Edward R. Lyons

Demonstration of trapping, motion control, sensing and fluorescence detection of polystyrene beads in a multi-fiber optical trap

We demonstrate a multi-functional optical trap capable of trapping, motion control, position sensing and fluorescence detection of chemically treated polystyrene beads, using off-the-shelve optical components. It consists of two collinearly aligned single-mode fibers separated by a spacing of 130-170mum for trapping, another single-mode fiber for probing/pumping and a fourth multi-mode fiber for optical detection. The fibers are mounted either on V-grooved Si or PDMS platforms fabricated using microfabrication and molding techniques, respectively. The result represents an important milestone towards a functional integrated trapping platform.

Highly efficient acoustooptic tunable filter based on cladding etched single-mode fiber

The efficiency enhancement of an acoustooptic tunable filter on cladding etched single-mode fiber (SMF) is investigated experimentally. When the fiber diameter is etched down to 30 /spl mu/m, the acoustooptic coupling efficiency from the LP/sub 01/ core mode to the LP/sub 11/ cladding mode was increased by an order of magnitude, and the RF power consumption was reduced by two orders of magnitude. A highly efficient 8-cm-long 25-/spl mu/m-thick AOTF on cladding etched SMF with an insertion loss of <0.2 dB, and RF power as low as 1.1 mW was demonstrated.

An efficient all-fiber variable optical attenuator via acoustooptic mode coupling

A novel broad-band variable optical attenuator is realized using acoustooptic mode coupling on a cladding etched single-mode fiber. Broad-band coupling bandwidth with low attenuation ripples is achieved by matching both the group index and dispersion parameter between the core and the LP/sub 11//sup cl/ cladding modes. A single-section device exhibits a 10-dB dynamic range with attenuation ripples of <0.5 dB over a spectral range of >100 nm, a response time of 20 /spl mu/s, an insertion loss of 0.3 dB, and a maximum power consumption of only 3.4 mW. Attenuation of 22 dB is obtained for a cascaded two-section device.

Dynamically reconfigurable all-optical correlators to support ultra-fast internet routing

To implement an effective optical bypass for an electronic router, the key design decision is to combine a software algorithm with a small set of dynamically configurable fiber-Bragg-grating based optical correlators. A conceptual diagram showing how the optical bypass is implemented in an IP router is shown.

Fiber-optic-based optical trapping and detection for lab-on-a-chip (LOC) applications

A three-fiber optical trapping/detection system has been molded in poly(dimethyl siloxane) (PDMS) using anisotropically etched Si V-grooves as the primary or master mold. The process of reverse molding in PDMS maintains the benefits of fiber optic self-alignment previously used in Si V-grooves. Two, pigtailed laser diodes emitting at 830 nm and 980 nm are connected to cleaved, single-mode (SM), counter-propagating fibers, used for trapping polystyrene beads. Orthogonal to the trapping fibers is a multi mode detection fiber coupled to a spectrometer. Chemically treated beads trapped by the 830 and 980 nm diode lasers were excited using a 660 nm diode laser. By utilizing the optical clarity of PDMS, the fourth excitation source fiber is mounted below the PDMS trap and used to excite the trapped beads. Changes in the relative intensity of the trapping light are used to indicate the capture and position of a bead in the trap. Additionally, detection of the excitation source and bead fluorescence is monitored.

A loss tunable long-period fiber gratings on corrugated silicon with on-chip microheater and temperature sensor

In summary, we report a strain induced long period grating (LPG) created by bonding an etched single mode fibre (SMF) onto a corrugated Si fixture with on-chip heater and temperature sensor. The loss of the LPG can be tuned electrically through the microheater current and monitored simultaneously. The use of Si fixture lends itself to easy integration of microheater and other cascaded filter structure. The results may be useful for dynamic spectral shaping in DWDM networks.

Optical trapping, excitation, and detection of polystyrene beads in a fiber-based silicon V-groove system

A four-fiber optical trapping/detection system build on silicon, utilizing the natural alignment of anisotropically etched Si V-grooves for positioning of the optical fibers, has been demonstrated. Two, pigtailed laser diodes emitting at 830 nm are connected to cleaved, single-mode, counter- propagating fibers, which are used for trapping polystyrene beads. Orthogonal to the trapping fibers are two additional fibers: one fiber is connected to a laser diode emitting at 660 nm (excitation source) and the opposing detection fiber is connected to a spectrometer. Changes in the relative intensity of the trapping light and the excitation light are used to indicate the capture and position of a bead in the trap. The spectrometer may be interfaced with a computer allowing for complete automation for position, size and fluorescence detection of the trap with an eventual goal of integration with MEMS (Micro ElectroMechanical Systems) and lab on a chip (LOC) technology.

Demonstration of an all-fiber acousto-optic tunable-filter-based spectrometer

We demonstrate a new all-fiber spectrometer based on acousto-optic tunable filter (AOTF) on cladding etched single-mode (SM) fiber. The spectrometer has a free spectral range (FSR) of 200 nm, a wavelength resolution of 2 nm, a dynamic range of 20 dB and a potential scanning rate of ~125 μs/sample. The spectrometer has the potential to be developed as a low-cost spectral monitoring device for dynamic gain equalizer (DGE) in Er-doped fiber amplifier modules.

Etched cladding tunable fiber Bragg grating filters integrated with Si V-grooves

We describe a novel electrically tunable fiber Bragg grating (FBG) filter with a chemically etched cladding and an evaporated metal coating on one side of the fiber. Wavelength tuning ranges up to 2.5 nm with efficiencies greater than 8.5 nm/watt have been demonstrated along with modulation bandwidths up to 14 Hz. We have also demonstrated tuning efficiencies over 200nm/Watt for 30micrometers diameter etched cladding devices tuned under moderate vacuum conditions. Such tunable FBG filters have potential applications in dense wavelength division multiplexing (DWDM), optical signal processing, or in wavelength tunable fiber lasers. In our paper we investigate the tuning efficiency and modulation bandwidth of etched cladding FBGs integrated with Silicon V-grooves that utilize temperature tuning of the filter. By passing an electrical current through a thin metal coating deposited onto an etched cladding FBG, the temperature of the grating can be controlled to tune the spectral characteristics of the FBG. Additionally, to simplify the fabrication process, we evaporate the metal coating onto the etched FBG from only one side. This radially asymmetric metal coating is simpler to fabricate, since it does not require any mechanical fixture to rotate the fiber during metal deposition. The etched cladding FBG is placed in a Si V-groove that serves the multiple functions of holding the FBG during etching and evaporation, and also provides a simple and compact means for scaling up to arrays of tunable FBGs.

Broadband variable optical attenuator based on acousto-optic coupling in single-mode fiber

Summary form only given. Single mode fiber acousto-optic tunable filters (AOTFs) operate on the principle of core-to-cladding modes coupling and have loss-filter like spectral characteristics. We demonstrated a novel, ultrabroadband all-fiber AO-based variable optical attenuator that with fast response time, large dynamic range, and low insertion loss.