Design of All-Normal Dispersion Microstructured Optical Fiber on Silica Platform for Generation of Pulse-Preserving Supercontinuum Under Excitation at 1550 nm

Abstract

We investigated numerically the possibility of all normal dispersion fiber design for near-infrared supercontinuum generation based on a standard air-silica microstructure. The design procedure includes finding of target dispersion profile and subsequent finding of appropriate geometrical fiber design by inverse dispersion engineering. It was shown that the tailoring of dispersion profile could increase the spectral width of generated supercontinuum while maintaining perfect spectral flatness. Conditions necessary for wide and flat supercontinuum generation as well as restrictions imposed by chosen materials were discussed. As a result of design and optimization procedure, an airsilica design was found providing normal dispersion up to 3 µm. Simulation results with 10 nJ, 100 fs pulses demonstrate supercontinuum generation up to 1.3 octave; whereas pumping with 30 nJ, 100 fs pulses could provide 1.8 octave supercontinuum.

Ultraflat, broadband, and highly coherent supercontinuum generation in all-solid microstructured optical fibers with all-normal dispersion

“…The SC spectrum shows high flatness with deviations of less than 3 dB covering from approximately 1030 to 2030 nm, corresponding to nearly an octave. Compared with results of previous papers [19,[27][28][29], the pump pulse duration is much longer. As shown in the above section, the dispersion possesses high flatness near the local maximum dispersion, and the local maximum dispersion is slightly normal to balance nonlinearity and dispersion effects.…”

“…The fiber, based on lead silicate glass, had many air holes with two different diameters; thus, it was difficult to precisely maintain the structures of the fiber during fabrication. Sukhoivanov et al numerically investigated the optimization of dispersion profiles through multiorder dispersion engineering to generate broadband ultraflat SC spectra with 100-fs pulses at 1.55 μm [28]. Nevertheless, the dispersion profile of optical fibers designed was not well-matched for the target.…”

“…However, the flatness of SC spectra degrades with an increase of pump pulse duration. A special ANDi could be an approach to achieve ultraflat SC generation with broader pump pulse duration, according to previous research [28,29].…”

Coherent supercontinuum generation in soft glass photonic crystal fibers

“…In the cases of near-infrared pumping of silica and silicate glass ANDi fibers, the strengths were often convenience and availability for particular experiments, while femtosecond lasers at fixed wavelengths compatible with these fibers were available as well. While Table 2 shows experimental data, a significant number of theoretical (numerical) simulations on ANDi SC generation have been published as well, and a reading list could include SC generation in silica PCFs [51,70], Ge-doped silica PCFs [71,72], and chalcogenide glass PCFs or waveguides [39].…”

Numerical Simulation of the CS2-Filled Active Fiber With Flattened All-Normal Dispersion

“…Both the passive and active highly nonlinear fibers (HNLFs) with flattened normal dispersion profiles can be employed for the coherent SCG. In the former case, the all-normal dispersion fibers were demonstrated experimentally using the air-silica photonic crystal fibers (PCFs) [4][5][6][7][8][9][10][11][12], or proposed in a numerical study of the heavily germanium-doped silica fiber [13]. The nonlinear parameter of the fiber can be enhanced further for the all-solid soft glass PCF [14][15][16], air-tellurite PCFs [17], tapered tellurite step-index optical fiber [18], As2Se3 chalcogenide glass triangular-core graded-index PCF [19] and hollow-core silica fibers filled with highly nonlinear liquids such as carbon disulfide (CS2) [20][21][22][23][24][25] and chloroform (CHCl3) [26].…”