US 5,675,432 A · Optical amplification apparatus

An optical amplification apparatus for amplifying inputted light having signal light at a plurality of different wavelengths multiplexed thereon and outputting the amplified light comprising:

optical power adjusting means coupled to receive said inputted light for amplifying or attenuating light at at least one wavelength included in said received light independently of the remaining light at wavelengths different from the wavelength of said light;
optical amplifying means for amplifying said light at the at least one wavelength amplified or attenuated by said optical power adjusting means;
and
control means for controlling a gain of amplification or attenuation performed by said optical power adjusting means and a gain of amplification performed by said optical amplifying means, respectively,
wherein said optical power adjusting means includes:
a plurality of paths for passing light therethrough;
a light separator for separating said received light into light at respective wavelengths included in said light and passing said separated light through each of said plurality of paths;
a light combiner for wavelength multiplexing the light at the respective wavelengths each having propagated through each of said plurality of paths;
and
an optical gain adjuster arranged in at least one of said plurality of paths for amplifying or attenuating light at a wavelength propagating through said path in accordance with control of said control means.

7 more elements

An optical amplification apparatus for amplifying inputted light having signal light at a plurality of different wavelengths multiplexed thereon and outputting the amplified light comprising:

optical power adjusting means coupled to receive said inputted light for amplifying or attenuating light at at least one wavelength included in said received light independently of the remaining light at wavelengths different from the wavelength of said light;
optical amplifying means for amplifying said light at the at least one wavelength amplified or attenuated by said optical power adjusting means;
and
control means for controlling a gain of amplification or attenuation performed by said optical power adjusting means and a gain of amplification performed by said optical amplifying means, respectively, wherein:
said optical power adjusting means includes:
a plurality of paths for passing light therethrough;
a light separator for separating said received light into light at respective wavelengths included in said light and for passing each separated light through each of said plurality of paths;
a light combiner for wavelength multiplexing the light at the respective wavelengths each having propagated through each of said plurality of paths;
and
an optical gain adjuster arranged in at least one of said plurality of paths for amplifying or attenuating light at a wavelength propagating through said path in accordance with control of said control means,
said light separator includes:
a first optical coupler for splitting said received light;
and
optical filters arranged between said optical coupler and said plurality of paths corresponding to the light split by said optical coupler, each said optical filter for bidirectionally transmitting only light at a particular wavelength,
said light combiner includes:
an optical star coupler for combining the light at the respective wavelengths having propagated through said plurality of paths,
said optical amplification apparatus comprises:
means for splitting pan of light amplified by said optical amplifying means as monitor light;
monitor light combining means for splitting said split monitor light by an optical star coupler and introducing said monitor light in the direction opposite to a propagating direction of the combined light including said light at the respective wavelengths;
and
a plurality of light detecting means for detecting power of the light at the respective wavelengths split by said optical coupler for splitting said monitor light which have transmitted said plurality of optical filters in the direction opposite to a direction of the light split by said optical coupler, and
said control means controls a gain of amplification or attenuation performed by said optical power adjusting means and a gain of amplification performed by said optical amplifying means, respectively, in accordance with the power of light at the respective wavelengths detected by said respective light detecting means.

19 more elements

An optical amplification apparatus for amplifying inputted light having signal light at a plurality of different wavelengths multiplexed thereon and outputting the amplified light comprising:

optical amplifying means for amplifying said inputted light;
optical power adjusting means coupled to receive said light amplified by said optical amplifying means for amplifying or attenuating light at at least one wavelength included in the received light independently of the remaining light at wavelengths different from the wavelength of said light;
and
control means for controlling a gain of amplification performed by said optical amplifying means and a gain of amplification or attenuation performed by said optical power adjusting means, respectively, wherein:
said optical power adjusting means includes:
a plurality of paths for passing light therethrough;
a light separator for separating said received light into light at respective wavelengths included in said light and for passing each separated light through each of said plurality of paths;
a light combiner for wavelength multiplexing the light at the respective wavelengths each having propagated through each of said plurality of paths;
and
an optical gain adjuster arranged in at least one of said plurality of paths for amplifying or attenuating light at a wavelength propagating through said path in accordance with control of said control means,
said light separator includes:
a first optical coupler for splitting said received light;
and
optical filters arranged between said optical coupler and said plurality of paths corresponding to the light split by said optical coupler, each said optical filter for bidirectionally transmitting only light at a particular wavelength,
said light combiner includes:
an optical star coupler for combining the light at the respective wavelengths having propagated through said plurality of paths,
said optical amplification apparatus comprises:
means for splitting part of light amplified by said optical amplifying means as monitor light;
monitor light combining means for splitting said split monitor light by an optical star coupler and introducing said monitor light in the direction opposite to a propagating direction of the combined light including said light at the respective wavelengths;
and
a plurality of light detecting means for detecting power of the light at the respective wavelengths split by said optical coupler for splitting said monitor light which have transmitted said plurality of optical filters in the direction opposite to a direction of the light split by said optical coupler, and
said control means controls a gain of amplification or attenuation performed by optical power adjusting means and a gain of amplification performed by said optical amplifying means, respectively, in accordance with the power of light at the respective wavelengths detected by said respective light detecting means.

19 more elements

An optical amplification apparatus for amplifying inputted light having signal light at a plurality of different wavelengths multiplexed thereon and outputting the amplified light comprising:

optical power adjusting means coupled to receive said inputted light for amplifying or attenuating light at at least one wavelength included in said received light independently of the remaining light at wavelengths different from the wavelength of said light;
optical amplifying means for amplifying said light at the at least one wavelength amplified or attenuated by said optical power adjusting means;
and
control means for controlling a gain of amplification or attenuation performed by said optical power adjusting means and a gain of amplification performed by said optical amplifying means, respectively, wherein:
said optical power adjusting means includes:
a plurality of paths for passing light therethrough;
a light splitter for splitting said received light to pass each split light through each of said plurality of paths;
a light combiner for extracting light at a particular wavelength from each light having propagated through each of said plurality of paths on each of said paths, and for wavelength multiplexing the extracted light at the respective wavelengths;
and
an optical gain adjuster arranged in at least one of said plurality of paths for amplifying or attenuating light propagating through said path in accordance with control of said control means,
said optical amplification apparatus includes:
means for splitting part of light amplified by said optical amplifying means as monitor light;
monitor light combining means for introducing the split monitor light in the direction opposite to a propagating direction of the combined light including said light at the respective wavelengths;
and
a plurality of light detecting means for detecting power of the light at the respective wavelengths split by said optical coupler for splitting said monitor light which have transmitted in the direction opposite to a direction of the light combined by said optical coupler, and
said control means controls a gain of amplification or attenuation performed by said optical power adjusting means and a gain of amplification performed by said optical amplifying means, respectively, in accordance with the power of the light at the respective wavelengths detected by said plurality of light detecting means.

13 more elements

An optical amplification apparatus for amplifying inputted light having signal light at a plurality of different wavelengths multiplexed thereon and outputting the amplified light comprising:

optical amplifying means for amplifying said inputted light;
optical power adjusting means coupled to receive said light amplified by said optical amplifying means for amplifying or attenuating light at at least one wavelength included in the received light independently of the remaining light at wavelengths different from the wavelength of said light;
and
control means for controlling a gain of amplification performed by said optical amplifying means and a gain of amplification or attenuation performed by said optical power adjusting means, respectively, wherein
said optical power adjusting means includes:
a plurality of paths for passing light therethrough;
a light splitter for splitting said received light to pass each split light through each of said plurality of paths;
a light combiner for extracting light at a particular wavelength from each light having propagated through each of said plurality of paths on each of said paths, and for wavelength multiplexing the extracted light at the respective wavelengths;
and
an optical gain adjuster arranged in at least one of said plurality of paths for amplifying or attenuating light propagating through said path in accordance with control of said control means,
said optical amplification apparatus includes:
means for splitting part of light amplified by said optical amplifying means as monitor light;
monitor light combining means for introducing the split monitor light in the direction opposite to a propagating direction of the combined light including said light at the respective wavelengths;
and
a plurality of light detecting means for detecting power of the light at the respective wavelengths split by said optical coupler for splitting said monitor light which have transmitted in the direction opposite to a direction of the light combined by said optical coupler, and
said control means controls a gain of amplification or attenuation performed by said optical power adjusting means and a gain of amplification performed by said optical amplifying means, respectively, in accordance with the power of the light at the respective wavelengths detected by said plurality of light detecting means.

13 more elements

An optical amplification apparatus for amplifying inputted light having signal light at a plurality of different wavelengths multiplexed thereon and outputting the amplified light comprising:

optical power adjusting means coupled to receive said inputted light for amplifying or attenuating light at at least one wavelength included in said received light independently of the remaining light at wavelengths different from the wavelength of said light;
optical amplifying means for amplifying said light at the at least one wavelength amplified or attenuated by said optical power adjusting means;
and
control means for controlling a gain of amplification or attenuation performed by said optical power adjusting means and a gain of amplification performed by said optical amplifying means, respectively, wherein:
said optical power adjusting means includes:
a plurality of paths for passing light therethrough;
a light separator for separating said received light into light at respective wavelengths included in said light and for passing each separated light through each of said plurality of paths;
a light combiner for wavelength multiplexing the light at the respective wavelengths each having propagated through each of said plurality of paths;
and
an optical gain adjuster arranged in at least one of said plurality of paths for amplifying or attenuating light at a wavelength propagating through said path in accordance with control of said control means,
said optical separator includes:
a first optical coupler for splitting said received light;
and
optical filters arranged corresponding to respective light split by said optical coupler, each said optical filter for bidirectionally transmitting only light at a particular wavelength,
said light combiner includes:
an optical star coupler for combining the light at the respective wavelengths each having propagated through each of said plurality of paths;
said optical amplification apparatus comprises:
means for splitting part of light amplified by said optical amplifying means as monitor light;
monitor light combining means for splitting said split monitor light by an optical star coupler and introducing said monitor light in the direction opposite to a propagating direction of the combined light including said light at the respective wavelengths;
and
a plurality of light detecting means for detecting power of the light at the respective wavelengths split by said optical coupler for splitting said monitor light which have transmitted said plurality of optical filters in the direction opposite to a direction of the light split by said optical coupler, and
said control means controls a gain of amplification or attenuation performed by optical power adjusting means and a gain of amplification performed by said optical amplifying means, respectively, in accordance with the power of light at the respective wavelengths detected by said respective light detecting means, said control means including a comparator for comparing the power of the light at each of the respective wavelengths detected by said each light detecting means with a predetermined reference value, and means for controlling the gain of the amplification performed by said optical amplifying means in accordance with a maximum value of a difference with said reference value.

19 more elements

An optical amplification apparatus for amplifying inputted light having signal light at a plurality of different wavelengths multiplexed thereon and outputting the amplified light comprising:

optical amplifying means for amplifying said inputted light;
optical power adjusting means coupled to receive said light amplified by said optical amplifying means for amplifying or attenuating light at least one wavelength included in the received light independently of the remaining light at wavelengths different from the wavelength of said light;
and
control means for controlling a gain of amplification performed by said optical amplifying means and a gain of amplification or attenuation performed by said optical power adjusting means, respectively, wherein:
said optical power adjusting means includes:
a plurality of paths for passing light therethrough;
a light separator for separating said received light into light at respective wavelengths included in said light and for passing each separated light through each of said plurality of paths;
a light combiner for wavelength multiplexing the light at the respective wavelengths each having propagated through each of said plurality of paths;
and
an optical gain adjuster arranged in at least one of said plurality of paths for amplifying or attenuating light at a wavelength propagating through said path in accordance with control of said control means,
said optical separator includes:
a first optical coupler for splitting said received light;
and
optical filters arranged corresponding to respective light split by said optical coupler, each said optical filter for bidirectionally transmitting only light at a particular wavelength, said light combiner includes an optical star coupler for combining the light at the respective wavelengths each having propagated through each of said plurality of paths;
said optical amplification apparatus comprises:
means for splitting part of light amplified by said optical amplifying means as monitor light;
monitor light combining means for splitting said split monitor light by an optical star coupler and introducing said monitor light in the direction opposite to a propagating direction of the combined light including said light at the respective wavelengths;
and
a plurality of light detecting means for detecting power of the light at the respective wavelengths split by said optical coupler for splitting said monitor light which have transmitted said plurality of optical filters in the direction opposite to a direction of the light split by said optical coupler, and
said control means controls a gain of amplification or attenuation performed by said optical power adjusting means and a gain of amplification performed by said optical amplifying means, respectively, in accordance with the power of light at the respective wavelengths detected by said respective light detecting means, said control means including a comparator for comparing the power of the light at each of the respective wavelengths detected by said each light detecting means with a predetermined reference value, and means for controlling the gain of the amplification performed by said optical amplifying means in accordance with a maximum value of a difference with said reference value.

17 more elements

An optical amplification apparatus for amplifying inputted light having signal light at a plurality of different wavelengths multiplexed thereon and outputting the amplified light comprising:

optical power adjusting means coupled to receive inputted light for amplifying or attenuating light at at least one wavelength included in said received light independently of the remaining light at wavelengths different from the wavelength of said light;
optical amplifying means for amplifying said light at least one wavelength amplified or attenuated by said optical power adjusting means;
and
control means for controlling a gain of amplification performed by said optical amplifying means, respectively, wherein:
said optical power adjusting means includes:
a plurality of paths for passing light therethrough;
a light splitter for splitting said receive light to pass each split light through each of said plurality of paths;
a light combiner for extracting light at a particular wavelength from each light having propagated through each of said plurality of paths on each of said paths, and for wavelength multiplexing the extracted light at the respective wavelengths;
and
an optical gain adjuster arranged in at least one of said plurality of paths for amplifying or attenuating light propagating through said path in accordance with control of said control means,
said optical amplification apparatus includes:
means for splitting part of light amplified by said optical amplifying means as monitor light;
monitor light combining means for introducing the split monitor light in the direction opposite to a propagating direction of the combined light including said light at the respective wavelengths;
and
a plurality of light detecting means for detecting power of the light at the respective wavelengths split by said optical coupler for splitting said monitor light which have transmitted in the direction opposite to a direction of the light combined by said optical coupler, and
said control means controls a gain of amplification or attenuation performed by said optical power adjusting means and a gain of amplification performed by said optical amplifying means, respectively, in accordance with the power of the light at the respective wavelengths detected by said plurality of light detecting means, said control means including a comparator for comparing the power of the light at each of the respective wavelengths detected by said each light detecting means with a predetermined reference value, and means for controlling the gain of the amplification performed by said optical amplifying means in accordance with a maximum value of a difference with said reference value.

13 more elements

An optical amplification apparatus for amplifying inputted light having signal light at a plurality of different wavelengths multiplexed thereon and outputting the amplified light comprising:

optical amplifying means for amplifying said inputted light;
optical power adjusting means coupled to receive said light amplified by said optical amplifying means for amplifying or attenuating light at at least one wavelength included in the received light independently of the remaining light at wavelengths different from the wavelength of said light;
and
control means for controlling a gain of amplification performed by said optical amplifying means and a gain of amplification or attenuation performed by said optical power adjusting means, respectively, wherein:
said optical power adjusting means includes:
a plurality of paths for passing light therethrough;
a light splitter for splitting said received light to pass each split light through each of said plurality of paths;
a light combiner for extracting light at a particular wavelength from each light having propagated through each of said plurality of paths on each of said paths, and for wavelength multiplexing the extracted light at the respective wavelengths;
and
an optical gain adjuster arranged in at least one of said plurality of paths for amplifying or attenuating light propagating through said path in accordance with control of said control means,
said optical amplification apparatus includes:
means for splitting part of light amplified by said optical amplifying means as monitor light;
monitor light combining means for introducing the split monitor light in the direction opposite to a propagating direction of the combined light including said light at the respective wavelengths;
and
a plurality of light detecting means for detecting power of the light at the respective wavelengths split by said optical coupler for splitting said monitor light which have transmitted in the direction opposite to a direction of the light combined by said optical coupler, and
said control means controls a gain of amplification or attenuation performed by said optical power adjusting means and a gain of amplification performed by said optical amplifying means, respectively, in accordance with the power of the light at the respective wavelengths detected by said plurality of light detecting means, said control means including a comparator for comparing the power of the light at each of the respective wavelengths detected by said each light detecting means with a predetermined reference value, and means for controlling the gain of the amplification performed by said optical amplifying means in accordance with a maximum value of a difference with said reference value.

13 more elements

An optical amplification apparatus for amplifying inputted light having signal light at a plurality of different wavelengths multiplexed thereon and outputting the amplified light comprising,

optical power adjusting means coupled to receive said inputted light for amplifying or attenuating light at at least one wavelength included in said received light independently of the remaining light at wavelengths different from the wavelength of said light;
optical amplifying means for amplifying said light at the at least one wavelength amplified or attenuated by said optical power adjusting means;
and
control means for controlling a gain of amplification or attenuation performed by said optical power adjusting means and a gain of amplification performed by said optical amplifying means, respectively, wherein:
i) a rare earth added optical fiber amplifier including a first rare earth added optical fiber for passing said received light therethrough, a first excitation light source for outputting light for exciting said rare earth added optical fiber, and a first light combiner for said first excitation light source for introducing light outputted from said first excitation light source into said first rare earth added optical fiber;
and
ii) an adjusting light source for outputting light in the same wavelength band as light at at least one wavelength included in said received light, and a light combiner for said adjusting light source for introducing the light outputted from said light source into said rare earth added optical fiber amplifier in the direction opposite to a propagating direction of said received light, and said optical amplifying means includes:
a second rare earth added optical fiber having the same composition as said first rare earth added optical fiber;
a second excitation light source for outputting light for exciting said second rare earth added optical fiber;
and
a light combiner for said second excitation light source for introducing the light outputted by said second excitation light source into said second rare earth added optical fiber.

8 more elements

An optical amplification apparatus for amplifying inputted light having signal light at a plurality of different wavelength multiplexed thereon and outputting the amplified light comprising:

optical amplifying means for amplifying said inputted light;
optical power adjusting means coupled to receive said light amplified by said optical amplifying means for amplifying or attenuating light at at least one wavelength included in the received light independently of the remaining light at wavelengths different from the wavelength of said light;
and
control means for controlling a gain of amplification performed by said optical amplifying means and a gain of amplification or attenuation performed by said optical power adjusting means, respectively, wherein:
i) a rare earth added optical fiber amplifier including a first rare earth added optical fiber for passing said received light therethrough, a first excitation light source for outputting light for exciting said rare earth added optical fiber, and a first light combiner for said first excitation light source for introducing light outputted from said first excitation light source into said first rare earth added optical fiber;
and
ii) an adjusting light source for outputting light in the same wavelength band as light at at least one wavelength included in said received light, and a light combiner for said adjusting light source for introducing the light outputted from said light source into said rare earth added optical fiber amplifier in the direction opposite to a propagating direction of said received light, and
said optical amplifying means includes:
a second rare earth added optical fiber having the same composition as said first rare earth added optical fiber;
a second excitation light source for outputting light for exciting said second rare earth added optical fiber;
and
a light combiner for said second excitation light source for introducing the light outputted by said second excitation light source into said second rare earth added optical fiber.

9 more elements

An optical amplification apparatus for amplifying inputted light having signal light at a plurality of different wavelengths multiplexed thereon and outputting the amplified light comprising:

optical power adjusting means coupled to receive said inputted light for amplifying or attenuating light at at least one wavelength included in said received light independently of the remaining light at wavelengths different from the wavelength of said light:
optical amplifying means for amplifying said light at the at least one wavelength amplified or attenuated by said optical power adjusting means;
and
control means for controlling a gain of amplification or attenuation performed by said optical power adjusting means and a gain of amplification performed by said optical amplifying means, respectively, wherein:
said optical power adjusting means includes:
a plurality of paths for passing light therethrough;
a light separator for separating said received light into light at respective wavelengths included in said light and for passing each separated light through each of said plurality of paths;
a light combiner for wavelength multiplexing the light at the respective wavelengths each having propagated through each of said plurality of paths;
and
an optical gain adjuster arranged in at least one of said plurality of paths for amplifying or attenuating light at a wavelength propagating through said path in accordance with control of said control means,
said optical gain adjuster includes:
a first rare earth added optical fiber constituting part of said paths;
a first excitation light source for outputting light for exciting said first rare earth added optical fiber;
and
a light combiner for said first excitation light source for introducing the light outputted by said excitation light source into said first rare earth added optical fiber and
said optical amplifying means includes:
a second rare earth added optical fiber having the same composition as said first rare earth added optical fiber;
a second excitation light source for outputting light for exciting said second rare earth added optical fiber;
and
a light combiner for said second excitation light source for introducing the light outputted by said second excitation light source into said second rare earth added optical fiber.

17 more elements

An optical amplification apparatus for amplifying inputted light having signal light at a plurality of different wavelengths multiplexed thereon and outputting the amplified light comprising:

optical amplifying means for amplifying said inputted light;
optical power adjusting means coupled to receive said light amplified by said optical amplifying means for amplifying or attenuating light at at least one wavelength included in the received light independently of the remaining light at wavelengths different from the wavelength of said light;
and
control means for controlling a gain of amplification performed by said optical amplifying means and a gain of amplification or attenuation performed by said optical power adjusting means, respectively, wherein:
said optical power adjusting means includes:
a plurality of paths for passing light therethrough;
a light separator for separating said received light into light at respective wavelengths included in said light and for passing each separated light through each of said plurality of paths;
a light combiner for wavelength multiplexing the light at the respective wavelengths each having propagated through each of said plurality of paths;
and
an optical gain adjuster arranged in at least one of said plurality of paths for amplifying or attenuating light at a wavelength propagating through said path in accordance with control of said control means,
said optical gain adjuster includes:
a first rare earth added optical fiber constituting part of said paths;
a first excitation light source for outputting light for exciting said first rare earth added optical fiber;
and
a light combiner for said first excitation light source for introducing the light outputted by said excitation light source into said first rare earth
added optical fiber, and
said optical amplifying means includes:
a second rare earth added optical fiber having the same composition as said first rare earth added optical fiber;
a second excitation light source for outputting light for exciting said second rare earth added optical fiber;
and
a light combiner for said second excitation light source for introducing the light outputted by said second excitation light source into said second rare earth added optical fiber.

18 more elements

An optical amplification apparatus for amplifying inputted light having signal light at a plurality of different wavelengths multiplexed thereon and outputting the amplified light comprising:

optical power adjusting means coupled to receive said inputted light for amplifying or attenuating light at at least one wavelength included in said received light independently of the remaining light at wavelengths different from the wavelength of said light:
optical amplifying means for amplifying said light at the at least one wavelength amplified or attenuated by said optical power adjusting means;
and
control means for controlling a gain of amplification or attenuation performed by said optical power adjusting means and a gain of amplification performed by said optical amplifying means, respectively, wherein:
said optical power adjusting means includes:
a plurality of paths for passing light therethrough;
a light splitter for splitting said received light to pass each split light through each of said plurality of paths;
a light combiner for extracting light at a particular wavelength from each light having propagated through each of said plurality of paths on each of said paths, and for wavelength multiplexing the extracted light at the respective wavelengths;
and
an optical gain adjuster arranged in at least one of said plurality of paths for amplifying or attenuating light propagating through said path in accordance with control of said control means, and
said optical gain adjuster includes:
a first rare earth added optical fiber constituting part of said paths;
a first excitation light source for outputting light for exciting said first rare earth added optical fiber;
and
a light combiner for said first excitation light source for introducing the light outputted by said excitation light source into said first rare earth added optical fiber, and
said optical amplifying means includes:
a second rare earth added optical fiber having the same composition as said first rare earth added optical fiber;
a second excitation light source for outputting light for exciting said second rare earth added optical fiber;
and
a light combiner for said second excitation light source for introducing the light outputted by said second excitation light source into said second rare earth added optical fiber.

17 more elements

An optical amplification apparatus for amplifying inputted light having signal light at a plurality of different wavelengths multiplexed thereon and outputting the amplified light comprising:

optical amplifying means for amplifying said inputted light:
optical power adjusting means coupled to receive said light amplified by said optical amplifying means for amplifying or attenuating light at at least one wavelength included in the received light independently of the remaining light at wavelengths different from the wavelength of said light;
and
control means for controlling a gain of amplification performed by said optical amplifying means and a gain of amplification or attenuation performed by said optical power adjusting means, respectively, wherein:
said optical power adjusting means includes:
a plurality of paths for passing light therethrough;
a light splitter for splitting said received light to pass each split light through each of said plurality of paths;
a light combiner for extracting light at a particular wavelength from each light having propagated through each of said plurality of paths on each of said paths, and for wavelength multiplexing the extracted light at the respective wavelengths;
and
an optical gain adjuster arranged in at least one of said plurality of paths for amplifying or attenuating light propagating through said path in accordance with control of said control means, and
said optical gain adjuster includes:
a first rare earth added optical fiber constituting part of said paths;
a first excitation light source for outputting light for exciting said first rare earth added optical fiber;
and
a light combiner for said first excitation light source for introducing the light outputted by said excitation light source into said first rare earth added optical fiber, and said optical amplifying means includes:
a second rare earth added optical fiber having the same composition as said first rare earth added optical fiber;
a second excitation light source for outputting light for exciting said second rare earth added optical fiber;
and
a light combiner for said second excitation light source for introducing the light outputted by said second excitation light source into said second rare earth added optical fiber.

16 more elements

Optical amplification apparatus

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Optical amplification apparatus

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Abstract

Claims47