Combination and Compression of Multiple Optical Pulses in Nonlinear Fibers with the Exponentially Decreasing Dispersion

Abstract

We propose a simple scheme to generate high energy ultrashort pulses by combination and compression of multiple input pulses which share the same chirp profile. First, the multiple raised-cosine pulses in the input pulse train are modulated by a phase modulator in which each modulation cycle covers two, three, four, or five pulses. Then, the modulated pulses are launched into a nonlinear fiber with the exponentially decreasing dispersion. We find that these pulses initially coalesce into a single pulse whose pulse profile is nearly hyperbolic secant, which then undergoes self-similar compression. Thus in the proposed method, first the combination of the multiple optical pulses occurs and then self-similar compression takes over. Besides, we also report the generation of ultrashort pulses by combination and compression of multiple hyperbolic secant pulses with the same chirp. The numerical results reveal that the resulting ultrashort pulse possesses a large portion of the input pulses for both raised-cosine and hyperbolic secant pulses. However, the compression factor and energy ratio are relatively higher for the hyperbolic secant pulses when compared to the raised-cosine pulses.

Simultaneous Pulse Combination and Nearly Self-Similar Pulse Compression in Tapered Silicon Waveguides at Around 2.0 μm

“…In Fig. 4(d), the two compression factor curves share the comparable trend in the final 1 cm waveguide, which reveals that the compression factor of the compressed pulse is 4.08 and the ideal compression factor value of 5.4 is calculated from self-similar pulse compression analytical expression [24].…”

“…4(d). The compression factor of the output pulse is 4.35 and the ideal compression factor value of 6.06 is considered from self-similar pulse compression analytical expression [24]. The corresponding results of the same and different center wavelengths are denoted in the Table I.…”

“…From the analysis in the previous research, the realization of the Si-TPCC process depends strongly upon the GVD decreasing exponentially [24], [25]. In this line, the decreasing exponentially GVD is described approximately as,…”

“…Previously, much of the advances on pulse compression has concentrated on the single-pulse compression. To obtain the extra functionalities of pulse controlling, the efficient multiplepulses combination and compression was firstly proposed in the exponentially dispersion decreasing nonlinear fiber, which indicates the ultimate compressed pulse possesses higher energy and comprises major portion of the total input light wave energy [24], [25]. However, the optical fiber is placing a serious challenge on the miniaturization and integration in the chip-scale.…”

Simultaneous Combination and Nearly Self-similar Pulse Compression of Five Pulses at Different Wavelengths

“…This kind of self-similar pulse compression maintained the advantages of integrally pedestal-free and nearly transform-limited features and pulse breakup as well avoided even at high peak powers during propagation [3]. Multiple raised-cosine (RC) optical pulses with the same central wavelengths can be combined and compressed in a dispersion decreasing nonlinear fiber to generate a single ultrashort pulse, which reveals that the final compressed pulse was a high-energy ultrashort pulse that contained major portion of the input light signal energy [4]. However, simultaneous combination and compression of multiple different-wavelength pulses is complex challenging dynamics that has never been reported.…”