US 11,870,205 B2
Efficient in-band pumping of Holmium-doped optical fiber amplifiers
Robert E. Tench, Allentown, PA (US); and Jean-Marc Delavaux, Pittstown, NJ (US)
Assigned to Cybel, LLC., Bethlehem, PA (US)
Filed by Cybel, LLC., Bethlehem, PA (US)
Filed on Jul. 14, 2020, as Appl. No. 16/929,072.
Prior Publication US 2022/0021173 A1, Jan. 20, 2022
Int. Cl. H01S 3/067 (2006.01); H01S 3/094 (2006.01); H01S 3/16 (2006.01)
CPC H01S 3/06716 (2013.01) [H01S 3/06712 (2013.01); H01S 3/06733 (2013.01); H01S 3/06754 (2013.01); H01S 3/094011 (2013.01); H01S 3/094042 (2013.01); H01S 3/094076 (2013.01); H01S 3/161 (2013.01); H01S 3/1616 (2013.01)] 17 Claims
OG exemplary drawing
 
1. An optical amplifier for operation at an eye-safe input signal wavelength λS within the 2 μm region, comprising:
a section of Holmium (Ho)-doped optical gain fiber responsive to an input optical signal for generating gain within the input optical signal as it propagates therealong by the presence of Ho ions, providing as an output an amplified optical signal, the section of Ho-doped optical gain fiber exhibiting a gain coefficient G and an absorption coefficient α that both vary as a function of an applied pump wavelength; and
a pump source coupled to the section of Ho-doped optical gain fiber and configured to provide pump light at a wavelength λP within an absorption-dominant pump wavelength range of 1820 nm to 1880 nm, where α(λP)>G(λP) regardless of the value of input signal wavelength λS within the 2 μm region.