Saturable absorber based on a hybrid structure of graded-index multimode fiber and graphene for a passive mode-locked erbium-doped fiber laser

Abstract

A saturable absorber based on a hybrid structure of graded-index multimode fiber and graphene is proposed and demonstrated for passive mode-locked fiber laser pulse generation. The center wavelength of the output pulses is 1564 nm, with a 3 dB bandwidth of 3.52 nm and pulse duration of 634 fs at a fundamental repetition rate of 18.72 MHz, with a signal-to-noise ratio of 71 dB. Compared with the saturable absorber based on a pure graded-index multimode fiber structure, the pulse duration is compressed by 253 fs, and the signal-to-noise ratio is increased by 10 dB. The hybrid structured saturable absorber has the advantages of simple structure, convenient operation, and good robustness, which makes it attractive in the generation of ultrafast pulses.

All-Optical Signal Processing by Nonlinear Multimode Interference in Ta2O5 Waveguides

“…Moreover, the nonlinear MMI effect can also be used as a variable transmissive device, for example a nonlinear MMI based saturable absorber was proposed by Nazemosadat and Mafi, 40 which can be installed in a laser cavity to initiate Q-switched operation and mode-locked operation. 41 Waveguide based nonlinear MMI saturable absorbers are found in the transmission taken at port 3 given that L MMI is an odd multiple of L π as shown in Figure 7A. Proper saturation fluence can be designed by manipulating the L MMI , X3 off , and X1 off , accordingly.…”

“…All-optical power-dependent switching had never been experimentally demonstrated prior to this work. Moreover, the nonlinear MMI effect can also be used as a variable transmissive device, for example a nonlinear MMI based saturable absorber was proposed by Nazemosadat and Mafi, which can be installed in a laser cavity to initiate Q-switched operation and mode-locked operation . Waveguide based nonlinear MMI saturable absorbers are found in the transmission taken at port 3 given that L MMI is an odd multiple of L π as shown in Figure A.…”

Generation and Dynamics of Multiple Pulses in an Ultrafast Fiber Laser with a Single-Mode Fiber–Graded-Index Multimode Fiber–Single-Mode Fiber-Based Saturable Absorber

“…Recently, a tapered GIMF-based modulator has been employed to realize tunable mode-locked pulses in a thulium-doped fiber laser [21]. In 2021, an innovative hybrid structure composed of GIMF and graphene for stable optical pulses was reported by Li X et al [22]. Moreover, some fascinating mode-locking phenomena in SMSbased mode-locked fiber lasers were observed, such as noise-like pulses [23], Q-switched mode-locking patterns [24], different bound solitons [20,25] and multi-wavelength modelocking patterns [26].…”

Generation of mode-locked pulses based on D-shaped fiber with CdTe as a saturable absorber in the C-band region

“…At a maximum pump power of 510 mW, the maximum average output and peak powers were 2.8 mW and 0.208 kW, respectively. A passive mode-locking approach has promising applications in various industries, such as optoelectronics, photovoltaics, and medicine, 66–68 due to the high-quality beam, ease of production, and cost-effective system 47 with the opportunity of generating short pulses with high peak power. 34…”