Here we propose a simulation model based on a previously reported analytical description of the Brillouin gain, that takes into account pump depletion, which allows us to make very accurate calculations for Brillouin fiber lasers (BFLs) working both in a single and cascaded multi-wavelength configurations. Output powers and conversion efficiencies are analyzed and compared with experimental results

Routing, spectrum assignment are key issues and the hot focus area in multi-domain elastic optical networks (EONs). When the EONs with multi-cores, more challenges will be faced, such as core allocation, crosstalk, etc. To tackle these challenges, we establish a mixed integer linear programming model with the maximum index used frequency slots (MIUFS) to be minimized, which is used to determine the

The nonlinear characteristics of the electro-optic components are the major limiting factor to realize a multi-level signal transmission. Cascaded multi-modulus algorithm (CMMA) is a popular blind equalization scheme that can compensate for only linear distortions without using any training sequence. In this paper, a modified CMMA is proposed to blindly adapt the tap weights of a receiver-side nonlinear

All optical wavelength converter (AOWC) play important functionalities to enhance the network reconfiguration, efficient wavelength routing and assignment, non-blocking capacity in future dynamic optical access networks. In optical access networks, bandwidth limitation and wavelength continuity constraints lead to inefficient utilization of wavelength resources. AOWCs are the premier option to cope

Given the importance of multicast traffic in current optical networks, many effective multicast routing and spectrum assignment (MRSA) algorithms have been proposed to achieve efficient multicast transmission in elastic optical networks (EONs). However, most of these MRSA algorithms were focus on optimizing only the spectrum resources allocated to multicast service requests, but ignored some fragmented

In many distributed Brillouin fiber-optic sensing systems, Stokes and anti-Stokes scattering have to be separated. Conventionally, optical filtering is adopted for the separation and inevitably incurs loss of the scattering signal due to the close frequency spacing between Stokes and anti-Stokes scattering. In this paper, a new technique to separate Stokes and anti-Stokes scattering is proposed based

In an immunoassay test, which is a representative analytical method for evaluating the performance of a biosensor, the change of the sensor’s output with respect to the continuous change of the measurement target concentration is represented by a graph and defined as the characteristic curve of the sensor. In most studies using biosensors (disposable or not disposable), the characteristic curve of

A low-cost liquid level sensor capable of continuous liquid level sensing is proposed in this work. The sensor is based on twisted tapered plastic optical fibers (POFs) which is fabricated by twisting the tapered POFs around each other. The tapered structure could enhance the evanescent field and the light transmission from one POF to the other. The changes of liquid level can lead to the variations

Brillouin optical correlation-domain reflectometry (BOCDR) is one of the fiber-optic Brillouin-based distributed sensing techniques for strain and temperature with single-end accessibility. Since the first proposal of the basic concept in 2008, the performance of BOCDR has been drastically improved from a variety of aspects including high-speed operation. Here, we focus on one of the high-speed BOCDR

5G mobile fronthaul (MFH) network requires data transmission with large bandwidth and ultra-low latency. Orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM) passive optical network (PON) system is the 5G MFH solution with low spectrum efficiency and large bandwidth. The OFDM/OQAM-PON transmission performance will be undermined by intrinsic imaginary interference

We experimentally demonstrate strain-induced speckle variation. When we take the whole speckle into consideration, the correlation function under different strain decreases dramatically at the beginning, and then it saturates as strain increasing. This tendency has nothing to do with the input wavelength and the length of multimode fiber (MMF), thus the operating cost will be largely reduced if multimode

Generally, broadband absorbers has much non-saturable loss and low laser damage threshold, which limits the average output power of the fiber lasers mode locked by broadband absorbers. Exceptions are the absorbers in evanescent wave mode locking, in which way only weak laser passes through the absorber section. However, evanescent wave mode locking method needs to change the original structure of the

In this review paper, we systematically summarize the various tapered optical fiber geometries and their sensing applications based on MZI. In addition, these geometries exploit strong evanescent field by giving appraise of the current issues with their sensing applications. The main advantage of these geometries is to minimize the size of optical devices, also it offers the possibility of enhanced

Aiming at the problem that traditional peak-seeking algorithms cannot directly detect multiple reflections of Fiber Bragg Grating (FBG) sensing systems, this paper proposes a multi-peak detection algorithm. A seven-point moving average filter is used to process the FBG reflection spectral signal, reduce the high-frequency noise in the spectral signal, and determine the optimal segmentation spectral

The nonlinear mapping characteristic of artificial neural network (ANN) is suitable for temperature extraction from Brillouin scattering spectra in optical fiber sensing system. To further improve the generalization ability of neural network, an optimized method for ANN training is proposed in this paper. Firstly, a set of noisy training data with different linewidth under various temperatures and

A type of total internal reflection photonic crystal fiber (TIR-PCF) with high birefringence and multiple zero dispersion wavelengths is presented. The optical characteristics are numerically investigated by using the full-vector finite element method. Results show that, by setting the geometrical parameters, the mode birefringence can reach to 2.28 × 10−2 at the wavelength of 1.55 μm, and two zero-dispersion

The measurement of pressure by using distributed optical fiber sensors has represented a challenge for many years. While single-point optical fiber pressure sensors have reached a solid level of technology maturity, showing to be very good candidates in replacing conventional electrical sensors due to their numerous advantages, distributed sensors are still a matter of an intense research activity

Transmission–Reflection Analysis (TRA) is an inexpensive technique used in distributed monitoring systems for single perturbation tracking. However, TRA is limited to long distance applications (~km), since it has poor spatial resolution (~m) when combined to standard silica fibers. This paper proposes the use of a magnesium and erbium co-doped optical fiber in conjunction with the TRA technique. The

In this paper, characteristics of tunable slow light of different modes based on intramodal stimulated Brillouin scattering in a few-mode fiber are calculated by the full-vector finite element method. In addition, the influences of doping concentration (GeO2 doped) on the effective refractive index, effective mode area, Brillouin frequency shift, Brillouin threshold, time delay and pulse broadening

Optical fiber based sensor systems often utilize thin dielectric films coated on non-planar surfaces are needed to be inspected for quality assurance. However, non-destructive optical characterization of these films is not a simple method especially on curved large surfaces. In this study, we propose a real time procedure to estimate the optical properties of sub-wavelength transparent dielectric films

Si core fibers were annealed at 1200 °C, the annealing was carried out for 20 min, 30 min, 40 min, 50 min and 60 min, respectively by muffle furnace. The effects of different annealing time on residual stress distribution, crystalline state and the propagation losses of Si core; and the effect of cladding on the residual stresses in Si core were mainly investigated. Annealing could decrease the residual

This study describes the deployment of machine learning algorithm called generalized linear model (GLM) to improve the temperature prediction performance in Brillouin optical time domain analysis (BOTDA) fiber sensor for distributed temperature sensing application. In GLM, the temperature prediction is made from the Brillouin gain spectrum (BGS) and the link function, without the need to determine

We demonstrate cascaded multiple Fabry–Perot interferometers in multimode fiber with a waveguide, inscribed by femtosecond laser micromachining. The device can sustain high temperature up to 1000 °C, and the temperature sensitivity obtained is 10.1 pm/°C and 17.1 pm/°C within the temperature region 100–400 °C and 400–1000 °C respectively. Compared with single-mode fiber, multimode fiber has a larger

Polar coding and sparse code multiple access (SCMA) technique are excellent candidates for 5G, and have a promising prospect in optical communication, the joint design of polar coded sparse code multiple access (PC-SCMA) system is important to enhance the overall system performance. In this paper, a serial joint iterative detection and decoding scheme is proposed by passing message between serial max-log

The re-absorption loss in quantum dot optical fibers (QD-OFs) affects the fiber emission and limits the device performance. This is not only related to fiber parameters (fiber length and diameter, QD concentration, etc.), but also depends on the properties of doped materials to a large extent. Therefore, the emission of QD-OFs for two different QD materials (PbSe and CuInS2/ZnS) were theoretically

In this study, we analyzed the optical fiber coil performance of different quadrupole winding patterns per the differences in birefringent and elastic optical effects of optical fibers. We established both physical and mechanical models of the fiber coil for this purpose. We calculated the distribution of temperature changes and stress points inside the fiber coil with the proposed models under uniform

Nanocrystalline pure and potassium doped α-Fe2−x KxO3−δ (x = 0.03, 0.05) fiber optic gas sensors are proposed for sensing acetone, ethanol, methanol, and ammonia at room temperature. The nanostructured pure α-Fe2O3 and potassium doped α-Fe2−x KxO3−δ (x = 0.03, 0.05) were synthesized by conventional co-precipitation method and crystallite sizes were determined to be 6.02 nm for pure, 5.79 nm for 3%K-Fe2O3

A high precision time delay calibration system based on optical fiber switches and fiber coils network for the satellite range measurement system is proposed in this paper. To reach the high time delay precision, the Phase Stabilized Optical Fiber (PSOF), is proposed to use as time delay component instead of the Single Mode Fiber (SMF) to minimize the temperature dependence of transmission delay time

In order to enhance the physical-layer security of the communication systems in the optical fiber channel, a novel secure communication scheme based on optical code-division multiple-access (OCDMA) technology is proposed and its physical-layer security is quantitatively analyzed. Due to the small capacity of the traditional OCDMA codewords, the address code used by legitimate user is vulnerable to

We propose to use high numerical aperture single mode optical fibers like photonic crystal fiber for lensless in-line holographic microscopy. Highly divergent beam helps to overcome the spatial sampling limitation of the image sensor. In this paper, a submicron lateral resolution has been demonstrated, with an imaging sensor of pixel pitch 1.12 μm and a photonic crystal fiber of mode field diameter

In this work it is proposed a novel all-fiber circular polarization beam splitter (CPBS). The design is based on helically twisted twin-core photonic crystal fiber coupler (HTTC-PCF). The main characteristic of the proposed CPBS device is the capacity to spatially split circularly polarized optical modes with opposite handedness at the twin-cores. For the CPBS to work, a single arbitrary rotated linearly

The frequency spectrum is becoming busier, thereby it might be appealing for more and more, for instance, eavesdroppers to try to gather some valuable data or identify the transmission frequencies for this specific data. To mitigate the possible risks concerning that, not only data encryption but also hiding of the data channels (creation of stealth channels) is necessary. For the success of stealth

A compact refractive index (RI) sensor, based on the Mach-Zehnder Interferometer (MZI), has been developed and experimentally evaluated for the highly sensitive detection and quantification of gases (Helium, Methane, and Carbon Dioxide). The RI sensor utilizes a variety of fibre types: Single Mode Fibre (SMF), Photonic Crystal Fibre (PCF), and Hollow-Core Photonic Crystal Fibre (HC-PCF). In order to

The positioning error of optical components is one of the crucial factors affecting the beam quality for high-power semiconductor laser diode and the fiber coupling efficiency. This paper, derives the evaluation equations for the influence of collimator positioning error of single emitter laser array on light intensity distribution, and explores the effect of positioning error on the shape and position

In this paper, we investigate routing and spectrum allocation (RSA) approaches in elastic optical networks for multicast traffic demands. We consider that a light-tree is constructed for each multicast traffic demand and spectrum is allocated to this light-tree using the first-fit spectrum allocation policy. We present an approximation based Steiner tree approach for RSA (STA-RSA) and compare it with

Different multiplexing techniques for passively addressing fiber-optic sensors and compensation schemes for overcoming the undesirable optical signal losses to provide self-referenced quasi-distributed sensing from intensity-based fiber-optic point sensors are revisited. Furthermore, a passive wavelength division multiplexing (WDM) network operating in reflective configuration with remote Radio-Frequency

This work assesses quasi-distributed Fiber Bragg Gratings (FBGs) and Rayleigh scattering-based distributed sensing for accurate and millimeter resolved thermometry in media undergoing laser ablation. Mono-, two- and three-dimensional temperature measurements were performed with a network of 1 mm-long FBGs in 10-25-40-FBGs-arrays and distributed-sensing fiber with gauge lengths (GL) of 5.2 and 1.3 mm

All-optical wavelength converters (AOWCs) based on state-of-the-art highly nonlinear optical fibers (HNLFs) are best matched with future large-capacity optical networks because of their characteristic of fast response. AOWCs play important roles in wavelength-routed optical networks to alleviate the constraint of conflicted wavelengths and in optical phase conjugation networks to mitigate the effects

Based on the primary electro-optic effect of lithium niobate crystal and combined with a polarizer and a Faraday rotator, a novel spatial non-reciprocal phase modulator design scheme suitable for Sagnac loop structure is proposed. On the one hand, this structure fundamentally eliminates the influence of eigenfrequency on the modulation mode of the system, and improves the sensitivity and accuracy of

A wavelength-number-tunable multi-wavelength SOA fiber laser incorporating a double pass Mach–Zehnder interferometer (MZI) is experimentally demonstrated in this paper. Due to the nonlinear polarization rotation (NPR) effect of SOA, the intensity-dependent loss (IDL) is induced by the combination consisting of SOA and polarization devices to achieve stable multiwavelength output with ultra-narrow wavelength

A magnetic field sensor based on silica microsphere resonator and ferrofluid is proposed and experimentally demonstrated in this paper. A silica fiber taper with a waist diameter of 2 μm is employed to couple the evanescent light into the microsphere with a diameter of 31.21 μm. Whispering gallery modes (WGMs) are excited inside the microsphere resonator and circulate inside the equatorial plane. The

In this paper, we present a simple compact and low threshold laser that has characteristics of Q-switched and multi-wavelength oscillation simultaneously. Multi-wavelength Q-switched oscillation is realized by inserting a Sagnac filter as a multi-wavelength filter and a section of unpumped erbium-ytterbium co-doped fiber (EYDF) into the laser cavity as a saturable absorber (SA). The characteristics

A layered metal carbide/nitride known as MXene owns superior optical properties such as high optical damage tolerance, fast-optical switching capability, and excellent nonlinear transmittance property, making it a favourable SA device for a fiber laser cavity. We synthesis the MXene Ti3C2Tx using selective etching and developed two SA devices, which were MXene-film and MXene D-shaped fiber (MXene-DS)

Distributed polarization coupling detection can be used for force sensing of polarization-maintaining fiber (PMF). In this paper, finite element analysis (FEA) is adopted to simulate the distributed polarization coupling force sensing of PMF. The initial thermal stress birefringence produced by the drawing process of PMF is simulated. In addition, the polarization coupling strength of PMF under transverse

The influence of temperature on a refractive index (RI) sensor based on an in-line fiber Mach-Zehnder interferometer (MZI) was investigated in both simulation and experiment. The RI sensing performance of the sensor was investigated at different temperature (25–60 °C) over an RI range of 1.33–1.37, and the RI sensitivity of the sensor was around −20.00 nm/RIU at different temperature. The results showed

In the current scenario, there is a huge advancement in Information and Communication Technology (ICT), and almost most of the devices used in a smart city are the Internet of Things (IoT) based smart devices. To support high-speed IoT devices, wavelength division multiplexed passive optical networks (WDM-PON) is one of the most promising and most commonly used technology in optical distribution network

Integration of Passive Optical Network (PON) and wireless network technologies can offer a high data rate with ubiquitous Internet access to the end-users. Due to the growing importance of reducing the carbon footprint of telecommunication networks, energy-saving mechanisms are dispensed in the networking equipment. One of the commonly used approaches to reduce energy consumption is the “sleep mode”

This paper proposes a new coding scheme for spectral amplitude coding (SAC) family, known as Sigma Shift Matrix (SSM). Two techniques are proposed for the design of SSM coding scheme. The first technique combines the identity and upper shift matrices to form an SSM coding matrix named as SSMI. The second approach adapts the assembly of a single – entry, lower and upper shift matrices to compose another

The passive generation of Q-switched pulses in an erbium-doped fiber (EDF) laser using a Ti3C2Tx MXene based saturable absorber (SA) was demonstrated. The SA was formed using Ti3AlC2 MAX phase as a precursor for Ti3C2Tx MXene which was obtained by etching Ti3AlC2 using a mixture of lithium fluoride and hydrochloric acid. The generated pulse output was obtained at a central wavelength of 1563 nm with

The sensing of ammonia leakage at room temperature has potential applications in many areas such as industry. A sensitive etched-tapered fiber Bragg grating (FBG) based ammonia sensor is developed and investigated towards different concentrations of ammonia. The investigations are performed at room temperature. FBGs are etched with 50 µm diameter and tapered with 15 and 30 µm waist diameters. These

The white-box optical ecosystem is considered as the future trend in transport networks, which includes the openness in both software and hardware. The openness in hardware decomposes the equipment into multiple independent components to reduce costs. And the openness in software including general YANG models make all components controllable, which enables fast innovation in the control plane of software-defined

An electro-optical polymer optical fiber modulator based on D-shaped few-mode fiber is proposed and optimized. In the D-shaped few-mode fiber, the electro-optic polymer coated on the few-mode fiber influences the refractive index of LP01 mode and LP02 mode, while LP01 mode is more sensitive. According to that, the mode field distribution has been analyzed and the varying properties of D-shaped FMF

An optical fiber crack sensor based on macro-bending loss for detecting the crack opening displacement (COD) is developed in this paper. The sensor incorporates an extremely simple design, light source and detector. The decrease of the light intensity with displacement variation was reported. The verification experiments to the sensing principle were conducted. The sensor shows a response over a wide

We demonstrate an optofluidic microcavity laser based on a hollow-core microstructured optical fiber (HCMOF), which uses the hexagonal silica membrane embedded in the HCMOF as resonator. Fluorescence resonant energy transfer (FRET) effect is introduced into the laser successfully when mixed anthocyanin dye solution is used as gain medium. The threshold of the laser is systematically investigated for

Thulium oxide (Tm2O3) film is demonstrated to work as a passive saturable absorber (SA) for stable pulse generation at 1.55-µm region. The Tm2O3 film was fabricated from a commercially available Tm2O3 embedded into polyvinyl alcohol (PVA) as a film host. The obtained Tm2O3 film has an absorption at 1.55-µm region, which corresponds to energy level diagram of thulium. The Tm2O3 film is switched into

A low-cost optical fibre sensor based on two cascaded balloon-like bent fibre (BBF) structures for simultaneous displacement and temperature measurement is reported. The sensor is fabricated by cascading two balloon-like bent single-mode fibres (SMFs) which with different bending radii, generating two separate interference dips within a limited wavelength range. The wavelength of the two interference

A switchable and tunable multi-wavelength fiber laser based on cascaded hybrid fiber filter (CHFF) is proposed and demonstrated. The CHFF is composed of a single ellipsoid hybrid structure optical fiber filter (SE-HSOFF) and a Sagnac loop interferometer. Here the SE-HSOFF consists of single mode fiber (SMF)-few mode fiber (FMF)-SMF, and there is an ellipsoidal structure fabricated by SMF-FMF. It has

Imperfection of coherent receiver frontend can rapidly degrade system performance in coherent optical transmission systems. Those imperfection, including in-phase/quadrature (I/Q) gain and phase imbalance, and voltage mismatch between the output of integrated coherent receiver (ICR) and the full scaling range of analog-to-digital converter (ADC), become increasingly important, especially when high