Liquid�Cliquid fluorescent waveguides using microfluidic-drifting-induced hydrodynamic focusing

We demonstrate fluorescent liquid-core/liquid-cladding (L ²) waveguides focused in three-dimensional (3-D) space based on a 3-D hydrodynamic focusing technique. In the proposed system, the core and vertical cladding streams are passed through a curved 90° corner in a microfluidic channel, leading to the formation of a pair of counter rotating vortices known as the Dean vortex. As a result, the core fluid is completely confined within the cladding fluid and does not touch the top and bottom poly(dimethylsiloxane) (PDMS) surfaces of the microfluidic channel. Because the core stream was not in contact with the PDMS channel, whose refractive index contrast and optical smoothness with the core fluid are lower than that between the core and the cladding fluids, the 3-D focused L ² waveguide exhibited a higher captured fraction (η) and lower propagation loss when compared to conventional two-dimensional (2-D) focused L ² waveguides. Because the proposed 3-D focused L ² waveguides can be generated in planar PDMS microfluidic devices, such optofluidic waveguides can be integrated with precise alignment together with other in-plane microfluidic and optical components to achieve micro-total analysis systems (μ-TAS).     

Integrated optical planar waveguide components

 Planar optical waveguides for applications in communication networks can be fabricated using conventional chip-manufacturing techniques. We present a planar optical waveguide technology that is based on a silicon-oxynitride (SiON) core and silicon-oxide cladding layers. In addition to more compact, conventional optical devices, it also enables enhanced optical functions such as dynamically reconfigurable planar integrated optical devices. Examples of adaptive devices realized in this technology include finite and infinite impulse response (FIR and IIR) filters. Received: 13 February 2002/Accepted: 28 February 2002 In realizing the SiON waveguide technology and the adaptive optical filter functions with the subsystem control, the dedicated work of the waveguide process technology, the photonic device technology, and the engineering services teams at IBM's Zurich Research Laboratory were instrumental and are gratefully acknowledged. For the concept-level optical-packaging work we thank Optospeed SA. This paper was presented at the Workshop “Optical MEMS and Integrated Optics” in June 2001.     

Research progresses of SOI optical waveguide devices and integrated optical switch matrix

1Introduction Dense wavelength division multiplexing(DWDM)is the most powerful method to upgrade the transmission capacity of the optical fiber transmission system.In DWDM system,the enormous available bandwidth is utilized by multiplexing laser beams with different wavelength in one single fiber.With DWDM technology,parallel transmission of data streams with different format leads to high speed information communication,thereby reduces the requirement for the high speed electronic device…     

Structures of 3-layer planar waveguide where core field can become uniform

Theoretical analysis and numerical results for typical examples are presented for three-layer planar waveguides with nonlinear claddings to find the appropriate structures in which the core electric field can become uniform at appropriate optical power while the cladding fields decay exponentially . It is shown that there are five kinds of such structures. The electric field profiles are plotted for the five typical examples. We notify that the occurrence of uniform field in a waveguide core may perhaps have prospective applications in waveguide, opto-electronic and photonic devices.     

A full scanning system and a new processing method for capillary electrophoresis

A system using a liquid-core waveguide for the full scanning of capillary electrophoresis processes is presented. The system utilizes the liquid-core waveguide as an efficient window for the excitation of separated samples and the collection of light through total internal reflectance, with zeptomolar detection limits. Scanning the excitation laser along the length of the electrophoresis capillary excites individually separated analyte bands, while the fluorescence is collected end-on by an optical fiber coupled to a photomultiplier. A new procedure for denoising and deconvolution was applied to the experimental electropherograms, removing the noise and resolving the highly overlapped peaks observed in early stages of the separation.     

Parallel Optical Packet Address Detection Using Planar Optical Interconnections

We propose a novel planar optical interconnection scheme for 100 Gb/s optical packet address detection, which consists of wave guide grating couplers and a diffractive microlens integrated on a glass substrate 3-dimensionally. Length and duty cycle of the grating couplers have been determined on the bases of ray-optic propagation-mode analysis in a slab waveguide and of rigorous coupled-wave diffraction analysis for out-coupled radiation-modes. The 3-dimensionally integrated planar optics makes it possible to connect each address bit-signal of the TE₀-waveguide mode to the detector with a power uniformity of 6.4% and a total coupling efficiency of 72.3%.     

A two-dimensional optical cross-connect with integrated waveguides and surface micromachined crossbar switches

The design, fabrication and test results of an all-optical cross-connect, which uses electrostatically actuated micromechanical digital mirrors to steer optical signals in a network of planar waveguides, are presented. The substrate consists of a network of spliced planar waveguides on silica substrates. The switches, located at the waveguide intersections, are formed with an electroplated T-structure consisting of a horizontal perforated square plate suspended by four elastic beams. When operated, the horizontal plate is pulled up making the mirror move out of the optical path thus steering the beam. An 8×8 switch array has been fabricated and tested. Actuation and relaxation switching times near 3 ms have been demonstrated with an actuation voltage of 120 V. The optical insertion loss for the array typically varied from 2.3 dB for a single trench in the optical path (shortest optical path) to 8 dB for 15 trenches in the optical path (longest optical path).     

一种基于SOI的集成光波导耦合系统的设计与制备

根据锥形光纤与平面环型微腔耦合原理,使用L-Edit版图设计软件设计并优化了锥形光波导与微腔耦合系统。利用MEMS工艺对SOI圆晶片进行加工,从而实现了锥形光波导与跑道型以及环型光波导微腔的集成。其中,光波导以及微腔通过ICP刻蚀顶层硅而成,矩形槽通过RIE刻蚀衬底硅而成。光波导两侧的矩形凹槽可方便光纤接人以及对出射光...     

On-chip optical interconnect using visible light

We propose and fabricate a monolithic optical interconnect on a GaN-on-silicon platform using a wafer-level technique. Because the InGaN/GaN multiple-quantum-well diodes (MQWDs) can achieve light emission and detection simultaneously, the emitter and collector sharing identical MQW structure are produced using the same process. Suspended waveguides interconnect the emitter with the collector to form in-plane light coupling. Monolithic optical interconnect chip integrates the emitter, waveguide, base, and collector into a multi-component system with a common base. Output states superposition and 1×2 in-plane light communication are experimentally demonstrated. The proposed monolithic optical interconnect opens a promising way toward the diverse applications from in-plane visible light communication to light-induced artificial synaptic devices, intelligent display, on-chip imaging, and optical sensing.     

测量电场的铌酸锂光传感器综述

铌酸锂(LiNbO3)光传感器具有灵敏度高,不受外部电磁场干扰的特性,吸引了越来越多科研工作者的注意。对基于不同类型传感器的制作工艺、传感原理和适用范围,介绍了3种用于测量电场的铌酸锂光传感器,它们分别是:基于Mach-Zehnder波导调制器与微多环天线的集成方位角铌酸锂光传感器;铌酸锂介质波导光传感器;室温直接粘接的铌酸锂晶体层高电压光传感器。     

Optofluidic waveguides: II. Fabrication and structures

We review fabrication methods and common structures for optofluidic waveguides, defined as structures capable of optical confinement and transmission through fluid filled cores. Cited structures include those based on total internal reflection, metallic coatings, and interference based confinement. Configurations include optical fibers and waveguides fabricated on flat substrates (integrated waveguides). Some examples of optofluidic waveguides that are included in this review are Photonic Crystal Fibers (PCFs) and two-dimensional photonic crystal arrays, Bragg fibers and waveguides, and Anti Resonant Reflecting Optical Waveguides (ARROWs). An emphasis is placed on integrated ARROWs fabricated using a thin-film deposition process, which illustrates how optofluidic waveguides can be combined with other microfluidic elements in the creation of lab-on-a-chip devices.     

Optofluidic waveguides: II. Fabrication and structures

We review fabrication methods and common structures for optofluidic waveguides, defined as structures capable of optical confinement and transmission through fluid filled cores. Cited structures include those based on total internal reflection, metallic coatings, and interference based confinement. Configurations include optical fibers and waveguides fabricated on flat substrates (integrated waveguides). Some examples of optofluidic waveguides that are included in this review are Photonic Crystal Fibers (PCFs) and two-dimensional photonic crystal arrays, Bragg fibers and waveguides, and Anti Resonant Reflecting Optical Waveguides (ARROWs). An emphasis is placed on integrated ARROWs fabricated using a thin-film deposition process, which illustrates how optofluidic waveguides can be combined with other microfluidic elements in the creation of lab-on-a-chip devices.     

InP-based optical waveguide MEMS switches with evanescent coupling mechanism

An optical waveguide MEMS switch fabricated on an indium phosphide (InP) substrate for operation at 1550 nm wavelength is presented. Compared to other MEMS optical switches, which typically use relatively large mirrors or long end-coupled waveguides, our device uses a parallel switching mechanism. The device utilizes evanescent coupling between two closely-spaced waveguides fabricated side by side. Coupling is controlled by changing the gap and the coupling length between the two waveguides via electrostatic pull-in. This enables both optical switching and variable optical coupling at voltages below 10 V. Channel isolation as high as -47 dB and coupling efficiencies of up to 66% were obtained with switching losses of less than 0.5 dB. We also demonstrate voltage-controlled variable optical coupling over a 17.4 dB dynamic range. The devices are compact with 2 /spl mu/m/spl times/2 /spl mu/m core cross section and active area as small as 500 /spl mu/m/spl times/5 /spl mu/m. Due to the small travel range of the waveguides, fast operation is obtained with switching times as short as 4 /spl mu/s. Future devices can be scaled down to less than 1 /spl mu/m/spl times/1 /spl mu/m waveguide cross-sectional area and device length less than 100 /spl mu/m without significant change in device design.     

MEMS on silicon for integrated optic metrology and communication systems

 Integrated optic micro-electromechanical systems (IO-MEMS) based on silicon-, Al₂O₃-SiO₂ and TiO₂-SiO₂ waveguides, doped with Ti, Cr, and Er on silicon substrates allow to generate complex metrology and optical communication systems. They exhibit low loss across a wide spectral range, occupy small space, and exhibit high functionality at low production cost. The waveguides are deposited by CVD and patterned by anisotropic plasma etching. The micro-electromechanical structures are formed by standard micro-machining processes and anodic bonding of silicon-glass. An integrated optical pressure sensor using the interferometer principle, a gas monitor for the near and middle infrared using elevated silicon single mode waveguides, an electrostatic-tuned Ti:/Cr:-sapphire laser, and a UV-VIS-NIR-spectrometer including integrated broad banded light sources represent metrology systems. Optical communication systems are described like a waveguide grating based wavelength demultiplexer, an optical transceiver using self aligned detector and emitter as well as a tapered fibre coupler, and an integrated optical amplifier. Received: 10 July 2001/Accepted: 15 August 2001 This work was funded by Deutsche Forschungsgemeinschaft, the Ministry of Research and Technology and the City of Hamburg. This paper was presented at the Workshop “Optical MEMS and Integrated Optics” in June 2001.     

Integration of optical waveguide on pneumatic balloon actuator for flexible scanner in endoscopic imaging diagnosis applications

This paper reports a flexible scanner consisting of a scanning actuator and optical waveguides for medical imaging applications such as endoscopic fluorescence imaging diagnosis. The 0.3-mm-thick and 5-mm-wide functional scanner was designed to be smaller enough than the 10 mm-diameter of channel of endoscope. The proposed device can be used to introduce an excitation light into the abdominal cavity or digestive tract. A pneumatic balloon actuator (PBA) consisting of polydimethylsiloxane (PDMS) is used as the scanning actuator for the scanner in consideration of its small, soft, and safe features. The SU-8 optical waveguides with high refractive index (n_SU-8 = 1.575) are integrated onto the PBA structure made of PDMS with a lower refractive index (n_PDMS = 1.405). Excitation light at a wavelength of 405 nm is transmitted through an optical fiber to the SU-8 waveguides. The outgoing light from the waveguide can be scanned by the bending motion of the PBA. The waveguide functions as a detector as well. Our developed device has successfully scanned, excited, and detected light from fluorescence beads at a wavelength of 540 nm distributed in a pseudo-tissue.     

Grating coupled optical waveguide interferometer for label-free biosensing

A phase shifting optical waveguide interferometer is demonstrated for label-free evanescent wave biosensing in aqueous solutions. In the proposed configuration, the reference and measurement arms of the interferometer are combined inside an integrated optical Ta₂O₅ waveguide using an ion implanted grating. Biomolecules adsorbing on the waveguide surface shift the phase in the measurement arm, which is modulated at the same time by a periodically relaxing liquid crystal phase modulator. It is demonstrated that by analyzing the periodic intensity response at the end facet of the waveguide, the phase shifts in the measurement arm can be monitored in real-time with a precision of 10⁻⁴ rad. The high phase resolution allows the detection of surface adsorbed molecule densities below 1 pg/mm² without using any labeling or on-chip referencing. The instrument performance is demonstrated by monitoring in situ protein adsorption and affinity binding of low molecular weight pure biotin to an immobilized avidin layer.     

Moving Polymer Waveguides and Latching Actuator for 2 $ times$ 2 MEMS Optical Switch

We describe a novel type of MEMS optical switch based on moving waveguide which has merits inherited from both MEMS and integrated optics technologies. It provides an expandable 2 $times$ 2 switching capability, a first in this category of switches. The switch is built by assembling independently optimized latching silicon actuator and soft polymer waveguides. The actuator is based on two new structures: a microhinge, dubbed the fork hinge, and a latching structure using a precompressed microspring. The mechanical switching speed was measured below 0.5 ms. The complex polymer waveguide structure was thoroughly characterized to obtain all the components of the optical loss. This analysis allowed us to estimate robustly the insertion loss of the assembled optical switch below 3 dB and to identify the possibilities to improve this figure. $hfill$[2008-0142]      

Integrated optics architecture for trapped-ion quantum information processing

Standard schemes for trapped-ion quantum information processing (QIP) involve the manipulation of ions in a large array of interconnected trapping potentials. The basic set of QIP operations, including state initialization, universal quantum logic, and state detection, is routinely executed within a single array site by means of optical operations, including various laser excitations as well as the collection of ion fluorescence. Transport of ions between array sites is also routinely carried out in microfabricated trap arrays. However, it is still not possible to perform optical operations in parallel across all array sites. The lack of this capability is one of the major obstacles to scalable trapped-ion QIP and presently limits exploitation of current microfabricated trap technology. Here we present an architecture for scalable integration of optical operations in trapped-ion QIP. We show theoretically that diffractive mirrors, monolithically fabricated on the trap array, can efficiently couple light between trap array sites and optical waveguide arrays. Integrated optical circuits constructed from these waveguides can be used for sequencing of laser excitation and fluorescence collection. Our scalable architecture supports all standard QIP operations, as well as photon-mediated entanglement channels, while offering substantial performance improvements over current techniques.

     

An improved three-dimensional full-vectorial finite-difference imaginary-distance beam propagation method

1 Introduction Recently, the importance of the planar lightwave circuits or photonic integrated cir- cuits (PLCs/PICs) has been widely recognized because the monolithic integration of various kinds of photonic or optoelectronic devices can be achieved via…     

Generalized Coincident Pulse Technique and New Addressing Schemes for Time-Division Multiplexing Optical Buses

Time-division multiplexing (TDM) optical buses have applications in computer networks, high-performance routers and switches, and interprocessor communication subsystems of parallel computers. Three waveguides are used to implement the previously proposed TDM optical bus. One waveguide is used for data transmission, and the other two waveguides are used for processor addressing. The coincident pulse technique is used to implement a unary addressing scheme. This architecture has two drawbacks: the bandwidth of address waveguides is wasted and the scalability of the bus is limited due to the unary addressing. In this paper, the coincident pulse technique is generalized in order to derive compact addressing schemes for TDM optical buses. Based on this new technique, optimal addressing schemes are presented. Several general methods for designing new addressing schemes are proposed to achieve various trade-offs. Compared with the previously proposed addressing scheme, the new schemes significantly improve the utilization of the bandwidth of optical waveguides and the scalability of a TDM optical bus.