Design Of Optical Fiber Research Articles

Vortex Polymer Optical Fiber with 64 Stable OAM States.

This research introduces a numerical design of an air-core vortex polymer optical fiber in cyclic transparent optical polymer (CYTOP) that propagates 32 orbital angular momentum (OAM) modes, i.e., it may support up to 64 stable OAM-states considering left- and right-handed circular polarizations. This fiber seeks to be an alternative to increase the capacity of short-range optical communication systems multiplexed by modes, in agreement with the high demand of low-cost, insensitive-to-bending and easy-to-handle fibers similar to others optical fibers fabricated in polymers. This novel fiber possesses unique characteristics: a diameter of 50 µm that would allow a high mechanical compatibility with commercially available polymer optical fibers, a difference of effective index between neighbor OAM modes of around 10−4 over a bandwidth from 1 to 1.6 µm, propagation losses of approximately 15 × 10−3 dB/m for all OAM modes, and a very low dispersion for OAM higher order modes (±l = 16) of up to +2.5 ps/km-nm compared with OAM lower order modes at a telecom wavelength of 1.3 µm, in which the CYTOP exhibits a minimal attenuation. The spectra of mutual coupling coefficients between modes are computed considering small bends of up to 3 cm of radius and slight ellipticity in the ring of up to 5%. Results show lower-charge weights for higher order OAM modes.

Design of few-mode optical fibers with air-hole structure for MIMO-less data transmission

Rapidly space-division multiplexing (SDM) techniques have drawn attention because the traditional available physical dimensions to orthogonally multiplex data have been almost exhausted. Few-mode fiber becomes a viable option to realize a high-density SDM system. Thus, we propose an air-hole assisted elliptical ring fiber. Four air-holes are introduced surrounding the elliptical ring fiber, and one air-hole is in the core, which can prevent higher-order modes to be cutoff and improve the degeneracy between modes to achieve multiple-input multiple-output-free data transmission. This fiber can support 14 modes in a wide wavelength range from 1.52 to 1.58 μm (h = 5.0 μm, dx = 0.3 μm, and dy = 1.1 μm), and the effective index difference of its adjacent modes is larger than 1.25 × 10 − 4. The fiber we designed would be a strong candidate for SDM to improve optical transmission capacity.

Design and experimental verification of a novel optical fiber for the full ocean depth communication

Micro optical fiber cable has been employed in the full ocean depth vehicle for scientific research, but the high performance of optical fiber requires to meet the demand of high water pressure resistant, large tension force, small bending radius and low loss attenuation. A new optical fiber with cladding-depressed profile was presented, and its attenuation property under high water pressure was simulated by finite element method. The optical fiber was fabricated based on the simulation and was tested by using a high pressure water tank. The experimental results show the additional attenuation change under the pressure of 127 MPa is almost to zero, which is consistent with the simulated result, thus demonstrating the feasibility of designed optical fiber for the full depth ocean research.

Machine learning aided inverse design for few-mode fiber weak-coupling optimization.

Few-mode fiber (FMF) supporting many modes with weak-coupling is highly desired in mode division multiplexing (MDM) systems. The multi-parameter design of FMF becomes comparably difficult, inaccurate and time-consuming when it comes for complex fiber structures and many high order modes. In this work, we demonstrate a machine learning method using neural network to inversely design the desired FMF based on multiple-ring structure. By using the minimum index difference between adjacent modes as the weak-coupling optimization aim, we realize the inverse design of 4-ring step-index FMFs for supporting 4, 6 and 10 -mode operation, and 6-ring step-index FMF for supporting 20-mode operation. This method provides high-accuracy, high-efficiency and low-complexity for fast and reusable design of optical fibers, including particularly weak-coupling FMF in this work. It can be widely extended to a lot of fibers and has great potential for instantaneous applications in the optical fiber industry.

The effect of the optical fiber design on reducing the nonlinear characteristics of the optical fiber

Fiber Bragg Grating FBG Works as a filter within a specific range to counteract the light whose wavelength is within the filter range and allows the light whose wavelength is outside the range of the filter to pass through the carrier light-medium. In communications (fiber-optic) the FBG is used to separate the optical signals. In this paper, the nonlinear optical properties study for optical transmission that consists of an optical transmitter that is transmitting the signal to two different fiber design first is single-mode fiber and second is Coarse Wavelength division multiplexing (CWDM) fiber. Then we enter the Bragg Grating on these two fiber and studies the effect of the Bragg on them. The nonlinear optical characteristic (Q factor and bit error rate BER) is calculated for different fiber length (Km) and input power (dBm) applied on these two fibers and found the best fiber type that has a high Q factor and zero BER. By using optiwave software and matlab (R2015) software program to measure the quality factor, eye diagram and BER of the received signal at the receiver, Results are obtained and installed with graphs and tables.

Designing silicon-core fiber tapers for efficient supercontinuum generation in the greenhouse gas absorption region

We propose a tapered silicon-core optical fiber design for extending the long-wavelength edge of supercontinuum generation to obtain a high spectral density source across the 3–4.5 µm regime. The taper works by generating sufficient spectral broadening of the driving laser pulse to produce a series of pumps for nondegenerate four-wave mixing, and then opening up new phase-matching conditions to transfer the power from these pumps to a target region of mid-infrared wavelengths. We show, by simulation, that this taper design works effectively when pumped with a conventional 2.1 µm femtosecond fiber laser, significantly improving the spectral coverage obtained with a fixed-diameter fiber. Thus, these tapered silicon-core fibers offer a potential platform for an efficient all-fiber spectroscopy solution to measure greenhouse gases.

Design of single-mode optical fiber for low latency used in IoT optical transport networks

Design of single-mode optical fiber for low latency used in IoT optical transport networks

Mathematical Representation of Joint Angle Measurement using Step Index Optic Fibre and Linear Array Photodiode Sensor

Human joint angle measurement involves various applications, for example monitoring of spine movement in sagittal and frontal planes, upper limb motion such as shoulder, neck and elbow, as well as lower limb motion such as hip, knee, and ankle. As the range of motions of different human joints are not similar, the output estimation of the designed sensor for these applications need to be carried out prior to sensor development. In this paper, the conceptual design of low-cost plastic optical fibre based on single step index fibre is illustrated, the mathematical modelling is explained, and the sensor’s hardware assemble is designed using CATIA software, before the estimated sensor output is presented. These results will be used as a reference values for actual optical fibre sensor design in the near future.

An estimation of far-field intensity distribution for photonic crystal fibers based on empirical relations

In this paper, we have reported the far-field intensity distribution for a varied configuration of air holes in the cladding region of the solid-core single-mode photonic crystal fibers (PCFs). Recently, an analytical approach based on the normalized frequency (V parameter) and normalized attenuation constant (W parameter) has been developed for index-guided PCF. Parameters V and W are frequently used in the design of conventional optical fibers. Using the empirical relations for the V parameter as well as W parameter of PCF, the dependence of the far-field intensity distribution on two structural parameters—the air hole diameter and the air hole pitch is calculated and presented. The results displayed here can find their utilization in the design and development of a sensor system based on PCFs for potential applications involving structural health monitoring, medicine, environmental monitoring sensors, and in certain areas of biology and chemistry.

Double-cladding optical fiber design and optimization for simplifying the STED system

Abstract A special double-cladding optical fiber with three-layer step-index structure was introduced for simplifying the stimulated-emission-depletion (STED) microscopy. With this special fiber, a dark hollow beam with decent doughnut-shaped focal spot can be generated for incident light in a specific wavelength range. At the same time, a Gaussian-like beam can be generated when the wavelength of incident light is out of (either longer or shorter than) the specific range. An all-fiber STED illumination system has been achieved by this special fiber. For special cases, a semi-fiber solution based on this special fiber has also been realized.

Design of dual-coated optical fibers to minimize thermally induced static fatigue caused by viscoelastic behavior of commercial polymeric coatings

Abstract The static fatigue test shows that the lifetime of dual-coated optical fibers is governed by the axial tensile stress exerted on the glass fibers. Polymeric coatings of optical fibers own viscoelastic behavior, so the axial tensile stress acted on the glass fibers depends on the time. After recognizing the exact viscoelastic performance of commercial polymeric coatings, the long-term tensile thermal stresses applied to the glass fiber of dual-coated optical fibers are obtained by viscoelastic theory. Following, the influence of thermal stresses on the fiber’s static fatigue is evaluated, and the selection of dual-coated optical fibers to lessen the static fatigue is acquired. To reduce these long-term thermal stresses, the radius, Young’s modulus, thermal expansion coefficient, and relaxation time of the secondary coating should be diminished, but the strain ratio of the secondary coating should be raised. Furthermore, the secondary coating should possess sufficiently radius and Young’s modulus to withstand external mechanical damage.

Robust ultra large bandwidth SMF design using hybrid GA-BF evolutionary algorithm

In this article, a specific design of broad band optical fiber with DWDM purpose is introduced. The key feature in the developed design is the stability in transmission characteristics in installation process. This superior feature is gained by inserting the temperature sensitivity of pulse broadening factor (PBF) and bandwidth (BW) in the cost function of the optimization algorithm. In selection of cost function, the trade-off between increment of BW and decrement of PBF is in target. The cost function consists four terms in which the first two terms control the BW increment and PBF decrement, simultaneously. The further two terms are responsible for stability of the abovementioned parameters against the variation in the environment temperature. Application of the hybrid optimization method of GA-BF in design process is developed.The designed structure holds an ultra-large bandwidth of 297 nm that covers the E + S+C + L communication bands. Also, the BW thermal factor is 22 pm/°C which is extremely small and negligible and shows the high stability of the structure dispersion and dispersion slope when used in field. The designed structure, despite the flattened dispersion, holds a high effective area. This effectively enhances the consequences of power rise due to increment in the number of channels.

Failure of the Weakly Guiding Approximation for Few-Mode Fiber Index Profiles

We demonstrate that for some few-mode fiber index profiles, the weakly guiding approximation (WGA) can be grossly inaccurate in wavelength regions where the true vector modes undergo an HE ↔ EH transition. Within this transition region, the true vector modes have unusual properties, so they cannot be combined with other modes to form LP pseudo-modes. The failure of the WGA in the transition region is likely related to the near degeneracy of the modes obtained under the WGA, signaling the breakdown of standard perturbation theory, under which the WGA modes serve as zeroth-order approximations. We also demonstrate that a small perturbation to a commercial few-mode fiber index profile can introduce an HE ↔ EH transition which is not present in the unperturbed design. Because the WGA can be grossly inaccurate at some wavelengths, it would seem safer to avoid its use for few-mode optical fiber design and simulation, using instead the exact version of Maxwell's equations. At the least, the exact equations should be used to check results obtained by the WGA in wavelength regions of interest.

Controlling the bandwidth of W-type plastic-clad silica optical fibers

A new design of a multimode plastic-clad silica optical fiber that takes the characteristic W-shaped index profile is proposed. The bandwidth and steady-state loss are determined for such a W-type plastic-clad silica optical fiber for the different structural parameters of the fiber. We have shown that the bandwidth of a W-type plastic-clad silica optical fiber is significantly higher (up to 15 times at a fiber length of 2 km) than the bandwidth of the singly clad step index plastic-clad silica optical fiber.

Design and fabrication of touch-sensitive polymeric optical fibre (POF) fabric

Polymeric optical fibres (POFs) can be integrated into a textile structure for illuminative fashion and interior fabric applications. In this study, the development of a touch-sensitive POF fabric system through the integration of conductive yarns and an electronic controlling system was explored. Distinct from conventional sensor applications, the capacitive sensor used in this study was embedded into the textile structure using conductive yarns via experimentations with different weave structures. With the embedded controlling system and RGB light-emitting diodes, the POF fabrics were able to transfer sensory signals into illumination. This study combined novel weaving techniques, different materials and electronic system development to develop a multi-touch interface based on textile capacitive sensors that can sense both touch contact and non-contact/proximity. The final prototype can be washed up to 10 laundry cycles. The results demonstrated that multiple functionalities can be integrated into the structure to produce an interactive textile based product.

Unconventional plastic optical fiber design for very short multimode fiber link.

We introduce a graded-index plastic optical fiber (GI POF) design for very short-distance household applications, in which the transmission quality is predominantly determined by system noise rather than the loss and bandwidth. The developed GI POF has strong mode coupling with low accompanying scattering loss, which is closely related to the specific microscopic heterogeneities in the core material. Such characteristic mode coupling significantly decreases reflection noise, improving the transmission quality compared with silica GI multimode fiber (MMF) for lengths below 30 m. Moreover, in the GI POF link, the transmission quality tends to improve with increasing fiber length, despite the increased loss and decreased bandwidth. This feature suggests that the system noise can be controlled by the microscopic heterogeneous properties of the GI POF for a very short MMF link, where the fiber loss and bandwidth are sufficiently low and high, respectively. This unconventional concept for optical-fiber design can advance fiber-optic communication in emerging applications in households located near optical network terminals.

A light-in-flight single-pixel camera for use in the visible and short-wave infrared.

Single-pixel cameras reconstruct images from a stream of spatial projection measurements recorded with a single-element detector, which itself has no spatial resolution. This enables the creation of imaging systems that can take advantage of the ultra-fast response times of single-element detectors. Here we present a single-pixel camera with a temporal resolution of 200 ps in the visible and short-wave infrared wavelengths, used here to study the transit time of distinct spatial modes transmitted through few-mode and orbital angular momentum mode conserving optical fiber. Our technique represents a way to study the spatial and temporal characteristics of light propagation in multimode optical fibers, which may find use in optical fiber design and communications.

Design of mode filtering optical fibers based on high-loss SPP modes

Selective filtering of guided modes in an all-solid bandgap cladding optical fiber based on the coupling between the cladding modes and surface plasmon polariton (SPP) modes of gold wires are investigated. The SPP mode was found to have a strong effect on the mode transmission loss of the guided modes, even when the index difference between the SPP mode and the guided mode is large. The results show that the introduction of metal wires in the fiber leads to ultra-high confinement loss for a specific guided mode, and low confinement loss for the other guided modes operating at the wavelength covering the entire C band.

Control of orbital angular momentum of light in optofluidic infiltrated circular photonic crystal fibers

Orbital angular momentum (OAM) of light has been of great interest to enhance the data transmission capacity in optical communication systems. In this regards, new designs of optical fibers have been developed to transmit OAM modes. Circular photonic crystal fibers (C-PCFs) with an air-core in the center are good candidates for guiding OAM of light. By changing the geometrical parameters of the C-PCFs, one can control the topological charge (l) associated with OAM order. However, practically it is of significant interest to keep the geometrical parameters fixed and control the OAM characteristics by introducing optical fluid into the C-PCF. Therefore, in this paper, we propose for the first time controlling OAM characteristics such as l, dispersion and confinement loss based on optofluidic infiltrated C-PCFs. To this end, optofluidics with various refractive indices are introduced into the first ring of air holes in the cladding and mode characteristics are compared with those of uninfiltrated C-PCF. The results show that the OAM modes can be well controlled in optofluidic-infiltrated C-PCFs over the wavelength range of 1.25–2.0μm with good dispersion and loss characteristics. Also, the dispersion curve can be flattened when an optical fluid with a proper refractive index is infiltrated into the C-PCF.

Design of Zero Dispersion Optical Fiber at Wavelength 1.3 m

In this article, an optical fiber was designed with zero- dispersion at wavelength of (1.3 m). The design took into consideration many factors of the fiber, such as; fiber cross- section, fiber material, refractive index. These factor can affect the operation of a fiber in optical communication system. A zero- dispersion fiber was obtained when the core was doped by (1.3%) of GeO2. Implementing the package of computer aided design (OptiFiber 2.0). We were able to attain the optimum values for refractive index core and clad as (1.48 and 1.45) respectively, i.e, a percentage difference of (0.02) for radius (6.728 and 8.46) respectively, for zero- dispersion at wavelength of (1.3 m) that is use in the optical communication.