Raman-assisted phase sensitive amplifier using a fiber Bragg grating-based tunable phase shifter

Area of Science:

• Optoelectronics
• Optical Amplification

Background:

• Phase sensitive amplification (PSA) is crucial for enhancing receiver sensitivity in optical communication systems.
• Traditional PSAs often suffer from high component losses and limited gain adjustment capabilities.

Purpose of the Study:

• To experimentally demonstrate a low-loss Raman-assisted phase sensitive amplifier (PSA).
• To investigate the effectiveness of non-uniform Raman gain and tunable fiber Bragg gratings (FBGs) for amplitude and phase control in the PSA.
• To evaluate the performance enhancement in terms of signal gain and receiver sensitivity for advanced modulation formats.

Main Methods:

• Utilized non-uniform Raman gain to adjust signal amplitude.
• Employed a tunable fiber Bragg grating (FBG) for precise phase control.
• Experimentally measured the net signal gain and component losses of the developed PSA system.
• Tested the PSA with 20 and 25 Gbaud quadrature phase shift keying (QPSK) and 10 Gbaud 16-quadrature amplitude modulation (16-QAM) signals.

Main Results:

• Achieved a signal net gain of approximately 20 dB with a total component loss of around 8 dB.
• Demonstrated up to 5.6 dB signal gain improvement by tuning the FBG central wavelength.
• Observed approximately 4 dB receiver sensitivity enhancement for the tested high-speed signals.

Conclusions:

• The developed Raman-assisted PSA offers a practical solution for low-loss signal amplification.
• The system effectively improves receiver sensitivity, enabling more robust high-speed optical communications.
• The combination of non-uniform Raman gain and tunable FBGs provides efficient amplitude and phase control for PSA.