Intrafiber visible pulse compression by cross-phase modulation in a birefringent optical fiber

Area of Science:

• Optics and Photonics
• Nonlinear Optics
• Fiber Optics

Background:

• Cross-phase modulation (XPM) is a nonlinear optical effect where one light pulse influences the phase of another.
• Birefringent optical fibers support multiple polarization modes, enabling distinct pulse propagation paths.
• Pulse compression is crucial for enhancing peak power and temporal resolution in optical systems.

Purpose of the Study:

• To investigate the time dependence of cross-phase-modulated pulses in birefringent optical fibers.
• To demonstrate and analyze intrafiber pulse compression in the normal group-velocity dispersion regime.
• To explore the role of group-velocity mismatch in enhancing pulse compression efficiency.

Main Methods:

• Subpicosecond time-resolved observations of pulse propagation.
• Utilizing a weak visible pulse and a strong pulse in orthogonal polarization modes of a birefringent fiber.
• Exploiting the group-velocity mismatch between fiber modes for pulse synchronization.

Main Results:

• Observed significant compression of a weak pulse via cross-phase modulation by a strong pulse.
• Achieved pulse compression in the normal dispersion regime without external optical components.
• Demonstrated enhanced compression efficiency by synchronizing the weak pulse with the strong pulse edge using group-velocity mismatch.
• Reported a compressed pulse width of 0.3 picoseconds from a 2-picosecond input pulse.

Conclusions:

• Intrafiber pulse compression in the normal dispersion regime is achievable through cross-phase modulation.
• Group-velocity mismatch can be strategically used to enhance the efficiency of this novel pulse compression technique.
• This method offers a new avenue for generating ultrashort optical pulses directly within optical fibers.