{'fraction_non_alphanumeric': 0.027388535031847135, 'fraction_numerical': 0.01019108280254777, 'mean_word_length': 5.600840336134453, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Unintentional Polarization Dependent Pulsewidth of Graphene Mode-Locked Er-Doped Fiber Lasers

The unique polarization dependent pulsation phenomenon in a graphene mode-locked erbium-doped fiber laser (ML-EDFL) is explored by the interaction between intracavity weak nonlinear polarization rotation and strong saturable absorption. With unintentional polarization dependent loss (PDL) induced by twisting single-mode fiber (SMF) in an intracavity polarization controller (PC), the unique pulsewidth tunability in a polarizer-free graphene ML-EDFL can be observed. Numerical and experimental procedures are established to combine the hybrid effects and to realize the possible detuning range of intracavity polarization angle for polarization dependent mode-locking dynamics. Twisting SMF induced unintentional PDL in the polarizer-free EDFL contributes a tiny self-amplitude modulation (SAM) coefficient of γNPR = 5.36 × 10-4 sin 2θP. The modelocking stability still relies on the graphene saturable absorption to optimize the SAM up to γtotal = 1.46 × 10-3 ands horten the EDFL pulsewidth to 330 fs. These clearly elucidate the enigma on polarization dependency of most polarizer-free ML-EDFLs with built-in PC. Even an unintentional weak polarization dependency in the EDFL without any polarizer can induce a residual PDL to introduce a polarization angle-dependent SAM coefficient, which declares the importance on controlling intracavity polarization for stabilizing and optimizing the graphene ML-EDFL with unintentional nonlinear polarization rotation induced PDL.