{'fraction_non_alphanumeric': 0.027827648114901255, 'fraction_numerical': 0.005385996409335727, 'mean_word_length': 5.229050279329609, '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}}
Ultra-fast full-field optical characterization of CW lasers based on optical frequency comb, wavelength-to-time mapping and phase-diversity.

Optical frequency comb (OFC), a periodic optical pulse train in time domain, has been widely employed to measure optical frequency due to its equidistant modes in the frequency domain. Here, we propose and demonstrate a novel optical spectrum analyzer for CW lasers based on stretching the OFC in a dispersive element and mapping the frequency comb into the time domain. The optical spectrum analyzer also provides instantaneous full-field (wavelength, amplitude and phase) optical characterization capability by combining with optical phase-diversity technology. Experimental results show that we successfully trace the evolution of modulated lasers with a measurement speed of ∼51 MHz (related to the pulse repetition of the OFC) and a high spectral resolution of ∼21 pm. Thanks to the use of wavelength-to-time mapping and OFC, the single channel measurement range of the proposed system can reach ∼10 nm, which breaks the restriction of the bandwidth of photodetector.