Yong Geng

All-optical multilevel amplitude regeneration in a single nonlinear optical loop mirror

We experimentally demonstrate all-optical amplitude regeneration of 4-level pulse amplitude modulated signals (PAM4) based on a single nonlinear optical loop mirror (NOLM). Four power-plateau regions are achieved using return-to-zero (RZ) pulses of narrow pulse-width, enabling large nonlinear phase shifts within the highly nonlinear fiber (HNLF). We quantify noise suppression characteristics at each amplitude level and obtain an overall EVM improvement of 0.92dB by optimizing input power and distortion strength. A theoretical analysis has been also carried out matching the experimental results and revealing the design characteristics of the regenerators nonlinear transfer function.

Multilevel power transfer function characterization of nonlinear optical loop mirror

The power transfer function of a nonlinear optical loop mirror (NOLM) is experimentally investigated for both continuous-wave and pulsed operation of the pump signal. The difference between transmission and reflection responses is discussed in view of using the interferometer for the amplitude regeneration of multilevel signals.

Kerr frequency comb dynamics circumventing cavity thermal behavior

We demonstrate arbitrary laser frequency detuning control in an optical microcavity, utilizing auxiliary laser heating method to simplify cavity thermal behavior. Novel Kerr comb dynamics and flexible manipulation of dissipative cavity solitons are reported.

Enhanced Single Cavity Soliton Generation in Kerr Microresonators Via Inverse-Kelly Sideband

The formation of dissipative cavity solitons in microresonators provides an efficient process for ultrashort pulse synthesis and mode-locking of Kerr frequency combs. However, as dissipative cavity solitons arise spontaneously from a continuous-wave pump, deterministically controlling the number of intracavity solitons remains challenging to date. In this paper, we propose an efficient yet easy way to access single cavity soliton formation in microresonators via inverse-Kelly sideband generation in Kerr comb spectrum. Our method only requires fixed-speed unidirectional pump frequency sweeping to achieve single soliton state, avoiding complex pump scanning trajectory and high frequency pump modulation. Moreover, we report on the determinacy of single-soliton generation using the proposed method; statistic analysis shows that excellent determinacy as high as 98.7% is achieved.

Investigation of pump noise transfer characteristics in degenerated four-wave mixing

The transfer characteristics of pump in-band and out-of-band noises to the signal in degenerated four-wave mixing are analyzed. The noise figure of a clock-pump fiber optical parametric amplifier is measured to be 4.3 dB.