US Patent No. 10,734,782

ULTRASHORT PULSE FIBER LASER EMPLOYING RAMAN SCATTERING IN HIGHER ORDER MODE FIBERS


Patent No. 10,734,782
Issue Date August 04, 2020
Title Ultrashort Pulse Fiber Laser Employing Raman Scattering In Higher Order Mode Fibers
Inventorship Siddharth Ramachandran, Boston, MA (US)
Lars Rishoj, Cambridge, MA (US)
Jeffrey D. Demas, Somerville, MA (US)
Assignee Trustees of Boston University, Boston, MA (US)

Claim of US Patent No. 10,734,782

1. A fiber laser, comprising:a higher-order-mode (HOM) fiber having a step index and a guidance diameter together defining respective wavelength-dependent anomalous dispersion characteristics and effective areas greater than 100 square micrometers for corresponding higher-order modes of optical signal propagation in the HOM fiber, the higher-order modes including a predetermined higher-order mode with corresponding anomalous dispersion characteristic and effective area defining a first wavelength and first power of a pulse optical signal for conversion to a second wavelength and second power by soliton self-frequency shifting in the HOM fiber, the second wavelength and second power being related to the first wavelength and first power by the anomalous dispersion characteristic and effective area for the predetermined higher-order mode; and
a source subsystem coupled to the HOM fiber to establish the pulse optical signal propagating in the HOM fiber in the predetermined higher-order mode;
wherein the pulse optical signal is a soliton having an energy Esol proportional to a dispersion value D and effective area Aeff for the predetermined higher-order mode as well as to a difference ?? between the first and second wavelengths, and wherein the pulse optical signal has a peak power of one kilowatt or greater.