{'fraction_non_alphanumeric': 0.022072936660268713, 'fraction_numerical': 0.007677543186180422, 'mean_word_length': 5.438271604938271, '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}}
Photonic Integrated Circuits for Radio-Frequency Signal Generation

This paper reviews the current state of the art of photonic-enabled generation of radio-frequency signals with frequencies within the millimeter wave range (30 to 300 GHz) and above using photonic-integrated circuits (RF-PICs). One of the most important applications to date is the generation of carrier wave frequencies for ultrabroadband wireless communications systems, with data rates up to 100 Gb/s. Among the different photonic signal generation techniques that are available, we focus on the approaches for which photonic integrated solutions have been explored. Optical heterodyning is first presented, based on achieving the integration of a dual wavelength sources. The second approach is through onchip integrated mode locked lasers, with excellent performance in terms of frequency stable, low phase-noise narrow linewidth sources. We review the different laser structures that have been reported, to support the advantages of the new structures that we propose.