{'fraction_non_alphanumeric': 0.023985239852398525, 'fraction_numerical': 0.014760147601476014, 'mean_word_length': 5.241379310344827, '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}}
Sub-picostrain sensing by laser frequency locking to a passive fiber Bragg resonator

We demonstrate, for the first time, a sensing architecture capable of detecting broadband dynamic strain beyond picostrain resolution, with signal frequencies extending from 100 Hz to beyond 100 kHz. The system uses a pre-stabilized external cavity diode laser to interrogate a passive fiber Bragg resonator, using the Pound-Drever-Hall frequency locking technique. The low-loss resonator comprises of a Bragg grating pair written in standard SMF-28 fiber.