Photonic Fiber Research Articles

All-optical group velocity manipulation in Mach-Zehnder fiber interferometers incorporating with Brillouin random lasing resonance

We proposed and experimentally demonstrated a novel scheme of light group velocity control via a Mach-Zehnder fiber interferometer incorporated with Brillouin random lasing resonance in a half-open linear cavity. A theoretical model of the proposed Brillouin random lasing resonance-based Mach-Zehnder interferometer (BRLR-MZI) for the light group velocity manipulation was derived, predicting optical power-dependent transmittance spectrum shift as well as the enhancement of the temporal advancement. Thanks to Brillouin random lasing-induced fast light effect, the proposed scheme not only achieves a flexible all-optical manipulation of its transmittance spectrum but also overcomes the saturation effect for the light speed control based on a traditional MZI. In experimental validation, sinusoidally modulated signals with the modulation frequency of 160 kHz ultimately experienced a maximum advancement of 4031 ns (corresponding to the group index of 0.875), which exhibits an advancement improvement of 1364 ns compared with the traditional MZI-based scheme. It suggests a promising platform for exploring applications in fields of all-optical signal processing, microwave photonic, and ultra-sensitive fiber sensing.

Numerical investigation on the D-SPR-PQF — High Refractive Index and temperature sensor for transport fuel adulteration

This study presents a Surface Plasmonic Resonance based D-shape oval open loop Photonic Quasi-Crystal Fiber (SPR-PQF). There is necessary to concurrently measure the changes in transport fuels temperature and Refractive index for onsite fuel quality measurements. However, the sensing methods and material selectivity significantly impact the sensor performance. The Finite Element Method (FEM) is a good choice for solving the propagation characteristics of the modes using Maxwell equations. The composite coating of Silver (Ag) and Graphene Oxide (GO) in the open loop D-PQF-structure effectively tunes the SPR condition in the external sensing approach. This FEM-based numerical study reaches the high-temperature sensitivity (22 nm/ ∘C), wavelength Sensitivity (150000 nm/ RIU), amplitude Sensitivity (-6000/ RIU), Figure of Merit (FoM) (1457.85), and detection accuracy (0.66 mg/L, 1.4 mg/L) in the RI range of 1.4185 to 1.448. This sensitivity response is six times larger than the existing SPR PCF sensor in the literature. Hence, this sensor has enormous potential in the petrochemical sensing applications.

Parameter optimization of hollow-core optical fiber phase modulators.

We studied the effect of varying gas concentration, buffer gas, length, and type of fibers on the performance of optical fiber photothermal phase modulators based on C2H2-filled hollow-core fibers. For the same control power level, the phase modulator with Ar as the buffer gas achieves the largest phase modulation. For a fixed length of hollow-core fiber, there exists an optimal C2H2 concentration that achieves the largest phase modulation. With a 23-cm-long anti-resonant hollow-core fiber filled with 12.5% C2H2 balanced with Ar, phase modulation of π-rad at 100 kHz is achieved with a control power of 200 mW. The modulation bandwidth of the phase modulator is 150 kHz. The modulation bandwidth is extended to ∼1.1 MHz with a photonic bandgap hollow-core fiber of the same length filled with the same gas mixture. The measured rise and fall time of the photonic bandgap hollow-core fiber phase modulator are 0.57 µs and 0.55 µs, respectively.

Mechanochromic photonic fibers composed of strain responsive colloidal crystals and spandex yarns

Mechanochromic photonic fibers can realize a visual dynamic color response to external stimuli, and are widely used in colorimetric sensing, smart display, and medical care. At present, colloidal crystals-based mechanochromic photonic fibers with a core-sheath structure have been successfully prepared by electrophoretic deposition and dip-coating. However, problems such as the complicated preparation process and the limited range of color change are still unsolved and hinder the applications of mechanochromic photonic fibers. Here, a mechanochromic photonic fiber with a wide color shift range is prepared by a simple and effective strategy. The fiber is fabricated by coating elastic rubber containing a non-close-packed array of silica particles onto spandex yarn. The obtained photonic fiber displays a structural color that can be controlled by adjusting the diameter and volume fraction of silica particles. Under stretching, the fiber shifts from red to blue with a color change range of 127 nm. More importantly, it achieves reversible color change in the visible range under mechanical strain. These mechanochromic photonic fibers based on colloidal crystals and spandex yarns are promising for smart wearables, display textiles, and visual sensors.

Ga-hybridization-mediated broadband optical amplification in Bi-activated photonic glass and fiber.

A Ga hybridization strategy is proposed for simultaneously enhancing the near-infrared activity and extending the bandwidth of Bi-activated photonic glass. Systematic studies on the near-infrared optical responses of Ga/Bi and Al/Bi co-doped silica glasses are performed. It is interesting to note that Ga/Bi co-doped glasses have a similar near-infrared emission center to Al/Bi co-doped glass, while the former is more effective in improving near-infrared activity. The different luminescence mechanisms of Ga/Bi and Al/Bi co-doped silica glasses are elucidated, and the corresponding microstructure-optical response relationship is discussed. In addition, the Ga/Bi co-doped silica optical fiber is successfully prepared, and the principal fiber amplifier device is fabricated. Furthermore, amplified spontaneous emission and broadband on-off gain are realized. The results suggest that Ga-hybridized Bi-activated photonic glass is a promising gain material for broadband fiber amplifiers.

Dual-Mode Fiber Strain Sensor Based on Mechanochromic Photonic Crystal and Transparent Conductive Elastomer for Human Motion Detection.

As an important component of wearable and stretchable strain sensors, dual-mode strain sensors can respond to deformation via optical/electrical dual-signal changes, which have important applications in human motion monitoring. However, realizing a fiber-shaped dual-mode strain sensor that can work stably in real life remains a challenge. Here, we design an interactive dual-mode fiber strain sensor with both mechanochromic and mechanoelectrical functions that can be applied to a variety of different environments. The dual-mode fiber is produced by coating a transparent elastic conductive layer onto photonic fiber composed of silica particles and elastic rubber. The sensor has visualized dynamic color change, a large strain range (0-80%), and a high sensitivity (1.90). Compared to other dual-mode strain sensors based on the photonic elastomer, our sensor exhibits a significant advantage in strain range. Most importantly, it can achieve reversible and stable optical/electrical dual-signal outputs in response to strain under various environmental conditions. As a wearable portable device, the dual-mode fiber strain sensor can be used for real-time monitoring of human motion, realizing the direct interaction between users and devices, and is expected to be used in fields such as smart wearable, human-machine interactions, and health monitoring.

Polymeric Photonic Crystal Fibers for Textile Tracing and Sorting

AbstractCircular supply chains require more accurate product labeling and traceability. In the apparel industry, product life cycle management is hampered in part by inaccurate, poorly readable, and detachable standard care labels. Instead, this article seeks to enable a labeling system capable of being integrated into the fabric itself, intrinsically recyclable, low‐cost, encodes information, and allows rapid readout after years of normal use. In this work, all‐polymer photonic crystals are designed and then fabricated by thermal drawing with >100 layers having sub‐micrometer individual thickness and low refractive index contrast (Δn = 0.1). The fibers exhibit reflectance features in the 1–5.5 µm wavelength range, characterized using insitu Fourier transform infrared spectroscopy. Drawn photonic fibers are then woven into fabrics, characterized by near‐infrared spectroscopy and short‐wave infrared imaging, techniques commonly used in industrial facilities for sorting materials. The fibers’ optical design also enables the use of overtone peaks to avoid overlap with parasitic molecular absorption, substantially improving the signal‐to‐noise ratio (and therefore ease and speed) of readout. The ability to produce kilometers of fiber that are compatible with existing textile manufacturing processes, coupled with low input material cost, make these a potential market‐viable improvement over the standard care label.

Numerical Demonstration of Photonic Quasi-Crystal Fiber–Surface Plasmonic Resonance Urinary Methanol Sensor

Numerical Demonstration of Photonic Quasi-Crystal Fiber–Surface Plasmonic Resonance Urinary Methanol Sensor

Quasiperiodic photonic crystal fiber [Invited

In the fields of light manipulation and localization, quasiperiodic photonic crystals, or photonic quasicrystals (PQs), are causing an upsurge in research because of their rotational symmetry and long-range orientation of transverse lattice arrays, as they lack translational symmetry. It allows for the optimization of well-established light propagation properties and has introduced new guiding features. Therefore, as a class, quasiperiodic photonic crystal fibers, or photonic quasicrystal fibers (PQFs), are considered to add flexibility and richness to the optical properties of fibers and are expected to offer significant potential applications to optical fiber fields. In this review, the fundamental concept, working mechanisms, and invention history of PQFs are explained. Recent progress in optical property improvement and its novel applications in fields such as dispersion control, polarization-maintenance, supercontinuum generation, orbital angular momentum transmission, plasmon-based sensors and filters, and high nonlinearity and topological mode transmission, are then reviewed in detail. Bandgap-type air-guiding PQFs supporting low attenuation propagation and regulation of photonic density states of quasiperiodic cladding and in which light guidance is achieved by coherent Bragg scattering are also summarized. Finally, current challenges encountered in the guiding mechanisms and practical preparation techniques, as well as the prospects and research trends of PQFs, are also presented.

A novel methane and hydrogen sensor with surface plasmon resonance-based photonic quasi-crystal fiber

The predecessor of China Optics was China Optics and Applied Optics Digest, which was founded in 1985. At that time, it was the only retrieval journal in the field of optics in China. At the end of 2008, China Optics and Applied Optics Digest was renamed

A Novel Methane and Hydrogen sensor with Surface Plasmon Resonance-Based Photonic Quasi-crystal Fiber

The predecessor of China Optics was China Optics and Applied Optics Digest, which was founded in 1985. At that time, it was the only retrieval journal in the field of optics in China. At the end of 2008, China Optics and Applied Optics Digest was renamed

Birefringent, low loss, and broadband semi-tube anti-resonant hollow-core fiber.

We report on the design, fabrication, and characterization of a low-loss birefringent semi-tube anti-resonant hollow-core fiber (AR-HCF). By optimizing the structure design and the stack-and-draw fabrication technique, a transmission loss of 4.8 dB/km at 1522 nm, a <10dB/km bandwidth of 154 nm, and a phase birefringence of 1.8 × 10-5 are demonstrated. This achieved loss is more than one order of magnitude lower than the previously reported birefringent AR-HCF and the bandwidth is one order of magnitude broader than the reported birefringent photonic bandgap hollow-core fiber (PBG-HCF) with the same loss level. The polarization extinction ratio (PER) reaches the ∼20 dB level in a 90m-long fiber under >25cm bending radius. Combined with the single mode and low dispersion features, the developed semi-tube AR-HCF may find a variety of applications in frequency metrology, interferometric fiber gyroscopes, and long-baseline stellar interferometry.

Generating Loss Dependent Bifid Dips of Optical Carrier Based Microwave With Self-Feedback Anti-Symmetric Coupled Fiber Ring Resonator

A self-feedback anti-symmetric coupled fiber ring resonator (SACFRR) is proposed and demonstrated to generate the distinctive loss dependent bifid dips. The universal derivation of the ring resonators in both lightwave and optical carrier based microwave domains considering different conditions including attenuation, coupling and self-feedback is systematically elaborated, which is applicable to diverse ring resonator configurations. The lightwave and optical carrier based microwave experience different phase evolution during the cross-coupling procedure, thereby causing very different output. The anti-symmetric coupling strategy is creatively introduced into the ring resonator, which dominates the splitting of the original resonance dip for the optical carrier based microwave interferometry (OCMI). And OCMI shows the noticeable bifid dips within the lower envelope which receives less attention before. By performing the measurement of temperature and bend-induced loss, the bifid dips based demodulation of OCMI is employed to present the property of SACFRR and compared with the conventional upper envelope based demodulation, contributing to the utilization of lower envelope information. The temperature sensitivity is 521.4 kHz/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> C at 3.05 GHz and the bend-induced loss sensitivity is 24.845 MHz/turn (diameter of 2.30 cm) at 10 turns where is adjacent to the critical point of bifid dips merging. The proposed scheme provides an extraordinary design avenue which can be extended to diverse ring resonators in both photonic integrated circuits and fiber links for exploring compelling functions.

Heterogeneous Structural Color Conductive Photonic Organohydrogel Fibers with Alternating Single and Dual Networks.

Intelligent interactive electronic devices can dynamically respond to and visualize various stimuli, promoting the rapid development of flexible electronics. In this paper, an alternating single- and dual-network design strategy was developed for ingeniously constructing an interactive electronic fiber sensor with heterogeneous structural color (HSCEF sensor). The resulting sensor can rapidly output the synchronous electrical and optical dual signals under strain by adjusting the transport distance of conductive ions and the lattice spacing of the photonic crystal (∼200 ms). Meanwhile, the addition of low-freezing-point glycerol endowed the HSCEF sensor with excellent low-temperature tolerance (-25 °C) and cyclic stability. Notably, benefiting from the alternating single- and dual-network structure, the HSCEF sensor exhibits attractive heterogeneous structural color, which achieves colorimetric changes in the full visible light region with high mechanochromic sensitivity (2.25 nm %-1) and large wavelength shift (Δλ ∼ 225 nm). An intelligent wearable interactive sensor is finally used for real-time dynamic detection of joint movements, realizing precise resolution of different amplitudes. This work provides a general strategy to transform conventional photonic gels into heterogeneous structural color ones, and the developed new interactive sensor with rich optical information could be further used for visual health and exercise monitoring, intelligent soft robotics, wearable sensors, etc.

Optimization of optical properties of Ge20Sb5Se75-based photonic crystal fibers

In this paper, we present a new design of solid-core photonic crystal fiber (PCF), a Ge20Sb5Se75 substrate with a hexagonal lattice structure. The fiber characteristics are studied in the long-wavelength range (from 1.5 µm to 7.0 µm). A full modal analysis and optical properties of designed photonic crystal fibers with lattice constant Λ and filling factor d/Λ are presented in terms of chromatic dispersion, effective refractive index, nonlinear coefficients, and confinement loss. All-normal and anomalous flat dispersion with high nonlinearity and low confinement loss are the outstanding advantages of these photonic crystalline fibers. From there, three optimal structures with Ʌ = 2.0 µm, d/Ʌ = 0.35; Ʌ = 2.5 µm, d/Ʌ = 0.3 and Ʌ = 3.0 µm, d/Ʌ = 0.3 are selected and analyzed in detail for application in supercontinuum (SC) generation.

Analytical Lah-Laguerre optical formalism for perturbative chromatic dispersion.

We present a generalized perturbative analytical formalism for evaluation and optimization of the chromatic dispersion of complex ultrafast optical systems. Notably, we identify polynomial and recursive relations associated with the chromatic dispersion orders that are identical to the Lah and Laguerre transforms. We explicitly outline the first ten dispersion terms and dispersion slope parameters and visualize the significance of the chromatic dispersion orders for several advanced ultrafast optical and photonic systems consisting of various optical materials and nanostructures, grating and prism-pair compressors, and hollow-core photonic anti-resonant fibers. The derived simple hypergeometric transforms are applicable for evaluation of infinitely high orders for any type of frequency-dependent phase and can facilitate the optimization of complex optical systems with controlled dispersion balance at the single-cycle waveform extreme.

Highly sensitive dual-core photonic quasicrystal fiber methane sensor based on surface plasmon resonance.

A highly sensitive dual-core photonic quasicrystal fiber methane sensor based on surface plasmon resonance is designed and analyzed. In this sensor, cryptophane E is doped with polysiloxane and Ag and used as the sensitive film and plasma medium, respectively, for sensitive detection of methane. The influence of the structural parameters on the sensor properties is analyzed by the finite element method. The optimized dual-quasi-D-shape structure has excellent methane-sensing properties such as maximum and average wavelength sensitivities of 14 and 10.98 nm/%, respectively, in the methane concentration range of 0%-3.5%. The sensitivity is better than that of similar sensors reported previously.

All-polarization-maintaining and high-energy fiber optical parametric chirped-pulse amplification system using a solid core photonic hybrid fiber.

We present an all-fiber optical parametric chirped-pulse amplification integrated system delivering a single-mode polarized beam. The system makes use of a specifically designed solid-core photonic hybrid fiber (i.e., combining modified total internal reflection and photonic bandgap mechanisms) that ensures sufficient birefringence to maintain the signal polarization. Moreover, the fiber combines a large mode area to handle energetic pump pulses (without generating damage or unwanted nonlinear effects) and weak dispersion to generate parametric gain bands broad enough to amplify ultrashort pulses. An efficient parametric process allows for obtaining a very high gain (>45 dB) with an output pulse energy reaching µJ range at 1053 nm by using a single 5-m hybrid fiber amplifier.

Sensitivity-Enhanced Fiber-Optic Sensor in a Microwave Photonics Fiber Loop Ringdown System

In this article we report a microwave photonics fiber loop ringdown (MWP-FLRD) interrogated fiber-optic sensor with enhanced sensitivity. A section of a single-mode fiber in the fiber loop is macro-bent into a circular ring as the element responsive to displacement. When the circular ring is subjected to external displacement, the transmission loss of the loop changes, resulting in a change in the ringdown time of the MWP-FLRD system. To enhance the measurement sensitivity, a multi-turn structure is proposed and experimentally demonstrated. Compared to the traditional time-domain FLRD system, the MWP-FLRD system employs a frequency domain measurement, showing a high signal-to-noise ratio and high measurement efficiency. The physics of MWP-FLRD, the displacement measurement principle, the sensitivity-enhancement scheme, and the temperature self-compensation capability of the system are discussed in this paper. The experimental results demonstrate that an averaged amplification factor of 0.8221 per turn is achieved for displacement measurement sensitivity using the multi-turn structure. Taking advantage of the mechanical strength of the multi-turn fiber structure with an intact polymer coating, the system is employed to monitor the elbow bending of human body movement in real-time, showing high sensitivity and fast responses. It is envisioned that the concept of the proposed multi-turn structure can be implemented onto other FLRD systems for sensitivity enhancement.

Liquid core photonic quasi-crystal fiber plasmonic refractive index sensor for wide refractive index detection range

In this paper, a photonic quasi-crystal fiber plasmonic refractive index sensor is numerically analyzed. The fiber core is infiltrated with six hypothetical liquids, which refractive indices of them vary from 1.44 to 1.49. The reason for filling the core with different refractive index of liquids is that changeable refractive index of the core is an option to adjust the sensor performance at different intervals of analyte refractive index. Due to changes in the core refractive index, a large RI detection range from 1.38 to 1.53 is obtained and the sensor exhibits maximum spectral sensitivity of 10,000 nm/RIU. The properties of the sensor are calculated by the finite element method. The geometrical parameters of the sensor such as analyte height and gold thickness are also evaluated. The proposed sensor has a tunable capability which can be suitable for RI detection of biomedical liquid analytes in various ranges of refractive indices.