Hollow-core fiber with stable propagation delay between -150°C and +60°C

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Metrology and Precision Measurement

Background:

• Optical fibers are crucial for frequency and timing transmission, but their temperature sensitivity (TCD) often limits performance.
• Existing low TCD fibers show variable temperature sensitivity, especially at sub-zero temperatures, hindering broad application.
• Improved fiber optic performance over extended temperature ranges is needed for applications like precise timing and laser stabilization.

Purpose of the Study:

• To develop and characterize optical fibers with stable, low temperature sensitivity over a wide temperature range.
• To investigate the performance of hollow core fibers (HCFs) with thin acrylate coatings at sub-zero temperatures.
• To demonstrate the potential of these fibers for applications requiring high precision near cryogenic temperatures.

Main Methods:

• Fabrication of a hollow core fiber (HCF) with a specialized thin acrylate coating.
• Measurement of the thermal coefficient of delay (TCD) across an extended temperature range (-150°C to +60°C).
• Analysis of temperature-induced delay variations in the optical fiber.

Main Results:

• The developed HCF exhibited a low TCD within ±2.0 ps/km/°C over the broad temperature range of -150°C to +60°C.
• The fiber demonstrated temperature insensitivity around -134°C, a significant finding for cryogenic applications.
• Performance was maintained across a wider temperature span than previously reported for similar optical fibers.

Conclusions:

• Thinly coated HCFs offer a viable solution for stable frequency and timing transmission over extreme temperature variations.
• The demonstrated temperature insensitivity near -134°C opens possibilities for laser stabilization in cryogenic environments.
• This advancement in optical fiber technology addresses key limitations in precision measurement and timing distribution.