IEEE Researchers Achieve Low-Power Ultrashort Mid-IR Pulse Compression

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Mar 11, 2026, 08:44 ET

Researchers demonstrate a fiber-based method for compressing mid-infrared laser pulses into ultrashort, low-noise bursts efficiently

NEW YORK, March 11, 2026 /PRNewswire/ -- A compact fiber-based system has been developed to compress mid-infrared laser pulses to 187 femtoseconds using low input power. By integrating a holmium-doped ZBLAN photonic crystal fiber within a nonlinear optical loop mirror, the approach achieves high compression efficiency with minimal pedestal energy, offering a simplified route to ultrafast mid-IR sources for spectroscopy and biomedical imaging.

Three-dimensional schematic and cross-sectional view of a holmium-doped ZBLAN photonic crystal fiber, illustrating the microstructured air-hole cladding, air-hole diameter (dₐ), and pitch (Λ). The tailored geometry enables precise dispersion control and strong nonlinear interaction, supporting efficient self-similar pulse evolution and ultrashort mid-infrared pulse compression.

Schematic of the nonlinear optical loop mirror (NOLM) configuration incorporating a tapered Ho:ZBLAN photonic crystal fiber. The setup shows counter-propagating pulses within the loop, nonlinear phase accumulation, and pulse compression, followed by a saturable absorber that produces clean, pedestal-free femtosecond mid-infrared pulses.

Ultrashort mid-infrared (mid-IR) laser pulses are essential for applications such as molecular spectroscopy, nonlinear microscopy, and biomedical imaging, but their generation often relies on complex and power-intensive systems. Researchers at SASTRA Deemed University, Thanjavur, have demonstrated a fiber-based approach that delivers clean ultrashort mid-IR pulses while significantly reducing the required input power.

The team designed a holmium-doped ZBLAN photonic crystal fiber integrated into a nonlinear optical loop mirror (NOLM). A carefully engineered tapered fiber geometry enables self-similar pulse evolution, while holmium doping provides optical gain near 2.86 μm. Together, these features enable efficient pulse compression, suppress unwanted temporal pedestals, and prevent fiber damage. The findings were made available online on 28 November 2025 and were published in Volume 62, Issue 1 of the IEEE Journal of Quantum Electronics on 01 February 2026.

"By combining rare-earth-enabled gain and nonlinear pulse shaping mechanism of nonlinear optical loop mirror configuration, we reduced the required input power from the kilowatt range to just 80 watts," said G. Sornambigai, the lead author.

At the optimized fiber length, the system compressed 5-picosecond pulses to 187 femtoseconds, achieving a compression factor of 26.7 with pedestal energy as low as 0.63%. "This architecture delivers clean, high-contrast pulses that are well suited for mid-IR spectroscopy and nonlinear imaging," added co-author R. Vasantha Jayakantha Raja.

Self-similar pulse modelling and system-level analysis were crucial for optimizing performance and ensuring reliable pulse compression. The researchers report the first demonstration of a Ho:ZBLAN-based NOLM system producing sub-200 femtosecond pulses in the mid-infrared, representing a key milestone in the development of compact, low-power, and efficient ultrafast mid-IR sources.

This robust, alignment-free, and energy-efficient fiber-based approach could accelerate advances in spectroscopy, nonlinear imaging, and other emerging photonic applications, bringing ultrafast mid-infrared technologies closer to practical real-world use.

Reference
Title of original paper: Pulse compression in Ho:ZBLAN photonic crystal fiber using a NOLM configuration for ultrashort Mid-IR generation
Journal: IEEE Journal of Quantum Electronics
DOI: 10.1109/JQE.2025.3638679

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SOURCE IEEE Photonics Society