Tailoring the dispersion properties of photonic crystal fibers

Abstract

Photonic crystal fibers (PCFs) have had a substantial impact on nonlinear fiber optics and shortpulsed fiber laser systems due to their novel dispersion properties. The large normal or anomalous waveguide dispersion available in such fibers opens up a number of new opportunities not accessible with standard fiber technology. In this contribution, the fundamentals of PCF dispersion are briefly reviewed along with earlier results. In addition, some of our recent work on dispersion tailoring to facilitate nonlinear processes, and dispersion control in lasers will be presented.

Designing microstructured polymer optical fibers for cascaded quadratic soliton compression of femtosecond pulses

“…Microstructured optical fibers allows for an elaborate dispersion control. Usually they are exploited to gain control over the group-velocity dispersion (GVD) [1] (see [2] for a recent literature overview over the dispersion properties of microstructured optical fibers). Also the group-velocity mismatch (GVM) for three-wave mixing processes can be completely removed [3], which is important in order to realize second-harmonic generation (SHG) of ultra-short fs pulses.…”

“…The large phase-mismatch ∆β can instead be exploited for cascaded χ (2) : χ (2) SHG processes [4]. The second harmonic (SH) is within a coherence length 2π/|∆β| generated and then back-converted to the fundamental wave (FW).…”

“…The fiber geometry can also help overcoming the problem of inhomogeneous compression in the transverse direction of the beam found in a bulk geometry [13]. 1 We have done a preliminary investigation of the potential in using silica microstructured optical fibers for CQSC [2,14], where the quadratic nonlinearity was assumed to come from thermal poling of the silica fiber [15]. We surprisingly found that zero GVM was not as such an advantage, since the compressed pulses became very distorted.…”

“…We surprisingly found that zero GVM was not as such an advantage, since the compressed pulses became very distorted. Another main result was that a very large quadratic nonlinearity d eff ∼ 3 − 5 pm/V was needed in order to generate suitably large Φ NL [2]. This is because the chosen fiber designs had very a large phase mismatch, and Φ NL ∝ d 2 eff /∆β.…”

Linear and nonlinear modeling of light propagation in hollow-core photonic crystal fiber

“…The dispersion alteration can be pictured as a wavelength dependent flowing of modal energy from within the core into the FRCH, which collectively act as a secondary low index core. As the FRCH are increased in size still further, modes associated with this secondary core enter the bandgap and interact strongly with the core mode, which can lead to a high dispersion with a relatively low slope [22]. The close proximity (in effective index) of FRCH related modes to the core modes implies, however, that such designs will suffer from a high degree of micro-and macro-bend loss.…”