Let R be an infinite ring with a maximal finite subring. We prove that R has a largest finite ideal and a largest finite nilpotent ideal N By a B ring, we mean an infinite ring with 1 containing a maximal finite subr...Let R be an infinite ring with a maximal finite subring. We prove that R has a largest finite ideal and a largest finite nilpotent ideal N By a B ring, we mean an infinite ring with 1 containing a maximal finite subring which is a subfield containing 1. It is shown that R/NUVW, where U is a finite ring, V is a finite direct sum of matrix rings over B rings, and W is a ring containing no nonzero finite subrings.展开更多
We demonstrate a stable narrow linewidth single-frequency erbium-doped fiber laser(EDFL)operating at 1.6μm.A Fabry–Perot fiber Bragg grating and two cascaded subrings are incorporated in the main ring cavity to achi...We demonstrate a stable narrow linewidth single-frequency erbium-doped fiber laser(EDFL)operating at 1.6μm.A Fabry–Perot fiber Bragg grating and two cascaded subrings are incorporated in the main ring cavity to achieve singlefrequency operation.The experimentally measured optical signal-to-noise ratio is greater than 73 dB.Furthermore,the linewidth of the EDFL is measured to be about 480 Hz by the self-built short-delayed self-heterodyne interferometry device.The laser shows superior stability,with no mode-hopping during the 60-min observation period.The proposed EDFL provides a new experimental idea for realizing a single-frequency fiber laser in the L-band.展开更多
文摘Let R be an infinite ring with a maximal finite subring. We prove that R has a largest finite ideal and a largest finite nilpotent ideal N By a B ring, we mean an infinite ring with 1 containing a maximal finite subring which is a subfield containing 1. It is shown that R/NUVW, where U is a finite ring, V is a finite direct sum of matrix rings over B rings, and W is a ring containing no nonzero finite subrings.
基金supported by the Shaanxi Key Science and Technology Innovation Team Project(No.2023-CX-TD-06)。
文摘We demonstrate a stable narrow linewidth single-frequency erbium-doped fiber laser(EDFL)operating at 1.6μm.A Fabry–Perot fiber Bragg grating and two cascaded subrings are incorporated in the main ring cavity to achieve singlefrequency operation.The experimentally measured optical signal-to-noise ratio is greater than 73 dB.Furthermore,the linewidth of the EDFL is measured to be about 480 Hz by the self-built short-delayed self-heterodyne interferometry device.The laser shows superior stability,with no mode-hopping during the 60-min observation period.The proposed EDFL provides a new experimental idea for realizing a single-frequency fiber laser in the L-band.
