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 in photonic crystal fiber

The detection and measurement of gas concentrations using the characteristic optical absorption of the gas species is important for both understanding and monitoring a variety of phenomena from industrial processes to environmental change. This study reviews the field, covering several individual gas detection techniques including non-dispersive infrared, spectrophotometry, tunable diode laser spectroscopy and photoacoustic spectroscopy. We present the basis for each technique, recent developments in methods and performance limitations. The technology available to support this field, in terms of key components such as light sources and gas cells, has advanced rapidly in recent years and we discuss these new developments. Finally, we present a performance comparison of different techniques, taking data reported over the preceding decade, and draw conclusions from this benchmarking.

/pdf/optical-gas-sensing-a-review-4uaf589xiq.pdf

Optical gas sensing: a review

Supercontinuum generation, photonic crystal fiber

Photonic crystal fibers are a kind of fiber optics that present a diversity of new and improved features beyond what conventional optical fibers can offer. Due to their unique geometric structure, photonic crystal fibers present special properties and capabilities that lead to an outstanding potential for sensing applications. A review of photonic crystal fiber sensors is presented. Two different groups of sensors are detailed separately: physical and biochemical sensors, based on the sensor measured parameter. Several sensors have been reported until the date, and more are expected to be developed due to the remarkable characteristics such fibers can offer.

/pdf/photonic-crystal-fibers-for-sensing-applications-3479q9acwh.pdf

Photonic crystal fibers for sensing applications

A review of optical fiber sensing demonstrations based on photonic crystal fibers is presented. The text is orga- nized in five main sections: the first three deal with sensing approaches relying on fiber Bragg gratings, long-period gratings and interferometric structures; the fourth one reports applica- tions of these fibers for gas and liquid sensing; finally, the last section focuses on the exploitation of nonlinear effects in pho- tonic crystal fibers for sensing. A brief review about splicing with photonic crystal fibers is also included.

/pdf/optical-sensing-with-photonic-crystal-fibers-2g41xr66t6.pdf

Optical sensing with photonic crystal fibers

We report on experimental studies of gas sensing using air-guiding photonic bandgap fibers. The photonic bandgap fibers have at one end been spliced to standard single mode fibers for ease of use and improved stability

/pdf/gas-sensing-using-air-guiding-photonic-bandgap-fibers-3a29fotlnp.pdf

Gas sensing using air-guiding photonic bandgap fibers

We analyze experimentally the polarization properties of highly nonlinear small-core photonic crystal fibers (PCFs) with no intentional birefringence. The properties of recently emerged polarization maintaining PANDA PCFs are also investigated. The wavelength and temperature dependence of phase and group delay of these fibers are examined in the telecommunications wavelength range. Compared to a standard PANDA fiber, the polarization characteristics and temperature dependence are found to be qualitatively different for both types of fibers.

/pdf/experimental-study-of-polarization-properties-of-highly-36qy2i9561.pdf

Experimental study of polarization properties of highly birefringent photonic crystal fibers.

Supercontinuum generation in large mode-area microstructured fibers is demonstrated by launching into the fiber ns pulses from a passively Q-switched Nd:YAG laser. The special properties of these fibers open the way to compact, single-mode, high-power supercontinuum sources with a low divergence of the output beam. The nonlinear phenomena leading to the formation of the broad spectrum are also described.

/pdf/supercontinuum-generation-in-large-mode-area-microstructured-25c6rfgct8.pdf

Supercontinuum generation in large mode-area microstructured fibers

http://lib.tkk.fi/Diss/2006/isbn9512282992/article2.pdf

Polarization-mode dispersion of large mode-area photonic crystal fibers

http://lib.tkk.fi/Diss/2006/isbn9512282992/article6.pdf

Tuomo Ritari

Papers

Gas sensing using air-guiding photonic bandgap fibers

Experimental study of polarization properties of highly birefringent photonic crystal fibers.

Supercontinuum generation in large mode-area microstructured fibers

Polarization-mode dispersion of large mode-area photonic crystal fibers

Gas filled photonic bandgap fibers as wavelength references