Optical switch

About: Optical switch is a research topic. Over the lifetime, 28538 publications have been published within this topic receiving 351176 citations.

Femtosecond laser excitation of the semiconductor‐metal phase transition in VO2

Abstract: We have measured the subpicosecond optical response of a solid‐state, semiconductor‐to‐metal phase transition excited by femtosecond laser pulses. We have determined the dynamic response of the complex refractive index of VO2 thin films by making pump‐probe optical transmission and reflection measurements at 780 nm. The phase transition was found to be largely prompt with the optical properties of the high‐temperature metallic state being attained within 5 ps. The ultrafast change in complex refractive index enables ultrafast optical switching devices in VO2.

Theory of optical signal amplification and processing by quantum-dot semiconductor optical amplifiers

Abstract: This work presents a theory of optical signal amplification and processing by quantum-dot semiconductor optical amplifiers (SOA's) based on the density matrix equations to treat electron-light interaction and the optical pulse propagation equations. The theory includes the linear optical response as well as the incoherent and coherent nonlinear response of the new devices with arbitrary spectral and spatial distribution of quantum dots in the active region under the multimode light. The incoherent nonlinear response was due to the incoherent spectral hole burning and the reduction in the carrier density by the stimulated emission. The coherent nonlinearity was due to the dynamic spectral hole burning caused by the population beating at the electronic states resonant to the multimode light and the carrier density pulsation caused by the carrier relaxation dynamics. Based on the theory, we numerically simulated the operation of quantum-dot SOA's, and succeeded in presenting their diverse promising features in a very systematical manner. We expect amplifiers with low power consumption, high saturation power, broad gain bandwidth, and pattern-effect-free operation under gain saturation, and also signal processing devices to realize high-speed (40 to 160 Gb/s) pattern-effect-free wavelength conversion by the cross-gain modulation with low frequency chirping and symmetric highly-efficient 1 to 2 THz wavelength conversion by the nondegenerate four-wave mixing. We point out that the nonlinear optical response due to the spectral hole burning plays a decisive role in the high-speed optical signal processing. Many of the theoretical predictions in this paper agree well with recent experimental demonstrations of device performance. This work will help not only design practical quantum-dot devices working in the photonic networks but also understand how carrier dynamics relates to the optical response of quantum dots with optical gain under current injection.

Ultracompact and low-power optical switch based on silicon photonic crystals

Abstract: Switching light is one of the most fundamental functions of an optical circuit. As such, optical switches are a major research topic in photonics, and many types of switches have been realized. Most optical switches operate by imposing a phase shift between two sections of the device to direct light from one port to another, or to switch it on and off, the major constraint being that typical refractive index changes are very small. Conventional solutions address this issue by making long devices, thus increasing the footprint, or by using resonant enhancement, thus reducing the bandwidth. We present a slow-light-enhanced optical switch that is 36 times shorter than a conventional device for the same refractive index change and has a switching length of 5.2

Linear and nonlinear optical properties of Ag-As-Se chalcogenide glasses for all-optical switching.

Abstract: We prepared Ag(x)(As0.4Se0.6)(100-x) chalcogenide glasses by a melt-quenching method and measured their linear and nonlinear optical properties to evaluate their potential applications to all-optical ultrafast switching devices. Their nonlinear refraction and absorption were measured by the Z-scan method at 1.05 microm. The addition of Ag to As2Se3 glass led to an increase in the nonlinear refractive index without introducing an increase in the nonlinear absorption coefficient. The glass with a Ag content of x = 20 at. % revealed high nonlinearity ranging from 2000 to 27,000 times that of fused silica, depending on the incident optical intensity.

Error-Free 320-Gb/s All-Optical Wavelength Conversion Using a Single Semiconductor Optical Amplifier

Abstract: We demonstrate error-free wavelength conversion at 320 Gb/s by employing a semiconductor optical amplifier that fully recovers in 56 ps. Error-free operation is achieved without using forward error correction technology. We employ optical filtering to select the blue sideband of the spectrum of the probe light, to utilize fast chirp dynamics introduced by the amplifier, and to overcome the slow gain recovery. This leads to an effective recovery time of less than 1.8 ps for the wavelength converter. The wavelength converter has a simple configuration and is implemented by using fiber-pigtailed components. The concept allows photonic integration