Rational Harmonic Mode-locked Laser Research Articles

Rational harmonic mode-locked laser using a bismuth-oxide-based highly nonlinear erbium-doped fiber

We report a rational harmonic mode-locked fiber laser employing a bismuth-oxide-based highly nonlinear erbium-doped fiber (Bi-HNL-EDF) with a length of 1.5m. The Bi-HNL-EDF is used as a broadband gain medium and as a noise suppressor based on self-phase modulation. The amplitude of the rational harmonic mode-locked pulses can be regulated by properly tuning the modulation parameters of the intracavity modulator. The cavity length as short as 6m enables generation of stable and clean short pulses with a repetition frequency up to 40GHz over the wavelength range covering both the conventional and the longer bands.

利用有源滤波器实现谐波锁模光脉冲的均衡

利用有源滤波器实现谐波锁模光脉冲的均衡

A Dual-Wavelength Rational Harmonic Mode-Locked Fiber Ring Laser With Different Repetition Frequencies

A dual-wavelength rational harmonic mode-locked fiber ring laser with different repetition frequencies is theoretically analyzed and experimentally demonstrated. In this scheme, two wavelength channels are inserted into the laser loop to form two resonant cavities. By tuning the length of each channel, required rational harmonic mode-locking conditions can be achieved, and dual-frequency mode-locked signals are simultaneously generated at different wavelengths. In addition, the supermode suppression ratio is further improved due to the mode competition caused by this dual-cavity configuration. In the experimental demonstration, when the fourth-order (or fifth-order) harmonic mode-locked signal is generated in Cavity 1, the first-, second-, and third-order (or fourth-order) harmonic mode-locked signals, respectively, can be generated in Cavity 2 by tuning its length. The measured radio frequency spectra and waveforms show that the signals have high quality. Compared with a conventional rational harmonic mode-locked laser (RHMLL), more than 10 dB supermode suppression ratio improvement is obtained. Since this system can flexibly implement multiwavelength and multifrequency signal generation without adding much cost, it may have wide applications in optical communication system, photonic microwave signal generation, and optical waveform synthesizers.