Suspended Core Photonic Crystal Fiber Research Articles

Reliable and easy-to-use SERS spectroscopy probe using a tapered opto-fluidic photonic crystal fiber.

Surface enhanced Raman spectroscopy (SERS) is one of the most sensitive biosensing techniques that offers label free detection for a variety of applications. Generally, SERS spectroscopy is performed on nano-functionalized planar substrates with plasmonic structures or colloidal nanoparticles. Recently, photonic crystal fibers (PCFs) have gained great interest for SERS based bio sensing applications due to the immense advantages such as improved sensitivity, flexibility and remote sensing capability that it offers compared to the planar substrates. However, the use of PCF based biosensors demand the alignment of it under a microscope, which can affect the reliability of SERS measurements and could be restrictive for practical end use applications. Herein, we aim to develop a tapered suspended core PCF fiber (Tapered-SuC-PCF) that represents an improvement in coupling efficiency and measurement reliability as well as it opens the way to the development of an easy-to-use bio-sensing probes with a plug and play option with conventional Raman spectrometers. We have fabricated several samples of the optimized tapered-SuC-PCF and demonstrated its superior SERS performance compared to standard SuC-PCF fibers with 2 µm core diameter. An excellent SERS measurement reliability is demonstrated using such a fiber in a plug and play type system demonstrating its versatility for practical end use applications.

Optical properties of As2S3-based suspended-core photonic crystal fiber

In this paper, the nonlinear properties of photonic crystal fibers (PCF) with As2S3 substrate were analyzed numerically. With the suspended-core design, we achieve an anomalous dispersion regime with one or two zero-dispersion wavelengths, which is flat and has a small value at the investigated wavelength. The high nonlinear coefficient and very low confinement loss in the wavelength range of 1–3 µm, in comparison with other publications, are the outstanding advantages of these suspended-core PCFs. The highest nonlinear coefficient (28,527.374 W–1·km–1), smallest effective mode area (0.593 µm2), and low confinement loss (6.050 × 10–17 dB·m–1) at the wavelength of 1.55 µm were observed in the PCFs with a fiber diameter of 16.07 μm. Based on the numerical simulation results, we proposed two optimal structures suitable for supercontinuum generation.

Plasmonic Ag/ZnO Nanoscale Villi in Microstructure Fibers for Sensitive and Reusable Surface-Enhanced Raman Scattering Sensing

Microstructure fibers, integrating microfluidic channels and light guidance in one fiber, enable three-dimensional surface-enhanced Raman scattering (SERS) detection for large signal accumulation. However, the available fiber SERS probes are complicated to prepare and they are not reusable. In addition, light interacts with analytes in a form of an evanescent field, which is very weak. In this paper, we developed a SERS platform based on suspended-core photonic crystal fibers decorated with Ag/ZnO nanocomposites on the inner surface for direct, ultrasensitive, and reusable analyte detection. The unique configuration not only transfers a core-localized field to the liquid interface to greatly enhance the light–analyte interaction but also facilitates charge transfer to further improve the SERS detection sensitivity and degradation efficiency. The detection limit of crystal violet solution is 10–13 M, and the enhancement factor reaches 1011. The relative standard deviation is as low as 5.4%, ensuring the reproducibility of SERS detection. The probe has good photocatalytic performance and can degrade molecules under ultraviolet-light illumination within 20 min. This ultrasensitive and reusable SERS probe shows great application potential in rapid and in situ liquid detection.

Lateral offset optical fiber modal interferometer sensor for simultaneous measurement of seawater temperature and salinity

An optical fiber sensor for simultaneous measurement of seawater temperature and salinity was designed and implemented based on a lateral offset Modal interferometer (MI) using a suspended core photonic crystal fiber (SCPCF). The MI was made by fusing single mode fiber and multimode fiber (SMF-MMF) structures with a lateral offset SCPCF coated with UV adhesive film on the inner wall. In the experiment, the response of the sensor to the change of seawater temperature and salinity was measured respectively. The results have shown that the temperature sensitivity of 1.486 nm/°C was obtained within the temperature range from 5 °C to 45 °C and the salinity sensitivity of 2.495 nm/‰ was obtained within the salinity range from 0‰ to 50‰. The sensor resolves the problem of cross-sensitivity between seawater temperature and salinity and provides a simple structure with low cost and high sensitivity.

Self-similar pulse compression by suspended core photonic crystal fiber with cubic-quintic nonlinearities

An enhanced self-similar pulse compression with suspended core photonic crystal fiber has been theoretically studied. The proposed model well support the essential criteria of having very low dispersion and increased nonlinearity with increasing suspension factor resulting high compression rate within short length of the fiber. Unlike the conventional tapering methods, the suspended core photonic crystal fiber can achieve the self-similar conditions more easily and reduces the practical difficulties to achieve the desired fiber parametric values. We have also studied the possible deformations of the fiber and temperature variations that can effect the pulse compression process and compression factor.

Design optimization of suspended core photonic crystal fiber for polarization maintaining applications

This work reports some important optical characteristics of porous core photonic crystal fiber (PC-PCF) for four different core structures which are elliptical, circular, square, and hexagonal. Numerical analysis based on the finite element method (FEM) shows that for the same core area, an elliptical core demonstrates the highest birefringence that ensures reliable polarization-maintaining applications. Moreover, other modal characteristics such as absorption loss, confinement loss, dispersion, power fraction, and effective area are also investigated thoroughly and compared. Besides, the suspended elliptical core PCFs can be fabricated easily with the existing fabrication technology.

Optimization and performance analysis of SERS-active suspended core photonic crystal fibers

Recently, surface enhanced Raman spectroscopy (SERS)-active photonic crystal fiber (PCFs) probes have gained great interest for biosensing applications due to the tremendous advantages it has over the conventional planar substrate based SERS measurements, with improvements on the detection sensitivity and reliability in measurements. So far, two main approaches were employed to get the analyte molecule in the vicinity of nanoparticles (NPs) inside PCFs in order to achieve the SERS effect. In the first case, analyte and NPs are pre-mixed and injected inside the holes of the PCF prior to the measurement. In the second approach, controlled anchoring of the NPs inside the inner walls of the PCF was achieved prior to the incorporation of the analyte. Although many studies have been conducted using one configuration or the other, no clear trend is emerging on which one would be the best suited for optimizing the biosensing properties offered by SERS active-PCF. In this paper, we investigate the performances of both configurations along with their interplays with the core size of the PCF probe. We have fabricated several samples of a standard PCF design with different core sizes, and SERS measurements of a standard Raman-active molecule are realized in the same conditions for enabling direct comparisons of the SERS intensity and measurement reliabilities between each configuration, yielding clear directions on the optimization of the SERS-active PCF probe. We envision that this study will pave the way for next-generation clinical biosensors for body fluid analysis, as it exhibits high sensitivity and excellent reliability.

A theoretical study on the supercontinuum generation in a novel suspended liquid core photonic crystal fiber

We theoretically propose a novel liquid filled suspended core photonic crystal fiber as a new class of microstructure optical fiber for ultrabroad supercontinuum generation. We emphasize the advantage of liquid infiltration in enhancing the fiber nonlinearity. To further enhance the nonlinearity of the liquid-infiltrated fibers, we introduce a suspended liquid core photonic crystal fiber which significantly elevates the fiber nonlinearity through reduced effective area. A comparative study on the continuum generated in conventional microstructured optical fiber (without suspension effect) and the suspended core microstructured optical fiber is performed. A broad continuum is numerically demonstrated through the suspended core fiber, which is substantially broader than the fiber without suspension effect. Thus, we propose a new means to enhance the nonlinearity beyond the intrinsic material dependence. The underlined suspended liquid core photonic crystal fiber can be a new class of fibers for next generation of broadband laser sources.

Development of highly reliable SERS-active photonic crystal fiber probe and its application in the detection of ovarian cancer biomarker in cyst fluid.

Conventionally Surface-enhanced Raman spectroscopy (SERS) is realized by adsorbing analytes onto nano-roughened planar substrate coated with noble metals (silver or gold) or their colloidal nanoparticles (NPs). Nanoscale irregularities in such substrates/NPs could lead to SERS sensors with poor reproducibility and repeatability. Herein, we demonstrate a suspended core photonic crystal fiber (PCF) based SERS sensor with extremely high reproducibility and repeatability in measurement with a relative SD of only 1.5% and 4.6%, respectively, which makes it more reliable than any existing SERS sensor platforms. In addition, our platform could improve the detection sensitivity owing to the increased interaction area between the guided light and the analyte, which is incorporated into the holes that runs along the length of the PCF. Numerical calculation established the significance of the interplay between light coupling efficiency and evanescent field distribution, which could eventually determine the sensitivity and reliability of the developed SERS active-PCF sensor. As a proof of concept, using this sensor, we demonstrated the detection of haptoglobin, a biomarker for ovarian cancer, contained within the ovarian cyst fluid, which facilitated in differentiating the stages of cancer. We envision that with necessary refinements, this platform could potentially be translated as a next-generation highly sensitive SERS-active opto-fluidic biopsy needle for the detection of biomarkers in body fluids.

Surface-enhanced Raman scattering-active photonic crystal fiber probe: Towards next generation liquid biopsy sensor with ultra high sensitivity.

The tremendous enhancement factors that surface-enhanced Raman scattering (SERS) possesses coupled with the flexibility of photonic crystal fibers (PCFs) pave the way to a new generation of ultrasensitive biosensors. Thanks to the unique structure of PCFs, which allows direct incorporation of an analyte into the axially aligned air channels, interaction between the analyte and excitation light could be increased many folds leading to flexible, reliable and sensitive probes that can be used in preclinical or clinical biosensing. SERS-active PCF probes provide unique opportunity to develop an opto-fluidic liquid biopsy needle sensor that enables one-step integrated sample collection and testing for disease diagnosis. Specificity being a key parameter to biosensors, the PCF inside the biopsy needle could be functionalized with targeting moieties to detect specific biomarkers. In this review article, we present some of the most promising recent biosensors based on PCFs including hollow-core PCFs, suspended-core PCFs and side-channel PCFs. We provide a wide range of applications of such platform using Raman spectroscopy, label free SERS or labeled SERS detection and analyze some of the main challenges to be addressed for translating it to a clinically viable next generation sensitive biopsy needle sensing probe.

Optimization of silica glass capillary and rods drawing process.

Diameter fluctuations of silica glass rods and capillaries, during drawing process have been studied. We investigated an influence of drawing conditions on the quality of capillaries and rods. We fabricated two preforms made from different quality material. Fabricated preforms were used to draw microstructured fibers. Full Text: PDF ReferencesS. Habib et al., "Broadband dispersion compensation of conventional single mode fibers using microstructure optical fibers", Int. J. Lig. Opt. 124, 3851-3855 (2013) CrossRef A. Ziolowicz et al. "Overcoming the capacity crunch: ITU-T G.657.B3 compatible 7-core and 19-core hole-assisted fibers", Proc SPIE 10130, 101300C (2017) CrossRef T.M. Monro et al. "Sensing with microstructured optical fibres", Meas. Sci. Technol. 12, 854-858 (2001) CrossRef G. Statkiewicz-Barabach et al.,"Hydrostatic Pressure and Temperature Measurements Using an In-Line Mach-Zehnder Interferometer Based on a Two-Mode Highly Birefringent Microstructured Fiber", Sensors 2017, 17, 1648 (2017) CrossRef T. Yoon, M. Bajcsy, "Laser-cooled cesium atoms confined with a magic-wavelength dipole trap inside a hollow-core photonic-bandgap fiber", Phys. Rev. A 99, 023415 (2019) CrossRef A.N. Ghosh et al., "Supercontinuum generation in heavy-metal oxide glass based suspended-core photonic crystal fibers", J. Opt. Soc. Am. B 35, 2311-2316 (2018) CrossRef G. Wójcik et al. "Microbending losses in optical fibers with different cross-sections", Proc. SPIE 10830, 108300H (2018) CrossRef F. Xu, Selected topics on optical fiber technology and applications (IntechOpen 2018) CrossRef

Supercontinuum generation in heavy-metal oxide glass based suspended-core photonic crystal fibers: erratum

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text A. N. Ghosh, M. Klimczak, R. Buczynski, J. M. Dudley, and T. Sylvestre, "Supercontinuum generation in heavy-metal oxide glass based suspended-core photonic crystal fibers: erratum," J. Opt. Soc. Am. B 35, 2815-2815 (2018) Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article Check for updates

Supercontinuum generation in heavy-metal oxide glass based suspended-core photonic crystal fibers

We investigate supercontinuum generation in several suspended-core soft-glass photonic crystal fibers pumped by an optical parametric oscillator tunable around 1550 nm. The fibers were drawn from lead-bismuth-gallium-cadmium-oxide glass (PBG-81) with a wide transmission window from 0.5-2.7 micron and a high nonlinear refractive index up to 4.3.10^(-19) m^2/W. They have been specifically designed with a microscale suspended hexagonal core for efficient supercontinuum generation around 1550 nm. We experimentally demonstrate two supercontinuum spectra spanning from 1.07-2.31 micron and 0.89-2.46 micron by pumping two PCFs in both normal and anomalous dispersion regimes, respectively. We also numerically model the group velocity dispersion curves for these fibers from their scanning electron microscope images. Results are in good agreement with numerical simulations based on the generalized nonlinear Schrodinger equation including the pump frequency chirp.

Multimodal Interferometer Based on a Suspended Core Fiber for Simultaneous Measurement of Physical Parameters

In this study, a multimodal interferometer based on a suspended core photonic crystal fiber (PCF) for simultaneous strain and temperature measurements is proposed. The structure is also employed for angle measurements. The sensor comprises a 3-mm-suspended core PCF between SMFs and is based on the combination of two multimodal interferences with different frequency fringe patterns. The interferometric patterns show different sensitivity responses to strain and temperature. Through a low-pass frequency filtering of the detected spectrum, the wavelength shift of the two patterns can be measured allowing the discrimination of strain and temperature effects with resolutions of 0.45 °C and 4.02 μϵ, respectively. The sensor is also characterized for angle measurements showing a maximum sensitivity of 9.17 pm/° in the range from 0° to 90°. It is demonstrated that with this sensing structure is possible to obtain simultaneous measurement of bend angle and temperature with resolutions of 1.69 ° and 0.92 °C, respectively.

Dispersion Engineering of Highly Nonlinear Chalcogenide Suspended-Core Fibers

Chalcogenide optical fibers are currently undergoing intensive investigation with the aim of exploiting the excellent glass transmission and nonlinear characteristics in the near- and mid-infrared for several applications. Further enhancement of these properties can be obtained, for a particular application, with optical fibers specifically designed that are capable of providing low effective area together with a properly tailored dispersion, matching the characteristics of the laser sources used to excite nonlinear effects. Suspended-core photonic crystal fibers are ideal candidates for nonlinear applications, providing small-core waveguides with large index contrast and tunable dispersion. In this paper, the dispersion properties of As <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> suspended-core fibers are numerically analyzed, taking into account, for the first time, all the structural parameters, including the size and the number of the glass bridges. The results show that a proper design of the cladding struts can be exploited to significantly change the fiber properties, altering the maximum value of the dispersion parameter and shifting the zero-dispersion wavelengths over a range of 400 nm.

Nanotag-enabled photonic crystal fiber as quantitative surface-enhanced Raman scattering optofluidic platform

Core-shell nanotags that are active in surface-enhanced Raman scattering (SERS) and entrapped with thiocyanate (SCN) label molecules were immobilized in the air channels of suspended-core photonic crystal fiber (PCF) to impart quantitative capacity to SERS-based PCF optofluidic sensing platform. The Raman intensity of Rhodamine 6G increases with concentration, whereas the intensity of SCN remains constant when measured using this platform. The signal from the SCN label can be used as an internal reference to establish calibration for quantitative measurements of analytes of unknown concentrations. The long optical path-length PCF optofluidic platform integrated with SERS-active core-shell nanotags holds significant promise for sensitive quantitative chem/bio measurements with the added benefit of small sampling volume. The dependence of SERS intensity on the nanotag coverage density and PCF length was interpreted based on numerical-analytical simulations.

Mid-infrared supercontinuum generation in soft-glass suspended core photonic crystal fiber

Supercontinuum from 800 to 2,600 nm has been obtained in a soft glass suspended-core photonic crystal fiber. The fiber has been fabricated using an in-house synthesized, lead-bismuth-galate oxide glass (PBG-08), which has a transmission window from 500 nm to 4,500 nm. Dispersion characteristic has been designed to enable efficient pumping in the anomalous regime, using typical telecommunication wavelengths and influence of discrepancy between design and physical dispersion profile of fiber is discussed. An optical parametric amplifier system seeded with a Ti:Sapphire oscillator has been used as a light source (70 fs pulses with 100 kHz repetition rate). Supercontinuum bandwidth on the mid-infrared side is limited by OH $$^-$$ absorption of the glass and presence of second zero-dispersion wavelength in the spectral area of interest. Flatness the spectrum remains under 7 dB from roughly 1,800 nm to about 2,500 nm.

Low-Loss Patch Cords by Effective Splicing of Various Photonic Crystal Fibers With Standard Single Mode Fiber

We report on low-loss patch cords composed of a highly reproducible low-loss fusion splicing of photonic crystal fibers (PCFs) with a standard single mode fiber (SMF). Distinct from other papers in this area we report on the results for different types of PCFs, including LMA fibers with similar to a SMF core size and a mode field diameter (MFD), as well as polarization maintaining (PM) Bow-Tie PCF with an elliptical GeO 2 doped core and also a suspended-core (SC) PCF with a tiny core. We show that all studied splices between SMF and PCFs exhibit dispersive and non-reciprocal, in view of a light propagation direction, transmission losses. Defined as a larger decrease of a transmitted optical power comparing both propagation directions, achieved splicing losses, are equal to 0.46 ±0.03 dB, 0.34±0.01 dB, 0.67 ±0.17 dB and 3.09 ±0.36 dB at 1550 nm for LMA8, LMA10, Bow-Tie PCF and SC PCFs, respectively. Moreover, additionally to developed low-loss splicing, we report on low-loss patch cords for all mentioned above PCFs spliced on both ends with SMF pigtails ended with FC/APC connectors achieving the total losses at 1550 nm equal to 1.07 ±0.07 dB for LMA8, 0.72 ±0.20 dB for LMA10, 1.30 ±0.06 dB for Bow-Tie PCF, and 9.36 ±0.20 dB for SC PCF.

Toward A Highly Specific DNA Biosensor: PNA-Modified Suspended-Core Photonic Crystal Fibers

The feasibility of a biosensor for DNA detection based on suspended-core photonic crystal fibers is investigated. The possibility of functionalization of the hole surface, which allows DNA strand binding, is demonstrated, along with the selective detection of DNA through hybridization of immobilized peptide nucleic acid probes with their full-complementary and mismatched DNA segments.