Hollow-core Anti-resonant Fiber Research Articles

All-Fiber Multicomponent Gas Raman Probe Based on Platinum-Coated Capillary Enhanced Raman Spectroscopy.

This paper presents a compact all-fiber multicomponent gas Raman probe using a dual-fiber architecture within a platinum-coated capillary. The probe eliminates the need for conventional optical components like filters and dichroic mirrors by strategically employing metal coating on the excitation fiber's surface to suppress interference signals. A detailed analysis of the silica Raman signal and fluorescence propagation within the system facilitated this design. Metal-coated capillary (MCC), produced via atomic layer deposition (ALD) of platinum on silica capillaries, exhibits excellent optical properties and environmental resilience, boosting gas Raman signal reception. Careful alignment of the dual fibers relative to the platinum-coated capillary optimizes signal-to-noise ratio enhancement. The system achieves detection limits of 21 ppm for CH4, 30 ppm for C2H4, and 51 ppm for C2H6 within 45 s of exposure, alongside a rapid response time of 25 s (relative to systems based on hollow-core antiresonant fibers) and robust stability. Its streamlined optical path and compact design enhance practicality across diverse fields, including agriculture, industry, environmental monitoring, and healthcare, advancing multicomponent gas detection technology.

Numerical simulation of in-fiber plasmonic polarization filter using silicon hollow-core anti-resonant fiber with dual aluminum wires

Numerical simulation of in-fiber plasmonic polarization filter using silicon hollow-core anti-resonant fiber with dual aluminum wires

Single-polarization single-mode hollow-core anti-resonant fiber with nested stadium-shaped tubes

Single-polarization single-mode hollow-core anti-resonant fiber with nested stadium-shaped tubes

Design and simulation study of double-cladding fiber for nonlinear Raman imaging

Abstract This paper presents a heterogeneous double-cladding Raman probe utilizing double-cladding hollow-core anti-resonant fiber (DC-HC-ARF). The core region constructed from HC-ARF is designated for the transmission of pump light, while the inner cladding, made of silica glass, is employed for the collection and transmission of Raman signals. The outer cladding,featuring a low refractive index, establishes a significant refractive index contrast with the inner cladding, thereby facilitating the efficient collection of Raman signal light from the inner cladding. By comparing the confinement loss (CL) and other properties of four distinct hollow-core anti-resonant fiber (HC-ARF) structures, along with an analysis of the energy transmission performance of the inner cladding structure, we validate the rationale behind the selected configurations for the core, inner cladding, and outer cladding. The HC-ARF used in the core region demonstrates a CL of 8.57×10⁻⁶ dB/m for its LP01 mode, a high-order mode extinction ratio (HOMER) of 243, and notable bending loss. The inner cladding attains a numerical aperture (NA) of up to 0.9, indicating that the fiber can effectively collect Raman light signals. This fiber achieves a high level of integration, facilitating both low-loss transmission of pump light and efficient collection and transmission of signal light simultaneously. By utilizing optical fiber Raman detection technology, real-time imaging of tissues can be achieved, assisting doctors in monitoring and making decisions during surgical procedures.

273.6 Tbit/s real-time S + C + L-band same-wavelength bidirectional wavelength division multiplexing transmission in anti-resonant hollow-core fiber.

Based on its ultra-low backscattering characteristic, anti-resonant hollow-core fiber is a good medium for bidirectional transmission, which means that the wavelengths of the transmission channels are the same in both directions. In this Letter, we present the first, to the best of our knowledge, demonstration of S + C + L-band same-wavelength bidirectional transmission in an anti-resonant hollow-core fiber. By using a commercial real-time coherent optical transceivers and amplified spontaneous emission (ASE) source, a total net throughput of 273.6 Tbit/s is achieved over 1.4 km nested anti-resonant nodeless fiber (NANF) with 19.65 THz bandwidth and bidirectional wavelength division multiplexing (WDM) transmission. Commercial 400 G, 1 T, and 800 G optical modules are employed in the S-band, C-band, and L-band, respectively. We experimentally evaluate the same-wavelength bidirectional WDM transmission performance by verifying 2 × 102 channels of 68 Gbaud probabilistically constellation-shaped (PCS) 16 quadrature amplitude modulation (QAM) in the S-band with 75 GHz grid, 2 × 48 channels of 118 Gbaud PCS-64QAM in a C-band with 125 GHz grid and 2 × 60 channels of 91.6 Gbaud PCS-64QAM in the L-band with 100 GHz grid. All 420 test channels could satisfy the bit error ratio (BER) requirements. The result shows great potential for same-wavelength bidirectional WDM transmission in an anti-resonant hollow-core fiber.

A novel hollow-core antiresonant fiber-based biosensor for blood component detection in the THz regime

This article proposes a novel biosensor based on a five-semi-circular cladding tube hollow core antiresonant fiber (HC-ARF) with a frequency range of 0.5-2.8 THz, using Zeonex as the background material. The HC-ARF biosensor analyses various blood components, namely water, plasma, white blood cells (WBC), hemoglobin (HB), and red blood cells (RBC). We utilized COMSOL Multiphysics to perform the numerical analysis of the sensor model. For water, plasma, WBC, HB, and RBC, the proposed HC-ARF biosensor exhibits the highest sensitivity levels of 99.50%, 99.58%, 99.43%, 99.58%, and 99.46%, respectively. Furthermore, it demonstrates confinement loss (CL) and effective material loss (EML) of 1.3 ×10-3dBcm-1and 5.3 ×10-5dBcm-1, respectively.

Fourfold truncated double-nested antiresonant hollow-core fiber with ultralow loss and ultrahigh mode purity

Hollow-core fibers (HCFs) are inherently multimode, making it crucial to filter out higher-order modes (HOMs) within the shortest possible fiber length for applications such as high-speed coherent communications and fiber-optic gyroscopes. However, current HCF designs face the challenges of simultaneously achieving ultralow fundamental mode (FM) loss and ultrahigh HOM suppression. In this study, we present a fourfold truncated double-nested antiresonant nodeless hollow-core fiber (4T-DNANF) structure that addresses this challenge. Our 4T-DNANF enables greater control over phase matching between core modes and air modes in the cladding, allowing for minimized FM loss and substantially increased HOM loss. Experimentally, we fabricated several HCFs: one with an FM loss of 0.1 dB/km and an HOM loss of 430 dB/km, and another achieving an FM loss of 0.13 dB/km with a HOM loss of 6500 dB/km, yielding a higher-order mode extinction ratio of 5×104—the highest reported to date.

Distributed measurement of polarization crosstalk in polarization-maintaining anti-resonant hollow-core fibers

Distributed measurement of polarization crosstalk in polarization-maintaining anti-resonant hollow-core fibers

A Hollow-Core Anti-Resonant Fiber Multi-Objective Multi-Modal Optimization Assisted by a Proxy Model Combined With Clustering Algorithm

A Hollow-Core Anti-Resonant Fiber Multi-Objective Multi-Modal Optimization Assisted by a Proxy Model Combined With Clustering Algorithm

Supercontinuum generation in methane-filled hollow-core antiresonant fiber

Supercontinuum generation in methane-filled hollow-core antiresonant fiber

Efficient, broadly tunable, hollow-fiber source of megawatt pulses for multiphoton microscopy

Three-photon fluorescence microscopy (3PM) has driven rapid progress in deep-tissue imaging beyond the depth limit of two-photon microscopy, with impacts in neuroscience, immunology, and cancer biology. Three-photon excitation places a premium on ultrashort pulses with high peak power in the 1300- and 1700-nm wavelength bands, which allow deepest imaging. The inefficiency and cost of current sources of these pulses present major barriers to the use of 3PM in biomedical research labs. Fiber sources of such pulses could potentially alleviate these problems, but the peak-power limitations of optical fibers have limited their use in 3PM. Here, we describe a fiber-based source of femtosecond pulses with multi-megawatt peak power. Femtosecond pulses at 1030 nm are launched into an antiresonant hollow-core fiber filled with argon. By varying only the gas pressure, pulses with hundreds of nanojoules of energy and sub-100 fs duration are obtained at wavelengths between 850 and 1700 nm. This approach is a new route to an efficient and potentially low-cost source for deep-tissue imaging. In particular, 960-nJ and 50-fs pulses are generated at 1300 nm with a conversion efficiency of 10%. The nearly 20-MW peak power is an order of magnitude higher than the previous best from a femtosecond solid-core fiber source at 1300 nm. As an example of the capabilities of the source, these pulses are used to image structure and neuronal activity in a mouse brain as deep as 1.1 mm below the dura.

Low-loss weakly coupled four-mode hollow-core antiresonant fiber based on centrosymmetric nested structure

Abstract This paper designs a novel centrosymmetric double-layer nested antiresonant fiber (CDNAF) with few-mode transmission characteristics. The cladding structure of the CDNAF incorporates glass plates and multilayer capillaries, effectively mitigating the coupling between various core modes and cladding modes. Simulation results show that the CDNAF can support four modes of low-loss transmission from LP01 to LP02 at 1550 nm. The confinement loss (CL) of the four modes is less than 0.008 dB km−1, 0.07 dB km−1, 0.42 dB km−1, and 4.8 dB km-1, respectively, and the CDNAF has a sizeable differential group delay (DGD) and weak bending sensitivity. The loss of high-order modes is much greater than that of the other four transmission modes, ensuring high-purity transmission of the four modes. In the wavelength range of 1200–1700 nm, the CDNAF ensures few-mode characteristics with at least two low-loss transmission modes. Furthermore, the effective refractive index difference (Δn eff ) between adjacent modes is much greater than 10–4, eliminating or significantly reducing the need for multiple-input multiple-output digital signal processing (MIMO-DSP) techniques in optical communication systems. Additionally, the results demonstrate that CDNAF can transmit three modes at an ultimate bending radius of 5 cm and can transmit four modes like a straight fiber at a bending radius of 18 cm, which demonstrates that CDNAF has excellent bending performance. These excellent characteristics give the CDNAF great potential for application in large-capacity optical communication systems.

Long period fiber gratings in anti-resonant hollow core fiber

Abstract Long period gratings, based on anti-resonant hollow core fibers (AR-HCFs), are fabricated using a high-frequency CO2 laser pulse by carving periodic grooves. This device exhibits both axial strain and bending sensing characteristics. Benefiting from the low thermal sensitivity and radiation resistance characteristic of AR-HCFs, this grating can be utilized in extreme environments, particularly in the high-radiation environment, such as nuclear power plants and space shuttles. Additionally, due to the characteristics of AR-HCFs, including low latency, low dispersion, low nonlinearity, and high damage threshold, this device also serves for long-distance fiber communication and high-power laser pulse shaping.

Design of Low-Loss Terahertz Hollow Core Anti-Resonant Fibers

Design of Low-Loss Terahertz Hollow Core Anti-Resonant Fibers

Hybrid structure hollow-core anti-resonant fiber with low confinement loss at 1550 nm and high birefringence in the C-band

Hybrid structure hollow-core anti-resonant fiber with low confinement loss at 1550 nm and high birefringence in the C-band

Low-Loss, Low-Back-Reflection Fusion Splicing of Large-Mode-Area Fibers With Nested Hollow-Core Antiresonant Fibers for All-Fiber High-Power, Single-Frequency Fiber Laser Transmission

Low-Loss, Low-Back-Reflection Fusion Splicing of Large-Mode-Area Fibers With Nested Hollow-Core Antiresonant Fibers for All-Fiber High-Power, Single-Frequency Fiber Laser Transmission

Numerical optimization of anti resonant hollow core fiber for high sensitivity methane detection

This study presents an innovative methane gas sensor design based on anti-resonant hollow-core fiber (AR-HCF) technology, optimized for high-precision detection at 3.3. Our numerical analysis explores the geometric optimization of the AR-HCF’s structural parameters, incorporating real-world component specifications. The proposed design features a 65 diameter hollow core surrounded by seven silica rings. We achieved significant improvements in confinement loss and optical power distribution through progressive structural modifications. The optimized structure demonstrated a confinement loss of and over 95% optical power confinement in the hollow core. Our model predicts a relative sensitivity of , a response time of 5.4 s, and a theoretical detection threshold of 2.24 ppm. The limit of detection (LoD) was estimated to be 3.8 ppbv, and the normalized noise equivalent absorption (NNEA) coefficient was . The sensor response exhibited excellent linearity over its operating range, with an R2 value of 0.9917 in the critical concentration range. These findings highlight the potential of our AR-HCF-based methane sensor design for real-time gas monitoring applications.

Highly integrated hollow-core anti-resonant fiber magnetic field sensor based on surface plasmon resonance

Highly integrated hollow-core anti-resonant fiber magnetic field sensor based on surface plasmon resonance

Highly birefringent and low loss anti-resonant hollow-core fiber with stadium-shaped nested structure

Abstract We propose a stadium-shaped nested anti-resonant hollow-core fiber (SSAF), designed to enable high birefringence and low loss in the near-infrared bands. Numerical investigation and simulation for variations in parameters of stadium-shaped nested structure are conducted, and confinement loss (CL) is reduced by parameters optimization while birefringence of 10−4 is maintained. With optimized SSAF structure, the birefringence and CL are improved to 1.39 × 10−4 and 26.5 dB km−1 at 1.38 µm, 1.28 × 10−4 and 2.64 dB km−1 at 1.55 µm, respectively. Meanwhile, it exhibits favorable single-mode characteristics and achieves a high high-order mode extinction ratio of up to 103, and the superior bending resistance characteristics are validated. Our work offers valuable guidance for designing and optimizing highly birefringent SSAF anti-resonant fiber, and the proposed SSAF has great application potential in polarization-dependent transmission and interferometric fiber gyroscope.

Silicon photonics integrated dual-wavelength frequency stabilized laser for spaceborne CO2 gas measurement LiDAR

A silicon photonic integrated chip was designed to further miniaturize the CO2 gas- gas-measurement LiDAR seed laser. The optical links of the laser frequency stabilization loop (FSL), optical phase-locked loop (OPLL), and thermo-optical switch (TOS) are integrated into a photonic integrated circuit (PIC). The frequency stabilization loop built by the silicon photonics chip stabilizes the center frequency of the reference laser (RL) to the R-18 absorption line of carbon dioxide gas (1572.0179 nm). The long-term relative stability of the laser wavelength reached at 1000 s averaging time, and the RMS was 113 kHz. The frequency reference is a 15 m anti-resonant hollow-core optical fiber (HCF) filled with CO2 gas at a pressure of 40 bar. By using OPLL, we locked the center frequency of the seed laser (slave laser) at 1572.0237 nm, and its Allan deviation is 38.2 kHz at 1000 s averaging time, and the RMS was 206 kHz. The wavelength stability of the RL and seed laser satisfies the requirements of CO2 measurement LiDAR, which requires laser long-term stability better than 300 kHz (Allan standard deviation). The MZI-structured thermo-optic switch operated with a switching period of 400 µs, a rise/fall time of approximately 20 µs was obtained, and the dynamic extinction ratio reached 26 dB.