Low-noise Raman fiber amplifier pumped by semiconductor disk laser

Area of Science:

• Optics and Photonics
• Fiber Lasers and Amplifiers

Background:

• Raman fiber amplifiers (RFAs) are crucial for optical communications.
• Efficient pumping is key to minimizing noise and maximizing gain in RFAs.
• Semiconductor disk lasers (SDLs) offer high beam quality suitable for fiber coupling.

Purpose of the Study:

• To demonstrate a 1.3 µm Raman fiber amplifier.
• To investigate the performance of a 1.22 µm semiconductor disk laser as a pump source.
• To evaluate the benefits of co-propagation geometry in this RFA system.

Main Methods:

• A 1.3 µm RFA was constructed using a 1.22 µm SDL pump source.
• Co-propagation pumping geometry was employed.
• Relative intensity noise (RIN) and amplifier-induced noise were measured.

Main Results:

• Achieved 9 dB signal gain with co-propagating pumping.
• Measured low relative intensity noise of -148 dB/Hz up to 3.5 GHz at 900 mW pump power.
• Demonstrated less than 2 dB additional noise induced by the amplifier.

Conclusions:

• The demonstrated 1.3 µm RFA utilizing a 1.22 µm SDL is highly effective.
• Co-propagation pumping with a high-quality SDL beam enables efficient core-pumping.
• This approach offers a practical solution for high-performance fiber Raman amplification.