Source: Signal Processing Stack Exchange

Pulse Trains

Parameters of Pulse Trains

Optical pulse trains are characterized by parameters such as pulse repetition rate, duty cycle, pulse energy, pulse duration, optical pulse bandwidth, chirp, timing jitter, pulse-to-pulse coherence, and carrier–envelope offset frequency noise.

Lasers Generating Pulse Trains

The most common types of laser sources producing pulse trains are repetitively Q-switched lasers and mode-locked lasers. Q-switched lasers typically operate at pulse repetition rates between 10 Hz and 100 kHz, while mode-locked lasers produce pulse trains at much higher repetition rates.

Pulse Repetition Rate Multiplication and Division

After the generation of a pulse train, the repetition rate can be modified using methods such as repetition rate multiplication or reduction. Repetition rate multiplication involves techniques like beam splitters or injection locking, while reduction can be achieved using a pulse picker.

Pulse Bursts

In some cases, pulse bursts are used, which are pulse trains with a limited duration. Burst mode lasers emit bursts in a regular fashion, with the repetition rate of bursts being lower than within a burst. Pulse spacing and pulse energy within a burst may vary.

Conclusion

Pulse trains play a crucial role in various applications in photonics. Understanding the parameters and characteristics of pulse trains, as well as the methods of generation and manipulation, is essential for optimizing their use in diverse fields such as telecommunications, spectroscopy, and laser processing.

Source: ResearchGate
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