Manipulating supercontinuum generation by minute continuous wave

Abstract

We report a simple triggering mechanism that greatly enhances and stabilizes supercontinuum generation by using an extremely weak cw light (~200,000 times weaker than the pump light). Such an active manipulation scheme can be enabled by a wide range of input conditions and circumvents complex techniques such as precise time delay tuning and dedicated feedback control. It thus offers a handy and versatile approach to control and optimize supercontinuum generation, expanding its range of applications, including ultrafast all-optical signal processing, spectroscopy, and imaging. The utility of the present technique for improving signal integrity in chirped pump optical parametric amplification is also demonstrated.

The role of phase coherence in seeded supercontinuum generation

“…For such lasers the pulse breakup is initiated by noise-driven modulational instability (MI), which causes large shot-to-shot fluctuations. It has been demonstrated that the noise can be significantly reduced by modulating the pump pulse in order to ensure a deterministic rather than noise-driven pulse breakup [3][4][5][6][7][8][9][10][11]. Seeding was numerically investigated in [5,6,10,11].…”

“…In all cases a phase coherent seed was used to achieve a coherent pulse break-up through the amplification of a cascade of four-wave mixing (FWM) side-bands. Experimentally, seeding was investigated in [3,4,[7][8][9]. In [3,8,9] the seed was used to trigger sub-threshold SC generation.…”

“…Experimentally, seeding was investigated in [3,4,[7][8][9]. In [3,8,9] the seed was used to trigger sub-threshold SC generation. The seed was generated by stretching and filtering a fraction of the pump in [3], while [8] used the signal and idler from an optical parametric amplifier as pump and seed.…”

“…The seed was generated by stretching and filtering a fraction of the pump in [3], while [8] used the signal and idler from an optical parametric amplifier as pump and seed. In [9] a separate continuous wave (CW) source was used as seed. It is thus fair to assume that the seeds in [3,8,9] were at least partially coherent with the pump.…”

Enhanced supercontinuum generation in highly nonlinear fibre by selected feedback seeding

“…Because the strong dependence of the SC generation process on initial conditions [1,2], it has been proposed to introduce additional parameters to actively control the SC generation process and improve specific SC properties. For example, by adding an external seed light or by modulating the pump pulse envelopes [3][4][5]. A different approach is to utilize a feedback to influence the SC generation, where a fraction of the generated SC was used as a seed for the following pump pulse [6][7][8].…”