Systems and methods to reduce the power consumption of an optical fiber amplifier
A method of reducing the power consumption of an optical fiber amplifier by which the optical output of a first optical fiber is filtered to prevent a detrimental portion of the optical output from reaching a second optical fiber, to transmit a signal for amplification, and to transmit a portion of the optical output that can contribute to optical pumping of the second optical fiber. By propagating an optical pumping portion output from the first optical fiber, as well as optical pumping from an independent source, the independent source's power level can be reduced. In a sequence of optical fibers, each fiber can provide some pumping output to one or more other fibers, as long as its optical output is properly filtered with appropriate optical components, such as a band-stop filter. A sequence can be terminated by a low-pass filter in order for a final output to contain the amplified signal free from any other optical output.
1 . A system for amplifying an optical signal comprising:
a first optical amplifier including a first segment of doped optical fiber configured to generate an optical output including the optical signal at a first wavelength band, an optical surplus wavelength band, and an optical pumping wavelength band, the optical surplus wavelength band being located spectrally between the first wavelength band and the optical pumping wavelength band;
a second optical amplifier including a second segment of doped optical fiber; and
at least one optical component optically coupled between the first optical amplifier and the second optical amplifier,
wherein:
the at least one optical component is configured to:
receive the optical output from the first segment of doped optical fiber of the first optical amplifier;
prevent a transmission of at least part of the optical surplus wavelength band from the first segment of doped optical fiber to the second segment of doped optical fiber; and
transmit the first wavelength band and the optical pumping wavelength band from the first segment of doped optical fiber to the second segment of doped optical fiber, the second segment of doped optical fiber being configured to be optically pumped by the transmitted optical pumping wavelength band to provide population inversion for amplifying the optical signal by stimulated emission of radiation.
2 . The system of claim 1 , wherein the at least one optical component is a band-stop filter.
3 . The system of claim 1 , further comprising at least one independent source of optical radiation configured to optically pump at least one of the first segment of doped optical fiber and the second segment of doped optical fiber.
4 . The system of claim 1 , further comprising, optically coupled between the first optical amplifier and the second optical amplifier, at least one of:
a gain flattening filter,
a variable optical attenuator,
an optical isolator,
a wavelength-division multiplexer,
a wavelength-division demultiplexer,
a lens, and
an optical circulator.
5 . The system of claim 1 , wherein the second segment of doped optical fiber is configured to amplify optical signals with optical wavelengths in the L-band.
6 . The system of claim 1 , wherein at least one of the first segment of doped optical fiber and the second segment of doped optical fiber is doped with erbium ions.
7 . The system of claim 1 , wherein at least one of the first segment of doped optical fiber and the second segment of doped optical fiber includes oxide glass.
8 . The system of claim 7 , wherein the oxide glass is silicate glass.
9 . The system of claim 1 , wherein at least one of the first segment of doped optical fiber and the second segment of doped optical fiber includes fluoride glass.
10 . The system of claim 9 , wherein the fluoride glass is one of zirconium fluoride glass and indium fluoride glass.
11 . The system of claim 1 , wherein at least one of the first segment of doped optical fiber and the second segment of doped optical fiber includes chalcogenide glass.
12 . The system of claim 1 , wherein the first optical amplifier comprises a first cable including a plurality of parallel doped optical fibers, wherein the first segment of doped optical fiber is one of the plurality of parallel doped optical fibers, and wherein, when the system is in operation, optical outputs from the first cable are directed to the at least one optical component.
13 . The system of claim 12 , wherein the first cable is ribbonized such that the plurality of parallel doped optical fibers lie in a common plane.
14 . The system of claim 1 , wherein the first segment of doped optical fiber is a multi-core fiber, and wherein, when the system is in operation, optical outputs of multi-core fiber are directed to the at least one optical component.
15 . The system of claim 14 , wherein: the multi-core fiber comprises multiple cores that are ribbonized and lie on a common plane.
16 . The system of claim 1 , wherein the first segment of doped optical fiber is a multi-mode optical fiber, and, when the system is in operation, an optical output of the multi-mode optical fiber includes a plurality of optical modes that are directed to the at least one optical component.
17 . The system of claim 1 , wherein the at least one optical component has a rejection level for the optical surplus wavelength band that is greater than 10 dB.
18 . The system of claim 1 , wherein the at least one optical component includes any of a thin film filter, a fiber Bragg grating, a volume Bragg grating, and a micro-structured optical fiber.
19 . The system of claim 1 , wherein the second segment of doped optical fiber is configured to emit an amplified optical output that includes the optical signal after being amplified.
20 . The system of claim 19 , further comprising a low-pass filter attenuating portions of the amplified optical output other than the optical signal after being amplified.
21 . A system for amplifying an optical signal comprising:
a first optical amplifier including a first segment of doped optical fiber configured to generate an optical output including the optical signal at a first wavelength band, an optical surplus wavelength band, and an optical pumping wavelength band, the optical surplus wavelength band being located spectrally between the first wavelength band and the optical pumping wavelength band;
a second optical amplifier including a second segment of doped optical fiber; and
at least one optical component optically coupled between the first optical amplifier and the second optical amplifier,
wherein:
the at least one optical component is configured to:
receive the optical output from the first segment of doped optical fiber of the first optical amplifier;
prevent a transmission of at least part of the optical surplus wavelength band from the first segment of doped optical fiber to the second segment of doped optical fiber; and
transmit the first wavelength band and the optical pumping wavelength band from the first segment of doped optical fiber to the second segment of doped optical fiber, the second segment of doped optical fiber being configured to be optically pumped by the transmitted optical pumping wavelength band and to amplify the optical signal by stimulated emission of radiation,
the system further comprising a third optical amplifier including a third segment of doped optical fiber, wherein the second optical amplifier is optically coupled in series with between the first optical amplifier and the third optical amplifier.
22 . A method of amplifying an optical signal comprising, the method comprising:
generating, from a first segment of doped optical fiber, an optical output that includes the optical signal at a first wavelength band, an optical pumping wavelength band, and an optical surplus wavelength band, the optical surplus wavelength band being located spectrally between the first wavelength band and the optical pumping wavelength band;
filtering the optical output with a band-stop filter to prevent transmission of at least part of the optical surplus wavelength band while transmitting the first wavelength band and the optical pumping wavelength to a second segment of doped optical fiber; and
amplifying the optical signal at the second segment of doped optical fiber by stimulated emission of radiation, wherein said amplifying is powered at least in part by optically pumping the second segment of doped optical fiber with the transmitted optical pumping wavelength band to provide population inversion.
23 . The method of claim 22 , further comprising optically pumping at least one of the first segment of doped optical fiber and the second segment of doped optical fiber with optical radiation from at least one independent source.