Patent US5638204A successfully refreshed from Google Patents.
US5638204A
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US
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Optical power amplifier with Al2 O3 and erbium doped active fiber
Assignee: Ii Vi Optical Systems Inc
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Filing: 1993-11-23
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Granted: 1997-06-10
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Expires: 2013-11-23
Abstract
Abstract An optical fiber power amplifier, particularly for telecommunication lines with optical fibers, including an active fiber doped with Erbium as a fluorescing substance, and with Al 2 O 3 as refraction index modifying dopant. The fiber is pumped with a laser providing a wavelength higher than 520 nm and preferably, 980 nm. The amplifier has a particularly high amplification efficiency close to the theoretical maximum efficiency.
Inventors
- 👤 Giorgio Grasso
- 👤 Aldo Righetti
- 👤 Fausto Meli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:46
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/05; H01S3/06; H01S3/063; H01S3/067; H01S3/06708; H01S3/09; H01S3/091; H01S3/094; H01S3/094003; H01S3/094011; H01S3/14; H01S3/16; H01S3/1691; H01S3/1693
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
252 words
An optical fiber telecommunication system comprising: an optical fiber power amplifier having an input and an output and comprising an active fiber having a core and a cladding, said core being doped with dopants consisting essentially of Erbium and Al 2 O 3 , said active fiber being pumpable by pumping light energy and being operable in saturation conditions with light energy at a wavelength in the range of 1500 nm to 1600 nm and of a predetermined power level supplied to said input of said amplifier, the output power of said amplifier being proportional to, and greater than 5% of, the power of said pumping light energy in said saturation conditions; an optical signal transmitter supplying a communication light signal at a wavelength in the range from 1500 nm to 1600 nm coupled to said input of said amplifier and supplying said communication light signal to said input at at least said predetermined power level whereby said amplifier operates in saturation conditions; pumping light power means coupled to said active fiber and supplying pumping light power at a wavelength of about 980 nm to said active fiber, the pumping light power causing amplification efficiency to exceed about 60% of quantum efficiency for the amplifier, the quantum efficiency equalling a ratio of the pumping light power wavelength to the communication light signal wavelength, and the amplification efficiency equalling a ratio of the amplifier output power to the pumping light power; and an optical receiving station coupled to said output of said amplifier.
Claim 2
Dependent Claim
252 words
An optical fiber telecommunication system comprising: an optical fiber power amplifier having an input and an output and comprising an active fiber having a core and a cladding, said core being doped with dopants consisting essentially of Erbium and Al 2 O 3 , said active fiber being pumpable by pumping light energy and being operable in saturation conditions with light energy at a wavelength in the range of 1500 nm to 1600 nm and of a predetermined power level supplied to said input of said amplifier, the output power of said amplifier being proportional to, and greater than 5% of, the power of said pumping light energy in said saturation conditions; an optical signal transmitter supplying a communication light signal at a wavelength in the range from 1500 nm to 1600 nm coupled to said input of said amplifier and supplying said communication light signal to said input at at least said predetermined power level whereby said amplifier operates in saturation conditions; pumping light power means coupled to said active fiber and supplying pumping light power at a wavelength of about 980 nm to said active fiber, the pumping light power causing amplification efficiency to exceed about 60% of quantum efficiency for the amplifier, the quantum efficiency equalling a ratio of the pumping light power wavelength to the communication light signal wavelength, and the amplification efficiency equalling a ratio of the amplifier output power to the pumping light power; and an optical receiving station coupled to said output of said amplifier.
Claim 3
Dependent Claim
184 words
Method for generating optical telecommunication signals at a wavelength in the range of 1500 nm to 1600 nm with an optical power amplifier, said method comprising the steps of: generating a light signal having a power greater than a predetermined value, at a wavelength in the range of from 1500 to 1600 nm; providing an optical power amplifier, comprising an input, an output and an active fiber having a core doped with dopants consisting essentially of Erbium and Al 2 O 3 ; supplying said light signal to said input of said optical amplifier; supplying pumping power to said active fiber of said optical amplifier at a wavelength of about 980 nm and at a predetermined pump power level thereby causing said light signal to be amplified at an output power value; said power of said light signal being of a magnitude which causes said optical amplifier to operate normally in saturation condition, in which said output power value of the optical amplifier is substantially more than 5% of said pump power and does not practically depend on said power of said light signal.
Claim 4
Dependent Claim
184 words
Method for generating optical telecommunication signals at a wavelength in the range of 1500 nm to 1600 nm with an optical power amplifier, said method comprising the steps of: generating a light signal having a power greater than a predetermined value, at a wavelength in the range of from 1500 to 1600 nm; providing an optical power amplifier, comprising an input, an output and an active fiber having a core doped with dopants consisting essentially of Erbium and Al 2 O 3 ; supplying said light signal to said input of said optical amplifier; supplying pumping power to said active fiber of said optical amplifier at a wavelength of about 980 nm and at a predetermined pump power level thereby causing said light signal to be amplified at an output power value; said power of said light signal being of a magnitude which causes said optical amplifier to operate normally in saturation condition, in which said output power value of the optical amplifier is substantially more than 5% of said pump power and does not practically depend on said power of said light signal.
Claim 5
Dependent Claim
34 words
An optical fiber telecommunication system as set forth in claim 1 wherein the Erbium concentration in said active fiber, in parts by weight, is in the range from 30 to 2000 parts per million.
Claim 6
Dependent Claim
33 words
An optical fiber telecommunication system as set forth in claim 3 wherein the Al 2 O 3 content of the fiber, in parts by weight, is in the range from 5% to 15%.
Claim 7
Dependent Claim
34 words
An optical fiber telecommunication system as set forth in claim 1 wherein the Erbium concentration in said active fiber, in parts by weight, is in the range from 30 to 1000 parts per million.
Claim 8
Dependent Claim
30 words
An optical fiber telecommunication system as set forth in claim 1 wherein said active fiber is monomodal at said fluorescent wavelength but not at said wavelength of said pumping power.
Claim 9
Dependent Claim
29 words
An optical fiber telecommunication system as set forth in claim 1 wherein said active fiber is monomodal at both said fluorescent wavelength and said wavelength of said pumping power.
Claim 10
Dependent Claim
143 words
An optical fiber telecommunication system as set forth in claim 1, wherein said optical signal transmitter is connected to said input of said optical amplifier and said pumping means is coupled to said active fiber by a dichroic coupler having an output and two inputs, said dichroic coupler having its output coupled to said input of said optical amplifier, said optical signal transmitter being connected to one of said inputs of said dichroic coupler and said pumping means being coupled to the other of said inputs of said dichroic coupler and further comprising a further dichroic coupler having an output and an input, said output of said further dichroic coupler being coupled to said output of said active fiber and a further said pumping means coupled to said input of said further dichroic coupler for applying further pumping power to said active fiber.
Claim 11
Dependent Claim
191 words
An optical fiber telecommunication system comprising: an optical fiber power amplifier, comprising an active fiber having a core and a cladding, the core being doped with dopants consisting essentially of erbium and Al 2 O 3 ; an optical signal transmitter supplying a communication light signal to an input of the amplifier, the communication light signal having a wavelength in a range from about 1500 nm to about 1600 nm and a power level of sufficient magnitude to cause the amplifier to operate in saturation; a pump source supplying pumping light power at a wavelength of about 980 nm to the amplifier, causing the amplifier to amplify the power of the communication light signal at an amplifier output, and, together with the power level of the communication light signal and the active fiber dopants, causing amplification efficiency to exceed about 60% of quantum efficiency for the amplifier, the quantum efficiency equalling a ratio of the pumping light wavelength to the communication light signal wavelength, and the amplification efficiency equalling a ratio of the amplifier output power to the pumping light power; and an optical receiving station coupled to the amplifier output.
Claim 12
Dependent Claim
191 words
An optical fiber telecommunication system comprising: an optical fiber power amplifier, comprising an active fiber having a core and a cladding, the core being doped with dopants consisting essentially of erbium and Al 2 O 3 ; an optical signal transmitter supplying a communication light signal to an input of the amplifier, the communication light signal having a wavelength in a range from about 1500 nm to about 1600 nm and a power level of sufficient magnitude to cause the amplifier to operate in saturation; a pump source supplying pumping light power at a wavelength of about 980 nm to the amplifier, causing the amplifier to amplify the power of the communication light signal at an amplifier output, and, together with the power level of the communication light signal and the active fiber dopants, causing amplification efficiency to exceed about 60% of quantum efficiency for the amplifier, the quantum efficiency equalling a ratio of the pumping light wavelength to the communication light signal wavelength, and the amplification efficiency equalling a ratio of the amplifier output power to the pumping light power; and an optical receiving station coupled to the amplifier output.
Claim 13
Dependent Claim
19 words
The optical fiber telecommunication system of claim 9, wherein the amplification efficiency is substantially equal to the quantum efficiency.
Claim 14
Dependent Claim
17 words
The optical fiber telecommunication system of claim 9, wherein normal operation of the amplifier is in saturation.
Claim 15
Dependent Claim
22 words
The optical fiber telecommunication system of claim 9, wherein the amplifier operates only in saturation with respect to the communication light signal.
Claim 16
Dependent Claim
15 words
The optical fiber telecommunication system of claim 9, wherein the amplifier operates only in saturation.
Claim 17
Dependent Claim
26 words
The optical fiber telecommunication system of claim 9, wherein the amplifier has a length, and at least a portion of the length operates only in saturation.
Claim 18
Dependent Claim
171 words
An optical fiber power amplifier comprising: an active fiber having an input and an output and being doped with dopants consisting essentially of erbium and Al 2 O 3 , the active fiber receiving an optical signal through the input, the optical signal having a wavelength in a range from about 1500 nm to about 1600 nm and a power level of sufficient magnitude to cause the active fiber to operate in saturation; and a pump source supplying pumping light power at a wavelength of about 980 nm to the active fiber, causing the active fiber to amplify the power of the optical signal at the active fiber output, and, together with the power level of the signal and the active fiber dopants, causing amplification efficiency to exceed about 60% of quantum efficiency for the active fiber, the quantum efficiency equalling a ratio of the pumping light wavelength to the optical signal wavelength, and the amplification efficiency equalling a ratio of the active fiber output power to the pumping light power.
Claim 19
Dependent Claim
171 words
An optical fiber power amplifier comprising: an active fiber having an input and an output and being doped with dopants consisting essentially of erbium and Al 2 O 3 , the active fiber receiving an optical signal through the input, the optical signal having a wavelength in a range from about 1500 nm to about 1600 nm and a power level of sufficient magnitude to cause the active fiber to operate in saturation; and a pump source supplying pumping light power at a wavelength of about 980 nm to the active fiber, causing the active fiber to amplify the power of the optical signal at the active fiber output, and, together with the power level of the signal and the active fiber dopants, causing amplification efficiency to exceed about 60% of quantum efficiency for the active fiber, the quantum efficiency equalling a ratio of the pumping light wavelength to the optical signal wavelength, and the amplification efficiency equalling a ratio of the active fiber output power to the pumping light power.
Claim 20
Dependent Claim
19 words
The optical fiber power amplifier of claim 15, wherein the amplification efficiency is substantially equal to the quantum efficiency.
Claim 21
Dependent Claim
18 words
The optical fiber power amplifier of claim 15, wherein normal operation of the active fiber is in saturation.
Claim 22
Dependent Claim
22 words
The optical fiber power amplifier of claim 15, wherein the active fiber operates only in saturation with respect to the optical signal.
Claim 23
Dependent Claim
16 words
The optical fiber power amplifier of claim 15, wherein the active fiber operates only in saturation.
Claim 24
Dependent Claim
26 words
The optical fiber power amplifier of claim 15, wherein the amplifier has a length, and at least a portion of the length operates only in saturation.
Claim 25
Independent Claim
184 words
A method for amplifying an optical telecommunication signal with an optical fiber power amplifier, said method comprising the steps of: supplying an optical signal to an input of the optical fiber power amplifier, the amplifier comprising an active fiber having a core doped with dopants consisting essentially of erbium and Al 2 O 3 , the optical signal having a wavelength in a range from about 1500 nm to about 1600 nm and a power level of sufficient magnitude to cause the active fiber to operate in saturation; and simultaneously supplying pumping light power to the active fiber at a wavelength of about 980 nm, causing the active fiber to amplify the power of the optical signal at the active fiber output, and, together with the power level of the optical signal and the active fiber dopants, causing amplification efficiency to exceed about 60% of quantum efficiency for the active fiber, the quantum efficiency equalling a ratio of the pumping light wavelength to the optical signal wavelength, and the amplification efficiency equalling a ratio of the active fiber output power to pumping light power.
Claim 26
Independent Claim
184 words
A method for amplifying an optical telecommunication signal with an optical fiber power amplifier, said method comprising the steps of: supplying an optical signal to an input of the optical fiber power amplifier, the amplifier comprising an active fiber having a core doped with dopants consisting essentially of erbium and Al 2 O 3 , the optical signal having a wavelength in a range from about 1500 nm to about 1600 nm and a power level of sufficient magnitude to cause the active fiber to operate in saturation; and simultaneously supplying pumping light power to the active fiber at a wavelength of about 980 nm, causing the active fiber to amplify the power of the optical signal at the active fiber output, and, together with the power level of the optical signal and the active fiber dopants, causing amplification efficiency to exceed about 60% of quantum efficiency for the active fiber, the quantum efficiency equalling a ratio of the pumping light wavelength to the optical signal wavelength, and the amplification efficiency equalling a ratio of the active fiber output power to pumping light power.
Claim 27
Dependent Claim
25 words
The amplifying method of claim 21, the step of supplying pumping light power causing the amplification efficiency to be substantially equal to the quantum efficiency.
Claim 28
Dependent Claim
22 words
The amplifying method of claim 21, the step of supplying an optical signal causing the active fiber to operate normally in saturation.
Claim 29
Dependent Claim
28 words
The amplifying method of claim 21, the step of supplying an optical signal causing the active fiber to operate only in saturation with respect to the optical signal.
Claim 30
Dependent Claim
22 words
The amplifying method of claim 21, the step of supplying an optical signal causing the active fiber to operate only in saturation.
Claim 31
Dependent Claim
33 words
The amplifying method of claim 21, wherein the amplifier has a length, and the step of supplying an optical signal causes at least a portion of the length to operate only in saturation.
Claim 32
Dependent Claim
254 words
An optical fiber telecommunication system comprising: an optical fiber power amplifier comprising an active fiber having a core and a cladding, the core being doped with erbium as a fluorescing dopant and Al 2 O 3 as an index modifying dopant, said active fiber having an input and an output; a pump source coupled to said active fiber and supplying pumping light at a predetermined power level and at a wavelength of about 980 nm to said active fiber; an optical signal transmitter supplying a communication light signal to said input of said active fiber, said communication light signal having a wavelength in the range from about 1500 nm to about 1600 nm and a power level sufficient to drive said active fiber into saturation, and said active fiber providing amplified communication light signal power at said output of said active fiber which is substantially independent of the communication light signal power supplied to said input of said active fiber; and said Al 2 O 3 dopant being present in said core in an amount sufficient, together with the power levels of the communication light signal and the pumping light, to cause amplification efficiency to exceed about 60% of quantum efficiency for the amplifier, the quantum efficiency equalling a ratio of the wavelength of the pumping light to the wavelength of the communication light signal, and the amplification efficiency equalling a ratio of the amplified communication light signal power at said output of said active fiber to said power level of said pumping light.
Claim 33
Dependent Claim
254 words
An optical fiber telecommunication system comprising: an optical fiber power amplifier comprising an active fiber having a core and a cladding, the core being doped with erbium as a fluorescing dopant and Al 2 O 3 as an index modifying dopant, said active fiber having an input and an output; a pump source coupled to said active fiber and supplying pumping light at a predetermined power level and at a wavelength of about 980 nm to said active fiber; an optical signal transmitter supplying a communication light signal to said input of said active fiber, said communication light signal having a wavelength in the range from about 1500 nm to about 1600 nm and a power level sufficient to drive said active fiber into saturation, and said active fiber providing amplified communication light signal power at said output of said active fiber which is substantially independent of the communication light signal power supplied to said input of said active fiber; and said Al 2 O 3 dopant being present in said core in an amount sufficient, together with the power levels of the communication light signal and the pumping light, to cause amplification efficiency to exceed about 60% of quantum efficiency for the amplifier, the quantum efficiency equalling a ratio of the wavelength of the pumping light to the wavelength of the communication light signal, and the amplification efficiency equalling a ratio of the amplified communication light signal power at said output of said active fiber to said power level of said pumping light.
Claim 34
Dependent Claim
25 words
The optical fiber telecommunication system of claim 27, wherein the amplification efficiency of the optical fiber power amplifier is substantially equal to the quantum efficiency.
Claim 35
Dependent Claim
18 words
The optical fiber telecommunication system of claim 27, wherein normal operation of the active fiber is in saturation.
Claim 36
Dependent Claim
23 words
The optical fiber telecommunication system of claim 27, wherein the active fiber operates only in saturation with respect to the communication light signal.
Claim 37
Dependent Claim
16 words
The optical fiber telecommunication system of claim 27, wherein the active fiber operates only in saturation.
Claim 38
Dependent Claim
26 words
The optical fiber power amplifier of claim 27, wherein the amplifier has a length, and at least a portion of the length operates only in saturation.
Claim 39
Dependent Claim
183 words
An optical fiber power amplifier comprising: an active fiber having a core and a cladding, the core including erbium and Al 2 O 3 , the active fiber receiving an optical signal through an input, the optical signal having a wavelength in a range from about 1500 nm to about 1600 nm and a power level of sufficient magnitude to cause the active fiber to operate in saturation; and a pump source supplying pumping light power at a wavelength of about 980 nm to the active fiber and causing the active fiber to amplify the power of the communication light signal at the active fiber output; and the Al 2 O 3 being present in the core in an amount sufficient, together with the power level of the optical signal and the pumping light power, to cause amplification efficiency to exceed 60% of quantum efficiency for the active fiber, the quantum efficiency equalling a ratio of the pumping light wavelength to the optical signal wavelength, and the amplification efficiency equalling a ratio of the active fiber output power to the pumping light power.
Claim 40
Dependent Claim
183 words
An optical fiber power amplifier comprising: an active fiber having a core and a cladding, the core including erbium and Al 2 O 3 , the active fiber receiving an optical signal through an input, the optical signal having a wavelength in a range from about 1500 nm to about 1600 nm and a power level of sufficient magnitude to cause the active fiber to operate in saturation; and a pump source supplying pumping light power at a wavelength of about 980 nm to the active fiber and causing the active fiber to amplify the power of the communication light signal at the active fiber output; and the Al 2 O 3 being present in the core in an amount sufficient, together with the power level of the optical signal and the pumping light power, to cause amplification efficiency to exceed 60% of quantum efficiency for the active fiber, the quantum efficiency equalling a ratio of the pumping light wavelength to the optical signal wavelength, and the amplification efficiency equalling a ratio of the active fiber output power to the pumping light power.
Claim 41
Dependent Claim
19 words
The optical fiber power amplifier of claim 33, wherein the amplification efficiency is substantially equal to the quantum efficiency.
Claim 42
Dependent Claim
18 words
The optical fiber power amplifier of claim 33, wherein normal operation of the active fiber is in saturation.
Claim 43
Dependent Claim
22 words
The optical fiber power amplifier of claim 33, wherein the active fiber operates only in saturation with respect to the optical signal.
Claim 44
Dependent Claim
16 words
The optical fiber power amplifier of claim 33, wherein the active fiber operates only in saturation.
Claim 45
Dependent Claim
26 words
The optical fiber power amplifier of claim 33, wherein the amplifier has a length, and at least a portion of the length operates only in saturation.
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