CA2055274C - Optical communication system with a fiber-optic amplifier - Google Patents
Optical communication system with a fiber-optic amplifierInfo
- Publication number
- CA2055274C CA2055274C CA002055274A CA2055274A CA2055274C CA 2055274 C CA2055274 C CA 2055274C CA 002055274 A CA002055274 A CA 002055274A CA 2055274 A CA2055274 A CA 2055274A CA 2055274 C CA2055274 C CA 2055274C
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- Prior art keywords
- fiber
- signal
- coupler
- optical
- amplifying
- Prior art date
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- Expired - Fee Related
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- 230000003287 optical effect Effects 0.000 title claims abstract description 68
- 238000004891 communication Methods 0.000 title claims abstract description 8
- 230000006854 communication Effects 0.000 title claims abstract description 8
- 239000000835 fiber Substances 0.000 claims abstract description 40
- 230000008878 coupling Effects 0.000 claims abstract description 8
- 238000010168 coupling process Methods 0.000 claims abstract description 8
- 238000005859 coupling reaction Methods 0.000 claims abstract description 8
- 239000000463 material Substances 0.000 claims description 7
- 238000001514 detection method Methods 0.000 claims description 5
- 239000013307 optical fiber Substances 0.000 claims description 2
- 230000003321 amplification Effects 0.000 abstract description 2
- 238000003199 nucleic acid amplification method Methods 0.000 abstract description 2
- 230000005540 biological transmission Effects 0.000 description 17
- 241000003910 Baronia <angiosperm> Species 0.000 description 1
- 230000002730 additional effect Effects 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/29—Repeaters
- H04B10/291—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/29—Repeaters
- H04B10/291—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form
- H04B10/2912—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form characterised by the medium used for amplification or processing
Abstract
In an optical communication system with a fiber-optic amplifier (10) which includes a wavelength-selective fiber-optic coupler (12) for coupling pump light into the amplifying length of fiber (11), according to the invention, an additional optical signal, e.g., a service-channel signal, is transmitted from the location of the fiber-optic amplifier (10) in one direction or the other by being used to modulate the pump light. Since the pump light is not completely absorbed in the amplifying length of fiber (11), a sufficient portion is transferred from the length of fiber (11) into the optical waveguide (15) of the optical communication system and passes down the optical waveguide to the end point (A) of the communica-tion system. There,it is coupled out and passed to an optical receiver (17) from whose output the transmitted additional signal is recovered by demodulation. To pre-vent the modulation of the pump light from modulating the amplification brought about by the amplifying length of fiber (11), the additional signal is modulated onto a carrier wave of sufficiently high frequency, and the re-sulting signal is used to modulate the pump light.
Description
~o 5~
-The present invention relates generally to a system for transmitting a first optical signal through an optical waveguide containing a fiber-optic amplifier which includes an amplifying length of fiber, a pump source, and a wavelength-selective fiber-optic coupler for coupling the pump source to the amplifying length of fiber.
Such a transmission system is known from "ECOC '89", Fifteenth European Conference on Optical Communication, September 10-14, 1989, Gothenburg, Sweden, Proceedings, Vol. 1, Regular Papers, TuA 5-7, pages 86 to 89.
In the above-referenced article, two different system configurations are explained. In the first ("copropagating configuration"), the light from the pump source is launched into the Er3 -doped length of fiber via a coupler which, as viewed in the direction of transmission of the optical signal to be amplified, is located in front of the amplifying length of fiber.
In the second system configuration ("counterpropagating configuration"), the coupler, as viewed in the direction of transmission of the signal to be amplified, is located behind the length of fiber.
Sometimes it is desirable or necessary in transmission systems to transmit, in addition to the first optical signal, a second optical signal, e.g., a service-channel signal, from the location of the fiber-optic amplifier in one direction or the other.
It is the object of the invention to provide a system suitable for the above purpose.
According to one aspect, the present invention provides a system for transmitting a first optical signal through two parts of an optical waveguide interconnected by a fiber-optic amplifier which includes an amplifying length of fiber connected at a first end to a selected one of the two parts of the optical waveguide, a wavelength-selective fiber-optic coupler interconnected between a second end of the amplifying length of fiber and the other one of the two parts of the optical waveguide, and a pump source for providing a pump light signal to the coupler, wherein the coupler 5~t is for coupling the pump light signal to the amplifying length of fiber, wherein in order to provide an additional information signal through the selected one of the two parts of the optical waveguide; a modulator is connected to the pump source for providing a modulating signal containing the additional information signal for modulating the pump light signal, at a point remote from the first end of the amplifying length of fiber of the fiber-optic amplifier, the selected one of the two parts of the optical waveguide has a second wavelength-selective fiber-optic coupler interconnected therein which couples the pump lightsignal received from the fiber-optic amplifier through the optical waveguide, and an optical receiver connected to the second wavelength-selective fiber-optic coupler and responsive to the pump light signal for receiving the additional information signal contained in the pump light signal.
According to another aspect, the present invention provides an optical fiber communication system comprising a pumped coupler-amplifier, responsive to a transmitted optical signal from a transmitting node, for providing an amplified optical signal to a receiving node, wherein the system further comprises: a modulator, responsive to an electrical information signal and an electrical carrier signal, for providing a modulated electrical carrier signal, and wherein the pumped coupler-amplifier is responsive to the modulated electrical carrier signal for providing a coupled, modulated, pumped light signal for detection;
a detection decoupler, responsive to the coupled, modulated pumped light signal from the coupler-amplifier, for providing a decoupled light signal; an optical-to-electrical converter, responsive to the decoupled light signal from the decoupler, for providing a modulated electrical signal; and a demodulator, responsive to the modulated electrical signal, for providing a recovered information signal.
The invention will now be explained by way of example with reference to the accompanying drawings, in which:
Fig. 1 shows an embodiment for transmitting the second optical signal in a direction opposite to that of the first ~_o 55~
optical signal, and Fig. 2 shows an embodiment for transmitting the second optical signal in the same direction as the first optical signal.
Fig. 1 shows a transmission system for transmitting an optical signal from a point A to a point B. At the end point A
there is an optical transmitter (not shown), and at the end point tB) there is an optical receiver (not shown). The optical signal to be transmitted from A to B has a wavelength~ 1 of 1540 nm. The transmission link is implemented with a single-mode optical waveguide 15 which has sufficiently good transmission properties at the wavelength ~1 2a Z~55~74 The system of fig. 1, like the prior art system referred to above, includes a fiber-optic amplifier lO consisting of an Er3 -doped length of fioer 11, a waveLength-selective fiber-optic coupler 12, and a pump source 13.
The coupler 12 has four ports 1 tG 4. Port 1 is connected to the Er3 -doped length of fiber 11, port 2 is connected via the optical waveguide 15 to the end point B of the optical trans-mission link, and port 3 is connected via an optical waveguide to the pump source 13. The coupler 12 is a wavelength-selective coupler which has the property of coupling the optical signal of wavelength A 1~ which is to be trans-mitted from A to B, from port 1 to port 2 with minimum loss, and of coupling the pump light generated by the pump source 13, which has a wavelength ~p of 980 nm, from port 3 to port 1 with minimum loss. Port 4 is unused.
To be able to transmit an additional information signal, e.g., a service-channel signal or slgnals for monitoring the fiber-optic amplifier itself, from the location of the pump source to the end point A of the optical trans-mission link, according to the invention,a modulator 14 is provided at the pump source 13. This modulator modu-lates the pump light generated by the pump source 13 with a modulating signal containing the additional in-formation signal. It is preferably a frequency modulator which modulates an analog or digital additional signal applied at its modulation input ME, e.g., a signal at baseband, onto a carrier wave of frequency fO from a generator 18. The output of the frequency modulator 14 thus provides the modulating signal for the pump source, i.e., the carrier wave frequency-moduLated with the additional signal. The pump source 13 must be thought of 2(!55274 as containing the necessary control circuits for its laser, i.e., the so-called laser driver, and a control circuit for the DC bias to be applied to the laser.
The modulating signal is injected into the laser driver of the pump source 13, thereby modulating the intensity of the light generated by the pump source 13.
In another embodiment, the pump source generates unmodu-lated light, and the modulating signal is used to modu-late the pump light in a modulator following the pump source. In that case, too, the pump light generated by the pump source is modulated.
During normal operation, the intensity of the pump light is so high that a considerable portion which is not ab-sorbed in the length of fiber 11 is transferred from the end of the length of fiber 11 remote from the coupler 12 into the optical waveguide 15 and passes dowr, the latter in the di rection of the end point A. In this manner, the additional sîgnal can be transmitted in the direction of the end point A up to the point where the pump light can be detected with a level sufficient for signal transmission.
At that point, the optical waveguide 15 containc a fiber-optic wavelength-selective coupler 16 which extracts the pump light from the optical waveguide. The output port of the coupler 16 is connected via an optical waveguide 19 to an optical receiver 17 whose output provides the elec-tric modulating signal impressed on the pump light. This modulating signal is finally demodulated in an FM de-modulator 20, so that the additional signal appears at the output of the demodulator.
Thus, according to the invention, the portion of the pump Light which unavoidabLy emerges from the Length of fiber 11 and couLd onLy be suppressed with filters is utiLized to transmit an additionaL signal from the Location of the pump source over the Length of fiber 11 to the distant end point of the opticaL transmission Link.
To prevent the moduLation of the pump Light from moduLat-ing the ampLification brought about by passing the op-ticaL signaL to be transmitted from end point A to end point B through the ampLifiying Length of fiber 11, a suitabLe vaLue is chosen for the frequency fO of the carrier used in the FM modulator 14. A suitable frequency fO has a value which is substantiaLLy greater than the reciprocaL of the Lifetime of those energy states of the Er -doped materiaL of the Length of fiber 11 which are excitabLe by the pump Light, i.e., a vaLue above 1 MHz.
One appLication of the noveL communication system shown in Fig. 1 is in a cabLe television distribution system in which an eLectric frequency-division muLtipLex signaL
with a bandwidth of 450 MHz has to be transmitted over the opticaL transmission Link, and in which front-end equipment, which distributes the opticaL signaL to a pLuraLity of opticaL waveguides running to individuaL
subscribers, contains the fiber-optic amplifier 10, which then serves to ampLify the opticaL signaL before it is distributed to the optical waveguides. In such a system, as shown in Fig. 1, a reverse channeL can be insta~Led from the Location of the pump source to the end point A, i.e., the head end, tor transmitt1ng an add;tionaL sig-naL~ e.g., a service-channeL signal.
2~527'1 The system described has the so-called counterpropagating configuration, in which the coupler coupling the pump light into the doped length of fiber, as viewed in the direction of transmission of the optical signal to be amplified, is located behind the amplifying length of fiber 11. With the aid of Fig. 2, a system configuration, the so-called copropagating configuration, will now be explained in which the coupler coupling the pump light into the doped length of fiber, as viewed in the direc-tion of transmission of the optical signal to be ampli-fied, is located before the amplifying length offiber.
In such a configuration, too, the pump light which is not absorbed in and emerges from the doped length of fiber can be used to transmit an additional signal.
In the sys~em according to the invention s~own in Fig.
2, parts having the same functions as in Fig. 1 are designated by similar reference characters and hence need not be explained again. The coupler 12, as viewed in the direction of transmission of the signal to be trans-mitted from A to B, is located before the Er3 -doped length of fiber 11. As in Fig. 1, it couples the signal from port 1 to port 2 and the pump light from port 3 to the length of fiber 11, the latter via port 2 instead of port 1 as in Fig. 1. In this configuration of Fig. 2, the pump light emerging from the doped length of the fiber 11 travels in the direction of the end point 8 of the trans-mission system, i.e., in the same direction as the first optical signal of wavelength ~1; in the system of Fig. 1, it travels in the opposite d;rection.
rhus, the embodiment of the invention shown in Fig. 1 can be used if an additional signal has to be transmitted 2C55;274 from the location of the pump source of the transmission link in the direction of the source of the first opti-cal signal, i.e., the end point A, and the system of Fig. Z can be used if an additional signal has to be transmitted from the location of the pump source of the fiber-optic amplifier in the direction of the sink of the first optical signal, i.e., to the end point B.
By combining the two embodiments, a fiber-optic ampli-fier is obtained whose doped length of fiber is fed from a pump source at each of its two ends, so that two addi-tional signals can be transmitted from the location of the fiber-optic amplifier in different directions of the transmission system.
The wavelengths mentionedin the foregoing description are only examples of wavelengths for which the available system components are su;table. It is, of course, possible to use other wavelengths, with the signal wavelength ~1 lying in the range between 1520 and 1570 nm, and the pump wavelength ~eing 5-~2 nm, 800 nm, 980 nm or 1489 nm.
-The present invention relates generally to a system for transmitting a first optical signal through an optical waveguide containing a fiber-optic amplifier which includes an amplifying length of fiber, a pump source, and a wavelength-selective fiber-optic coupler for coupling the pump source to the amplifying length of fiber.
Such a transmission system is known from "ECOC '89", Fifteenth European Conference on Optical Communication, September 10-14, 1989, Gothenburg, Sweden, Proceedings, Vol. 1, Regular Papers, TuA 5-7, pages 86 to 89.
In the above-referenced article, two different system configurations are explained. In the first ("copropagating configuration"), the light from the pump source is launched into the Er3 -doped length of fiber via a coupler which, as viewed in the direction of transmission of the optical signal to be amplified, is located in front of the amplifying length of fiber.
In the second system configuration ("counterpropagating configuration"), the coupler, as viewed in the direction of transmission of the signal to be amplified, is located behind the length of fiber.
Sometimes it is desirable or necessary in transmission systems to transmit, in addition to the first optical signal, a second optical signal, e.g., a service-channel signal, from the location of the fiber-optic amplifier in one direction or the other.
It is the object of the invention to provide a system suitable for the above purpose.
According to one aspect, the present invention provides a system for transmitting a first optical signal through two parts of an optical waveguide interconnected by a fiber-optic amplifier which includes an amplifying length of fiber connected at a first end to a selected one of the two parts of the optical waveguide, a wavelength-selective fiber-optic coupler interconnected between a second end of the amplifying length of fiber and the other one of the two parts of the optical waveguide, and a pump source for providing a pump light signal to the coupler, wherein the coupler 5~t is for coupling the pump light signal to the amplifying length of fiber, wherein in order to provide an additional information signal through the selected one of the two parts of the optical waveguide; a modulator is connected to the pump source for providing a modulating signal containing the additional information signal for modulating the pump light signal, at a point remote from the first end of the amplifying length of fiber of the fiber-optic amplifier, the selected one of the two parts of the optical waveguide has a second wavelength-selective fiber-optic coupler interconnected therein which couples the pump lightsignal received from the fiber-optic amplifier through the optical waveguide, and an optical receiver connected to the second wavelength-selective fiber-optic coupler and responsive to the pump light signal for receiving the additional information signal contained in the pump light signal.
According to another aspect, the present invention provides an optical fiber communication system comprising a pumped coupler-amplifier, responsive to a transmitted optical signal from a transmitting node, for providing an amplified optical signal to a receiving node, wherein the system further comprises: a modulator, responsive to an electrical information signal and an electrical carrier signal, for providing a modulated electrical carrier signal, and wherein the pumped coupler-amplifier is responsive to the modulated electrical carrier signal for providing a coupled, modulated, pumped light signal for detection;
a detection decoupler, responsive to the coupled, modulated pumped light signal from the coupler-amplifier, for providing a decoupled light signal; an optical-to-electrical converter, responsive to the decoupled light signal from the decoupler, for providing a modulated electrical signal; and a demodulator, responsive to the modulated electrical signal, for providing a recovered information signal.
The invention will now be explained by way of example with reference to the accompanying drawings, in which:
Fig. 1 shows an embodiment for transmitting the second optical signal in a direction opposite to that of the first ~_o 55~
optical signal, and Fig. 2 shows an embodiment for transmitting the second optical signal in the same direction as the first optical signal.
Fig. 1 shows a transmission system for transmitting an optical signal from a point A to a point B. At the end point A
there is an optical transmitter (not shown), and at the end point tB) there is an optical receiver (not shown). The optical signal to be transmitted from A to B has a wavelength~ 1 of 1540 nm. The transmission link is implemented with a single-mode optical waveguide 15 which has sufficiently good transmission properties at the wavelength ~1 2a Z~55~74 The system of fig. 1, like the prior art system referred to above, includes a fiber-optic amplifier lO consisting of an Er3 -doped length of fioer 11, a waveLength-selective fiber-optic coupler 12, and a pump source 13.
The coupler 12 has four ports 1 tG 4. Port 1 is connected to the Er3 -doped length of fiber 11, port 2 is connected via the optical waveguide 15 to the end point B of the optical trans-mission link, and port 3 is connected via an optical waveguide to the pump source 13. The coupler 12 is a wavelength-selective coupler which has the property of coupling the optical signal of wavelength A 1~ which is to be trans-mitted from A to B, from port 1 to port 2 with minimum loss, and of coupling the pump light generated by the pump source 13, which has a wavelength ~p of 980 nm, from port 3 to port 1 with minimum loss. Port 4 is unused.
To be able to transmit an additional information signal, e.g., a service-channel signal or slgnals for monitoring the fiber-optic amplifier itself, from the location of the pump source to the end point A of the optical trans-mission link, according to the invention,a modulator 14 is provided at the pump source 13. This modulator modu-lates the pump light generated by the pump source 13 with a modulating signal containing the additional in-formation signal. It is preferably a frequency modulator which modulates an analog or digital additional signal applied at its modulation input ME, e.g., a signal at baseband, onto a carrier wave of frequency fO from a generator 18. The output of the frequency modulator 14 thus provides the modulating signal for the pump source, i.e., the carrier wave frequency-moduLated with the additional signal. The pump source 13 must be thought of 2(!55274 as containing the necessary control circuits for its laser, i.e., the so-called laser driver, and a control circuit for the DC bias to be applied to the laser.
The modulating signal is injected into the laser driver of the pump source 13, thereby modulating the intensity of the light generated by the pump source 13.
In another embodiment, the pump source generates unmodu-lated light, and the modulating signal is used to modu-late the pump light in a modulator following the pump source. In that case, too, the pump light generated by the pump source is modulated.
During normal operation, the intensity of the pump light is so high that a considerable portion which is not ab-sorbed in the length of fiber 11 is transferred from the end of the length of fiber 11 remote from the coupler 12 into the optical waveguide 15 and passes dowr, the latter in the di rection of the end point A. In this manner, the additional sîgnal can be transmitted in the direction of the end point A up to the point where the pump light can be detected with a level sufficient for signal transmission.
At that point, the optical waveguide 15 containc a fiber-optic wavelength-selective coupler 16 which extracts the pump light from the optical waveguide. The output port of the coupler 16 is connected via an optical waveguide 19 to an optical receiver 17 whose output provides the elec-tric modulating signal impressed on the pump light. This modulating signal is finally demodulated in an FM de-modulator 20, so that the additional signal appears at the output of the demodulator.
Thus, according to the invention, the portion of the pump Light which unavoidabLy emerges from the Length of fiber 11 and couLd onLy be suppressed with filters is utiLized to transmit an additionaL signal from the Location of the pump source over the Length of fiber 11 to the distant end point of the opticaL transmission Link.
To prevent the moduLation of the pump Light from moduLat-ing the ampLification brought about by passing the op-ticaL signaL to be transmitted from end point A to end point B through the ampLifiying Length of fiber 11, a suitabLe vaLue is chosen for the frequency fO of the carrier used in the FM modulator 14. A suitable frequency fO has a value which is substantiaLLy greater than the reciprocaL of the Lifetime of those energy states of the Er -doped materiaL of the Length of fiber 11 which are excitabLe by the pump Light, i.e., a vaLue above 1 MHz.
One appLication of the noveL communication system shown in Fig. 1 is in a cabLe television distribution system in which an eLectric frequency-division muLtipLex signaL
with a bandwidth of 450 MHz has to be transmitted over the opticaL transmission Link, and in which front-end equipment, which distributes the opticaL signaL to a pLuraLity of opticaL waveguides running to individuaL
subscribers, contains the fiber-optic amplifier 10, which then serves to ampLify the opticaL signaL before it is distributed to the optical waveguides. In such a system, as shown in Fig. 1, a reverse channeL can be insta~Led from the Location of the pump source to the end point A, i.e., the head end, tor transmitt1ng an add;tionaL sig-naL~ e.g., a service-channeL signal.
2~527'1 The system described has the so-called counterpropagating configuration, in which the coupler coupling the pump light into the doped length of fiber, as viewed in the direction of transmission of the optical signal to be amplified, is located behind the amplifying length of fiber 11. With the aid of Fig. 2, a system configuration, the so-called copropagating configuration, will now be explained in which the coupler coupling the pump light into the doped length of fiber, as viewed in the direc-tion of transmission of the optical signal to be ampli-fied, is located before the amplifying length offiber.
In such a configuration, too, the pump light which is not absorbed in and emerges from the doped length of fiber can be used to transmit an additional signal.
In the sys~em according to the invention s~own in Fig.
2, parts having the same functions as in Fig. 1 are designated by similar reference characters and hence need not be explained again. The coupler 12, as viewed in the direction of transmission of the signal to be trans-mitted from A to B, is located before the Er3 -doped length of fiber 11. As in Fig. 1, it couples the signal from port 1 to port 2 and the pump light from port 3 to the length of fiber 11, the latter via port 2 instead of port 1 as in Fig. 1. In this configuration of Fig. 2, the pump light emerging from the doped length of the fiber 11 travels in the direction of the end point 8 of the trans-mission system, i.e., in the same direction as the first optical signal of wavelength ~1; in the system of Fig. 1, it travels in the opposite d;rection.
rhus, the embodiment of the invention shown in Fig. 1 can be used if an additional signal has to be transmitted 2C55;274 from the location of the pump source of the transmission link in the direction of the source of the first opti-cal signal, i.e., the end point A, and the system of Fig. Z can be used if an additional signal has to be transmitted from the location of the pump source of the fiber-optic amplifier in the direction of the sink of the first optical signal, i.e., to the end point B.
By combining the two embodiments, a fiber-optic ampli-fier is obtained whose doped length of fiber is fed from a pump source at each of its two ends, so that two addi-tional signals can be transmitted from the location of the fiber-optic amplifier in different directions of the transmission system.
The wavelengths mentionedin the foregoing description are only examples of wavelengths for which the available system components are su;table. It is, of course, possible to use other wavelengths, with the signal wavelength ~1 lying in the range between 1520 and 1570 nm, and the pump wavelength ~eing 5-~2 nm, 800 nm, 980 nm or 1489 nm.
Claims (10)
1. System for transmitting a first optical signal through two parts of an optical waveguide interconnected by a fiber-optic amplifier which includes an amplifying length of fiber connected at a first end to a selected one of the two parts of the optical waveguide, a wavelength-selective fiber-optic coupler interconnected between a second end of the amplifying length of fiber and the other one of the two parts of the optical waveguide, and a pump source for providing a pump light signal to the coupler, wherein the coupler is for coupling the pump light signal to the amplifying length of fiber, wherein in order to provide an additional information signal through the selected one of the two parts of the optical waveguide; a modulator is connected to the pump source for providing a modulating signal containing the additional information signal for modulating the pump light signal, at a point remote from the first end of the amplifying length of fiber of the fiber-optic amplifier, the selected one of the two parts of the optical waveguide has a second wavelength-selective fiber-optic coupler interconnected therein which couples the pump light signal received from the fiber-optic amplifier through the optical waveguide, and an optical receiver connected to the second wavelength-selective fiber-optic coupler and responsive to the pump light signal for receiving the additional information signal contained in the pump light signal.
2. A system as claimed in claim 1, wherein the second wavelength-selective fiber-optic coupler is responsive to the additional information signal from the fiber-optic amplifier and transmitted through the selected one of the two parts of the optical waveguide in a direction opposite to that of the first optical signal.
3. A system as claimed in claim 2, characterized in that the modulator modulates the additional information signal onto a carrier wave whose frequency is substantially higher than a reciprocal of a lifetime of those energy states of a light-amplifying material of the amplifying length of fiber which are excitable in the amplifying length of fiber by the pump light signal.
4. A system as claimed in claim 3, characterized in that the modulator modulates the additional information signal onto a carrier wave whose frequency is substantially higher than a reciprocal of a lifetime of those energy states of a light-amplifying material of the amplifying length of fiber which are excitable in the amplifying length of fiber by the pump light signal.
5. A system as claimed in claim 1, wherein the second wavelength-selective fiber-optic coupler is responsive to the additional information signal from the fiber-optic amplifier and transmitter through the selected one of the two parts of the optical waveguide in the same direction as the first optical signal.
6. A system as claimed in claim 1, characterized in that the modulator modulates the additional information signal onto a carrier wave whose frequency is substantially higher than a reciprocal of a lifetime of those energy states of a light-amplifying material of the amplifying length of the fiber which are excitable in the amplifying length of fiber by the pump light signal.
7. An optical fiber communication system comprising a pumped coupler-amplifier, responsive to a transmitted optical signal from a transmitting node, for providing an amplified optical signal to a receiving node, wherein the system further comprises: a modulator, responsive to an electrical information signal and an electrical carrier signal, for providing a modulated electrical carrier signal, and wherein the pumped coupler-amplifier is responsive to the modulated electrical carrier signal for providing a coupled, modulated, pumped light signal for detection; a detection decoupler, responsive to the coupled, modulated pumped light signal from the coupler-amplifier, for providing a decoupled light signal; an optical-to-electrical converter, responsive to the decoupled light signal from the decoupler, for providing a modulated electrical signal; and a demodulator, responsive to the modulated electrical signal, for providing a recovered information signal.
8. The system of claim 7, wherein the decoupler is connected between the transmitting node and the pumped coupler-amplifier.
9. The system of claim 7, wherein the decoupler is connected between the pumped coupler amplifier and the receiving node.
10. The system of claim 7, wherein the pumped coupler-amplifier comprises: an optical pump, responsive to the modulated carrier signal, for providing a modulated pumped light signal; a coupler, responsive to the modulated, pumped light signal, for providing a coupled, modulated, pumped light source; and an amplifying length of fiber having light-amplifying material therein, the material having energy states with a known lifetime, the amplifying length of fiber responsive to the coupled, modulated, pumped light signal, wherein the carrier signal has a frequency substantially higher than the reciprocal of the lifetime of the energy states of the light amplifying material, for providing the coupled, modulated pumped light signal to the detection decoupler.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4036327.9 | 1990-11-15 | ||
| DE4036327A DE4036327A1 (en) | 1990-11-15 | 1990-11-15 | OPTICAL MESSAGE TRANSMISSION SYSTEM WITH A FIBER OPTICAL AMPLIFIER |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2055274A1 CA2055274A1 (en) | 1992-05-16 |
| CA2055274C true CA2055274C (en) | 1998-01-27 |
Family
ID=6418272
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002055274A Expired - Fee Related CA2055274C (en) | 1990-11-15 | 1991-11-13 | Optical communication system with a fiber-optic amplifier |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US5285306A (en) |
| EP (1) | EP0485813B1 (en) |
| JP (1) | JPH04273624A (en) |
| AT (1) | ATE139877T1 (en) |
| AU (1) | AU647200B2 (en) |
| CA (1) | CA2055274C (en) |
| DE (1) | DE4036327A1 (en) |
| ES (1) | ES2091272T3 (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3137632B2 (en) * | 1989-08-31 | 2001-02-26 | 富士通株式会社 | Optical communication system with optical fiber amplifier |
| JP3425964B2 (en) * | 1992-03-19 | 2003-07-14 | 富士通株式会社 | Optical signal generator and optical transmission system using stimulated Brillouin scattering |
| IL106766A (en) * | 1992-08-28 | 1995-12-31 | Hughes Aircraft Co | Bi-directional optical fiber amplifier for missile guidance data link repeater |
| DE4310292A1 (en) * | 1993-03-30 | 1994-10-06 | Sel Alcatel Ag | Fiber optic amplifier with a device for monitoring the input power |
| DE4324984A1 (en) * | 1993-07-26 | 1995-02-02 | Sel Alcatel Ag | Fiber optic amplifier as a wavelength converter |
| US5481391A (en) * | 1994-02-17 | 1996-01-02 | At&T Corp. | Optical fiber system and method for overcoming the effects of polarization gain anisotropy in a fiber amplifier |
| FR2721158B1 (en) * | 1994-06-14 | 1996-07-12 | Alcatel Submarcom | Transmission system on a fiber optic line without repeater, with remote and local amplifications. |
| US5532864A (en) * | 1995-06-01 | 1996-07-02 | Ciena Corporation | Optical monitoring channel for wavelength division multiplexed optical communication system |
| US5847853A (en) * | 1995-12-29 | 1998-12-08 | Micron Technology, Inc. | Modulation and demodulation of light to facilitate transmission of information |
| US6424445B1 (en) | 1997-02-25 | 2002-07-23 | Hitachi, Ltd. | Optical transmission apparatus and optical systems |
| JP4647147B2 (en) * | 2001-07-16 | 2011-03-09 | 富士通株式会社 | Optical transmission method and optical transmission system using Raman amplification |
| US6731428B2 (en) * | 2001-11-21 | 2004-05-04 | Lucent Technologies Inc. | Pump monitoring and control in a fiber Raman amplifier |
| DE102004037549A1 (en) * | 2004-08-03 | 2006-03-16 | Deutsche Telekom Ag | Device for generating and modulating a high-frequency signal |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6175326A (en) * | 1984-09-21 | 1986-04-17 | Nec Corp | In-fiber optical amplifying and transmitting device |
| DE3827228A1 (en) * | 1988-08-11 | 1990-02-15 | Standard Elektrik Lorenz Ag | TRANSMITTER / RECEIVER FOR A BIDIRECTIONAL COHERENT-OPTICAL TRANSMISSION SYSTEM |
| JP3137632B2 (en) * | 1989-08-31 | 2001-02-26 | 富士通株式会社 | Optical communication system with optical fiber amplifier |
| IT1238032B (en) * | 1990-01-30 | 1993-06-23 | Pirelli Cavi Spa | FIBER OPTIC TELECOMMUNICATION LINE WITH SEPARATE SERVICE CHANNELS |
| US5153762A (en) * | 1990-03-19 | 1992-10-06 | General Instrument Corporation | Method and apparatus for recovering AM channell signals distributed on an optical fiber |
| US5229876A (en) * | 1990-03-26 | 1993-07-20 | At&T Bell Laboratories | Telemetry for optical fiber amplifier repeater |
| US5035481A (en) * | 1990-08-23 | 1991-07-30 | At&T Bell Laboratories | Long distance soliton lightwave communication system |
| US5140656A (en) * | 1991-08-12 | 1992-08-18 | At&T Bell Laboratories | Soliton optical fiber communication system |
-
1990
- 1990-11-15 DE DE4036327A patent/DE4036327A1/en not_active Withdrawn
-
1991
- 1991-10-31 AT AT91118606T patent/ATE139877T1/en not_active IP Right Cessation
- 1991-10-31 ES ES91118606T patent/ES2091272T3/en not_active Expired - Lifetime
- 1991-10-31 EP EP91118606A patent/EP0485813B1/en not_active Expired - Lifetime
- 1991-11-06 AU AU87068/91A patent/AU647200B2/en not_active Ceased
- 1991-11-13 JP JP3297199A patent/JPH04273624A/en active Pending
- 1991-11-13 CA CA002055274A patent/CA2055274C/en not_active Expired - Fee Related
- 1991-11-14 US US07/791,370 patent/US5285306A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04273624A (en) | 1992-09-29 |
| ES2091272T3 (en) | 1996-11-01 |
| EP0485813B1 (en) | 1996-06-26 |
| EP0485813A3 (en) | 1992-09-23 |
| AU8706891A (en) | 1992-05-21 |
| DE4036327A1 (en) | 1992-05-21 |
| CA2055274A1 (en) | 1992-05-16 |
| US5285306A (en) | 1994-02-08 |
| AU647200B2 (en) | 1994-03-17 |
| ATE139877T1 (en) | 1996-07-15 |
| EP0485813A2 (en) | 1992-05-20 |
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| Date | Code | Title | Description |
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| EEER | Examination request | ||
| MKLA | Lapsed |