Tuning Of The Optical Frequency Combs Via Parametric Seeding In Microresonators With Normal Dispersion

With the explosive development of the internet industry, ultra-large capacity, ultra-high speed and low-cost are desirable for the fiber optical telecommunication network, which is one of the key techniques of the broadband networks. Optical frequency combs(OFC) generated on the basis of the Four-Wave-Mixing(FWM) effects in microresonators can be used in multi-wavelength light sources, which reduces the number of laser and the cost, well satisfying the requirement of the fiber optical telecommunication network. According to the reported Kerr frequency combs, combs preferably generate in the microresonators with anomalous dispersion, since the modulational instability of the CW pump is enabled by anomalous dispersion. Obtaining anomalous dispersion in arbitrary wave band is challenging, conversely, normal dispersion is easy to access, therefore, normal-dispersion OFCs are of significant interests. OFCs generation in microresontor with normal dispersion has been reported by experiments and theory, however,controlling the characteristics of the normal-dispersion is still a challenge. We propose a novel method to flexibly tune the optical frequency combs generated in normal-dispersion microresonators based on parametric seeding.To simulate the OFCs via parametric seeding, we utilize a modified Lugiato-Lefever equation. We propose using optical single-sideband frequency shift technique to generate the seeding signal, which can synchronously tune the frequency of the seeding and the pump, as well as solving the limited frequency interval of the reported electro-optic modulated technique. Split-step Fourier algorithm is used to slove the LLE and the Numerical simulation is carried out using the MATLAB procedure. Introducing a seeding signal nFSR away from the pump is shown to be able to generate platicon, which is a normal-dispersion OFC of high conversion efficiency. The effects of the seeding power, phase and frequency on the platicon are analysised respectively. The duration and conversion efficiency of platicons can be tuned by varying the seeding power, the increase of the seeding power from 1 mW to 5 mW can lead to a variation of the duration by 2.376 ps, which is greater than the half of the roundtrip time. Varying the phase of the seeding signal induces a temporal shift of the platicon, the shift is reached for an maximumRt 2 when phase is odd times of ±?. The repetition rate could increase N times by setting the seeding frequency at N times free spectral range away from the pump. Parametric seeding in normal-dispersion microresonator enable deterministic ways to flexibly and effectively control the normal-dispersion OFCs.