Attenuator (electronics)

About: Attenuator (electronics) is a research topic. Over the lifetime, 9227 publications have been published within this topic receiving 53175 citations.

Adjustable optical attenuator

Abstract: An optical attenuator for attenuating a collimated beam of light propagating along an optical path while preserving the composition of polarization of the collimated beam of light is disclosed. The optical attenuator comprises a beam attenuator for attenuating a portion of the collimated beam of light when a portion of the beam attenuator is disposed within the optical path. The beam attenuator has a cross section along a plane perpendicular to the direction of propagation of the collimated beam of light of the portion of the attenuator in the shape of a wedge. The attenuation is varied using a controller for moving the beam attenuator in order to vary a size of the portion of the wedge within the optical path.

A silicon MEMS optical switch attenuator and its use in lightwave subsystems

Abstract: A single-mode fiber connectorized microelectromechanical systems (MEMS) reflective optical switch attenuator operating in the 1550-nm wavelength region is described The device consists of an electrostatically actuated gold-coated silicon vane interposed in a fiber gap yielding 081-dB minimum insertion loss in the transmit state and high transmission isolation in the reflection state with 215-dB minimum return loss The switch attenuators also work as continuously variable optical attenuators capable of greater than 50-dB dynamic range and can be accurately regulated with a simple feedback control circuit Switching voltages were in the range of 5-40 V and a switching time of 64 /spl mu/s was achieved The MEMS switch can be used in optical subsystems within a wavelength-division-multiplexed (WDM) optical network such as optical power regulators, crossconnects, and add/drop multiplexers We used a discrete array of 16 switch attenuators to implement a reconfigurable 16-channel 100-GHz spacing WDM drop module of an add/drop multiplexer Thru-channel extinction was greater than 40 dB and average insertion loss was 21 dB Both drop-and-transmit of multiple channels (11-18-dB contrast, 14-19-dB insertion loss) and drop-and-detect of single channels (>20-dB adjacent channel rejection, 10-14-dB insertion loss) were demonstrated

Relative Intensity Measurements in Microwave Spectroscopy

Abstract: A method is described for the measurement of peak intensity ratios of gas phase microwave absorption lines. Large errors associated with multiple reflections in the waveguide have been eliminated by careful design and the use of ferrite isolators. Detector nonlinearities have been neutralized by using a precisely calibrated step attenuator allowing both lines involved in a ratio to be displayed with approximately the same amplitude. Means of minimizing additional sources of error are discussed. Application of the method to a number of problems indicates that ratios accurate to a few percent can be obtained.

Electromagnetic field quantization in absorbing dielectrics

Abstract: The electromagnetic field is quantized for normal transmission of incident waves through a parallel-sided dielectric slab. The dielectric material is dispersive and it acts as a linear amplifier over limited ranges of the frequency and as a linear attenuator at the remaining frequencies. The field operators derived for the three spatial regions within and on either side of the slab are shown to satisfy the canonical commutation relations. The noise fluxes emitted by the slab are evaluated and shown to satisfy the general requirements for the minimum noise associated with linear amplifiers and attenuators. The behavior of the amplifier gain profile on the approach to the lasing threshold of the slab is determined, but the results are restricted to the below-threshold state of the system. The spectra of the electric-field fluctuations are evaluated for the three spatial regions and for amplifying and attenuating frequencies.

Single-Mode Fiber Refractive Index Sensor Based on Core-Offset Attenuators

Abstract: Mach-Zehnder and Michelson interferometers using core-offset attenuators were demonstrated. As the relative offset direction of the two attenuators in the Mach-Zehnder interferometer can significantly affect the extinction ratio of the interference pattern, single core-offset attenuator-based sensors appear more robust and repeatable. A novel fiber Michelson interferometer refractive index (RI) sensor was subsequently realized by a single core-offset attenuator and a layer of ~ 500-nm gold coating. The device had a minimum insertion loss of 0.01 dB and maximum extinction ratio over 9 dB. The sensitivity (0.333 nm) of the new sensor to its surrounding RI change (0.01) was found to be comparable to that (0.252 nm) of an identical long period gratings pair Mach-Zehnder interferometric sensor, and its ease of fabrication makes it a low-cost alternative to existing sensing applications.