Harmonic vector noise-like square pulse in an Er/Yb co-doped fiber laser

Abstract

Vector noise-like square pulse (NLSP) has been experimentally observed in an Er/Yb co-doped figure-eight fiber laser. The energy of a single NLSP at the fundamental repetition rate reaches 346.6 nJ. By adjusting the intracavity devices with the pump power fixed, 2nd to 7th harmonic mode-locked (HML) NLSP has also been formed. Further investigation shows that the pulse width of both fundamental repetition rate NLSP and HML NLSP change monotonically with pump power, and both of them exhibit polarization-locked vector (PLV) character. The experimental results would enrich the comprehension of the vector nature of HML NLSPs.