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Showing papers on "Optical fiber published in 2019"


Journal ArticleDOI
TL;DR: This work is focused on a review of three types of distributed optical fiber sensors which are based on Rayleigh, Brillouin, and Raman scattering, and use various demodulation schemes, including optical time-domain reflectometry, optical frequency-domainreflectometry, and related schemes.
Abstract: Over the past few decades, optical fibers have been widely deployed to implement various applications in high-speed long-distance telecommunication, optical imaging, ultrafast lasers, and optical sensors. Distributed optical fiber sensors characterized by spatially resolved measurements along a single continuous strand of optical fiber have undergone significant improvements in underlying technologies and application scenarios, representing the highest state of the art in optical sensing. This work is focused on a review of three types of distributed optical fiber sensors which are based on Rayleigh, Brillouin, and Raman scattering, and use various demodulation schemes, including optical time-domain reflectometry, optical frequency-domain reflectometry, and related schemes. Recent developments of various distributed optical fiber sensors to provide simultaneous measurements of multiple parameters are analyzed based on their sensing performance, revealing an inherent trade-off between performance parameters such as sensing range, spatial resolution, and sensing resolution. This review highlights the latest progress in distributed optical fiber sensors with an emphasis on energy applications such as energy infrastructure monitoring, power generation system monitoring, oil and gas pipeline monitoring, and geothermal process monitoring. This review aims to clarify challenges and limitations of distributed optical fiber sensors with the goal of providing a pathway to push the limits in distributed optical fiber sensing for practical applications.

329 citations


Journal ArticleDOI
TL;DR: A detailed overview of the experimentally verified optical solitons in fiber lasers can be found in this article, where an outlook for the development on the soliton in fiber laser is provided and discussed.
Abstract: Solitons are stable localized wave packets that can propagate long distance in dispersive media without changing their shapes. As particle-like nonlinear localized waves, solitons have been investigated in different physical systems. Owing to potential applications in optical communication and optical signal processing systems, optical solitons have attracted intense interest in the past three decades. To experimentally study the formation and dynamics of temporal optical solitons, fiber lasers are considered as a wonderful nonlinear system. During the last decade, several kinds of theoretically predicted solitons were observed experimentally in fiber lasers. In this review, we present a detailed overview of the experimentally verified optical solitons in fiber lasers, including bright solitons, dark solitons, vector solitons, dissipative solitons, dispersion-managed solitons, polarization domain wall solitons, and so on. An outlook for the development on the solitons in fiber lasers is also provided and discussed.

272 citations


Journal ArticleDOI
TL;DR: An in-depth review of four devices for generating SPR is presented, and optical fiber is finally adopted for a substrate to generate SPR, and key challenges are identified to develop orientation of optical fiber biosensor based on SPR.

272 citations


Journal ArticleDOI
TL;DR: In this article, a review of the main classes of silica-based optical fibers are presented: radiation tolerant pure-silica core or fluorine doped optical fibers, germanosilicate optical fibers and radiation sensitive phosphosilicates and aluminosa-ilimideal optical fibers.

195 citations


Journal ArticleDOI
TL;DR: Polymer optical fiber Bragg gratings (POFBGs) as discussed by the authors have been used in a wide range of applications, such as sensors, sensors, and actuators, with the consequences of fiber breakage in situ being less hazardous than silica.
Abstract: Interest in polymer optical fiber Bragg gratings (POFBGs) arises from the different material properties and sensing modalities brought by polymers relative to silica. Polymer fibers typically offer twice the sensitivity to temperature of conventional silica fiber and increased sensitivity to strain overall. In addition, polymer fibers have higher elastic limits and as a result a larger range of operation for physical constraints. While some polymers are effectively humidity insensitive, others present inherent humidity sensitivity. Their organic properties also allow a variety of chemical processes to create (bio)chemical sensors, with the consequences of fiber breakage in situ being less hazardous than silica. These attributes have led to the use of POFBGs for applications that remain complex using silica fibers. This review paper covers the progress toward commercialization and the increasing number of specific applications.

180 citations


Journal ArticleDOI
TL;DR: In this article, the basic requirements for the rare-earth (RE) ions and host matrix material for obtaining efficient NIR-MIR laser output, a review of the background of processing fundamentals on the fabrication and characterization for newly developed soft optical glass fibers, an outline of the key issues of platinum removal and the dehydration technique, effective doping of RE, and low splicing loss together with the recent theoretical and experimental results.

163 citations


Journal ArticleDOI
TL;DR: In this article, a novel optic fiber Fabry-Perot interferometer (FPI) based on graphene quantum dots (GQDs) and Polyvinyl Alcohol (PVA) is first proposed for relative humidity (RH) sensing and experimentally demonstrated.
Abstract: A novel optic fiber Fabry-Perot interferometer (FPI) based on graphene quantum dots (GQDs) and Polyvinyl Alcohol (PVA) is first proposed for relative humidity (RH) sensing and experimentally demonstrated. The GQDs-PVA compounds are filled into the hollow core fiber (HCF), which is spliced at the end of a single mode fiber (SMF). The refractive index of GQDs-PVA compounds reduces and the length of the FP cavity elongates with the increase of RH, which will lead the reflective spectrum shift to length wavelength, and the variation can characterize the change of RH values. The humidity environment is generated by different saturated saline solution, and the RH values are calibrated by a moisture meter. Experiment results reveal that the wavelength shift shows good linearity with the RH changing from 13.47%RH to 81.34%RH, and the sensitivity is 117.25 pm/%RH with the linearity relevancy of 0.9983. In addition, reversibility and repeatability experiments are carried out and the mean square deviation of six sets of data is 1.425 × 10−3, which indicates good practical development prospects. Taking the practical application into account, the influence of hydrogen and nitrogen in the air on the sensor is studied before humidity experiment, and the experiment results shows that hydrogen and nitrogen in the air have a negligible effect on the humidity sensor proposed in this paper.

151 citations


Journal ArticleDOI
TL;DR: A novel scattering-matrix-assisted retrieval technique (SMART) to demultiplex OAM channels from highly scattered optical fields is proposed and high-fidelity transmission of both gray and color images under scattering conditions is demonstrated, reducing the error rate by 21 times compared to previous reports.
Abstract: Multiplexing multiple orbital angular momentum (OAM) channels enables high-capacity optical communication. However, optical scattering from ambient microparticles in the atmosphere or mode coupling in optical fibers significantly decreases the orthogonality between OAM channels for demultiplexing and eventually increases crosstalk in communication. Here, we propose a novel scattering-matrix-assisted retrieval technique (SMART) to demultiplex OAM channels from highly scattered optical fields and achieve an experimental crosstalk of –13.8 dB in the parallel sorting of 24 OAM channels after passing through a scattering medium. The SMART is implemented in a self-built data transmission system that employs a digital micromirror device to encode OAM channels and realize reference-free calibration simultaneously, thereby enabling a high tolerance to misalignment. We successfully demonstrate high-fidelity transmission of both gray and color images under scattering conditions at an error rate of <0.08%. This technique might open the door to high-performance optical communication in turbulent environments.

147 citations


Journal ArticleDOI
20 Nov 2019
TL;DR: In this article, a perspective overview of the emerging field of nonlinear optics in multimode optical fibers is provided for the ultrafast light-activated control of temporal, spatial, and spectral degrees of freedom of intense, pulsed beams of light for a range of different technological applications.
Abstract: We provide a perspective overview of the emerging field of nonlinear optics in multimode optical fibers. These fibers enable new methods for the ultrafast light-activated control of temporal, spatial, and spectral degrees of freedom of intense, pulsed beams of light, for a range of different technological applications.

142 citations


Journal ArticleDOI
TL;DR: In this paper, the shape of a flexible instrument is reconstructed using Frenet-Serret equations in conjunction with the calculated curvature and torsion of the instrument, and the results show that shape sensing for flexible medical instruments is feasible with FBG sensors in multi-core fibers.
Abstract: This paper presents a technique to reconstruct the shape of a flexible instrument in three-dimensional Euclidean space based on data from fiber Bragg gratings (FBGs) that are inscribed in multi-core fibers. Its main contributions are the application of several multi-core fibers with FBGs as shape sensor for medical instruments and a thorough presentation of the reconstruction technique. The data from the FBG sensors are first converted to strain measurements, which is then used to calculate the curvature and torsion of the fibers. The shape of the instrument is reconstructed using Frenet–Serret equations in conjunction with the calculated curvature and torsion of the instrument. The reconstruction technique is validated with a catheter sensorized with four multi-core fibers that have FBG sensors. The catheter is placed in eight different configurations and the reconstruction is compared to the ground truth. The maximum reconstruction error among all the configurations is found to be 1.05 mm. The results show that shape sensing for flexible medical instruments is feasible with FBG sensors in multi-core fibers.

125 citations


Journal ArticleDOI
17 May 2019-Sensors
TL;DR: A review of the basic sensing platforms implemented using tapered optical fibres and their application for development of fibre-optic physical, chemical and bio-sensors is presented.
Abstract: The development of reliable, affordable and efficient sensors is a key step in providing tools for efficient monitoring of critical environmental parameters. This review focuses on the use of tapered optical fibres as an environmental sensing platform. Tapered fibres allow access to the evanescent wave of the propagating mode, which can be exploited to facilitate chemical sensing by spectroscopic evaluation of the medium surrounding the optical fibre, by measurement of the refractive index of the medium, or by coupling to other waveguides formed of chemically sensitive materials. In addition, the reduced diameter of the tapered section of the optical fibre can offer benefits when measuring physical parameters such as strain and temperature. A review of the basic sensing platforms implemented using tapered optical fibres and their application for development of fibre-optic physical, chemical and bio-sensors is presented.

Journal ArticleDOI
TL;DR: In this paper, a 32 × 32 silicon photonics switch on a 300mm silicon-on-insulator wafer was fabricated using a complementary metaloxide-semiconductor pilot line equipped with an immersion ArF scanner and demonstrated an average fiber-to-fiber insertion loss of 10.8 dB with a standard deviation of 0.54 dB, and on-chip electric power consumption of 1.9 W.
Abstract: We fabricate a 32 × 32 silicon photonics switch on a 300-mm silicon-on-insulator wafer by using our complementary metal-oxide-semiconductor pilot line equipped with an immersion ArF scanner and demonstrate an average fiber-to-fiber insertion loss of 10.8 dB with a standard deviation of 0.54 dB, and on-chip electric power consumption of 1.9 W. The insertion loss and the power consumption are approximately 1/60, and less than 1/4 of our previous results, respectively. These significant improvements are achieved by design and fabrication optimization of waveguides and intersections on the chip, and by employing a novel optical fiber connector based on extremely-high-Δ silica planar-lightwave-circuit (PLC) technology. The minimum crosstalk was −26.6 dB at a wavelength of 1547 nm, and −20-dB crosstalk bandwidth was 3.5 nm. Furthermore, we demonstrate low-crosstalk bandwidth expansion by using output port exchanged element switches. We achieve a −20 dB crosstalk bandwidth of 14.2 nm, which is four-times wider than that of the conventional element switch based 32 × 32 switch.

Journal ArticleDOI
TL;DR: In this article, a hybrid sensing network constituted by fiber Bragg gratings and Fabry-Perot cavities is proposed for the discrimination of strain and temperature in Li-ion batteries.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed and demonstrated a scheme to optimize the fiber input powers for UWB transmission systems considering the signal power transition caused by the inter-band stimulated Raman scattering (SRS).
Abstract: Ultra-wideband (UWB) wavelength division multiplexed (WDM) transmission using high-order modulation formats is one of the key techniques to expand the transmission capacity per optical fiber. For UWB systems, the nonlinear interaction caused by inter-band stimulated Raman scattering (SRS) must be considered. Therefore, we have proposed and demonstrated a scheme to optimize the fiber input powers for UWB transmission systems considering the signal power transition caused by the inter-band SRS. We demonstrated a single-mode capacity of 150.3 Tb/s using the proposed power optimization scheme with 13.6-THz UWB in the S-, C-, and L-bands over 40-km transmission. Spectral efficiency of 11.05 b/s/Hz was achieved with 272-channel 50-GHz spaced WDM signals of 45-GBaud polarization division multiplexed 128 quadrature amplitude modulation.


Journal ArticleDOI
Xue Zhou1, Xuegang Li1, Shuguang Li1, Guowen An1, Tonglei Cheng1 
TL;DR: Compared with other optical fiber magnetic field sensors, the advantages of the proposed sensor in this paper are simple structure, small in size, easy to make, low cost, high sensitivity, and anti-interference.
Abstract: A novel magnetic field sensing system based on surface plasma resonance (SPR) optical fiber sensor and filled with magnetic fluid (MF) is proposed and demonstrated for the first time. In the magnetic field SPR optical fiber sensor, SPR is excited by Ag as metallic material and MF is filled into the capillary sealed with epoxy glue, which utilizes the tunable refractive index (RI) of MF, and the transmission spectrum will change with different magnetic field intensities. The magnetic-optic effect of MF and the high RI sensitivity of optical fiber SPR sensor are utilized to enhance the sensitivity of the novel magnetic field sensor significantly. In the experiment, the performances of the magnetic field sensing system are tested by applying different measured magnetic fields. The final results indicated that a sensitivity of 303 pm/Gs is achieved. Compared with other optical fiber magnetic field sensors, the advantages of the proposed sensor in this paper are simple structure, small in size, easy to make, low cost, high sensitivity, and anti-interference.

Journal ArticleDOI
TL;DR: A state-of-the-art review on strain transfer theory of optical fiber based sensors developed for civil structures is addressed and provides scientific guidance for the better understanding of the multi-layered sensing model and the theoretical instruction for the optimum design, calibration and measurement accuracy enhancement of optical Fiber sensors.
Abstract: Optical fiber sensors are the most promising technique in monitoring physical and chemical variables of civil structures. For the brittle material characteristics, a bare sensing fiber is prone to breakage under the shear or torsional action existed in the construction and operation. To guarantee the survival and long-term service of the sensors, the packaging measure is particularly significant. This treatment generates an intermedium layer between the sensing fiber and the monitored structure, which leads to the strain of the host material not entirely transferred to the sensing fiber for a portion of strain loss in the transferring path. To correct the error and improve the measurement accuracy, strain transfer theory is developed to establish the quantitative strain relationship between the sensing fiber and the host material. A state-of-the-art review on strain transfer theory of optical fiber based sensors developed for civil structures is addressed. It aims to demonstrate the advance, the application and the challenge of strain transfer theory and provide scientific guidance for the better understanding of the multi-layered sensing model and the theoretical instruction for the optimum design, calibration and measurement accuracy enhancement of optical fiber sensors.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the different materials of optical fibers, two of them are plastic optical fibers that are namely polysulfone (PSU)/vinyl-phenyl acetate (VPAC) with refractive indices of 1.63/1.567, and the second plastic material namely sapphire (S)/polysulone(PSU) with this paper.
Abstract: This paper investigated the different materials of optical fibers, two of them are plastic optical fibers that are namely polysulfone (PSU)/vinyl-phenyl acetate (VPAC) with refractive indices of 1.63/1.567, and the second plastic material namely sapphire (S)/polysulfone (PSU) with refractive indices of 1.77/1.63. One of the other materials consists of fluorite (FT)/polytetrafluorophenylmethacrylate (PTFPMA) with refractive indices of 1.433/1.422, where the second material consists of fluoride (FD)/poly methylmethacrylate (PMMA) with refractive indices of 1.56/1.49. Finally, the third material consists of silica (Si)/tetrafluoropropylmethacrylate (TFPMA) with refractive indices of 1.46/1.373. The simulation results are done by using optiwave simulation version 13. FT/PTFPMA fiber channel has outlined 19.23 Tb/s bit-rate with maximum Q-factor of 11.01, a minimum bit error rate of 1.05 × 10−28, gain value of 36.57 dB, and noise figure of 5.67 dB in the presence of vertical-cavity surface-emitting laser (VCSEL). It is observed that VCSEL has superior to continuous wave (CW) laser by the improvement of the performance parameters understudy at the same operating conditions.

Journal ArticleDOI
TL;DR: A simple, but highly sensitive sensor based on two intrinsic Fabry-Perot interferometers inscribed in a standard single-mode optical fiber that allows real-time and in situ strain and temperature monitoring under harsh environments.
Abstract: In this Letter, we report on a simple, but highly sensitive sensor based on two intrinsic Fabry–Perot interferometers (FPIs) inscribed in a standard single-mode optical fiber. A brief theoretical study on the Vernier effect is presented, in which a simulation of the sensitivity magnification factor dependence on the FPI’s length is performed. Based on the simulation results, the FPIs were fabricated using a custom micromachining setup that integrates a near-infrared femtosecond laser and a motorized XYZ platform. Using the Vernier effect, sensitivities of 145 pm/μe and 927 pm/°C were obtained for strain and temperature, respectively. The sensor’s performance combined with its versatile and customizable configuration allows real-time and in situ strain and temperature monitoring under harsh environments.

Journal ArticleDOI
TL;DR: A low-loss mode size converter for coupling between a standard lensed fiber and sub-micrometer LN rib waveguides is experimentally demonstrated and opens the door for practical integrated LN photonic circuits efficiently interfaced with optical fibers.
Abstract: Integrated lithium niobate (LN) photonic circuits have recently emerged as a promising candidate for advanced photonic functions such as high-speed modulation, nonlinear frequency conversion, and frequency comb generation. For practical applications, optical interfaces that feature low fiber-to-chip coupling losses are essential. So far, the fiber-to-chip loss (commonly >10 dB/facet) has dominated the total insertion losses of typical LN photonic integrated circuits, where on-chip losses can be as low as 0.03–0.1 dB/cm. Here we experimentally demonstrate a low-loss mode size converter for coupling between a standard lensed fiber and sub-micrometer LN rib waveguides. The coupler consists of two inverse tapers that convert the small optical mode of a rib waveguide into a symmetrically guided mode of a LN nanowire, featuring a larger mode area matched to that of a tapered optical fiber. The measured fiber-to-chip coupling loss is lower than 1.7 dB/facet with high fabrication tolerance and repeatability. Our results open the door for practical integrated LN photonic circuits efficiently interfaced with optical fibers.

Journal ArticleDOI
TL;DR: In this paper, the most significant contributions in the field of fiber optic plasmonic sensors (FOPS) in recent years are discussed in detail, including the optical transduction mechanisms of FOPS with different geometrical structures and the photonic properties of the geometries.
Abstract: The survey focuses on the most significant contributions in the field of fiber optic plasmonic sensors (FOPS) in recent years. FOPSs are plasmonic sensor-based fiber optic probes that use an optical field to measure the biological agents. Owing to their high sensitivity, high resolution, and low cost, FOPS turn out to be potential alternatives to conventional biological fiber optic sensors. FOPS use optical transduction mechanisms to enhance sensitivity and resolution. The optical transduction mechanisms of FOPS with different geometrical structures and the photonic properties of the geometries are discussed in detail. The studies of optical properties with a combination of suitable materials for testing the biosamples allow for diagnosing diseases in the medical field.

Journal ArticleDOI
TL;DR: In this paper, a multimode random fiber laser with multi-ransverse modes is used as an illumination light source to effectively reduce the speckle in imaging, which can naturally inherit all the advantages of single-mode random fiber lasers, including flexible wavelength, robust structure, and high power.
Abstract: Light sources with high radiance are increasingly required for full-field real-time imaging. Conventional lasing sources are poorly suited for such imaging due to their high spatial or temporal coherence, which generates a speckle that deteriorates image quality. Here, a random fiber laser with multitransverse modes is used as an illumination light source to effectively reduce the speckle in imaging. Low spatial coherence and low temporal coherence of the random fiber laser give birth to significant reduction in the speckle. Under the power-limited condition, the multimode random fiber laser is verified to have a comparable or even better imaging quality compared to a multimode amplified spontaneous emission source. Furthermore, its potential to generate ultrahigh power of up to hundreds of Watts with extremely-high spectral density would make a breakthrough in the development of a new generation of high-power low-coherence light sources for many speckle-free imaging applications, where conventional light sources are not usable. As the multimode random fiber laser can naturally inherit all the advantages of single-mode random fiber lasers, including flexible wavelength, robust structure, and high power, this paper may provide a platform to develop powerful low-coherence light sources to meet wide range requirements of the full-field real-time speckle-free imaging.

Journal ArticleDOI
TL;DR: In this paper, the authors exploit modal properties of tapered optical fibers (TFs) to enable light collection over an extent of up to 2'mm of tissue and multisite photometry along the taper.
Abstract: Fiber photometry is increasingly utilized to monitor fluorescent sensors of neural activity in the brain. However, most implementations are based on flat-cleaved optical fibers that can only interface with shallow tissue volumes adjacent to the fiber. We exploit modal properties of tapered optical fibers (TFs) to enable light collection over an extent of up to 2 mm of tissue and multisite photometry along the taper. Using a single TF, we simultaneously observed distinct dopamine transients in dorsal and ventral striatum in freely moving mice performing a simple, operant conditioning task. Collection volumes from TFs can also be engineered in both shape and size by microstructuring the nonplanar surface of the taper, to optically target multiple sites not only in the deep brain but, in general, in any biological system or organ in which light collection is beneficial but challenging because of light scattering and absorption. Fiber photometry with tapered fibers allows monitoring of neural activity in larger volumes than with flat-cleaved fibers. In addition, signals from different depths can be resolved with the same tapered fiber.

Journal ArticleDOI
TL;DR: In this article, a new fiber optic reflective probe is designed for simultaneous detection of salinity, temperature, and pressure in seawater, which is the first time that these three parameters are measured by an integrated reflex optical fiber sensor.

Journal ArticleDOI
TL;DR: Thanks to the outstanding nonlinear effect and semimetal of the bismuthene, dual-pulses, octonary-pulse molecules with tightly and loosely temporal separation can be achieved for the first time, to the best of the authors' knowledge.
Abstract: Bismuthene, a mono-elemental two-dimensional material with a novel kind of few-layer structure purely consisting of bismuth, has been predicted to have a prominent optical response and enhanced stability in theory. In this paper, few-layer bismuthene is employed as the saturable absorber. The mode-locker is fabricated by dropping bismuthene on a microfiber in a passively mode-locked, Er-doped fiber laser. The single pulse can be obtained at 122.1 mW, with 621.5 fs pulse duration at 1557.5 nm central wavelength, 10.35 nm spectral width and fundamental repetition of 22.74 MHz. Thanks to the outstanding nonlinear effect and semimetal of the bismuthene, dual-pulses, octonary-pulses and fourteen-pulses soliton molecules with tightly and loosely temporal separation can be achieved for the first time, to the best of our knowledge. The preceding indicates that bismuthene will have wide potential in many applications, such as optical fiber communications, optical logical gate, and laser materials processing, etc.

Journal ArticleDOI
TL;DR: In this article, a low-loss mode size converter for coupling between a standard lensed fiber and sub-micrometer LN rib waveguides is proposed, which consists of two inverse tapers that convert the small optical modes of a rib waveguide into a symmetric guided mode of a LN nanowire.
Abstract: Integrated lithium niobate (LN) photonic circuits have recently emerged as a promising candidate for advanced photonic functions such as high-speed modulation, nonlinear frequency conversion and frequency comb generation. For practical applications, optical interfaces that feature low fiber-to-chip coupling losses are essential. So far, the fiber-to-chip loss (commonly > 10 dB) dominates the total insertion losses of typical LN photonic integrated circuits, where on-chip propagation losses can be as low as 0.03 - 0.1 dB/cm. Here we experimentally demonstrate a low-loss mode size converter for coupling between a standard lensed fiber and sub-micrometer LN rib waveguides. The coupler consists of two inverse tapers that convert the small optical mode of a rib waveguide into a symmetric guided mode of a LN nanowire, featuring a larger mode area matched to that of a tapered optical fiber. The measured fiber-to-chip coupling loss is lower than 1.7 dB/facet with high fabrication tolerance and repeatability. Our results open door for practical integrated LN photonic circuits efficiently interfaced with optical fibers.

Journal ArticleDOI
TL;DR: The enhancement of performance operation efficiency of submarine optical communication systems toward multi Tb/s and the importance of minimizing dispersion slope within choosing suitable hybrid commercial submarine optical fibers to ensure good channel performance and wide system bandwidth is shown.

Journal ArticleDOI
TL;DR: The nonlinear photonics characteristics of Cu2S and its application in ultrafast lasers have been systematically studied for the first time and indicate that superior nonlinear saturable absorption properties with a modulation depth of 0.51% are achieved.
Abstract: 2D metal chalcogenide materials have received enormous attention due to their extraordinary bio-chemical, electronic, magnetic, thermal and optical properties. Compared with the typical two-dimensional transition metal dichalcogenides (TMDs) and topological insulators, cuprous sulfide (Cu2S) has very different two-dimensional lattice structures, along with excellent electro-catalysis and high conductivity. However, the nonlinear optical properties of Cu2S have never been studied until now. Here, the nonlinear photonics characteristics of Cu2S and its application in ultrafast lasers have been systematically studied for the first time. Through optical deposition of Cu2S nanosheets on a tapered fiber, the nonlinear optical properties of Cu2S nanosheets are measured through the interaction with the evanescent field. The results indicate that superior nonlinear saturable absorption properties with a modulation depth of 0.51% are achieved. An erbium-doped fiber (EDF) laser is constructed to verify the performance of the Cu2S saturable absorber (SA). The results show that an output pulse with 8.06 MHz repetition rate, 1.04 ps pulse duration, 1530.4 nm central wavelength and 3.1 nm spectral width without an obvious Kelly sideband is obtained. Considering the diversity of the metal chalcogenide family, various engineering applications may be developed from the nonlinear saturable absorption characteristics of Cu2S, including optical fiber communication/sensing, precision optical metrology, material processing and nonlinear optics.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a highly sensitive optical fiber strain sensor based on two cascaded Fabry-Perot interferometers and Vernier effect, which is formed by two pairs of in-fiber reflection mirrors fabricated by femtosecond laser pulse illumination to induce refractive index-modified area in the fiber core.
Abstract: One of the efficient techniques to enhance the sensitivity of optical fiber sensor is to utilize Vernier effect. However, the complex system structure, precisely controlled device fabrication, or expensive materials required for implementing the technique creates the difficulties for practical applications. Here, we propose a highly sensitive optical fiber strain sensor based on two cascaded Fabry–Perot interferometers and Vernier effect. Of the two interferometers, one is for sensing and the other for referencing, and they are formed by two pairs of in-fiber reflection mirrors fabricated by femtosecond laser pulse illumination to induce refractive-index-modified area in the fiber core. A relatively large distance between the two Fabry–Perot interferometers needs to be used to ensure the independent operation of the two interferometers. The fabrication of the device is simple, and the cavity's length can be precisely controlled by a computer-controlled three-dimensional micromachining platform. Moreover, as the device is based on the inner structure inside the optical fiber, good robustness of the device can be guaranteed. The experimental results obtained show that the strain sensitivity of the device is ∼28.11 pm/μϵ, while the temperature sensitivity achieved is ∼278.48 pm/°C.

Journal ArticleDOI
TL;DR: The performance signature of the engagement of hybrid symmetrical hybrid compensation techniques for ultra wide bandwidth and ultra long haul optical transmission systems is presented and it is observed that the optimum case for maximum quality factor and minimum BER is achieved with 15 m EDFA amplifier length and 150 mW EDFA pump power.
Abstract: This paper presents the performance signature of the engagement of hybrid symmetrical hybrid compensation techniques for ultra wide bandwidth and ultra long haul optical transmission systems. These schemes that are namely optigrating, ideal dispersion compensation fiber Bragg Grating (IDCFBG), and dispersion compensation fiber (DCF). The combination of mixing these techniques together which is called hybrid symmetrical dispersion compensation techniques in that case. The employment of these mixing schemes is in symmetrical configuration with the presence of Erbium doped fiber amplifiers in order to upgrade optical fiber system capacity to reach transmission distance up to 432 km and transmission data rate up to 320 Gb/s. Maximum signal quality factor, minimum bit error rate (BER), output optical signal to noise ratio, electrical received power after APD photodetector, noise figure, and gain are the major interesting performance parameters for measuring the system operation efficiency. It is observed that the optimum case for maximum quality factor and minimum BER is achieved with 15 m EDFA amplifier length and 150 mW EDFA pump power.