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Ambiguity function analysis of pulse train propagation: applications to temporal Lau filtering
Jorge Ojeda-Castañeda1, Jesús Lancis, Cristina M Gómez-Sarabia
1Grup de Recerca d'Optica de Castelló, Departament de Física, Universitat Jaume 1, Castelló, Spain.
Summary
We visualize optical signal evolution using the periodic-signal ambiguity function. Temporal coherence acts as a low-pass filter, enabling harmonic filtering and increased pulse train repetition rates.
Area of Science:
- Optics and Photonics
- Signal Processing
Background:
- Understanding light propagation in dispersive media is crucial for optical signal processing.
- The intensity-spectrum evolution of optical signals dictates their behavior during propagation.
- Temporal coherence of optical sources influences signal characteristics.
Purpose of the Study:
- To visualize the intensity-spectrum evolution of optical signals in a first-order dispersive medium.
- To investigate the role of temporal coherence in filtering optical signal ambiguity functions.
- To present a method for filtering harmonics and increasing pulse train repetition rates.
Main Methods:
- Utilizing the periodic-signal ambiguity function for visualization.
- Analyzing the low-pass filtering effect of temporal coherence on the ambiguity function.
- Establishing conditions for the temporal Lau effect to filter harmonics at specific fractions of the Talbot length.
Main Results:
- The degree of temporal coherence acts as a low-pass filter on the signal's ambiguity function.
- A condition for the temporal Lau effect is presented for filtering harmonics.
- This method allows for the enhancement of pulse train repetition rates from phase-modulated continuous-wave (CW) signals.
Conclusions:
- The periodic-signal ambiguity function is effective for visualizing intensity-spectrum evolution.
- Temporal coherence significantly impacts optical signal filtering in dispersive media.
- The proposed method offers a pathway to increase the repetition rate of optical pulse trains.
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