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Optical modulator
About: Optical modulator is a research topic. Over the lifetime, 14068 publications have been published within this topic receiving 196932 citations.
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TL;DR: In this article, a room-temperature nanomechanical transducer that couples efficiently to both radio waves and light allows radio-frequency signals to be detected as an optical phase shift with quantum-limited sensitivity.
Abstract: A room-temperature nanomechanical transducer that couples efficiently to both radio waves and light allows radio-frequency signals to be detected as an optical phase shift with quantum-limited sensitivity Many applications, from medical imaging and radio astronomy to navigation and wireless communication, depend on the faithful transmission and detection of weak radio-frequency microwaves Here Eugene Polzik and co-workers demonstrate a completely new capability in this area — the conversion of weak radio waves into laser signals using a nanomechanical oscillator The oscillator, a membrane made from silicon nitride, can couple simultaneously to radio signals and light reflected off its surface and this feature can be used to measure the radio signals as optical phase shifts, with quantum-limited sensitivity Compared to existing detectors, this approach has the advantage of working at room temperature, and the signals produced can be readily transferred into standard optical fibres Low-loss transmission and sensitive recovery of weak radio-frequency and microwave signals is a ubiquitous challenge, crucial in radio astronomy, medical imaging, navigation, and classical and quantum communication Efficient up-conversion of radio-frequency signals to an optical carrier would enable their transmission through optical fibres instead of through copper wires, drastically reducing losses, and would give access to the set of established quantum optical techniques that are routinely used in quantum-limited signal detection Research in cavity optomechanics1,2 has shown that nanomechanical oscillators can couple strongly to either microwave3,4,5 or optical fields6,7 Here we demonstrate a room-temperature optoelectromechanical transducer with both these functionalities, following a recent proposal8 using a high-quality nanomembrane A voltage bias of less than 10 V is sufficient to induce strong coupling4,6,7 between the voltage fluctuations in a radio-frequency resonance circuit and the membrane’s displacement, which is simultaneously coupled to light reflected off its surface The radio-frequency signals are detected as an optical phase shift with quantum-limited sensitivity The corresponding half-wave voltage is in the microvolt range, orders of magnitude less than that of standard optical modulators The noise of the transducer—beyond the measured Johnson noise of the resonant circuit—consists of the quantum noise of light and thermal fluctuations of the membrane, dominating the noise floor in potential applications in radio astronomy and nuclear magnetic imaging Each of these contributions is inferred to be when balanced by choosing an electromechanical cooperativity of with an optical power of 1 mW The noise temperature of the membrane is divided by the cooperativity For the highest observed cooperativity of , this leads to a projected noise temperature of 40 mK and a sensitivity limit of Our approach to all-optical, ultralow-noise detection of classical electronic signals sets the stage for coherent up-conversion of low-frequency quantum signals to the optical domain8,9,10,11
470 citations
TL;DR: A high-speed silicon optical modulator with a low V(pp) (peak-to-peak driving voltage) and ultralow energy consumption based on a microring resonator, with the refractive index modulation achieved by electric-field-induced carrier depletion in a reverse-biased lateral pn diode embedded in the ring structure.
Abstract: We present a high-speed silicon optical modulator with a low Vpp (peak-to-peak driving voltage) and ultralow energy consumption based on a microring resonator, with the refractive index modulation achieved by electric-field-induced carrier depletion in a reverse-biased lateral pn diode embedded in the ring structure. With a Vpp of 2 V, we demonstrate a silicon modulator with a 3 dB bandwidth of 11 GHz, a modulation depth of 6.5 dB together with an insertion loss of 2 dB, ultralow energy consumption of 50 fJ per bit, and a small device active area of ~1000 µm2.
463 citations
TL;DR: A new, to the knowledge, technique for encoding amplitude information onto a phase-only filter with a single liquid-crystal spatial light modulator, effectively allowing for amplitude modulation of either the first-order or the zero-order diffracted light.
Abstract: We report a new, to our knowledge, technique for encoding amplitude information onto a phase-only filter with a single liquid-crystal spatial light modulator. In our approach we spatially modulate the phase that is encoded onto the filter and, consequently, spatially modify the diffraction efficiency of the filter. Light that is not diffracted into the first order is sent into the zero order, effectively allowing for amplitude modulation of either the first-order or the zero-order diffracted light. This technique has several applications in both optical pattern recognition and image processing, including amplitude modulation and inverse filters. Experimental results are included for the new technique.
452 citations
Book•
02 Feb 2001
TL;DR: In this article, a planar waveguide is proposed for optical fiber communications. But it is not shown how it can be used in the case of a single mode fiber and it cannot be shown how to be used with other fiber types.
Abstract: (NOTE: Each chapter concludes with Questions and Problems.) 1. Wave Nature of Light. Light Waves in a Homogeneous Medium. Refractive Index. Group Velocity and Group Index. Magnetic Field, Irradiance and Poynting Vector. Snell's Law and Total Internal Reflection (TIR). Fresnel's Equations. Multiple Interference and Optical Resonators. Goos-Hanchen and Optical Tunneling. Temporal and Spatial Coherence. Diffraction Principles. 2. Dielectric Waveguides and Optical Fibers. Symmetric Planar Dielectric Slab Waveguide. Modal and Waveguide Dispersion in the Planar Waveguide. Step Index Fiber. Numerical Aperture. Dispersion in Single Mode Fibers. Bit-Rate, Dispersion, Electrical and Optical Bandwidth. The Graded Index Optical Fiber. Light Absorption and Scattering. Attenuation in Optical Fibers. Fiber Manufacture. 3. Semiconductor Science and Light Emitting Diodes. Semiconductor Concepts and Energy Bands. Direct and Indirect Bandgap Semiconductors: E-k Diagrams. pn Junction Principles. The pn Junction Band Diagram. Light Emitting Diodes. LED Materials. Heterojunction High Intensity LEDs. LED Characteristics. LEDs for Optical Fiber Communications. 4. Stimulated Emission Devices Lasers. Stimulated Emission and Photon Amplification. Stimulated Emission Rate and Einstein Coefficients. Optical Fiber Amplifiers. Gas Laser: The He-Ne Laser. The Output Spectrum of a Gas Laser. LASER Oscillation Conditions. Principle of the Laser Diode. Heterostructure Laser Diodes. Elementary Laser Diode Characteristics. Steady State Semiconductor Rate Equation. Light Emitters for Optical Fiber Communications. Single Frequency Solid State Lasers. Quantum Well Devices. Vertical Cavity Surface Emitting Lasers (VCSELs). Optical Laser Amplifiers. Holography. 5. Photodetectors. Principle of the pn Junction Photodiode. Ramo's Theorem and External Photocurrent. Absorption Coefficient and Photodiode Materials. Quantum Efficiency and Responsivity. The pin Photodiode. Avalanche Photodiode. Heterojunction Photodiodes. Phototransistors. Photoconductive Detectors and Photoconductive Gain. Noise in Photodetectors. 6. Photovoltaic Devices. Solar Energy Spectrum. Photovoltaic Device Principles. pn Junction Photovoltaic I-V Characteristics. Series Resistance and Equivalent Circuit. Temperature Effects. Solar Cells Materials, Devices and Efficiencies. 7. Polarization and Modulation of Light. Polarization. Light Propagation in an Anisotropic Medium: Birefringence. Birefringent Optical Devices. Optical Activity and Circular Birefringence. Electro-Optic Effects. Integrated Optical Modulators. Acousto-Optic Modulator. Magneto-Optic Effects. Non-Linear Optics and Second Harmonic Generation. Notation and Abbreviations. Index. CD-ROM: Optoelectronics and Photonics Contents.
440 citations
TL;DR: In this article, a Mach-Zehnder modulator with high-contrast waveguide based on a Silicon and Lithium Niobate hybrid integration platform has been demonstrated for high-speed, energy efficient and cost-effective optical communication networks.
Abstract: Optical modulators are at the heart of optical communication links Ideally, they should feature low insertion loss, low drive voltage, large modulation bandwidth, high linearity, compact footprint and low manufacturing cost Unfortunately, these criteria have only been achieved on separate occasionsBased on a Silicon and Lithium Niobate hybrid integration platform, we demonstrate Mach-Zehnder modulators that simultaneously fulfill these criteria The presented device exhibits an insertion loss of 25 dB, voltage-length product of 22 Vcm, high linearity, electro-optic bandwidth of at least 70 GHz and modulation rates up to 112 Gbit/s The high-performance modulator is realized by seamless integration of high-contrast waveguide based on Lithium Niobate - the most mature modulator material - with compact, low-loss silicon circuits The hybrid platform demonstrated here allows for the combination of 'best-in-breed' active and passive components, opening up new avenues for enabling future high-speed, energy efficient and cost-effective optical communication networks
431 citations