Phase-squeezing properties of non-degenerate PSAs using PPLN waveguides

Area of Science:

• Quantum optics
• Nonlinear optics
• Integrated photonics

Background:

• Phase-sensitive amplifiers (PSAs) are key for quantum information processing.
• Periodically-poled-lithium-niobate (PPLN) waveguides offer nonlinear optical functionalities.
• Signal regeneration requires managing noise and phase squeezing.

Purpose of the Study:

• To investigate phase squeezing in non-degenerate PSAs using PPLN waveguides.
• To compare idler generation in PPLN versus highly-non-linear-fiber (HNLF).
• To analyze the impact of phase sensitive dynamic range (PSDR) on signal regeneration.

Main Methods:

• Implemented two PSA configurations with varying idler generation schemes.
• Utilized PPLN waveguides and HNLF for nonlinear processes.
• Measured phase squeezing and BPSK signal regeneration.

Main Results:

• Demonstrated regeneration of noisy BPSK signals in both PSA configurations.
• Observed that phase squeezing scales with the phase sensitive dynamic range (PSDR).
• Found HNLF for idler generation yields the largest PSDR, while PPLN idler generation is limited.
• Identified pump phase modulation for stimulated Brillouin scattering suppression introduces amplitude noise that increases with PSDR.

Conclusions:

• HNLF is superior for maximizing PSDR and phase squeezing in PSA-based signal regeneration.
• Achievable PSDR in PPLN-based PSA is limited by weak idler generation.
• Amplitude noise introduced by pump modulation is a critical factor in PSA performance, especially at higher PSDRs.