US 12,272,920 B1
Broadband laser system enhanced in later part of mid infrared spectrum
Pingxue Li, Beijing (CN); Xuan Wang, Beijing (CN); and Chuanfei Yao, Beijing (CN)
Assigned to Beijing University of Technology, Beijing (CN)
Filed by Beijing University of Technology, Beijing (CN)
Filed on Dec. 9, 2024, as Appl. No. 18/973,149.
Claims priority of application No. 202410026458.8 (CN), filed on Jan. 9, 2024.
Int. Cl. H01S 3/108 (2006.01); H01S 3/067 (2006.01); H01S 3/08 (2023.01); H01S 3/0941 (2006.01); H01S 3/1115 (2023.01); H01S 3/16 (2006.01); H01S 3/23 (2006.01)
CPC H01S 3/1115 (2013.01) [H01S 3/06716 (2013.01); H01S 3/06733 (2013.01); H01S 3/06791 (2013.01); H01S 3/08013 (2013.01); H01S 3/0941 (2013.01); H01S 3/108 (2013.01); H01S 3/161 (2013.01); H01S 3/1616 (2013.01); H01S 3/2316 (2013.01); H01S 2302/00 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A broadband laser system enhanced in a later part of mid infrared spectrum, comprising a mode-locked fiber laser, a pre amplifier, an optical fiber stretcher, an amplifier, a main amplifier, a first nonlinear optical fiber, a mid infrared amplifier, and a second nonlinear optical fiber, wherein the mode-locked fiber laser, the pre amplifier, the optical fiber stretcher, the amplifier, the main amplifier, the first nonlinear optical fiber, the mid infrared amplifier, and the second nonlinear optical fiber are connected in sequence, and each of the mode-locked fiber laser, the pre amplifier, the optical fiber stretcher, the amplifier, the main amplifier, the first nonlinear optical fiber, the mid infrared amplifier, and the second nonlinear optical fiber adopts a water cooling device or a thermo electric cooler, and is connected by optical fiber fusion,
the mode-locked fiber laser generates a mode-locked pulse laser at a wavelength of 2 μm,
the pre amplifier pre amplifies power of the mode-locked pulse laser to obtain a pre amplified mode-locked pulse laser,
the optical fiber stretcher stretches the pre amplified mode-locked pulse laser,
the amplifier amplifies power of the pre amplified mode-locked pulse laser after pulse broadening to obtain output power of the pre amplified mode-locked pulse laser and expands spectrum to 2.5 μm wavelength band,
the main amplifier further improves output power of the pre amplified mode-locked pulse laser, expands the spectrum to 3 μm wavelength band, and increases pulse energy of 2.1 μm later wavelength band,
the first nonlinear optical fiber extends the spectrum to 3.5 μm wavelength band,
the mid infrared amplifier amplifies power of the pre amplified mode-locked pulse laser in the 3.5 μm wavelength band, improves pulse energy of 3.5 μm later wavelength band, and expands the spectrum to 4 μm wavelength band, and
the second nonlinear optical fiber expands the spectrum to more than 5 μm wavelength band to obtain a mid infrared broadband laser source enhanced in the 3.5 μm later wavelength band,
wherein the main amplifier comprises a third fiber combiner, a first fiber laser, a large mode area holmium doped fiber, and a mode field adapter, the first fiber laser is a 1125 nm or 1950 nm semiconductor laser, wherein the 1125 nm or 1950 nm semiconductor laser provides a first pump light for the large mode area holmium doped fiber by the third fiber combiner, the mode field adapter connects the large mode area holmium doped fiber and a single-mode fiber to match the first nonlinear optical fiber.