title: Versatile mode-locked fiber laser with switchable operation states of bound solitons.
abstract: Bound states of two solitons are among the typical forms of bound states and can be observed in various operation states of mode-locked fiber lasers. We experimentally investigated bound solitons (BSs) in a passively mode-locked erbium-doped fiber laser based on a semiconductor saturable absorber mirror, whose operation states can be switched among multiple pulses, passively harmonic mode-locking, and "giant pulses" by simply adjusting the in-line polarization controller with the pump power fixed. Up to four pulses, fourth-order harmonic mode-locking (HML), and a "giant pulse" with four BSs were obtained with increasing pump power. Experimental results showed a correlative relationship among those operation states (N pulses/Nth-order HML/"giant pulses" of N bound solitons) at different pump power levels. The birefringence induced by the erbium-doped fiber inside the laser cavity played a vital role in the transitions of those operation states.
authors.forename: Xin
authors.initials: X
authors.lastname: Zou
authors.forename: Jifang
authors.initials: J
authors.lastname: Qiu
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Wang
authors.forename: Zi
authors.initials: Z
authors.lastname: Ye
authors.forename: Jindan
authors.initials: J
authors.lastname: Shi
authors.forename: Jian
authors.initials: J
authors.lastname: Wu