Overview of photonic devices based on functional materials-integrated photonic crystal fibers

Photonic crystal fibers (PCFs) have brought tremendous advancements due to their predominant features of peculiar air-holes arrangement in two-dimentional direction. Functional materials like metals, magnetic fluids, nematic liquid crystals, graphene and so on, are extensively adopted to integrate with PCFs to get extraordinary transmission properties. This review takes the development stages of photonic devices based on functional materials-infiltrated PCFs into consideration, covering the overview of common materials and their photoelectric characteristics, the state-of-art infiltrating/coating techniques, as well as the corresponding applications involving polarization filtering and splittering devices in optical communication and sensing elements related to multiple parameters measurement. The cladding air hole of PCFs provides a natural optofluidic channel for materials being introduced, light-matter interaction being enhanced, and transmission properties being extended, where a lab on a fiber are able to be proceeded. It paves a space for the development of photonic devices in the aspects of compact, multi-functional integration, and electromagnetic resistance as well. According to surface plasmon resonance, the property of tunable refractive indices, and the flexible geometry structures, it comes up to some representative researches on polarization filters, multiplexer-demultiplexers, splitters, couplers and sensors, making a candidate for widespread fields of telecommunication, signal-capacity, and high-performance sensing.

NONLINEAR PROPERTIES OF STRUCTURAL HETEROGENEOUS PHOTONIC CRYSTAL FIBERS WITH As2Se3 SUBSTRATE

We examine the possibility of improving the nonlinear properties of photonic crystal fibers (PCFs) with As2Se3 substrates by creating a difference in the diameters of the air holes of the rings around the core. With the new design, all-normal dispersion properties, small effective mode area, high nonlinear coefficient, and low confinement loss were achieved in the long-wavelength range of 2.0–7.0 µm. The highest nonlinear coefficient is 4414.918 W-1.km-1 at 4.5 µm for the lattice constant (Ʌ) of 3.0 µm and the filling factor (d/Ʌ) of 0.85, while the lowest loss is 1.823´10-21 dB/cm with Ʌ = 3.5 µm and d/Ʌ = 0.8. Based on the numerical simulation results, the characteristics of two optimal structures have been analyzed in detail to guide the application in supercontinuum generation.

COMPARISON OF DISPERSION CHARACTERISTICS OF SOLID-CORE PCFs INFILTRATED WITH PROPANOL AND ETHANOL

In this paper, we propose the solid-core photonic crystal fibers (PCFs) with hexagonal cladding infiltrated with propanol in the air-holes. The dispersion characteristics and zero- dispersion wavelengths of these PCFs have been compared with previous publications and analyzed in detail. By investigating the dependence of the dispersion characteristics on the air-hole diameters, we determine the optimal structures with 1 µm of that. The PCF infiltrated with propanol exhibits flatter and smaller dispersion characteristic and the zero-dispersion wavelength shifted towards a longer wavelength, 24 nm compared with ethanol permeable PCFs [17]. This result shows that structure with a diameter of air-holes by 1µm is suitable for supercontinuum (SC) generation in the near- infrared wavelength range.

Low pedestal sub-17 fs pulse generation through cascaded self-similar compression in photonic crystal fibers

We propound a realistic numerical model based on cascaded self-similar pulse compression to generate low pedestal ultrashort pulses at 2.5 µm. Self-similarity has been attained by modeling exponential dispersion decreasing and exponentially nonlinearity increasing chalcogenide photonic crystal fibers (PCFs). Initially, fundamental soliton compression in As2S3tapered PCF is investigated for the pedestal-free reduction of the pulse width. Subsequently, the compression factor is further enhanced in the As2Se3 PCF-based nonlinear optical loop mirror. Numerical outcomes reveal a compression of 1 ps pulse down to a pulse width of 16.6 fs with a peak power of 116 W in a total fiber length of L=61 cm.