kW Mid-IR Raman Fiber Lasers
Abstract
Kilo-watt-class high-energy lasers (HELs) are in great demand for many DOD applications including LIDAR, imaging, free-space optical, communications, laser weapons and countermeasures, in addition to a variety of civil and fundamental research applications. Fiber l,asers are an excellent platform technology, because they can be used as HELs with high beam quality by taking advantage of their inh,erent attractive aspects including optical confinement in glass fibers, compactness, robust operation, easy thermal management, high, power scalability, alignment-free operation, and low maintenance. Ytterbium (Yb3+) doped fiber lasers with output power of 10-kW or, higher at the 1 m wavelength band have been extensively used for directed-energy weapons due to their high optical efficiency and,mature technologies. However, the 1 m lasers are neither eye-safe nor highly transparent in the atmosphere. There is a dramatic inc,reased demand for kW-class HELs at 2 um and longer mid-infrared (IR) regions because they are more eye-safe and more transparent in,the atmosphere. In recent years, kW-level HELs operating at 2 um have been demonstrated with highly thulium (Tm3+) doped fibers usin,g one-to-two optical conversion in the cross-relaxation energy transfer process when pumped at 793 nm. It is most likely that kW-cla,ss Tm-doped fiber lasers at 2 um will be developed and extensively deployed for a variety of DoD applications in the near future bec,ause of their longer atmosphere propagation distance and much lower turbulence transition and thermal blooming compared to HELs at 1, um. However, there is little research on kW-class fiber lasers beyond 2 um, especially in the 3-5 um atmospheric transparency windo,w. Here, we propose to conduct research on tellurite fiber Raman lasers in an all-fiber configuration, which is the most promising a,pproach toward kW-class mid-IR HELs at 2-5 um. In this program, we will investigate the fabrication of tellurite fiber Bragg gratin,g (FBG) and the development of all-fiber Raman lasers for kW-class HELs at 2-5 um by performing the following tasks using the reques,ted equipment in addition to our existing facilities and capabilities at the University of Arizona: (1) High quality tellurite glass, and low-loss fiber fabrication and characterization; (2) Tellurite FBG fabrication and characterization; (3) All-fiber Raman laser,development and characterization; (4) Design and demonstrate kW-class tellurite fiber Raman lasers.Supported by the Navy, we are cur,rently establishing a Directed Energy T&E Center, the first university-based center of excellence in the United States to perform re,search on HEL materials, components and lasers. The proposed equipment will improve our existing facilities and capabilities, advanc,ing our ability to develop HELs at 2-5 um. The College of Optical Sciences will become a distinguished United States institute pione,ering in a full-spectrum of research in mid-IR Raman fiber lasers, covering specialty nonlinearmid-IR fibers, mid-IR FBGs, all-fiber, Raman lasers, and complete mid-IR HELs. This funding will also provide an excellent opportunity to train students in multiple resea,rch areas including photonics, laser physics, material sciences, and advanced nonlinear fiber lasers. Students and researchers invo,lved in the research will be exposed to cutting edge science and engineering at the interface of different disciplines.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 01, 2022
- Source ID
- N000142212387
Entities
People
- Xiushan Zhu
Organizations
- Office of Naval Research
- United States Navy
- University of Arizona