Dissipative soliton resonance (DSR) is an efficient way to achieve high energetic pulses without wave breaking. In fiber laser, DSR operation manifests as square pulses emission. Based on this principle, we have experimentally demonstrated pulses in the micro joule range. Experiments have been conducted using double-clad Er:Yb-doped fiber lasers in different optical configurations. In particular, we demonstrate 10 μJ DSR emission in an optimized cavity and also the possibility to observe wave breaking in DSR regime. In the latter case, harmonic mode-locking of square pulses is demonstrated.
Owing to its strong optical characteristics, graphene has emerged in the field of ultrafast lasers as a prominent saturable absorber. In this communication, we present a passively mode-locked Er:Yb doped double-clad fiber laser using a graphene deposited tapered fiber (GDTF). Averaging 20 μm of diameter with a length of 6 mm, the taper enables a strong light–graphene interaction owing to the evanescent field of the excited cladding mode. To create the saturable absorber device, graphene solution is carefully deposited via a micro syringe so that the waist of the taper is completely immersed into the aqueous solution. Then, a continuous wave laser with output power up to 95-mW centered at 1550 nm is injected into the taper. Deposition of graphene onto the taper by the optical tweezers effect started when the transmitted power dropped significantly. Afterwards, the GDTF is implemented in a fiber cavity to test its mode-locking performance. At the maximum available pump power, we obtain the 326th harmonic mode locking of soliton bunches with average output power of 520 mW.
We present a widely adjustable high energy square pulse laser operating in DSR in a passively mode-locked F8L using dual Er:Yb co-doped double clad amplifiers. By manually controlling the power of each amplifier, the pulse width can be varied in a range of 360 ns without generating multi-pulsing instabilities. To ensure that DSR would dominate the modelocking mechanism, we use a 1.5 km standard single-mode fiber in the cavity. At a maximum pumping power, the laser generated square pulses with 416 ns duration and an average output power of about 1.33 W with a repetition frequency of 133 KHz corresponding to a record pulse energy of 10 μJ.
In this communication, we demonstrate a passive mode-locked Er:Yb co-doped double-clad fiber laser using a tapered microfiber topological insulator (Bi<sub>2</sub>Se<sub>3</sub>) saturable absorber (TISA). The topological insulator is drop-casted onto the tapered fiber and optically deposited by optical tweezer effect. We use a ring laser setup including the fabricated TISA. By carefully optimizing the cavity losses and output coupling ratio, the mode-locked laser can operate in L-band with a high average output power. At a maximum pump power of 5 W, we obtain the 91<sup>st</sup> harmonic mode-locking of soliton bunches with a 3dB spectral bandwidth of 1.06nm, a repetition rate of 640.9 MHz and an average output power of 308mW. As far as we know, this is the highest output power yet reported of a mode-locked fiber laser operating with a TISA.