Parametric amplification and processing in optical fibers

Abstract

We review recent progress made in parametric amplification and signal processing using high confinement fibers. In contrast to crystalline and semiconductor devices, fiber parametric amplifiers offer interaction lengths that can vary from 10 m to 1 km and are not limited by waveguide losses. The operation, design and impairment physics of general fiber parametric devices are reviewed. The technology prospects for advanced signal processing are discussed.Two-pump parametric interaction combines at least two nondegenerate and one degenerate four-photon mixing process: phase conjugation (blue), Bragg scattering (green) and MI (red).

Inter-modal four-wave mixing study in a two-mode fiber

“…Today, however, km-long few-mode fibers of much higher uniformity and thus low mode coupling are commercially available [2]. For example, this has allowed the recent experimental verification of IM FWM in a 4.7-km long two-mode fiber (TMF) at communication wavelengths [3,4] and mode conversion based on FWM [5], thus suggesting that IM FWM may become feasible for optical signal processing as was the case for single-mode fiber optical parametric processes more than two decades ago [6][7][8]. Compared to the single mode nonlinear platform, the multi-mode one opens up an extra (spatial) degree of freedom to the system and, thus, could be a very interesting potential means for enhancing the performance of many ultra fast signal processing applications, namely parametric amplification and wavelength conversion.…”

Generation of wideband coherent frequency comb from a single continuous-wave

“…While suboptimal, the historic choice of MLL seeding can be easily understood in practical terms since efficient frequency comb generation dictates strict power and phasematching requirements [2,3,12].…”

“…Consequently, a high mixer FoM is historically achieved using MLL lasers with peak powers [8][9][10]. Unfortunately, this also greatly increases noise generated during the frequency generation process: not only that MLLs seed noise is higher than that of CW laser, but the mixer operates as high-gain parametric element [12,13] that efficiently amplifies the seed and inherent (vacuum) noise. Worse, once that MLL is selected as a seed, any ability to quickly change comb frequency pitch is effectively lost since MLL cavity strictly dictates the entire frequency plan henceforth.…”

“…Surprisingly, this simple observation is in direct conflict with the seed laser choice made with majority of frequency combs to date [8][9][10][11]. Indeed, starting from the early demonstration [8], reported work commonly relies [5,7] on pulsed (MLL) sources, in spite of its inherently higher noise levels.While suboptimal, the historic choice of MLL seeding can be easily understood in practical terms since efficient frequency comb generation dictates strict power and phasematching requirements [2,3,12].In ideal case, when wide-band phase matching condition is met, parametric efficiency depends exponentially on mixer figure of merit (FoM), defined by the product of optical power (P), effective interaction length (L) and mixer nonlinearity () [12]. With conventional comb generation, parametric process takes place in either crystalline or photonics crystal fiber (PCF) mixers possessing short physical length.…”

All-optical time-stretch digitizer

“…This approach maps the signal under test onto a chirped optical carrier using four-wave mixing (FWM) process in a highly nonlinear fiber (HNLF). Over the last decades, FWM process has formed the basis for a class of versatile parametric devices enabling amplification and regeneration, [16][17][18][19] frequency conversion, 18,20 phase conjugation, 21-23 and optical sampling. 24 Our all-optical timestretch digitizer exploits ultrafast FWM process between a pulsed pump and a signal to encode wideband optical signals onto the spectrum of a pre-chirped broadband optical carrier.…”