20 dB net-gain polarization-insensitive fiber optical parametric amplifier with >2 THz bandwidth

Area of Science:

• Optical Engineering
• Telecommunications
• Nonlinear Optics

Background:

• Fiber optical parametric amplifiers (FOPAs) are crucial for optical communications.
• Polarization sensitivity and crosstalk are key challenges in FOPA design.
• Existing amplification technologies like EDFAs have limitations in bandwidth and gain.

Purpose of the Study:

• To characterize a novel polarization-insensitive FOPA (PI-FOPA) for the first time.
• To evaluate the performance of the Half-Pass Loop FOPA (HPL-FOPA) architecture.
• To assess signal amplification, gain bandwidth, OSNR penalty, and crosstalk.

Main Methods:

• Characterization using a commercial 127 Gb/s polarization-division multiplexed PDM-QPSK transponder.
• Testing within a multiplex of twenty-two DWDM signals across 2.3 THz bandwidth.
• Employing a diversity loop arrangement with two lengths of highly nonlinear fiber (HNLF).
• Analysis across three different pump power regimes.

Main Results:

• Record equivalent 2.3 Tb/s data amplified with net-gains of 10, 15, and 20 dB.
• Gain bandwidth observed to extend beyond the C-band for 15 dB and 20 dB gain.
• Average OSNR penalty of 0.5 ± 0.3 dB for 10^-3 BER under 15 dB gain.
• Signal-signal crosstalk found to be gain independent for fixed output power.

Conclusions:

• The HPL-FOPA architecture provides polarization-insensitive amplification.
• The design demonstrates potential for amplifying signals over bandwidths comparable to or exceeding EDFAs.
• An effective length model predicts crosstalk behavior, suggesting configurations for reduction.