{'fraction_non_alphanumeric': 0.03567567567567568, 'fraction_numerical': 0.0, 'mean_word_length': 5.475524475524476, '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}}
Using optimal cavity loss and saturable-absorber passive filter for stable and tunable dual-wavelength erbium fiber laser in single-longitudinal-mode operation

In this investigation, we propose and demonstrate experimentally tunable and stable dual-wavelength erbium doped fiber (EDF) double-ring laser scheme using different coupling losses inside cavity loop for wavelength and mode spacing tuning. Besides, a shorter unpumped EDF is also used to filter the side-modes for lasing wavelength in single-longitudinal-mode (SLM) operation. However, the output mode spacing of dual-wavelength could be limited owing to the homogeneous broadening nature of EDF. As a result, the output performance of the proposed fiber laser have also been analyzed and discussed, such as wavelength tuning range, output power, side-mode suppression ratio (SMSR), stabilities of lasing wavelength and power, relative intensity noise (RIN), etc.