Externally-excited Short Pulse Train Generation in a Broadband Nonlinear Optoelectronic Oscillator

Abstract

The excitation behavior of a broadband nonlinear optoelectronic oscillator (OEO) under periodic square-wave signal injection is experimentally studied. Through setting the repetition frequency of the externally-injected long square-wave signal equal to the free spectrum range (FSR) of the OEO cavity, a positive pulse train with a pulse width of 1.56 ns and a negative pulse train with a pulse width of 2.16 ns are obtained when the dual-drive Mach-Zehnder modulator in the OEO cavity is biased near its minimum transmission point and maximum transmission point, respectively. The repetition frequency of the generated pulse train can be varied at an integral multiple of the FSR of the OEO cavity through setting the repetition frequency of the externally-injected square-wave signal. In addition, the recovered phase portraits and the calculated cross-correlation results indicate that the OEO has a good stability under external excitation, and the generated short pulse trains are with good pulse-to-pulse coherence.