Accurately Shaping Supercontinuum Spectrum via Cascaded PCF

Abstract

Shaping is very necessary in order to obtain a wide and flat supercontinuum (SC). Via numerical simulations, we accurately demonstrated shaping the SC using the fiber cascading method to significantly increase the width as well as the flatness of the spectrum in silica photonic crystal fiber (PCF). The cascaded PCF contains two segments, each of which has dual zero-dispersion frequencies (ZDFs). The spectral range of the SC can be expanded tremendously by tuning the spacing between the two ZDFs of the first segmented cascaded PCF. Increasing the pump power generates more solitons at the red edge, which accelerates solitons trapping and improves the spectral flatness of the blue edge. Furthermore, cascading the second segmented PCF by choosing appropriate fiber parameters ensures the flatness of the red end of SC. Therefore, a cost-effective alternative method for broad and flat supercontinuum generation in the near-infrared range is proposed here, which can be implemented easily in any photonics laboratory, where dual ZDFs PCFs are commonly found.

Low peak power broadband supercontinuum spectra generated in a square lattice toluene-core photonic crystal fiber with different air hole diameters

“…In such a case, combination of nonlinear self-seeded processes and MI suppression enable pulse-preserving (i.e., uniform temporal profile and spectral power density) and mitigating effects of vacuum noises for high coherence. However, fibers with ANDi typically have sophisticated fiber structures (e.g., fiber with liquid infiltration [8,9], tapered [10], and cascaded [11]). In addition, ANDi SC generation with broad bandwidth typically needs high peak values of pump lasers, this may lead to fiber damage due to opto-thermal effects.…”

Interactions of the second-order solitons with an external probe pulse in the optical event horizon

“…These pulses exhibit similar characteristics, such as periodicity, particle-like property, as well as stability [1] . But they are sensitive to high-order dispersion (HOD) and nonlinear perturbation, which induce the split of higher-order solitons [5][6][7][8][9][10] . The soliton fission dynamics has been previously studied under the perturbations of self-steepening (SS), HOD, and stimulated Raman scattering, where a series of fundamental solitons with different group velocities as well as phase-matched dispersive waves (DWs) are generated [11][12][13] .…”

“…As one of the vital physical mechanisms for ultra-broadband SC generation, the interaction between fundamental solitons and DWs in nonlinear waveguides has been thoroughly studied in the past decade [6,13] . When a relatively weak probe wave transmits along with an energetic soliton with a different group velocity, the boundary of the soliton acts as a fiber-optical analog of the event horizon, preventing the escape or entry of the probe wave, which imitates the boundary of the black hole and white hole, respectively [14] .…”

Special Issue on Enabling Technology in Optical Fiber Communications: From Device, System to Networking

“…Furthermore, it features low nonlinearity, which is critical for on-chip high-power systems. For fiber-based devices, Rong, J. et al numerically simulated shaping the supercontinuum (SC) using the fiber cascading method to significantly increase the SC spectral width and flatness in silica photonic crystal fiber (PCF) [ 5 ]. To characterize linear frequency-modulated continuous-wave (FMCW) lasers, Yang, J. et al [ 6 ] proposed a scheme for measuring the mapping relationship between instantaneous frequency and time of a FMCW laser based on a modified coherent optical spectrum analyzer (COSA) and digital signal processing (DSP) method.…”