Optically controlled in-line graphene saturable absorber for the manipulation of pulsed fiber laser operation

Abstract

We demonstrate an optically tunable graphene saturable absorber to manipulate the laser operation in pulsed fiber laser system. Owing to the strongly enhanced evanescent field interaction with monolayer graphene, we could realize an efficient control of modulation depth in the graphene saturable absorber by optical means through cross absorption modulation method. By integrating the tunable graphene saturable absorber into the fiber laser system, we could switch the laser operation from Q-switching through Q-switched mode-locking to continuous wave mode-locking by adjusting only the optical power of the control beam. In addition, we realized a hybrid Q-switching of fiber laser by periodical modulation of the absorption of the graphene saturable absorber, where we observed that the repetition rate of the Q-switched laser could be continuously tuned according to the modulation frequency of the applied external signal.

2D Layered Materials: Synthesis, Nonlinear Optical Properties, and Device Applications

“…These early efforts have promoted the rapid development of layered materials in Q‐switched lasers. For example, Q‐switched fiber lasers based on layered materials including graphene, topological insulators, TMDCs, and BP, have been obtained, as illustrated in Table . It can be seen that these lasers have excellent performance in output power, pulse width, repetition frequency, and peak power, which is not inferior to the traditional lasers based on semiconductor saturable absorption mirrors and carbon nanotubes.…”

Ultrafast Fiber Lasers with Low-Dimensional Saturable Absorbers: Status and Prospects

“…Therefore, it is obvious that exploring novel 2D materials as SA is continuous since it was first implemented. In addition, the controllability of key features in current 2D SAs and engineering in the laser cavity with tunable behavior of SAs also offers more functionalities in the development of controllable ultrafast fiber lasers [ 25 , 26 , 27 , 66 , 68 , 101 ]. Combining two or more similar or different 2D materials and building van der Waals heterostructures prospects towards developing multi-functional, high efficiency, broadband controllable photonic devices [ 102 , 103 ].…”

“…All these LD SA devices also have been studied to build Q-switched or Q-switched mode-locked fiber laser by changing the cavity conditions such as polarization state, pump power or even by changing the fiber length of the cavity [ 67 , 68 ]. That means there is an additional regime of the fiber laser using these LD SA, including Q-switching and bound-state soliton mode-locking, to achieve high repetition rate fiber lasers in the gigahertz ranges useful for diverse applications.…”

“…Since the CNT and graphene were firstly suggested in 2004 and 2009 as an optical SA for mode-locked ultrafast fiber lasers, respectively [ 21 , 22 ], many other LD materials other than graphene, comprising TMDs, TIs, black phosphorus, bismuthine, MXenes, and metal-organic frameworks, quantum dots have been consecutively investigated, implying the significant growth of new SAs based on LD for ultrafast fiber lasers [ 8 , 35 , 58 , 65 ]. In addition to these, externally tunable in-line nonlinear LD SAs, where the fiber laser operation can be tuned from continuous wave, through Q-switched to passively mode-locked regime employing electrical gating or external optical bias, have also been demonstrated using various LD SAs [ 25 , 26 , 27 , 66 , 67 , 68 ].…”

Electro-optically gated in-line saturable absorbers for fibre lasers

“…Several recent publications [9][10][11][12][13] are dedicated to research into ways of dynamic modification by electric field or optical radiation of parameters of saturable absorbers made either with carbon nanotubes or noncarbon materials. Dynamic adjustment of saturable absorber parameters not only allows variation of the laser generation regime, but may also lead to a variety of generation regimes, thus providing a possibility of controllable switching between such different regimes.…”