Wideband amplifier with erbium-doped fiber
A wideband amplifier is provided with at least one erbium-doped fiber, for use in a wavelength division multiplexing optical communication system that performs transmission/receipt of wavelength-division-multiplexed optical signals through at least one optical fiber. The wideband amplifier comprises an erbium-doped fiber, pumped by a first pump light that pumps erbium ions and a second pump light that induces a Raman amplification, that amplifies the optical signals, a first pumping light source that outputs a predetermined wavelength of first pump light such that the erbium ions are pumped from the erbium-doped fiber, a first wavelength selective coupler that passes through optical signals amplified at the erbium-doped fiber and that inputs the first pump light into the erbium-doped fiber, a second pumping light source that outputs a predetermined wavelength of the second pump light such that a Raman pumping is performed of the erbium-doped fiber, and a second wavelength selective coupler that passes through optical signals amplified at the erbium-doped fiber and that inputs the second pump light into the erbium-doped fiber.
1. A wideband amplifier for use in a wavelength division multiplexing optical communication system that at least one of transmits and receives wavelength-division-multiplexed optical signals through at least one optical fiber, comprising:
at least one erbium-doped fiber, pumped by a first pump light that pumps erbium ions and a second pump light that induces a Raman amplification, such that the at least one erbium-doped fiber amplifies the optical signals;
a first pumping light source that outputs a predetermined wavelength of the first pump light such that the erbium ions are pumped from the erbium-doped fiber;
a first wavelength selective coupler that passes through optical signals amplified by the erbium-doped fiber and that inputs the first pump light into the erbium-doped fiber;
a second pumping light source that outputs a predetermined wavelength of the second pump light such that a Raman pumping is performed of the erbium-doped fiber; and
a second wavelength selective coupler that passes through optical signals amplified by the erbium-doped fiber and that inputs the second pump light into the erbium-doped fiber.
2. The wideband amplifier according to claim 1 , further comprising:
a first isolator that prevents optical signals inputted through the optical fiber from traveling in a reverse direction; and
a second isolator that prevents optical signals outputted through the optical fiber from traveling in a reverse direction.
3. The wideband amplifier according to claim 1 , wherein the first pumping light source has a wavelength selected from the group consisting of 980 nm and 1480 nm and pumps the erbium-doped fiber in a backward direction to amplify optical signals of the C-band.
4. The wideband amplifier according to claim 1 , wherein the second pumping light source has a wavelength range selected from the group consisting of 1350 nm to 1410 nm and 1465 nm to 1510 nm and pumps the erbium-doped fiber in a backward direction to amplify optical signals of the L-band and S-band.
5. The wideband amplifier according to claim 4 , wherein the second pumping light source is a laser diode.
6. The wideband amplifier according to claim 1 , wherein the erbium-doped fiber causes concentration of erbium ions to be set so that the first and second pump light each have an absorptance of approximately 1.0 dB/km.
7. The wideband amplifier according to claim 1 , wherein the erbium-doped fiber further comprises silica such that it concurrently amplifies the optical signals through erbium ions as one constituent material of the erbium-doped fiber and through vibration energy of silica as another constituent material of the erbium-doped fiber.
8. The wideband amplifier according to claim 1 , wherein: the Raman gain at a narrow wavelength band is given by the equation
G
(
λ
)
=
exp
(
g
(
λ
)
A
eff
P
p
L
eff
)
,
and
L
eff
=
1
α
p
(
1
-
ⅇ
-
α
p
L
)
wherein g(λ) is the Raman gain coefficient of the erbium-doped fiber, P p is the power of the second pumping light, A eff is the effective area with respect to the second pump light, L eff is the effective length, L is the total length of the erbium-doped fiber, and α p is the loss.
9. A wideband amplifier for use in a wavelength division multiplexing optical communication system for at least one of transmits and receives wavelength-division-multiplexed optical signals through at least one optical fiber, comprising:
at least one erbium-doped fiber, pumped by a first pump light that pumps erbium ions and a second pump light that induces a Raman amplification, that amplifies the optical signals;
a first pumping light source for outputting a predetermined wavelength of a first pump light such that the erbium ions of the erbium-doped fiber are pumped in a forward direction;
a first wavelength selective coupler for inputting the optical signals and the first pump light into the erbium-doped fiber;
a second pumping light source for outputting a predetermined wavelength of a second pump light such that a Raman pumping is performed of the erbium-doped fiber in a forward direction; and
a second wavelength selective coupler for inputting the optical signals and the second pump light into the erbium-doped fiber.
10. The wideband amplifier according to claim 9 , further comprising:
a first isolator that prevents optical signals inputted through the optical fiber from traveling in a reverse direction; and
a second isolator that prevents optical signals outputted through the optical fiber from traveling in a reverse direction.
11. The wideband amplifier according to claim 9 , wherein the first pumping light source has a wavelength of 980 nm and pumps the erbium-doped fiber in a forward direction to amplify optical signals of the C-band.
12. The wideband amplifier according to claim 9 , wherein the second pumping light source has a wavelength range selected from the group consisting of 1350 nm to 1410 nm and 1465 nm to 1510 nm and pumps the erbium-doped fiber in a forward direction to amplify optical signals of the L-band and S-band.
13. The wideband amplifier according to claim 12 , wherein the second pumping light source is a laser diode.
14. A wideband amplifier for use in a wavelength division multiplexing optical communication system that at least one of transmits and receives wavelength-division-multiplexed optical signals through at least one optical fiber, comprising:
at least one erbium-doped fiber, pumped by a first pump light that pumps erbium ions and a second pump light that induces a Raman amplification, that amplifies the optical signals;
a first pumping light source that outputs a predetermined wavelength of the first pump light such that the erbium ions of the erbium-doped fiber are pumped in a forward direction;
a first wavelength selective coupler that inputs the optical signals and the first pump light into the erbium-doped fiber;
a second pumping light source that outputs a predetermined wavelength of the second pump light such that a Raman pumping is performed of the erbium-doped fiber in a forward direction; and
a second wavelength selective coupler that passes through optical signals amplified at the erbium-doped fiber and that inputs the second pump light into the erbium-doped fiber.
15. The wideband amplifier according to claim 14 , further comprising:
a first isolator that prevents optical signals inputted through the optical fiber from traveling in a reverse direction; and
a second isolator that prevents optical signals outputted through the optical fiber from traveling in a reverse direction.
16. The wideband amplifier according to claim 14 , wherein the second pumping light source has a wavelength range selected from the group consisting of 1350 nm to 1410 nm and 1465 nm to 1510 nm and pumps the erbium-doped fiber in a backward direction to amplify optical signals of the L-band and S-band.
17. The wideband amplifier according to claim 16 , wherein the second pumping light source is a laser diode.
18. A wideband amplifier for use in a wavelength division multiplexing optical communication system that at least one of transmits and receives wavelength-division-multiplexed optical signals through at least one optical fiber, comprising:
at least one erbium-doped fiber, pumped by a first pump light that pumps erbium ions and a second pump light that induces a Raman amplification, that amplifies the optical signals;
a first pumping light source that outputs a predetermined wavelength of the first pump light such that the erbium ions of the erbium-doped fiber are pumped in a backward direction;
a first wavelength selective coupler that passes through optical signals amplified at the erbium-doped fiber and that inputs the first pump light into the erbium-doped fiber;
a second pumping light source that outputs a predetermined wavelength of second pump light such that a Raman pumping of the erbium-doped fiber is performed in a forward direction; and
a second wavelength selective coupler that inputs the optical signals and the second pump light into the erbium-doped fiber.
19. The wideband amplifier according to claim 18 , further comprising:
a first isolator that prevents optical signals inputted through the optical fiber from traveling in a reverse direction; and
a second isolator that prevents optical signals outputted through the optical fiber from traveling in a reverse direction.
20. A wideband amplifier for use in a wavelength division multiplexing optical communication system that at least one of transmits and receives wavelength-division-multiplexed optical signals through at least one optical fiber, comprising:
at least one erbium-doped fiber, pumped by a second and a third pump light that pump erbium ions and by a first and a fourth pump light that induces a Raman amplification, that amplifies the optical signals;
a second pumping light source that outputs a predetermined wavelength of the second pump light such that the erbium ions of the erbium-doped fiber are pumped in a forward direction;
a second wavelength selective coupler that inputs the optical signals and the second pump light into the erbium-doped fiber;
a first pumping light source that outputs a predetermined wavelength of the first pump light such that a Raman pumping of the erbium-doped fiber is performed in a forward direction;
a first wavelength selective coupler that inputs the optical signals and the first pump light into the erbium-doped fiber;
a third pumping light source that outputs the third pump light such that erbium ions of the erbium-doped fiber are pumped in a backward direction, using a laser diode with a different wavelength from the second pump light;
a third wavelength selective coupler that passes through optical signals amplified at the erbium-doped fiber and that inputs the third pump light into the erbium-doped fiber;
a fourth pumping light source that outputs the fourth pump light such that a Raman pumping of the erbium-doped fiber is performed in a backward direction, using a laser diode with a different wavelength from the first pump light; and
a fourth wavelength selective coupler that passes through optical signals amplified at the erbium-doped fiber and that inputs the fourth pump light into the erbium-doped fiber.