Showing papers in "Fiber and Integrated Optics in 2016"
TL;DR: In this paper, an analytical and numerical investigation of the transmission performance of an optical Single Sideband (SSB) modulation technique generated by a Mach Zehnder Modulator (MZM) with a 90° and 120° hybrid coupler is presented.
Abstract: This work addresses the analytical and numerical investigations of the transmission performance of an optical Single Sideband (SSB) modulation technique generated by a Mach Zehnder Modulator (MZM) with a 90° and 120° hybrid coupler. It takes into account the problem of chromatic dispersion in single mode fibers in Passive Optical Networks (PON), which severely degrades the performance of the system. Considering the transmission length of the fiber, the SSB modulation generated by maintaining a phase shift of π/2 between the two electrodes of the MZM provides better receiver sensitivity. However, the power of higher-order harmonics generated due to the nonlinearity of the MZM is directly proportional to the modulation index, making the SSB look like a quasi-double sideband (DSB) and causing power fading due to chromatic dispersion. To eliminate one of the second-order harmonics, the SSB signal based on an MZM with a 120° hybrid coupler is simulated. An analytical model of conventional SSB using 90°...
12 citations
TL;DR: An experimental investigation on the behavior of transmission control protocol in throughput measurements to be used in the verification of the service-level agreement between the Internet service provider and user in terms of line capacity for ultra-broadband access networks typical of fiber-to-the-x architectures.
Abstract: This article describes an experimental investigation on the behavior of transmission control protocol in throughput measurements to be used in the verification of the service-level agreement between the Internet service provider and user in terms of line capacity for ultra-broadband access networks typical of fiber-to-the-x architectures. It is experimentally shown different conditions in high bandwidth-delay product links where the estimation of the line capacity based on a single transmission control protocol session results are unreliable. Simple equations reported in this work, and experimentally verified, point out the conditions in terms of packet loss, time delay, and line capacity, that allow consideration of the reliability of the measurement carried out with a single transmission control protocol session test by adopting a suitable measurement time duration.
8 citations
TL;DR: In this article, an inductively coupled plasma etching process was used to fabricate notched long-period fiber gratings for CO2 gas sensing, which showed good performance and is suitable as a gas sensor for monitoring the CO2 adsorption process.
Abstract: An inductively coupled plasma etching process to fabricate notched long-period fiber gratings for CO2 gas sensing is proposed in this article. In the gas sensing test, the 15% mixed CO2 gas was used for characterization of CO2 adsorption by the amine-modified nanoporous silica foams of the notched long-period fiber grating sensor. The results shows the spectra were changed with the CO2 gas flow within 13 min. During the absorption process, the transmission of the resonant dip was decreased by 2.884 dB. Therefore, the proposed notched long-period fiber grating gas sensor shows good performance and is suitable as a gas sensor for monitoring the CO2 adsorption process.
6 citations
TL;DR: In this paper, a non-blocking optical Ethernet switching architecture with liquid crystal on a silicon-based beam-steering switch and optical output buffer strategies are proposed for preserving service packet sequencing and fairness of routing sequence.
Abstract: A non-blocking optical Ethernet switching architecture with liquid crystal on a silicon-based beam-steering switch and optical output buffer strategies are proposed. For preserving service packet sequencing and fairness of routing sequence, priority and round-robin algorithms are adopted at the optical output buffer in this research. Four methods were used to implement tunable fiber delay modules for the optical output buffers to handle Ethernet packets with variable bit-rates. The results reported are based on the simulations performed to evaluate the proposed switching architecture with traffic analysis under a traffic model captured from a real-core network.
5 citations
TL;DR: In this article, an integrated Bragg grating using an alloy of GaAs, AlGaAs, and InGaAs with a controllable refractive index is presented.
Abstract: This article presents a methodology for an integrated Bragg grating using an alloy of GaAs, AlGaAs, and InGaAs with a controllable refractive index to obtain an adaptive Bragg grating suitable for many applications on optical processing and adaptive control systems, such as limitation and filtering. The refractive index of a Bragg grating is controlled by using an external electric field for controlling periodic modulation of the refractive index of the active waveguide region. The designed Bragg grating has refractive indices programmed by using that external electric field. This article presents two approaches for designing the controllable refractive indices active region of a Bragg grating. The first approach is based on the modification of a planar micro-strip structure of the iGaAs traveling wave as the active region, and the second is based on the modification of self-assembled InAs/GaAs quantum dots of an alloy from GaAs and InGaAs with a GaP traveling wave. The overall design and results ...
5 citations
TL;DR: The method to improve the information confidentiality in optical fiber telecommunications is extended to a four-dimensional physical space to demonstrate the general applicability of the cryptographic method and to achieve better performance in terms of transmission throughput.
Abstract: We investigate a technique to improve the information confidentiality in optical fiber telecommunications. Starting from a basic scheme of unconventional coding technique [1] applied to a three-dimensional polarization shift keying, we extend the method to a four-dimensional physical space [2] to demonstrate the general applicability of the cryptographic method and to achieve better performance in terms of transmission throughput. Bit error rate (BER) is calculated for hypercube constellation modulation in two, three, and four dimensions, and an interesting relation among BER, transmission power, and space dimension is derived.
4 citations
TL;DR: In this article, a Mach-Zehnder Interferometer (MZI) was used to achieve a high temperature sensitivity of 1.56 nm/°C for surrounding material with a refractive index (RI) of 0.45.
Abstract: We propose a highly sensitive temperature fiber sensor based on a Mach-Zehnder Interferometer (MZI). The MZI is composed of a piece of no-core fiber (NCF), a single-mode fiber (SMF), and a fiber taper (FT) structure. To accomplish high sensitivity, the component was immersed in a material with high thermo-optic coefficient (TOC). The experimental results showed that a high temperature sensitivity of 1.56 nm/°C was achieved for surrounding material with a refractive index (RI) of 1.45. The presented sensor has numerous advantages, for instance, extremely high sensitivity, easy fabrication, simple structure, compact size, and in-line applications.
4 citations
TL;DR: The history of optical communications can be traced back to the 1970s, when fiber and integrated optics (FI) technology was first introduced as discussed by the authors. At the time, I worked with Honeywell's Systems and Research Center.
Abstract: Anyone reading Fiber and Integrated Optics has a story about the history of optical communications. Mine started the 1970s. At the time, I worked with Honeywell’s Systems and Research Center. In a ...
4 citations
TL;DR: In this article, Fano lineshape whispering gallery modes were observed in the light scattering spectrum of a silicon microsphere in near-infrared telecommunication wavelengths and the quality factor of the Lorentzian and Fano resonances were on the order of 105.
Abstract: In this article, Fano lineshape whispering gallery modes were observed in the light scattering spectrum of a silicon microsphere in near-infrared telecommunication wavelengths. A simple model is presented to explain the transition from Lorentzian lineshape to the Fano lineshape resonances with the coupled-mode theory of multiple whispering gallery modes. Polar mode spacing of 0.23 nm is observed in the spectra, which correlates well with the calculated value. The quality factor of the Lorentzian and Fano resonances are on the order of 105. By using an appropriate interface design for the microsphere coupling geometries, Fano lineshape optical resonances herald novel device applications for silicon volumetric lightwave circuits.
3 citations
TL;DR: In this paper, the authors comprehensively compared and compared Ti:LiNbO3 integrated optic electric-field sensors, including the asymmetric Mach-Zehnder interferometer (MZI), 1 × 2 directional coupler (DC), and Y-fed balanced-bridge Mach Zehnder (YBB-MZI) based on operating principles, the electrical and optical performance, and measurements of each fabricated device.
Abstract: The need for electric-field sensing technology has widely increased, playing a critical role in various scientific and technical areas. This article comprehensively reviews and compares Ti:LiNbO3 integrated optic electric-field sensors, including the asymmetric Mach-Zehnder interferometer (MZI), 1 × 2 directional coupler (DC), and Y-fed balanced-bridge Mach-Zehnder interferometer (YBB-MZI), based on the operating principles, the electrical and optical performance, and measurements of each fabricated device. We also discuss future works to improve the sensitivity, operating stability, response speed, and bandwidth.
2 citations
TL;DR: In this article, a Reconfigurable design of a post-equalizer aimed to improve the inherent narrow modulation bandwidth of red-, green-, and blue-based LEDs has been experimentally implemented, and its effectiveness with optical filters at the receiver is investigated.
Abstract: In this research, an experimental short-range visible light communication link using red-, green-, and blue-based light-emitting diodes (LEDs) for portable micro-projector applications is presented. A Reconfigurable design of a post-equalizer aimed to improve the inherent narrow modulation bandwidth of red-, green-, and blue-based LEDs has been experimentally implemented, and its effectiveness with optical filters at the receiver is investigated. Reflective liquid-crystal-on-silicon-based micro-projection architecture, widely used in portable micro-projectors, was set up to evaluate the proposed visible light communication system. The measurement results demonstrated that a significant aggregative bandwidth improvement of 162 MHz as well as an aggregative data transmission rate of nearly 400 Mb/s can be achieved by using a non-return-to-zero–on-off keying (NRZ–OOK) modulation scheme based on only one polarization state of incident light without any offline signal processing.
TL;DR: In this article, the proposed module with system-in-package (SiP) integration is demonstrated, and the silicon photonic chip is included, which is a promising technology to be applied in the next-generation data exchanging centers.
Abstract: With the development of the multicore processor, the bandwidth and capacity of the memory, rather than the memory area, are the key factors in server performance. At present, however, the new architectures, such as fully buffered DIMM (FBDIMM), hybrid memory cube (HMC), and high bandwidth memory (HBM), cannot be commercially applied in the server. Therefore, a new architecture for the server is proposed. CPU and memory are separated onto different boards, and optical interconnection is used for the communication between them. Each optical module corresponds to each dual inline memory module (DIMM) with 64 channels. Compared to the previous technology, not only can the architecture realize high-capacity and wide-bandwidth memory, it also can reduce power consumption and cost, and be compatible with the existing dynamic random access memory (DRAM). In this article, the proposed module with system-in-package (SiP) integration is demonstrated. In the optical module, the silicon photonic chip is includ...
TL;DR: In this article, the authors investigated the non-linear noise contribution in single-channel systems adopting generic modulation-detection formats in long links with both managed and unmanaged dispersion compensation and its impact in system performance.
Abstract: This article reports an analytical investigation, confirmed by numerical simulations, about the non-linear noise contribution in single-channel systems adopting generic modulation-detection formats in long links with both managed and unmanaged dispersion compensation and its impact in system performance. This noise contribution is expressed in terms of a pulse non-linear interaction length and permits a simple calculation of the Q-factor. Results point out the dependence of this non-linear noise on the number of amplifiers spans, N, according to the adopted chromatic dispersion compensation scheme, the modulation-detection format, and the signal baud rate. It is also shown how the effects of polarization multiplexing can be taken into account and how this single-channel non-linear noise contribution can be used in a wavelength-division multiplexing (WDM) environment.
TL;DR: In this article, a broadband gallium-nitride-based light-emitting diode with a one-dimensional photonic crystal layer is investigated, which has high reflectance over a 270nm bandwidth in visible light at an arbitrary incidence angle.
Abstract: In this article, a broadband gallium-nitride-based light-emitting diode with a one-dimensional photonic crystal layer is investigated. The broadband light-emitting diode using the proposed backside reflector has high reflectance (>95%) over a 270-nm bandwidth in visible light at an arbitrary incidence angle. A broadband light-emitting diode of high output power due to the high reflectivity is achieved. Also reported are the results for light-emitting diodes by the transistor outline can (TO-can) package. The proposed light-emitting diodes possess broadband high reflected spectra, high output power for light extraction, and a good view angle.
TL;DR: In this paper, a dual-mode reflection filter is proposed based on the photonic energy band of a coupled microring resonator string and the resonant condition of the circular array.
Abstract: A circular array consisting of an odd number of microring resonators is a dual-mode reflection filter. Based on the photonic energy band of a coupled microring resonator string and the resonant condition of the circular array, reflection characteristics of the circular array filter are discussed in detail. The parameters that influence the reflection characteristics and their effect mechanisms are demonstrated. The critical coupling phenomenon and its condition are revealed. We also show that the existence of loss in the rings can suppress split peaks and subsequently flatten the reflection spectrum to the whole pass band. Our work illuminates the application potential of a circular array of an odd number of microring resonators as an integrated photonics reflection filter.
TL;DR: In this paper, the authors review the key technology developments of the last century up to the present and discuss the criteria that are needed to justify the application of a new technology like optical fibers to existing communication and sensing systems, and make it cost effective.
Abstract: In the first part of this presentation, I review the key technology developments of the last century up to the present. These developments are what led us to the communication and information revolution. This is followed by a discussion of how the use of optical fibers brought about the fusion of these two elements and the resultant proliferation of smart phones and social networks. In the second part, I recollect some of my work in fiber optics over a period of forty years in the context of those key developments. In particular, I stress what it takes for a company small in comparison to the giants in the field to capture niche markets. I also discuss the criteria that are needed to justify the application of a new technology like optical fibers to existing communication and sensing systems, and make it cost effective. I end this presentation with a few personal considerations regarding technology developments and innovation.
TL;DR: In this paper, an experimental demonstration of an SCM-PON system with baseband embedded optical time domain reflectometer (OTDR) monitoring is presented, and the results show a negligible power penalty while achieving a ~12dB dynamic range (DR) with 10-meters spatial resolution.
Abstract: The fibre and wireless convergence in access network is motivating the use of different technologies in order to enable the fifth generation mobile communications (5G). On this scope, the combination of subcarrier multiplexing (SCM) and passive optical networks (PON) can provide an efficient and cost-effective solution for the transportation of different radio access technologies (RAT). Moreover in order to reduce the operational expenditure (OPEX), a reliable monitoring technique should provide in-service, rapid and detailed evaluation of the physical layer. Here, we perform the experimental demonstration of an SCM-PON system with baseband embedded optical time domain reflectometer (OTDR) monitoring. Based on the long term evolution (LTE) downlink test model (E-TM 3.1) our results show a negligible power penalty while achieving a ~12dB dynamic range (DR) with 10-meters spatial resolution.
TL;DR: A new technique, working at the physical layer, provides strong information security without introducing complex processing and thus latency in optical-fiber communications without bandwidth consumption.
Abstract: A new technique is proposed to improve information confidentiality in optical-fiber communications without bandwidth consumption. A pseudorandom vectorial sequence was generated by a dynamic system algorithm and used to codify a multi-level polarization modulation based on the Stokes vector. Optical-fiber birefringence, usually considered as a disturbance, was exploited to obfuscate the signal transmission. At the receiver end, the same pseudorandom sequence was generated and used to decode the multi-level polarization modulated signal. The proposed scheme, working at the physical layer, provides strong information security without introducing complex processing and thus latency.
Journal Article•
TL;DR: In this paper, the authors investigated the optical resonance spectra of free-standing monolithic single crystal silicon microspheres immersed in various amorphous fluids, such as air, water, ethylene glycol, and 4-Cyano-4’-pentylbiphenyl nematic liquid crystal.
Abstract: This study investigates the optical resonance spectra of free-standing monolithic single crystal silicon microspheres immersed in various amorphous fluids, such as air, water, ethylene glycol, and 4-Cyano-4’-pentylbiphenyl nematic liquid crystal. For the various amorphous fluids, morphology-dependent resonances with quality factors on the order of 105 are observed at 1428 nm. The mode spacing is always on the order of 0.23 nm. The immersion in various amorphous fluids affects the spectral response of the silicon microsphere and heralds this technique for use in novel optofluidics applications. Even though the nematic liquid crystal is a highly birefringent, scattering, and high-index optical medium, morphology-dependent resonances with quality factors on the order of 105 are observed at 1300 nm in the elastic scattering spectra of the silicon microsphere, realizing a liquid-crystal-on-silicon geometry. The relative refractive index and the size parameter of the silicon microsphere are the paramete...
TL;DR: Initial observations drawn from numerical survey data gathered over the last decade in several countries/regions are overviewed, and one result implies that implementing new/future services must consider the gross domestic product impact.
Abstract: The recent dramatic advances in information and communication technologies have yielded new environments. However, adoption still differs area by area. To realize the future broadband environment that everyone can enjoy everywhere, several technical issues have to be resolved before network penetration becomes ubiquitous. One such key is the use of fiber optics for the home and mobile services. This article overviews initial observations drawn from numerical survey data gathered over the last decade in several countries/regions, and gives some example scenarios for network/service evolution. One result implies that implementing new/future services must consider the gross domestic product impact.