label: url

en: Terahertz wireless communication in a 560-GHz band using a Kerr micro-resonator soliton comb

en: Optics Continuum

ja: Optics Continuum


en: Graphene-assisted synthesis NH3 gas sensor based on silicon photonics crystal fiber and surface plasmon resonance

en: Optik

ja: Optik


en: Simultaneous measurement of temperature and refractive index based on an SPR Silicon core fiber sensor with a fused silica grating design

en: Optical and Quantum Electronics

ja: Optical and Quantum Electronics


en: Accurate Peak Detection for Optical Sensing with Reduced Sampling Rate and Calculation Complexity

en: Sensors

ja: Sensors


en: Broadband silicon core photonics crystal fiber polarization filter based on surface plasmon resonance effect

en: Optics Communications

ja: Optics Communications


en: D-shaped silicon core fiber-based surface plasmon-resonance refractive index sensor in 2 um

en: Applied Optics

ja: Applied Optics


en: Pilot beam-assisted adaptive compensation for atmospheric turbulence in free-space optical transmission of beams carrying orbital angular momentum

en: Japanese Journal of Applied Physics

ja: Japanese Journal of Applied Physics


en: 8-ary OAM Shift Keying for Free-Space Optical Communication System

en: Optical Engineering

ja: Optical Engineering


en: A Simple Beam Expanded for Indoor Optical Wireless Communication with Short Transmission Distance


en: All-Optical Modulation Format Conversion Between OOK, QPSK and 8QAM

en: IEEE/OSA Journal of Lightwave Technology


en: Optical Ammonia Gas Sensor with Adjustable Sensitivity Using Silicon Microring Resonator Covered with Monolayer Graphene

en: Japanese Journal of Applied Physics, Part 1 (Special Issues)


en: Adaptive Compensation for Angular Deflection of Beams Carrying Orbital Angular Momentum on Mode Sorting

ja: Japanese Journal of Applied Physics, Part 1 (Special Issues)


en: Waveguide-Type Optical Circuits for Recognition of Optical 8PSK-Coded Labels


en: Analysis of Optical OAM Mode Conversion Using Elastic Vortex Wave in Graded Index Optical Fiber


en: Mode Sorting Performance for Optical Beams Carrying Orbital Angular Momentum Suffering Lateral Displacement and Angular Deflection


en: Waveguide-type optical circuits for recognition of optical 8QAM-coded label


en: All-Optical Modulation Format Conversion from QPSK to Symbol Rate Doubled BPSK Using FWM and Pulse Width Compression

ja: IEEE/OSA Journal of Lightwave Technology


en: Optical Thresholder Consisting of Two Cascaded Mach-Zehnder Interferometers with Nonlinear Microring Resonators


en: Multi-point temperature sensing using a linear-cavity lasing system

en: A multi-point fiber sensing system formed from a linear cavity laser is proposed. Various optical sensing systems have been investigated, for example, using fiber Bragg grating (FBG) and Brillouin scattering for multi-point sensing. This paper focuses on a simple sensing system by using multi-wavelength lasing with parallel cavities and a semiconductor optical amplifier (SOA). First, optical nonlinearity in amplification of the SOA is discussed to clarify the effects of gain saturation and four-wave mixing on the proposed multi-channel sensing system. And then lasing conditions in the linear cavity laser consisting of an SOA, an arrayed waveguide grating (AWG), and FBGs are theoretically investigated. The multi-wavelength lasing power is found to be limited mainly by gain saturation in the SOA. The lasing power for the eight-channel system is evaluated to be -8.5 dBm when the total loss in the linear cavity is 10 dB. The lasing power can be increased by 3 dB when the channel number is decreased to four. Next, multi-wavelength lasing in the cavity consisting of an SOA, an AWG, a loop mirror, and fiber mirror reflectors is experimentally demonstrated up to eight channels. Finally, two-channel temperature sensing ranging from 13°C to 76°C is experimentally confirmed by using two FBGs as the sensing elements with an AWG having 100-GHz bandwidth.

en: Applied Optics


en: Increase of Recognizable Label Number with Optical Passive Waveguide Circuits for Recognition of Encoded 4- and 8-Bit BPSK Labels

en: Optical label processing is expected to reduce power consumption in label switching network nodes. Previously, we proposed passive waveguide circuits for the recognition of BPSK labels with a theoretically infinite contrast ratio. The recognizable label number was limited to four and eight for 4-bit and 8-bit BPSK labels, respectively. In this paper, we propose methods to increase the recognizable label number. The proposed circuits can recognize eight and sixteen labels of 4-bit BPSK codes with a contrast ratio of 4.00 and 2.78, respectively. As 8-bit BSPK codes, 64, 128, and 256 labels can be recognized with a contrast ratio of 4.00, 2.78, and 1.65, respectively. In recognition of all encoded labels, that is, 16 and 256 labels for 4-bit and 8-bit BPSK labels, a reference signal is employed to identify the sign of the optical output signals. The effect of phase deviation and loss along the optical waveguides of the devices is also discussed.

en: IEICE Transactions on Electronics

ja: IEICE Transactions on Electronics


en: All-Optical Wavelength Preserved Modulation Format Conversion From PDM-QPSK to PDM-BPSK Using FWM and Interference


en: Noise Tolerance in Optical Waveguide Circuits for Recognition of Optical 16 Quadrature Amplitude Modulation Codes

en: Optical Engineering


en: Improvement of Contrast Ratio in QPSK Optical Label Recognition with Passive Optical Waveguide Circuit


en: Microscopic Raman Study of Graphene on 4H-SiC Two-Dimensionally Enhanced by Surface Roughness and Gold Nanoparticles

en: Japanese Journal of Applied Physics


en: Performance Analysis of All-Optical Wavelength-Shift-Free Format Conversion from QPSK to Two BPSK Tributaries Using FWM and Interference


en: All-Optical Switch with Cascaded Two-Stage Mach-Zehnder Interferometers Using Saturable Absorption Accompanied by Refractive-Index Change in Graphene

en: IEEE/OSA Journal of Lightwave Technology


en: 409-Tb/s + 409-Tb/s crosstalk suppressed bidirectional MCF transmission over 450 km using propagation-direction interleaving

en: We demonstrate bidirectional transmission over 450 km of newly-developed dual-ring structured 12-core fiber with large effective area and low crosstalk. Inter-core crosstalk is suppressed by employing propagation-direction interleaving, and 409-Tb/s capacities are achieved for both directions.

en: Optics Express

ja: Optics Express


en: Proposal of Optical Waveguide Circuits for Recognition of Optical QAM Codes


en: Optical Label Routing Processing for BPSK Labels Using Complex-Valued Neural Network


en: Optical QPSK Label Recognition by Time-Space Conversion using Two-Dimensional Matched Filtering

en: Journal of Communication and Computer

ja: Journal of Communication and Computer


en: All-optical switch consisting of two-stage interferometers controlled by using saturable absorption of monolayer graphene

en: At routing nodes in future photonic networks, pico-second switching will be a key function. We propose an all-optical switch consisting of two-stage Mach-Zehnder interferometers, whose arms contain graphene saturable absorption films. Optical amplitudes along the interferometers are controlled to perform switching between two output ports instead of phase control used in conventional switches. Since only absorption is used for realizing complete switching, insertion loss of 10.2 dB is accompanied in switching. Picosecond response can be expected because of the fast response of saturable absorption of graphene. The switching characteristics are theoretically analyzed and numerically simulated by the finite-difference beam propagation method (FD-BPM).


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


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

en: 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.

en: IEICE Transactions on Electronics


en: All-Optical Wavelength-Selective Switch Consisting of Asymmetric X-junction Couplers and Raman Amplifiers for Wide Wavelength Range


en: Designing of Optical Switch Controlled by Light Intensity in Cascaded Optical Couplers

en: Optical Engineering


en: Optical Switch by Light Intensity Control in Cascaded Coupled Waveguides

en: Lightwave switching is discussed with a cascaded connection of optical couplers with light intensity control elements. By employing wavelength-selective amplifiers such as a waveguide-type Raman amplifier, all-optical wavelength-selective switching can be realized. We discuss analytically using coupled-mode theory that the lightwave switching is feasible by controlling the intensity of propagating lightwave. The switching operation is verified numerically using finite-difference beam-propagation method. As a result, the expected operation is realized and some characteristics involved with dependencies of wavelength and phase are also investigated. A preliminary experiment using attenuators, beam splitters and mirrors is also described to verify the switching operation with only light-intensity control in interferometers.


en: Proposal of All-Optical Wavelength-Selective Switching Using Waveguide-Type Raman Amplifiers and 3dB Couplers

en: IEEE/OSA Journal of Lightwave Technology


en: Fiber Bragg grating sensing system with wavelength-swept-laser distribution and self-synchronization

en: Fiber Bragg gratings (FBGs) with various interrogation schemes to estimate the FBG's spectrum shift have been widely used in fiber sensing systems. Wavelength swept laser (WSL) based interrogation architectures have been proposed to offer rapid and high-quality sensing performance. However, for getting higher sensing accuracy, the demands for high-performance WSL may push the system cost. Under these considerations, a WSL distribution architecture allowing multiple sensing processing units (SPUs) to share the WSL is studied in this Letter. A self-synchronization scheme is proposed to enable flexible SPU deployment with no concerns for the clock calibration. The proposed system is experimentally studied. Temperature estimation error of ∼2.5 and ∼0.5 with sensitivities of 0.13°C/ms and 0.14°C/ms, respectively, for the high and small temperature ranges are demonstrated.

en: Optics Letters

ja: Optics Letters


en: Simultaneously two-parameter measurement using tilted fiber grating and long period fiber grating

en: Microwave and Optical Technology Letters


en: Experimental demonstration of simultaneous SPM and XPM mitigation using combined techniques of optical compensation and multichannel single-stage DBP

en: Electronics Letters

ja: Electronics Letters


en: Switching Characteristics of All-Optical Wavelength-Selective Switch Using Waveguide-Type Raman Amplifiers and 3-dB Couplers

en: Switching characteristics such as wavelength dependency and phase dependency are investigated for our proposed switch which consists of waveguide-type Raman amplifiers and 3-dB couplers. As a result, the available range of wavelength and phase shift due to nonlinear effect are estimated about ±20nm around 1.55m and about ±1.0 degrees, respectively.