Overview
This paper details a method for generating sequences of short, Fourier-limited pulses from a continuous wave (CW) laser field through the manipulation of its spectral components' phases. The technique specifically investigates phase modulation using a modulus function of sine (MFS) form. This approach is described as capable of producing pedestal-free pulses, offering control over their repetition rate and duty cycle. An observation regarding sidelobe suppression is included, noting that appropriate modulation index selection can exclude them. The method is also stated to facilitate the production of pulses with a 50% duty ratio. Additionally, the research indicates that a three-tone modulation of the phase can emulate MFS phase modulation.
Approach
The core approach involves phase manipulation of a periodically phase-modulated CW laser field's spectral components. The specific form of phase modulation considered is the modulus function of sine (MFS). This MFS phase modulation is identified as a mechanism for achieving pedestal-free pulses. A key aspect of the method is the capability to control the repetition rate and duty cycle of the generated pulses. The investigation also encompasses the impact of the modulation index on pulse characteristics, specifically its role in excluding sidelobes. The paper further explores the use of three-tone phase modulation as a simulation of MFS phase modulation.
Findings
- Generation of Fourier-limited pulses from a periodically phase-modulated CW laser field is achievable through phase manipulation of its spectral components.
- Phase modulation in the form of a modulus function of sine (MFS) enables the production of pedestal-free pulses.
- The MFS-based method allows for controllable repetition rate and duty cycle of the generated pulses.
- Sidelobes of these pulses can be excluded by selecting a proper modulation index.
- The proposed method facilitates the production of pulses with a 50% duty ratio.
- Three-tone modulation of phase is shown to simulate MFS phase modulation.