Optical Label Research Articles

Optical Serial-to-Parallel Conversion Technique With Phase-Shifted Preamble for Optical Label Switching Systems

We have investigated the fundamental operation of optical serial-to-parallel converter (OSPC) scheme with phase-shifted preamble, and its application to optical label switching operation. The OSPC consists of a π/2 phase-shifted preamble at the top of the packet generated at a transmitter-side, and a -π/2 phase-biased Mach-Zehnder delayed interferometer with the delay length of the timing position of the gated bit followed by a balanced photodetector at a receiver-side. Firstly, we simulated the fundamental performance of the OSPC. The possibility of the serial-to-parallel operation was confirmed. The operation tolerance against the optical phase discrepancy from the ideal conditions, waveguide loss, extinction ratio, and chirp of the input signal were considered. Then, OSPC operation was experimentally investigated. 4-bit operation could be achieved with a suppression ratio of 8 dB in case of the input signal extinction ratio of 13 dB. For the purpose of verifying if the OSPC worked stably and if it could apply to optical label switching systems, packet transfer operation at a bit rate of 40 Gb/s with 2-bit label was also investigated, and we achieved error-free performance successfully for the first time.

All-optical recognition method of double two-dimensional optical orthogonal codes-based labels using four-wave mixing

A novel all-optical label recognition method is proposed and demonstrated experimentally which is based on fiber Bragg gratings (FBGs)-based encoder/decoder and semiconductor optical amplifier (SOA). In this scheme, the optical label is firstly decoded properly, the decoded signal then generates the 1st and the 2nd order four-wave mixing (FWM) effect in different SOA, any of the frequencies achieved by the 2nd order FWM is extracted to recognize the optical label. The proposed solution can favor hardware simplicity over bandwidth efficiency in order to achieve the double two-dimensional optical orthogonal codes (2D-OOCs)-based optical label recognition in an optical packet switching (OPS) system where the bandwidth efficiency can be improved by FWM effect in SOA to achieve optical label processing and reasonable spacing of wavelengths for the payloads and optical label. The feasibility of the proposed method is validated by two experiments of the double 2D-OOCs-based optical label generation and recognition, the effect of the optical label on the payloads is also considered. These results show that the proposed method can (1) reduce effectively the code auto-correlation /cross-correlation requirements of the optical label identification and remove the cross-correlation pulses after optical decoding, (2) increase greatly the coding capacity and the number of the available optical labels, (3) improve the reliability and bandwidth efficiency of the optical label identification. The experimental results also show that the optical label has a high extinction ratio and can be operated easily.

Label swapper device for spectral amplitude coded optical packet networks monolithically integrated on InP

In this paper the design, fabrication and experimental characterization of an spectral amplitude coded (SAC) optical label swapper monolithically integrated on Indium Phosphide (InP) is presented. The device has a footprint of 4.8x1.5 mm2 and is able to perform label swapping operations required in SAC at a speed of 155 Mbps. The device was manufactured in InP using a multiple purpose generic integration scheme. Compared to previous SAC label swapper demonstrations, using discrete component assembly, this label swapper chip operates two order of magnitudes faster.

Techniques for Studying In Situ Corrosion and Related Surface and Interfacial Phenomena

An in situ optical microscopy and electrochemical analysis method is presented for studying corrosion processes of metals and alloys (316L SS, Al 6061, Mg) in aerated and deaerated solutions (0.5 M and 6M NaCl, 1M H2SO4). Real time optical images were recorded for various in situ physical surface changes (etching, pitting, surface discoloration, gas bubbles), microstructure (inclusions, grain boundaries, dislocation slip traces, twins) and correlated to the electrochemical (potentiostatic, potentiodynamic, polarization) data measured simultaneously. This technique is reviewed along with other in situ surface analytical probes including recent advances in optical microscopy methods involving higher resolution imaging and the results are discussed in terms of theories and current applications in the field of study. This super-resolution patent review highlights developments in optical microscopy [14], phototransformable optical labels [14, 17, 19], and double confocal microscopy [17], and corrosion results from near-field scanning optical microscopy, and in situ confocal laser scanning microscopy compared to our in situ optical microscopy plus electrochemical analysis. Keywords: In situ, optical, potentiostatic, potentiodynamic, SEM-EDS, etching, pitting, grain boundaries, twins, 316L, Al6061, Mg 0.5M, 6M NaCl, 1M H2SO4, Situ Corrosion, chloride ions, oxide film, aluminum oxide, tunneling microscopy

Passive Waveguide Device Consisting of Cascaded Asymmetric X-Junction Couplers for High-Contrast Recognition of Optical BPSK Labels

Fast all-optical processing is expected for packet routing in high-speed photonic networks. In photonic label networks, recognition of optical labels is one of the key functions. We propose a scalable passive waveguide device to recognize binary phase shift keying (BPSK) labels. The label recognition device consists of cascaded asymmetric X-junction couplers. The proposed basic device recognizes four labels consisting of parallel four pulses. Since an output is obtained at only one output port out of four ports with high contrast ratio, the device can be scaled up for labels of a larger number of bits. The devices for four, eight and sixteen labels are theoretically analyzed. To confirm the operation in the devices, the label recognition of four- and eight-bit labels is numerically simulated by finite-difference beam propagation method (FD-BPM). Expanded circuits based on the four-bit basic device to increase the number of recognizable labels are also presented.

Quantitative and Specific Molecular Imaging of Cancer With Labeled Engineered Monoclonal Antibody Fragments

The high target specificity of antibodies and related constructs makes them excellent scaffolds for molecular-imaging probes. Quantitative data on biodistribution and pharmacokinetics can be acquired by radiolabeling these agents. Such studies demonstrate prolonged circulation times and resulting nonspecific accumulation with high background signal using antibody-based agents. Antibody fragments demonstrate more rapid clearance, but lower tumor uptake. Optical labeling of antibodies provides a basis for developing activatable probes that can image antigens with very high specificity, potentially allowing for the simultaneous visualization of multiple targets. While radioimmunoimaging provides valuable whole-body, quantitative information, activatable optical antibody-based agents could generate real-time diagnostic and prognostic information about near-surface lesions at high-spatial and temporal resolution without requiring ionizing radiation.

An Overview of Optical Label Switching Technology

Optical label switching is a new technology of optical switching, which can overcome the electronic bottleneck of optical communication effectively, optical label switching (OLS) network as a specific implementation of future optical packet network has been paid more and more attention, its key technology is the generation and extraction of optical label. In this paper, subcarrier multiplexing label, OCDM optical code label and orthogonal modulation label are described and discussed. Their strength and weakness are analyzed.

Single-walled carbon nanotubes as optical materials for biosensing

In this review, we summarize recent progress in the development of single-walled carbon nanotubes (SWNTs) as optical materials for biosensing applications. First, as optical labels, we discuss the use of SWNTs in Raman-based protein detection. Strong and simple resonance Raman spectroscopy of SWNTs opens up a method of protein microarray with detection sensitivity down to femtomolar range. Also, tunable isotopic SWNT-Raman signature enables the simultaneous detection of multiple analytes in complex fluids. Second, the photoluminescence properties of SWNTs are also explored. We examine fluorescence biosensors that integrate the quenching property of SWNTs and the recognition property of functional nucleic acids. Particularly, SWNTs are established as an efficient signal transduction substrate in different biosensing systems, including the detection of specific proteins and DNA sequences, regulation of singlet oxygen generation and label-free fluorescence assays, and all have exhibited very high selectivity and sensitivity.

Label swapping and packet transmission of DPSK-labeled PPM signal in optical label switching

A label swapping scheme of an optical labeled signal with differential phase shift keying (DPSK) for label at 2.5 Gb/s and pulse position modulation (PPM) for payload at 40 Gb/s is demonstrated by simulation. Power penalties of ?1.8 and ?0.8 dB are achieved for both the payload and label over 80-km single mode fiber (SMF) transmission. This labeling scheme allows the use of four-wave mixing (FWM) in semiconductor optical amplifier (SOA) to perform label erasure, with advantages of transparence for bit rate, high processing rate, simple architecture, and low cost. Label swapping is demonstrated with appropriate penalties of ?3.5 and 0.8 dB for PPM payload and new DPSK label, respectively. To further prove the effectiveness of the proposed scheme, label swapping in the case of using 10-Gb/s DPSK label is also investigated with the power penalties of 6 and 2 dB for PPM payload and new DPSK label.

Optimization of Two-Dimensional Filter in Time-to-Space Converted Correlator for Optical BPSK Label Recognition Using Genetic Algorithms

A two-dimensional filter for photonic label recognition system using time-to-space conversion and delay compensation was designed using Genetic-Algorithms (GA). For four-bit Binary Phase Shift Keying (BPSK) labels at 160Gbit/s, contrast ratio of the output for eight different labels was improved by optimization of two-dimentional filtering. The contrast ratio of auto-correlation to cross-correlation larger than 2.16 was obtained by computer simulation. This value is 22% larger than the value of 1.77 with the previously reported system using matched filters.

Silver nanostructure sensing platform for maximum-contrast fluorescence cell imaging

We present herein a silver nanostructure-assisted sensing platform which consists of a combined structure of Ag nanowire (NW) and nanodot (ND) array. Highly enhanced fluorescence from fluorophore is attributed to a strongly coupled optical near-field interaction between proximately located Ag NW and NDs. We obtained enhanced fluorescence intensity with up to 140 folds, as contrasted from background intensity, reaching a theoretical maximum value. On the other hand, fluorescence lifetime was greatly reduced to 0.27 ns (from 2.17 ns for the same fluorophores without nanostructure). This novel platform can be a promising utility for optical imaging and labeling of biological systems with a great sensitivity.

Research Progress in Hemicyanine-Based Polymers

Hemicyanine is a group of acentric cation-type dyes, in which one side of the conjugated chain is composed of a quaternary nitrogen-containing heterocycle, and the other side of the conjugated chain is connected to substituted nitrogen through an aryl ring. Different chemical constitutions of hemicyanine and its various connecting modes in polymer lead to abundant topological hemicyanine-based polymers, including linear, star-shaped, brush-shaped, dendritic and hyperbranched macromolecules. These polymers have been used for applications in various roles, such as photographic sensitizers, nonlinear optical materials and biomolecular labeling probes. We will give an overview of the synthesis, structure, properties and applications of series hemicyanine-based polymers.

Плазмонно-резонансные золотые частицы как носители лекарственных веществ и оптические метки в цитологических исследованиях

Плазмонно-резонансные золотые частицы как носители лекарственных веществ и оптические метки в цитологических исследованиях

Optical Labelling Scheme Based on Dedicated Wavelength and Hybrid Modulation Techniques

Optical Labelling Scheme Based on Dedicated Wavelength and Hybrid Modulation Techniques

Frequency-swept coherently detected spectral amplitude code for flexible implicit optical label switching

A new optical label switching system with coherently detected implicit spectral amplitude code (SAC) labels is proposed in this letter. The implicit SAC labels are recognized using a frequency-swept local light source oscillator. Intensity modulation payloads of 625 Mb/s and 1.25 Gb/s are considered. Label and payload bit error rate (BER) performances are assessed and compared by simulations. The results reveal that, at a BER value of 10^{-9}, -32.4-dBm label received power can be obtained. In addition, 8.3-dB optical signal-to-noise ratio (OSNR) is obtained when carrying a payload of 625 Mb/s. The label BER value hardly reaches 10^{-9} if the payload bit rate is at 1.25 Gb/s; however, a high payload bit rate only has little influence on received payload quality at a BER value of 10^{-9}. Finally, a payload of 1.25 Gb/s could obtain -28.2 dBm received power and 9.5-dB OSNR.

Poly(styrene-co-acrylic acid) core and silver nanoparticle/silica shell composite microspheres as high performance surface-enhanced Raman spectroscopy (SERS) substrate and molecular barcode label

A new type of polymer core and silver nanoparticle/silica shell multifunctional composite microsphere is reported. The monodisperse polymer core of poly(styrene-co-acrylic acid), prepared by surfactant-free emulsion polymerization, serves as the supporting template to facilitate the synthesis and handling of the highly functionalized substrates to achieve consistent mechanical and surface chemical properties. The shell of silver nanoparticles, formed in situ by controlled interfacial reduction of AgNO3 with polyvinylpyrrolidone (PVP), serves as the optimal metal enhancer for surface enhanced Raman spectroscopy (SERS). The Ag nanoparticle shell is stabilized with a silica layer using a sol–gel process, which is also functionalizable with reactive epoxides for further bio-conjugation using epoxy ring-opening methods. Preliminary results indicated that the microspheres are easily prepared with exceptional chemical and physical uniformity. SERS experiments with 4-aminobenzenethiol (4-ABT) as the indicator showed that the resulting multifunctional microspheres allowed the production of highly consistent enhancement of the Raman signals down to nM concentrations of 4-ABT, making them highly desirable candidates as the enhancers for high performance SERS analysis and as SERS optical labels in biomedical imaging. The microspheres are robust and the high density of the SERS active Ag nanoparticles on the microspheres provided unique signal averaging for the method to be potentially quantitative which is an urgent goal for SERS substrate design and SERS analysis.

Nanoparticles for the development of improved (bio)sensing systems

Nanoparticles serve as fundamental building blocks for nanobiotechnology, especially in several applications in the development of novel (bio)sensing systems. Nanoparticles can be used for modification of the surfaces of (bio)sensing transducers or as optical or electroactive labels to improve different aspects of performance, for example sensitivity, detection limit, multidetection capability, and response stability. Nanoparticles can be integrated into the transducer materials on an individual basis or inside other matrices to ensure the immobilization of recognition biomolecules and/or receptors which are the principal components of the (bio)sensing systems. Incorporation of nanoparticles into optical and electrochemical (bio)sensing systems, including their use in microfluidic based systems has the advantages of enabling the design of robust, easy to use, portable, and cost-effective devices.

Tailoring immobilization of immunoglobulin by excimer laser for biosensor applications

The sheltered transfer and immobilization of rabbit anti-human antiserum immunoglobulin G (IgG) by matrix-assisted pulsed laser evaporation (MAPLE) are reported. The iced targets submitted to laser irradiation consisted of 0.2-2 mg/mL IgG blended or not with lipid (L-α-phosphatidylcholine dipalmitoyl) dissolved in distilled water-based saline buffer. Thin IgG coatings were obtained at room temperature onto glass, fused silica, or silicon substrates. Ten thousand subsequent laser pulses of 0.33, 0.5, or 0.67 J/cm(2) fluence were applied for the synthesis of each sample. Morphology and composition of the thin films were studied by optical, scanning, and atomic force microscopy and Fourier transformed infrared spectrometry. Optical labeling methods such as spectrofluorimetry and fluorescence microscopy were selected to verify the biosensor transduction principle because of their high sensitivity for detecting low amounts of antigen (IgG). Protein immobilization to the substrate surface was demonstrated for all obtained structures after immersion in the donkey anti-rabbit secondary antibody solution. The IgG transfer and immobilization onto substrates were improved by addition of lipid to MAPLE solutions.

A Novel Optical Code-Based Label Switching Architecture for WDM Packet Switched Networks

To cope with ever-increasing traffic demands in transport networks, all-optical switching is currently perceived as a solution to remove bottlenecks imposed by O/E/O conversions. Optical label switching accomplishes packet switching using the optical-labels. It simplifies the design of switching devices in the optical domain and speeds up packet forwarding significantly. In this paper, we propose a novel design of optical switches, and present a performance analysis to show its in-depth behavior. The analysis results demonstrate the effectiveness of the proposed switching architecture.

Four-wave mixing imaging to study protein entry and release in mammalian cells

Optical microscopy is a powerful tool for tracking the binding, internalisation and subcellular trafficking of delivery vectors to mammalian cells. By exploiting multiphoton processes, subcellular structures can be imaged with intrinsic three-dimensional (3D) spatial resolution. Common fluorescent labels in multiphoton microscopy include organic fluorophores, which suffer from photobleaching, and quantum dots which are more photostable but contain cytotoxic elements (such as Cd or In). Gold nanoparticles (GNPs) are ideal optical labels in terms of photostability and bio-compatibility, but emit weak fluorescent signal. We have developed a novel multiphoton microscopy technique that exploits the third-order nonlinearity called four-wave mixing (FWM) of GNPs in resonance with their surface plasmon. In terms of imaging performances, FWM microscopy features a spatial resolution better than the one-photon diffraction limit and optical sectioning capabilities. We show high-contrast background-free imaging of gold-labels (down to 5 nm size) and sensitivity to the single particle level. We are also able to demonstrate a directed dissociation of the GNP from bound proteins at their surface. These results pave the way for active tracking of conjugated nanoparticles, before the controlled release of therapeutically relevant proteins to a localised site of interest.