 Hz bandwidth, with a minimum detectable field of 20 mV/m/root-Hz at 100 MHz, and a 1 dB compression field greater than 30 kV/m.
ABSTRACT An electro-optic, solid-state electric field sensor system for noncontact detection of e... more ABSTRACT An electro-optic, solid-state electric field sensor system for noncontact detection of energized objects at power frequency (60 Hz) was investigated. In laboratory testing, the sensor system was found to have a minimum detectable field amplitude of 4 ${rm mV}/{rm m}/{rm Hz}^{1/2}$, which was further reduced by a factor of 2 through vector averaging over 20 cycles. In an experimental setup emulating the realistic scenario of an energized conducting structure (such as a street light or metal fence post), the detection of a 1-m object energized at 1 VAC at a distance of 2 m was demonstrated.
Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications VI, 2013
ABSTRACT This paper reports on the development of thin film lithium niobate (TFLN™) electro-optic... more ABSTRACT This paper reports on the development of thin film lithium niobate (TFLN™) electro-optic devices at SRICO. TFLN™ is formed on various substrates using a layer transfer process called crystal ion slicing. In the ion slicing process, light ions such as helium and hydrogen are implanted at a depth in a bulk seed wafer as determined by the implant energy. After wafer bonding to a suitable handle substrate, the implanted seed wafer is separated (sliced) at the implant depth using a wet etching or thermal splitting step. After annealing and polishing of the slice surface, the transferred film is bulk quality, retaining all the favorable properties of the bulk seed crystal. Ion slicing technology opens up a vast design space to produce lithium niobate electro-optic devices that were not possible using bulk substrates or physically deposited films. For broadband electro-optic modulation, TFLN™ is formed on RF friendly substrates to achieve impedance matched operation at up to 100 GHz or more. For narrowband RF filtering functions, a quasi-phase matched modulator is presented that incorporates domain engineering to implement periodic inversion of electro-optic phase. The thinness of the ferroelectric films makes it possible to in situ program the domains, and thus the filter response, using only few tens of applied volts. A planar poled prism optical beam steering device is also presented that is suitable for optically switched true time delay architectures. Commercial applications of the TFLN™ device technologies include high bandwidth fiber optic links, cellular antenna remoting, photonic microwave signal processing, optical switching and phased arrayed radar.
2008 IEEE Avionics, Fiber-Optics and Photonics Technology Conference, 2008
ABSTRACT This work compares the performance of two manual fiber cleavers, which are specifically ... more ABSTRACT This work compares the performance of two manual fiber cleavers, which are specifically intended to solve the problem of field cleaving fibers in the presence of durable coatings such as polyimide.
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Books
The book is divided into three major sections: materials, devices, and applications. The first section explains the fundamental physics that gives rise to the electro-optic effect, classes of electro-optic materials, electro-optic properties of lithium niobate, and the physics and uses of ferroelectric domain inversion. The differences among the available types of lithium niobate crystals (congruent vs. stoichiometric, magnesium-doped) are discussed, and the production of thin films by crystal ion slicing is introduced.
Part 2 explains the principles of operation, performance measures and design considerations for the most common types of electro-optic devices: beam deflectors, intensity and phase modulators, including quasi-phased matched devices. A chapter on the potential and challenges of photonic crystal fabrication in lithium niobate is also included.
Part 3 deals with the most important applications of lithium niobate electro-optic devices in microwave photonics, sensing, signal processing, and data transmission. The final chapter introduces the burgeoning area of optical and quantum frequency conversion using periodically poled lithium niobate.
Papers
The book is divided into three major sections: materials, devices, and applications. The first section explains the fundamental physics that gives rise to the electro-optic effect, classes of electro-optic materials, electro-optic properties of lithium niobate, and the physics and uses of ferroelectric domain inversion. The differences among the available types of lithium niobate crystals (congruent vs. stoichiometric, magnesium-doped) are discussed, and the production of thin films by crystal ion slicing is introduced.
Part 2 explains the principles of operation, performance measures and design considerations for the most common types of electro-optic devices: beam deflectors, intensity and phase modulators, including quasi-phased matched devices. A chapter on the potential and challenges of photonic crystal fabrication in lithium niobate is also included.
Part 3 deals with the most important applications of lithium niobate electro-optic devices in microwave photonics, sensing, signal processing, and data transmission. The final chapter introduces the burgeoning area of optical and quantum frequency conversion using periodically poled lithium niobate.