High gain holmium-doped fibre amplifiers

Area of Science:

• Optics and Photonics
• Laser Technology
• Materials Science

Background:

• Holmium-doped fiber amplifiers (HDFAs) are crucial for generating light in the 2.1 µm spectral region.
• Previous HDFAs typically required complex pumping schemes, limiting their practical applications.
• Optimizing gain and bandwidth is essential for various spectroscopic and medical applications.

Purpose of the Study:

• To demonstrate the first diode-pumped holmium-doped fiber amplifier (HDFA).
• To investigate the performance of HDFAs pumped at different wavelengths (1950 nm and 2008 nm).
• To characterize the gain, gain bandwidth, and noise figure of the developed HDFAs.

Main Methods:

• Development and characterization of a diode-pumped holmium-doped fiber amplifier.
• Comparative analysis of HDFA performance when pumped at 1950 nm versus 2008 nm.
• Measurement of peak gain, 15 dB gain window, and external noise figure (NF) across different configurations.

Main Results:

• A diode-pumped HDFA achieved a peak gain of 25 dB at 2040 nm with a 15 dB gain window from 2030-2100 nm and NF of 4-6 dB.
• Pumping at 1950 nm yielded a peak gain of 41 dB at 2060 nm (gain window 2050-2120 nm) with NF of 7-10 dB.
• Pumping at 2008 nm shifted the gain bandwidth to longer wavelengths, providing a peak gain of 39 dB at 2090 nm (gain window 2050-2150 nm) with NF of 8-14 dB.

Conclusions:

• Diode-pumping is a viable and effective method for operating HDFAs in the 2.1 µm region.
• The choice of pump wavelength significantly influences the gain bandwidth and performance characteristics of HDFAs.
• The demonstrated HDFAs offer promising performance for applications requiring high gain and broad spectral coverage in the 2.1 µm range.