Adiabatic Soliton Laser

The key to generating stable optical pulses is mastery of nonlinear light dynamics in laser resonators. Modern techniques to control the buildup of laser pulses are based on nonlinear science and include classical solitons, dissipative solitons, parabolic pulses (similaritons) and various modifications and blending of these methods. Fiber lasers offer remarkable opportunities to apply one-dimensional nonlinear science models for the design and optimization of very practical laser systems. Here, we propose a new concept of a laser based on the adiabatic amplification of a soliton pulse in the cavity—the adiabatic soliton laser. The adiabatic change of the soliton parameters during evolution in the resonator relaxes the restriction on the pulse energy inherent in traditional soliton lasers. Theoretical analysis is confirmed by extensive numerical modeling.

Figure 1

The experimental setup. SMF: single-mode fiber, WDM: wavelength-division multiplexer, FBG: fiber Bragg grating, OF: optical filter, PC: polarization controller, and CNT: nanotube-based saturable absorber.

Figure 2

The calculated output pulse duration (a), soliton number (b), peak power (c), and energy (d) versus the cavity length. Black circles (c) show the soliton order $N$. Pink triangles show the pulse characteristics achieved with the use of adiabatic soliton amplification.

Figure 3

Evolution of the pulse duration, peak power, and energy along the SMF for different cavity lengths: (a) 2.5 m, (b) 450 m and (c) 4000 m . The last row corresponds to the adiabatic soliton amplification along the SMF. Dashed lines show the prediction of soliton perturbation theory.

Figure 4

Evolution of the pulse shape (a) and spectrum (b) along fiber sections. Shown are the long SMF section (marked with “1”) and the short cavity section providing coupling, filtering, mode-locking and amplification of the optical pulse (marked with “2”).

Figure 5

The calculated duration (a), peak power (b), and energy (c) of the output pulse versus the effective gain coefficient (adiabatic amplification of the soliton).