A topical review of numerical and experimental studies of supercontinuum generation in photonic crystal fiber is presented over the full range of experimentally reported parameters, from the femtosecond to the continuous-wave regime. Results from numerical simulations are used to discuss the temporal and spectral characteristics of the supercontinuum, and to interpret the physics of the underlying spectral broadening processes. Particular attention is given to the case of supercontinuum generation seeded by femtosecond pulses in the anomalous group velocity dispersion regime of photonic crystal fiber, where the processes of soliton fission, stimulated Raman scattering, and dispersive wave generation are reviewed in detail. The corresponding intensity and phase stability properties of the supercontinuum spectra generated under different conditions are also discussed.

Supercontinuum generation, photonic crystal fiber

Comparative study of one-dimensional photonic crystal heterostructure doped with a high and low-transition temperature superconducting for a low-temperature sensor

In this paper, a novel tellurite glass based hybrid-core photonic crystal fiber (HCPCF) with large birefringence and high nonlinearity is designed. The optical characteristics including the birefringence, nonlinearity, and group-velocity dispersion are studied by using full-vector finite element method. Simulation results show that large birefringence of 0.119 and high nonlinear coefficient of 3.42 W−1/m around 1550 nm can be obtained simultaneously, and the dispersion parameter can be flexibly adjusted. The HCPCF designed can find significant applications in optical communication, signal processing, and sensing systems.

Design on a novel hybrid-core photonic crystal fiber with large birefringence and high nonlinearity

We design a solid hexagonal photonic crystal fiber (PCF) with air holes of different diameters in the cladding region using the finite element method. We achieve a low group velocity dispersion of −5.483  ps2/km and a high nonlinearity of 111.4  W−1  km−1 at 450 nm with d1/Λ being 0.345, which could ensure single-mode propagation. The low dispersion and high nonlinearity form the crucial requirements to generate the supercontinuum (SC) pulse. The designed PCF exhibits a broad SC spectrum of bandwidth 600 nm at an operating wavelength of 450 nm which might find a great relevance in optical sensing applications.

Supercontinuum generation in low dispersion and highly nonlinear hexagonal photonic crystal fibers

Spontaneous emission control of quantum dots embedded in photonic crystals: Effects of external fields and dimension

Waveguiding properties of a silicon nanowire embedded photonic crystal fiber

We design various silicon nanowire embedded photonic crystal fibers (SN-PCFs) with different core geometries, namely, circular, rectangular and elliptical using finite element method. Further, we study the optical properties such as group velocity dispersion (GVD), third order dispersion (TOD) of x and y-polarized modes and effective nonlinearity for a wavelength range from 0.8 to 1.6 μ m. The proposed structure exhibits almost flat GVD (0.8 to 1.2 μ m wavelength), zero GVD (≈ 1.31 μ m) and small TOD (0.00069 ps 3 /m) at 1.1 μ m wavelength and high nonlinearity (2916 W -1 m -1 ) at 0.8 μ m wavelength for a 300 nm core diameter of circular core SN-PCF. Besides, we have been able to demonstrate the supercontinuum for the different core geometries at 1.3 μ m wavelength with a less input power of 25 W for the input pulse of 20 fs. The numerical simulation results reveal that the proposed circular core SN-PCF could generate the supercontinuum of wider bandwidth (900 nm) compared to that from rest of the geometries. This enhanced bandwidth turns out to be a boon for optical coherence tomography (OCT) system.

Supercontinuum generation in silicon nanowire embedded photonic crystal fibers with different core geometries

We design a photonic silicon nanowire embedded microstructured optical fiber which is a special class of waveguide whose core diameter is of subwavelength or nanometer size with the air holes in the cladding. We study the optical waveguiding properties, namely, waveguide dispersions and effective nonlinearity by varying the core diameter. The results reveal that the air-clad silicon subwavelength nanowire exhibits several interesting properties such as a large normal dispersion (82385 ps2/km) for 300 nm core diameter and a large anomalous dispersion (-6817.3 ps2/km) for 500 nm core diameter at 1.95 µm wavelength. The structure provides a large nonlinearity (3648 1/Wm) at 0.450 µm wavelength for 300 nm core diameter. These enhanced optical properties might find suitable for various nonlinear applications that include the generation of fewcycle pulses, supercontinuum generation and optical processing.

Large dispersion and high nonlinearity in silicon nanowire embedded photonic crystal fiber

We explore the optical properties of a proposed solid-core photonic quasi-crystal fiber (SC-PQF) of 10-fold for the wavelengths from 300 to 1100 nm. The proposed SC-PQF exhibits a admissible low dispersion of −8.6481 ps2/km, a third order dispersion of 0.00415 ps3/km and a large nonlinearity of 1684 W−1 km−1 at 450 nm, which turn out to be the desired optical properties for generating the few-cycle laser pulses. By exploiting these optical properties, we numerically demonstrate the generation of few-cycle laser pulses at 450 nm wavelength by means of higher-order soliton effect compression.

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Generation of Few-Cycle Laser Pulses Using A Photonic Quasi-crystal Fiber

We design a 10-fold photonic quasi-crystal fiber (PQF) for analyzing the efficiency of second harmonic generation (SHG). In this study we emphasize on lowering two factors, namely, overlap area and wave-vector mismatch which determine the efficiency of SHG. We find a trade off variation between these two factors with increment in pitch. Finally we optimize the relative efficiency of SHG as 84.87 %W−1cm−2 for a 10-fold PQF, which is 35% higher than that of earlier reported relative efficiency of 6-fold PQF (62.96% W−1cm−2).

P. Ramesh Babu

Papers

Waveguiding properties of a silicon nanowire embedded photonic crystal fiber

Supercontinuum generation in silicon nanowire embedded photonic crystal fibers with different core geometries

Large dispersion and high nonlinearity in silicon nanowire embedded photonic crystal fiber

Generation of Few-Cycle Laser Pulses Using A Photonic Quasi-crystal Fiber

Designing a 10-fold photonic quasi-crystal fiber for enhancing the efficiency of second harmonic generation