Generation of bidirectional stretched pulses in a nanotube-mode-locked fiber laser

Abstract

The bidirectional stretched pulses in a nanotube-based erbium-doped fiber laser are observed experimentally for the first time to our best knowledge. The proposed fiber laser generates two stable pulse trains in opposite directions with different central wavelengths, pulse widths, and repetition rates. In addition, the bidirectional operations with the same central wavelengths are also demonstrated by changing the polarization controller and pump power. Experimental results suggest that the cavity asymmetries together with the fiber birefringence play key roles in the formation of these unique features.

Generation regimes of bidirectional hybridly mode-locked ultrashort pulse erbium-doped all-fiber ring laser with a distributed polarizer

“…Moreover, we proposed the "focus" point to coincide with a C:BNNT-SA position in the ring providing additional stabilization of the USP generation. In the case of colliding pulse ML operation this assumption is also quite reasonable since C:BNNT-SA is disposed in the vicinity of the center of the negative dispersion cavity segment [10,29]. It is well known that slightly positive total GVD favors broadband stretched-pulse generation in the dispersion-managed laser cavity, which has been realized in the given bidirectional Er-doped all-fiber laser.…”

“…Thus, we claim the generation of almost bandwidth-limited Gaussian pulses in both CW and CCW directions of the ring. Since pulse spectra are quite narrow as compared to the spectra of common dispersion-managed stretched-pulse lasers [10] we should not expect significant pulse breathing in the cavity. On the contrary, pulses propagate along the cavity nearly keeping their widths.…”

“…It is quite obvious due to the excellent intrinsic stability against different perturbations that is inherent to CSs. More recently Yao [10] has presented a bidirectional stretched-pulse erbium-doped fiber ring laser by means of the appropriate intracavity dispersion management that allowed significant pulse-width shortening down to ∼200 fs in each channel. However, none of the schemes demonstrated by now enables broad tunability of countercirculating pulse characteristics, which, in turn, would be quite useful for gyroscopic applications.…”

“…In addition, pulse fluence should be of the order of the SA saturation fluence to promote total loss reduction in the case of the simultaneous arrival of countercirculating pulses to the SA [11]. Modern saturable absorbers, such as semiconductor saturable absorber mirror (SESAM) [7] or carbon nanotubes [2,4,6,9,10] and graphene [8], easily satisfy these requirements being the best candidates for bidirectional ML fiber laser development.…”

Delivering dispersion-managed soliton and Q-switched pulse in fiber laser based on graphene and nonlinear optical loop mirror

“…Simultaneous mode-locking in 1.55 mm and 2 mm in a fiber laser has been reported [33]. Bidirectional DMS fiber laser was achieved [34]. On the other hand, exploiting distinct formation mechanisms acquire CS and dissipative soliton (DS) in a fiber laser, respectively [35] or simultaneously [36].…”