Ultrafast Picosecond Mode-locked Pulse with Dissipative soliton Generation Using Polyaniline Boron Nitride Nanocomposite as Saturable Absorber

This study demonstrates ultrafast picosecond mode-locked pulse production in an erbium-doped fiber laser, using a Polyaniline–Boron Nitride (PANI–BN) nanocomposite as a saturable absorber. The nanocomposite features substantial nonlinear optical absorption and quick recovery dynamics, which make it feasible for robust self-starting mode-locked operation. It was feasible to make stable dissipative soliton pulses in the normal-dispersion domain by adding the PANI–BN saturable absorber to the laser cavity. The laser's core wavelength is 1531.4 nm, and it emits steady picosecond pulses that recur every 1.860 MHz. The pulse width of 240.1 ps reveals that the system operates extremely swiftly, in the region of picoseconds. The output power rose boosted from 4.6 to 8.08 mW when the input pump power was raised from 122.9 to 210.6 mW (which is the same as an LD current range of (310–500 mA). This means that the slope efficiency was 10.1%. The most energy in a pulse was 4.34409 nJ. The mode-locked pulses had a high signal-to-noise ratio (SNR) of 66.24 dB, which implies they were highly steady and did not change much in amplitude. Dissipative solitons emerge when the cavity's normal dispersion, nonlinearity, gain, and spectral filtering are all in balance. The PANI–BN nanocomposite is particularly critical for beginning and retaining the phase locking of longitudinal modes since its intensity affects how well it works. The findings indicate that the PANI–BN nanocomposite serves as an effective and robust saturable absorber for generating stable ultrafast picosecond dissipative soliton pulses. This work demonstrates the applicability of polymer-based nanocomposite materials in sophisticated ultrafast photonic applications, including optical communications, precision metrology, and high-resolution spectroscopy.