Low-noise octave-spanning mid-infrared supercontinuum generation in a multimode chalcogenide fiber

Area of Science:

• Photonics and Optical Engineering
• Materials Science

Background:

• Supercontinuum generation is crucial for various spectroscopic and sensing applications.
• Controlling noise in supercontinuum sources is essential for practical high-performance systems.

Purpose of the Study:

• To demonstrate a low-noise, octave-spanning mid-infrared supercontinuum generation.
• To investigate the noise characteristics of supercontinuum generation in the normal dispersion regime of multimode chalcogenide fiber.
• To compare the noise performance with supercontinuum generated in the anomalous dispersion regime of multimode fluoride fiber.

Main Methods:

• Injecting femtosecond pulses into the normal dispersion regime of a multimode step-index chalcogenide fiber (100 µm core diameter).
• Systematic study of intensity noise across the supercontinuum spectrum.
• Comparative analysis of noise characteristics with supercontinuum generated in multimode fluoride fiber.

Main Results:

• Generation of an octave-spanning mid-infrared supercontinuum from 1700 to 4800 nm.
• Pump laser fluctuations amplified by at most a factor of three across the spectrum.
• Demonstrated superior noise characteristics for the normal dispersion supercontinuum in chalcogenide fiber compared to anomalous dispersion in fluoride fiber.

Conclusions:

• Multimode chalcogenide fibers in the normal dispersion regime offer a promising route to low-noise, broadband mid-infrared supercontinuum generation.
• The demonstrated source exhibits favorable noise properties, making it suitable for demanding applications.
• Results open new possibilities for applications like long-distance remote sensing requiring high power and low noise.