Femtosecond laser system for fiber-optic sensor fabrication
Abstract
Abstract: This DURIP proposal seeks to purchase a near-infrared femtosecond (fs)-laser system that allows fast fabrication of mechanically-durable, spatially localized, and highly-flexible fiber Bragg grating (FBGs) in a variety of optical fibers for sensing applications in structural health monitoring. At the heart of the system is a fs-laser with a pulse width <100 fs, pulse energy > 4.0 mJ and repetition rate of 1 kHz. The system also includes external mirrors, lens and highprecision motorized stages required in the fabrication set up. The FBG fabrication exploits a nonlinear multiphoton absorption process that occurs at the focus of ultra-short laser pulses inside the transparent fiber material, which leads to highly-localized index modifications in a 3-D space for FBG fabrication. The laser system will provide us with the following new capabilities to significantly enhance the research in three ongoing ONR-funded projects: 1) fabrication of mechanically durable FBGs localized in the fiber core without the removal of the protective fiber coating for permanently surface-mounted or embedded sensors in structural health monitoring: 2) fabrication of designed FBGs in selected cores of a multicore fiber for acoustic emission sensors that can self-adapt to large background strains and for high-capacity sensor network; and 3) fabrication of FBGs in active fibers without photonsensitivity for fiber-laser acoustic emission sensors. In addition, the laser system is also capable of high-resolution micro-machining of optical materials in three dimensions, which provides us with many other new and exciting fiber-optic sensor research capabilities for DoD applications. For example, the laser system will be used to fabricate fibertip sensors for high-speed temperature measurement for study of ocean turbulence and straininsensitive in-line temperature sensors under harsh environment for engine evaluation and test.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 08, 2016
- Source ID
- N000141512934
Entities
People
- Ming Han
Organizations
- Office of Naval Research
- United States Navy