Hollow Photonic Crystal Fiber Research Articles

Investigation on the Effect of Fluorescence Material based on D-Shaped Hollow Core Photonic Crystal Fiber

In this paper, we report the outcomes when fluorescence material coated the hollow core (inner part) of D-shaped photonic crystal fiber (PCF) that has internal diameter (ID), 10 μm. Fluorescence involves the emission of light by a substance that has absorbed light or other electromagnetic radiation. The coated material namely, allene has contributed significantly to the output of transmission spectra at the visible region. The changes in transmission wavelength are remarked when certain parameters vary along the study. The air hole deposited with allene exhibits strong electromagnetic interaction which is good for optical absorption and hence could promote high-sensitivity performance. The optimum condition on how allene covered the hollow PCF which this includes the number of days dipping leads to the bigger wavelength shifting comparing to its emission at 530 nm. Therefore, this study report that allene material could promote an important role in sensing applications at the visible as it displays a good response.

Dynamic Temperature Characteristics of Liquid Filled Photonic Crystal Fiber

The dynamic characteristics of high sensitivity temperature sensor are studied by using siphon method to fill the air hole near the core of the hollow photonic crystal fiber with Cargille matching liquid, and the two ends are fused with single-mode fiber in this work. We analyzed the working principle of filled photonic crystal fiber sensor by using the standard coupling mode theory of directional coupler. The coupling process was simulated by COMSOL software. When the photonic crystal fiber filled with 10 mm liquid was scanned by tunable laser, the temperature sensitivity was 7.50 nm /°C, the average temperature response time was 0.317 s, the average release time was 3.732 s, and the temperature variation linearity was 100%. The experimental results show that the liquid filled photonic crystal fiber has the advantages of high temperature sensitivity, fast response time and good linearity.

Frequency tuning ratio testing of a laser via a hollow photonic crystal fiber resonator.

In order to satisfy the requirements of laser frequency tuning ratio (FTR) measurement, experimental equipment based on a hollow photonic crystal fiber resonator (HPCFR) is proposed in this paper. First, the principle scheme of the equipment consisting of HPCFR is designed, and the resonance curves of the HPCFR are theoretically analyzed, calculated, and simulated; second, the transmissive HPCFR sample is fabricated and the resonance curve is obtained; eventually, the experimental results from the established laser FTR experimental setup demonstrate that the FTRs of a narrow-linewidth fiber laser and semiconductor laser are 17.6 MHz/V and 30.9 MHz/mA, respectively, which are basically in accordance with the factory parameters of the lasers. This work shows that the FTR experimental equipment via HPCFR has the advantages of high precision and good long-term stability.

基于空心光子晶体光纤谐振腔的激光器频率调谐系数测试

基于空心光子晶体光纤谐振腔的激光器频率调谐系数测试

Nanoplasmonic Filters for Hollow Core Photonic Crystal Fibers

We demonstrate a method to add photonic functionalities to the tip of hollow photonic crystal fibers, for ultracompact and integrated lab-on-fiber applications. Specifically we present an angularly robust passband filter that is directly applied to the facet of a fiber, without adhesive or etching. The filter exploits the engineered plasmonic response of metallic features realized on a polymeric membrane and works over a range of 10 degrees, with a passband of 50 nm, centered at a wavelength of 800 nm. This result extends the available functionalities offered by the lab-on-fiber methodology to photonic crystal fibers, as well as providing a reversible method of functionalizing any type of fiber.

Waveform shaping of stretched-pulse fiber laser output with a hollow photonic-crystal fiber

A hollow-core photonic-crystal fiber (PCF) is integrated with a stretched-pulse ytterbium fiber oscillator to enable ultrafast optical waveform shaping, demonstrated through the pulse compression of single-pulse fiber-laser output and tunable ultrashort-pulse pair generation in the regime where the fiber laser delivers a double-pulse output. A hollow PCF with a properly designed dispersion profile is shown to allow the stretched 6.2-ps Yb fiber laser output to be compressed to a pulse width of less than 160 fs, which is only 6% longer than the pulse width supported by the entire 18-nm bandwidth of the fiber laser output.

Air-guided photonic-crystal-fiber pulse-compression delivery of multimegawatt femtosecond laser output for nonlinear-optical imaging and neurosurgery

Large-core hollow photonic-crystal fibers (PCFs) are shown to enable a fiber-format air-guided delivery of ultrashort infrared laser pulses for neurosurgery and nonlinear-optical imaging. With an appropriate dispersion precompensation, an anomalously dispersive 15-lm-core hollow PCF compresses 510-fs, 1070-nm light pulses to a pulse width of about 110 fs, providing a peak power in excess of 5MW. The compressed PCF output is employed to induce a local photodisruption of corpus callosum tissues in mouse brain and is used to generate the third harmonic in brain tissues, which is captured by the PCF and delivered to a detector through the PCF cladding. V C 2012 American Institute of Physics. [doi:10.1063/1.3681777]

Structural analysis of photonic crystal fibers by side scattering of laser light

A side-scattering technique for investigating the inner microstructure of photonic crystal fibers (PCFs) is reported. Multiple scattering is reduced by filling the hollow PCF channels with index-matching fluid. The scattered signal is measured for fixed angles of incidence and detection while the fiber is rotated. A pattern of peaks, unique to each PCF, whether solid or hollow core, correlates closely with the symmetry planes of the PCF structure. As an example of the technique, the twist profile of a structural rocking filter is directly measured.

Silica aerogel core waveguide

We have selectively filled the core of hollow photonic crystal fibre with silica aerogel. Light is guided in the aerogel core, with a measured attenuation of 0.2 dB/cm at 1540 nm comparable to that of bulk aerogel. The structure guides light by different mechanisms depending on the wavelength. At long wavelengths the effective index of the microstructured cladding is below the aerogel index of 1.045 and guidance is by total internal reflection. At short wavelengths, where the effective cladding index exceeds 1.045, a photonic bandgap can guide the light instead. There is a small region of crossover, where both index- and bandgap-guided modes were simultaneously observed.

Biological sensor based on a hollow-core photonic crystal fiber

A new class of hollow photonic crystal fibers (PCFs) that can be used as sensitive elements of chemical and biological sensors is presented. The spectral characteristics of a PCF change depending on the physical properties of a medium filling its periodic structure. The concentration of a solution of an organic compound influences the spectrum of radiation guided in the PCF. A method of measuring the response of the PCF-liquid system to changes in the concentration of a substance dissolved in the analyzed medium is developed.

Broadband dynamic phase matching of high-order harmonic generation by a high-peak-power soliton pump field in a gas-filled hollow photonic-crystal fiber

Hollow-core photonic-crystal fibers are shown to enable dynamically phase-matched high-order harmonic generation by a gigawatt soliton pump field. With a careful design of the waveguide structure and an appropriate choice of input-pulse and gas parameters, a remarkably broadband phase matching can be achieved for a soliton pump field and a large group of optical harmonics in the soft-x-ray-extreme-ultraviolet spectral range.

Raman perturbation and surface core soliton in hollow photonic crystal fiber

Effect of Raman scattering and higher order dispersion are investigated in case of surface core or gap solitons, known to exist in hollow core photonic crystal fibers. The necessary conditions for the existence of the soliton are analyzed in the parameter plane. It is observed that these conditions are compatible with the famous Vakhitov–Kolokolov (VK) criterion. In the later part the system of partial differential equations are solved by ETDRK method from which the shapes of the pulses are investigated as it travels along the z direction. Both the terms, intrapulse Raman scattering and higher order dispersion have important effect on the propagation characteristics

Ionization-induced blueshift of high-peak-power guided-wave ultrashort laser pulses in hollow-core photonic-crystal fibers

Ionization-induced change in the refractive index of a gas is shown to give rise to a substantial spectral blueshift of megawatt light pulses transmitted through a gas-filled hollow photonic-crystal fiber (PCF). This effect suggests the ways of controlling not only the rate, but also the sign of the soliton frequency shift for high-peak-power ultrashort light pulses guided in hollow PCFs filled with Raman-active ionizing gases.

Ionization-induced effects in the soliton dynamics of high-peak-power femtosecond pulses in hollow photonic-crystal fibers

Ionization phenomena are shown to modify the soliton propagation dynamics of high-peak-power laser pulses in hollow-core photonic-crystal fibers (PCFs). Based on the numerical solution of the pulse-evolution equation for a high-peak-power laser field in an ionizing gas medium in a hollow PCF, we demonstrate that hollow PCFs filled with gases having high ionization potentials ${I}_{p}$ can support soliton transmission regimes for gigawatt femtosecond laser pulses. In hollow PCFs filled with low-${I}_{p}$ gases, on the other hand, the ionization-induced change in the refractive index of the gas leads to a blueshifting of soliton transients, pushing their spectrum beyond the point of zero group-velocity dispersion, thus preventing the formation of stable high-peak-power solitons.

Frequency-shifted megawatt soliton output of a hollow photonic-crystal fiber for time-resolved coherent anti-Stokes Raman scattering microspectroscopy

Hollow-core photonic-crystal fibers (PCFs) provide soliton delivery and frequency shifting of 2.8 MW femtosecond pulses with an input central wavelength of 618 nm. The frequency-shifted megawatt soliton output of the hollow PCF is used as a high-peak-power Stokes field for coherent anti-Stokes Raman scattering (CARS) microspectroscopy, providing a dynamic range of nearly four decades for anti-Stokes signal detection, thus enabling time-resolved CARS studies of ultrafast relaxation processes on time scales from tens of femtoseconds up to tens of picoseconds.

Raman-resonance-enhanced composite nonlinearity of air-guided modes in hollow photonic-crystal fibers

Coherent anti-Stokes Raman scattering (CARS) is used to measure relations between the resonant (Raman) and nonresonant (Kerr-type) optical nonlinearities of air-guided modes in a hollow-core photonic-crystal fiber (PCF). We demonstrate that, due to its interference nature, CARS provides a convenient tool for measuring the contribution of the fiber cladding to the total nonlinearity sensed by air-guided modes in hollow PCFs. On a Raman resonance with molecular vibrations in the gas that fills the fiber core, a two-color laser field is shown to induce optical nonlinearities that are several orders of magnitude higher than the nonresonant Kerr-type nonlinearities typical of air-guided PCF modes.

Pulse compression and multimegawatt optical solitons in hollow photonic-crystal fibers

Solitonic phenomena in hollow photonic-crystal fibers are shown to offer new solutions for the control, transmission, and spectral-temporal transformation of ultrashort high-power laser pulses. With the initial parameters of laser radiation accurately matched with fiber dispersion and nonlinearity, submicrojoule laser pulses are shown to exhibit a self-compression and soliton dynamics in the regime of anomalous dispersion. Regimes of solitonic pulse evolution giving rise to few-cycle field waveforms are demonstrated. Based on simple arguments of soliton theory, we derive semiempirical relations providing interesting insights into the minimum pulse width of the laser field in a hollow photonic-crystal fiber as a function of the input laser energy.

Soliton dynamics of megawatt ultrashort light pulses in a hollow photonic-crystal fiber: Effect of high-order dispersion and retarded nonlinearity

The properties of megawatt optical solitons in hollow photonic-crystal fibers (PCFs) are studied. We demonstrate regimes where high-power laser pulses can be compressed to a few cycles of light field and identify the main tendencies in the soliton dynamics of ultrashort laser pulses in hollow PCFs originating from dispersion properties and limited transmission band of such waveguides. The influence of retarded nonlinearity on the soliton dynamics of high-power laser pulses in a hollow PCF is analyzed. In a multisoliton regime, retarded nonlinearity and high-order dispersion are shown to result in the formation of high-power pulses displaying no oscillations of their temporal envelope, which would be typical of standard high-order solitons.

Optical transmission of hollow glass photonic-crystal fibers

A photonic-crystal fiber (PCF) with a forbidden photon band (FPB) in the visible spectral range has been created for the first time. The PCF shell comprises concentric layers of hollow circular air-filled channels with variable diameters. The optical transmission of the proposed PCF and the influence of the geometric parameters on the FPB width and position in the visible spectral range have been studied. By varying the PCF structure and geometry, it is possible to change the FPB characteristics, which offers broad possibilities of output light control.

Form-induced birefringence in elliptical hollow photonic crystal fiber with large mode area

We propose a novel type of photonic crystal fiber (PCF), including an elliptical hole in its solid core. We prove the feasibility of such a fiber and investigate both experimentally and theoretically the dependence of its group birefringence on the geometric hole parameters. We show, for the first time, that form-induced birefringence can be achieved in single mode PCFs with large mode area and suggest it as a possible route for the development of polarization maintaining PCF-based LMA fiber devices.