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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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Patent
16 Mar 1994
TL;DR: In this paper, an optical short pulse generating device is presented, in which semiconductor laser light of a fixed intensity is launched into a first semiconductor electroabsorption optical modulator which is driven by a 0V or forward bias voltage and a sinusoidal voltage.
Abstract: An optical short pulse generating device is disclosed, in which semiconductor laser light of a fixed intensity is launched into a first semiconductor electroabsorption optical modulator which is driven by a 0V or forward bias voltage and a sinusoidal voltage, and the output light from the first optical modulator is launched into a second electroabsorption optical modulator to which is applied a bias voltage and a sinusoidal voltage having delayed from the said sinusoidal voltage for a period of time corresponding to the phase reversal thereof, whereby it is possible to generate optical short pulses of a repetition frequency twice higher than the oscillation frequency of a sinusoidal voltage generator.

65 citations

Patent
Yuichi Akiyama1
17 May 2006
TL;DR: An optical DQPSK modulator comprises a pair of phase modulators, each of which is provided with first and second driving signals as mentioned in this paper, and the driving signals are amplified by first-and second amplifiers, respectively.
Abstract: An optical DQPSK modulator comprises a pair of phase modulators. Each of the pair of the phase modulators is provided with first and second driving signals. The first and second driving signals are amplified by first and second amplifiers, respectively. An RZ intensity modulator generates an optical RZ-DQPSK signal from an optical DQPSK signal output from the optical DQPSK modulator. A photodetector generates a monitor signal from the optical RZ-DQPSK signal. A gain adjuster unit adjusts the gains of the first and second amplifiers so as to minimize the power of the monitor signal.

65 citations

Journal ArticleDOI
TL;DR: The first depletion-mode carrier-plasma optical modulator fabricated in a standard advanced complementary metal-oxide-semiconductor (CMOS) logic process (45 nm node SOI CMOS) with no process modifications is demonstrated.
Abstract: We demonstrate the first (to the best of our knowledge) depletion-mode carrier-plasma optical modulator fabricated in a standard advanced complementary metal–oxide-semiconductor (CMOS) logic process (45 nm node SOI CMOS) with no process modifications. The zero-change CMOS photonics approach enables this device to be monolithically integrated into state-of-the-art microprocessors and advanced electronics. Because these processes support lateral p-n junctions but not efficient ridge waveguides, we accommodate these constraints with a new type of resonant modulator. It is based on a hybrid microring/disk cavity formed entirely in the sub-90 nm thick monocrystalline silicon transistor body layer. Electrical contact of both polarities is made along the inner radius of the multimode ring cavity via an array of silicon spokes. The spokes connect to p and n regions formed using transistor well implants, which form radially extending lateral junctions that provide index modulation. We show 5 Gbps data modulation at 1265 nm wavelength with 5.2 dB extinction ratio and an estimated 40 fJ/bit energy consumption. Broad thermal tuning is demonstrated across 3.2 THz (18 nm) with an efficiency of 291 GHz/mW. A single postprocessing step to remove the silicon handle wafer was necessary to support low-loss optical confinement in the device layer. This modulator is an important step toward monolithically integrated CMOS photonic interconnects.

65 citations

Journal ArticleDOI
TL;DR: This work reports on complete wave-front control with amplitude- and phase-modulation liquid-crystal devices (LCD's) and discusses LCD performance requirements for high-quality reconstruction.
Abstract: We report on complete wave-front control with amplitude- and phase-modulation liquid-crystal devices (LCD’s) A twisted nematic device is used for amplitude modulation, and an electrically controlled birefringent device is used for phase modulation Because the LCD’s are optically coupled with afocal optics and are driven by individual LCD driver circuits, the amplitude and the phase can be controlled two dimensionally and independently Complex amplitude data are calculated, and on-axis computer-generated holograms are directly recorded Furthermore, we discuss LCD performance requirements for high-quality reconstruction

65 citations

Journal ArticleDOI
TL;DR: Terahertz detectors based on antenna-coupled graphene field-effect transistors exploit the nonlinear response to the oscillating radiation field at the gate electrode, with contributions of thermoelectric and photoconductive origin are demonstrated.
Abstract: The unique optoelectronic properties of graphene [1] make it an ideal platform for a variety of photonic applications [2], including fast photodetectors [3], transparent electrodes [4], optical modulators [5], and ultra-fast lasers [6]. Owing to its high carrier mobility, gapless spectrum, and frequency-independent absorption coefficient, it has been recognized as a very promising element for the development of detectors and modulators operating in the Terahertz (THz) region of the electromagnetic spectrum (wavelengths in the hundreds of micrometers range), which is still severely lacking in terms of solid-state devices. Here we demonstrate efficient THz detectors based on antenna-coupled graphene field-effect transistors (FETs). These exploit the non-linear FET response to the oscillating radiation field at the gate electrode, with contributions of thermoelectric and photoconductive origin. We demonstrate room temperature (RT) operation at 0.3 THz, with noise equivalent power (NEP) levels < 30 nW/Hz^(1/2), showing that our devices are well beyond a proof-of-concept phase and can already be used in a realistic setting, enabling large area, fast imaging of macroscopic samples.

65 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202342
2022154
2021166
2020289
2019311
2018325