Vladimir A. Aksyuk

Wavelength add-drop switching using tilting micromirrors

This paper describes a single-mode optical fiber switch which routes individual signals into and out of a wavelength multiplexed data stream without interrupting the remaining channels. The switch uses free-space optical wavelength multiplexing and a column of micromechanical tilt-mirrors to switch 16 channels at 200 GHz spacing from 1531 to 1556 nm. The electrostatically actuated tilt mirrors use an 80 V peak-to-peak 300 KHz sinusoidal drive signal to switch between /spl plusmn/10/spl deg/ with a 20 /spl mu/s response. The total fiber-to-fiber insertion loss for the packaged switch is 5 dB for the passed signals and 8 dB for added and dropped signals, with 0.2 dB polarization dependence. Switching contrast was 30 dB or more for all 16 channels and all input and output states. We demonstrate operation by switching 622 Mb/s data on eight wavelength channels between the two input and output ports with negligible eye closure.

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

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 0.81-dB minimum insertion loss in the transmit state and high transmission isolation in the reflection state with 2.15-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.

Giant piezoelectricity on Si for hyperactive MEMS.

High-quality piezoelectric thin films are grown and exhibit superior properties for microelectromechanical systems. Microelectromechanical systems (MEMS) incorporating active piezoelectric layers offer integrated actuation, sensing, and transduction. The broad implementation of such active MEMS has long been constrained by the inability to integrate materials with giant piezoelectric response, such as Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT). We synthesized high-quality PMN-PT epitaxial thin films on vicinal (001) Si wafers with the use of an epitaxial (001) SrTiO3 template layer with superior piezoelectric coefficients (e31,f = –27 ± 3 coulombs per square meter) and figures of merit for piezoelectric energy-harvesting systems. We have incorporated these heterostructures into microcantilevers that are actuated with extremely low drive voltage due to thin-film piezoelectric properties that rival bulk PMN-PT single crystals. These epitaxial heterostructures exhibit very large electromechanical coupling for ultrasound medical imaging, microfluidic control, mechanical sensing, and energy harvesting.

Nonlinear micromechanical Casimir oscillator.

The Casimir force between uncharged metallic surfaces originates from quantum-mechanical zero-point fluctuations of the electromagnetic field. We demonstrate that this quantum electrodynamical effect has a profound influence on the oscillatory behavior of microstructures when surfaces are in close proximity (< or =100 nm). Frequency shifts, hysteretic behavior, and bistability caused by the Casimir force are observed in the frequency response of a periodically driven micromachined torsional oscillator.

Wavelength-selective 1/spl times/K switches using free-space optics and MEMS micromirrors: theory, design, and implementation

The design and performance of several generations of wavelength-selective 1/spl times/K switches are reviewed. These optical subsystems combine the functionality of a demultiplexer, per-wavelength switch, and multiplexer in a single, low-loss unit. Free-space optics is utilized for spatially separating the constituent wavelength division multiplexing (WDM) channels as well as for space-division switching from an input optical fiber to one of K output fibers (1/spl times/K functionality) on a channel-by-channel basis using a microelectromechanical system (MEMS) micromirror array. The switches are designed to provide wide and flat passbands for minimal signal distortion. They can also provide spectral equalization and channel blocking functionality, making them well suited for use in transparent WDM optical mesh networks.

1100 x 1100 port MEMS-based optical crossconnect with 4-dB maximum loss

We present a microelectromechanical systems-based beam steering optical crossconnect switch core with port count exceeding 1100, featuring mean fiber-to-fiber insertion loss of 2.1 dB and maximum insertion loss of 4.0 dB across all possible connections. The challenge of efficient measurement and optimization of all possible connections was met by an automated testing facility. The resulting connections feature optical loss stability of better than 0.2 dB over days, without any feedback control under normal laboratory conditions.

Beam-steering micromirrors for large optical cross-connects

This paper describes Si-micromachined two-axis beam-steering micromirrors and their performance in 256 /spl times/ 256- and 1024 /spl times/ 1024-port large optical cross-connects (OXCs). The high-reflectivity wavelength-independent mirrors are electrostatically actuated; capable of large, continuous, controlled, dc tilt in any direction at moderate actuation voltages; and allow setting times of a few milliseconds. Packaged two-dimensional (2-D) arrays containing independently addressable identical 256 and 1296 mirrors are used to build fully functional bitrate and wavelength-independent single-stage, low-insertion-loss, single-mode fiber OXC fabrics.

Optomechanical transduction of an integrated silicon cantilever probe using a microdisk resonator

Sensitive transduction of the motion of a microscale cantilever is central to many applications in mass, force, magnetic resonance, and displacement sensing. Reducing cantilever size to nanoscale dimensions can improve the bandwidth and sensitivity of techniques like atomic force microscopy, but current optical transduction methods suffer when the cantilever is small compared to the achievable spot size. Here, we demonstrate sensitive optical transduction in a monolithic cavity-optomechanical system in which a subpicogram silicon cantilever with a sharp probe tip is separated from a microdisk optical resonator by a nanoscale gap. High quality factor (Q ≈ 10(5)) microdisk optical modes transduce the cantilevers megahertz frequency thermally driven vibrations with a displacement sensitivity of ≈4.4 × 10(-16) m/(Hz)(1/2) and bandwidth >1 GHz, and a dynamic range >10(6) is estimated for a 1 s measurement. Optically induced stiffening due to the strong optomechanical interaction is observed, and engineering of probe dynamics through cantilever design and electrostatic actuation is illustrated.

1296-port MEMS transparent optical crossconnect with 2.07 petabit/s switch capacity

A 1296-port MEMS transparent optical crossconnect with 5.1dB/spl plusmn/1.1dB insertion loss at 1550 nm is reported. Measured worst-case optical crosstalk in a fabric was n38 dB and nominal switching rise/fall times were 5 ms. A 2.07 petabit/s switch capacity was verified upon cross-connecting a forty-channel by 40 Gb/s DWDM data stream through a prototype fabric.

238 x 238 micromechanical optical cross connect

This letter describes a 238/spl times/238 beam-steering optical cross connect constructed using surface micromachined mirrors. Its innovative optical configuration resulted in superior optical performance, achieving a mean fiber-to-fiber insertion loss of 1.33 dB and a maximum insertion loss for all 56 644 connections of 2 dB.