JP2003283435A - Optical transmission module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical transmission module capable of building up a transmission system, particularly a long range optical transmission system without complicating but improving the maintenance and the extendability of the system. <P>SOLUTION: The optical transmission module 10 has a module main body 11. The module main body 11 is provided with: a port 12 for connection to a first optical fiber 61; a port 16 for connection to a second optical fiber 62; a port 13 for input of transmission information; a port 15 for output of received information; a reception circuit 72 for receiving optical information from the first optical fiber 61 and leading the information to the port 15; a transmission circuit 73 for transmitting the transmission information from the port 13 to the first optical fiber 61; a relay circuit 74 for outputting the information from the first optical fiber 61 to the second optical fiber 62; a stimulated light circuit 71 for transmitting a stimulated light to an optical amplifier provided to the first optical fiber 61; and an optical component group for switching an optical path to configure each circuit. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of telecommunications business using optical fibers, which is represented by the CATV business, and FTTH (Fiber To The Hom) which connects each home with optical fibers.
The present invention relates to an optical transmission module used for the conversion.

[0002]

2. Description of the Related Art Optical fiber communication has become a public infrastructure indispensable for today's information society. CATV
Optical transmission is a common technology in the trunk line of
Further, with the entry into the Internet business, the CATV company will play the role of a telecommunications carrier, and the services and functions are being expanded.

However, in optical transmission, the practical transmittable distance when the semiconductor laser is directly modulated by the current analog method is limited to 40 to 50 km. This is because the relationship between the injection current and the optical output of the semiconductor laser is not completely linear and the wavelength chirping is accompanied by the fluctuation of the injection current, which causes waveform distortion due to transmission. Therefore, if the transmission distance becomes longer due to the expansion of the services and functions as described above, it cannot be handled as it is.

On the other hand, by using the external modulation method, the influence as described above can be avoided, and long-distance optical transmission becomes possible by combining with the optical amplifier. In particular, when the remote excitation method using EDF (Erbium Doped Fiber) is used, there is no need for an active element that uses electricity in the amplification section, so there is no need for power supply and it is possible to avoid blackouts due to lightning strikes It is possible to construct an optical transmission system that secures the property.

[0005]

By the way, in the case of the above-mentioned optical transmission system, if the system is designed to be capable of long-distance optical transmission, various information related to the information transmission function, the reception function, and the relay function are required. Since the parts, the above-mentioned amplifier of the remote excitation system and the parts accompanying it are required, the system construction is extremely complicated. Further, it is necessary to perform maintenance for each of these various parts, and the maintainability is poor. Furthermore, when expanding the system, it is necessary to newly connect these various parts, and the expandability of the system is inevitably low.

The present invention has been made in view of the above circumstances, and it is possible to construct an optical transmission system, particularly a long-distance optical transmission system without complexity, and to improve the maintainability and expandability of the system. It is an object of the present invention to provide an optical transmission module that can be manufactured.

[0007]

In order to solve the above-mentioned problems, the present invention is an optical transmission module used in a system for transmitting optical information using an optical fiber, which is provided in a module body and the module body. The first
A first port to which the optical fiber is connected, a second port provided to the module main body to which a second optical fiber is connected, and a third port provided to the module main body for inputting transmission information, A fourth port provided in the module main body for outputting reception information, and optical information transmitted through the first optical fiber are received via the first port, and reception information is output from the fourth port. A receiving circuit, a transmitting circuit for transmitting the transmission information input from the third port to the first optical fiber, and a relay circuit for outputting the information input from the first optical fiber to the second optical fiber, A pumping optical circuit that sends pumping light to an optical amplifier provided in the first optical fiber, and an optical component group that switches an optical path to configure each circuit. To provide an optical transmission module, wherein the door.

In the present invention, the receiving circuit electrically guides the optical information guided through the first port, an optical amplifier for amplifying the optical information guided to the optical circuit, and an optical amplifier for amplifying the optical information. It may have an O / E converter for converting into information and a signal line for guiding the electric information converted by the O / E converter to the fourth port.

Further, the transmission information input from the third port is optical information, and the transmission circuit has an optical circuit for guiding the transmission information input via the third port to the first port. can do.

Further, the relay circuit may have an optical circuit connecting the first port and the second port.

Furthermore, the pumping light circuit includes a pumping light source,
A driver for driving the pumping light source and an optical circuit for guiding pumping light from the pumping light source to the first port can be provided.

Still further, it may be so arranged that a loopback circuit for outputting the optical information inputted from the first port from the first port is further provided. Further, it may be configured to further include a relay / reception circuit that branches the optical information transmitted through the relay circuit by the reception circuit and guides it to the fourth port.

According to the present invention, the module body is provided with the first
The first optical fiber is provided with a first port to which the optical fiber is connected, a second port to which the second optical fiber is connected, a third port for inputting transmission information, and a fourth port for outputting reception information. Receiving circuit for receiving the optical information transmitted through the first port and outputting the receiving information from the fourth port, and a transmitting circuit for transmitting the transmission information input from the third port to the first optical fiber And the first
Since it has a relay circuit that outputs information input from the optical fiber to the second optical fiber and a pumping optical circuit that sends pumping light to the optical amplifier provided in the first optical fiber, the optical transmission module alone It is possible to configure a transmission / reception unit, a transmission unit, a reception unit, and a relay device for transmission. Therefore, by using the optical transmission module of the present invention, it is possible to increase the maintainability and expandability of the system without complicating the construction of the optical transmission system, particularly the long distance optical transmission system. Further, by using one kind of multi-functional optical transmission module as described above, it is not necessary to classify backup modules into a transmission unit, a reception unit, and a relay device, which is economical.

Furthermore, by providing a function as an optical receiving device which is indispensable for optical communication as a receiving circuit, that is, a function of amplifying input signal light and converting it into an electric signal, other parts can be provided with the receiving device. Since it is not necessary to have a function, the construction of the optical transmission system can be further simplified.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing an example of an optical transmission system to which the optical transmission module of the present invention can be applied.

FIG. 1 (a) shows a system having a transmitting unit and a receiving unit, and transmitting / receiving units 1a and 1b having both transmitting and receiving functions are provided at both ends, The optical fiber 2 is arranged between them. Two EDFs 3 for optical amplification are provided in the middle of the optical fiber 2. Signal light and pumping light are output from the transmitting / receiving units 1a and 1b, and the respective EDFs are excited by exciting the EDF 3 with each pumping light.
Optical amplification is performed in DF3, and signal light is sent to each receiving end. This system allows bidirectional communication with a single optical fiber. In the case of this system, the optical module of the present invention can be applied to the transmission / reception units 1a and 1b.

FIG. 1 (b) shows a system having a transmitting section, a receiving section, and a relaying apparatus, in which a transmitting section 4 and a receiving section 5 are provided at both ends, and a relaying apparatus 6 is provided between them. The optical fiber 2 is provided between the transmitter 4 and the relay device 6 and between the relay device 6 and the receiver 5. An EDF 3 is provided in each of the optical fibers 2 between the transmitter 4 and the relay device 6 and between the relay device 6 and the receiver 5. In this system, the signal light transmitted from the transmitter 4 is optically amplified by the EDF 3 and reaches the relay device 6, and the signal light from the relay device 6 is optically amplified by the EDF 3 and reaches the receiver 5. In the case of this system, the optical module of the present invention can be applied to the transmission unit 4, the reception unit 5, and the relay device 6.

The system shown in FIG. 1 (c) is one in which relay devices are provided in multiple stages, and a transmitter 4 and a receiver 5 are provided at both ends, respectively, and relay devices 6a and 6b are provided between them. ing. In the case of this system, the optical module of the present invention can be applied to the transmission unit 4, the reception unit 5, and the relay devices 6a and 6b.

Next, an embodiment of the optical transmission module of the present invention applied as described above will be described. Figure 2
FIG. 1 is a schematic configuration diagram showing an optical transmission module according to an embodiment of the present invention. The optical transmission module 10 has a module body 11. A first optical fiber 61 for optical transmission can be connected to the module main body 11, and functions as an output port for signal light and pumping light, a port 12 that functions as a reception port for signal light, and an input port for transmission. Port 13, a control signal to the excitation light source and a drive signal of a drive system such as an optical switch are input, a port 15 that outputs the received signal light as an electric signal to the outside, and a second optical fiber 62. And a port 16 that relays the signal light input from the port 12 and outputs the signal light as signal light.

Inside the module body 11, the port 1
An optical fiber 21 connected to the optical fiber 21 is provided, and the optical fiber 21 is provided with a WDM optical coupler 22, an optical circulator 23, and an optical switch 24 in this order. An optical fiber 25 is connected to one terminal 24a of the optical switch 24.
It is connected to the port 16 via a 10 dB optical coupler 26.

An optical fiber 27 is connected to the WDM optical coupler 22, and an excitation light source 28 is connected to the optical fiber 27. Then, the excitation light source 28
Of the excitation light is output from the port 12 via the optical fiber 27 and the optical fiber 21.

An optical switch 30 is connected to the optical circulator 23 via an optical fiber 29. An optical fiber 31 is connected to one terminal 30 a of the optical switch 30, and the optical fiber 31 is connected to the port 13. An optical fiber 32 is connected to the other terminal 30b of the optical switch 30.

An optical fiber 34 is connected to the other terminal 24b of the optical switch 24, and the optical fiber 34 is connected to one terminal 36b of the optical switch 36. An optical fiber 35 is connected to the 10 dB optical coupler 26, and the optical fiber 35 is connected to the other terminal 36a of the optical switch 36.

An optical fiber 37 is connected to the proximal end side of the optical switch 36, and an optical isolator 38, an optical coupler 39, an optical isolator 40, an EDF 41 and an optical switch 42 are provided in this order in the optical fiber 37.

An end of the optical fiber 32 is connected to one terminal 42a of the optical switch 42, and an optical fiber 45 is connected to the other terminal 42b. The optical fiber 45 has a variable wavelength filter 46 and an O / E.
The converter 47 is connected, and the electric signal output from the O / E converter 47 reaches the port 15 through the signal line 48.

The signal from the port 14 reaches the drivers 50, 51 and 52 via the interface 49. The driver 50 drives the excitation light sources 28 and 44, the driver 51 drives the optical switches 30, 36 and 42, and the driver 52 drives the variable wavelength filter 46.

The optical transmission module thus configured has various functions, and the transmission path for each function will be described below.

(1) EDF pumping FIG. 3 shows a pumping optical circuit for remote pumping an EDF. As shown in this figure, in the pumping light circuit 71,
The control signal input through the port 14 is guided to the pumping light source 28 through the interface 49 and the driver 50, the pumping light source 28 emits the pumping light, and the light is pumped from the port 12 to the external optical fiber through the optical fibers 27 and 21. Transmit light.

(2) A receiving circuit for receiving the received signal light is shown in FIG. As shown in this figure, in the receiving circuit 72, the signal light received from the port 12 is transmitted through the optical fiber 21 to the WD.
It is guided to the optical switch 24 through the M optical coupler 22 and the optical circulator 23, and further reaches the optical fiber 37 via the terminal 24b of the optical switch 24, the optical fiber 34 connected thereto, and the terminal 36b of the optical switch 36. Then, this signal light is guided by the optical fiber 37 to the optical switch 42 through the optical isolator 38, the WDM optical coupler 39, the optical isolator 40, and the EDF 41 for amplifying the signal light, and the terminal 4 of the optical switch 42.
Optical fiber 45 connected thereto via 2b
Is guided to the O / E converter 47 through the variable wavelength filter 46, is converted into an electric signal there, and the electric signal reaches the port 15 through the signal line 48 and the port 15
Is output from. The excitation of the EDF 41 is performed by the excitation light source 44, the optical fiber 43, the WDM optical coupler 39,
E via the isolator 40 and the optical fiber 37
This is performed by the excitation light reaching the DF41. The variable wavelength filter 46 has a function of removing spontaneous emission light generated in the EDF 41.

(3) A transmission circuit for transmitting the transmission signal light is shown in FIG. As shown in this figure, in the transmission circuit 73, the signal light for transmission input from the port 13 is transmitted through the optical fiber 31.
Optical switch 30 switched to terminal 30a by
To the optical circulator 23 via the optical fiber 29, and the light from the optical circulator 23 is output from the port 12 via the optical fiber 21.

Therefore, considering the above-mentioned receiving and transmitting functions, bidirectional optical transmission becomes possible by arranging the optical transmission modules 10 of this embodiment so as to face each other and connecting them with a single optical fiber.

(4) Relay FIG. 6 shows a relay circuit when this optical transmission module is used as a relay device. As shown in this figure, in the repeater circuit 74, the signal light input from the port 12 is
The optical fiber 21 guides the light to the optical switch 24 through the WDM optical coupler 22 and the optical circulator 23, and further reaches the terminal 24a of the optical switch 24 and the optical fiber 25 connected thereto, and the optical fiber 25 causes the 10 dB optical coupler 26. Through port 1
6 and the signal light is output from the port 16 to the receiving unit or another relay device.

(5) Reception at the relay point In order to receive information at the relay point, as shown in FIG. 7, the optical switch 36 is switched from the state of the terminal 36b side of FIG. 6 to the terminal 36a side and relayed. By configuring the receiving circuit 75, the optical isolators 38 and 40 provided in the optical fibers 37 and 45 and the EDF 4 are provided.
1. O / the predetermined signal light that has passed through the variable wavelength filter 46
It is guided to the E converter 47, converted into an electric signal there, and the electric signal is output from the port 15 through the signal line 48.

(6) Loopback Function Next, the loopback function for confirming the faulty section will be described. When the optical transmission module 10 of the present embodiment is used as a relay device, a failure on the transmission line can be confirmed by configuring a loopback circuit 76 that folds back a signal as shown in FIG. Specifically, in the loopback circuit 76, the signal light input from the port 12 is guided by the optical fiber 21 to the optical switch 24 through the WDM optical coupler 22 and the optical circulator 23, and further, to the optical switch 24. Terminal 24
a, via the optical fiber 25 connected to it 1
It reaches the 0 dB optical coupler 26. Since the optical switch 36 is connected to the terminal 36a side, the signal light reaching the 10 dB optical coupler 26 reaches the optical fiber 37 through the optical fiber 35 and the terminal 36a of the optical switch 36.
Optical isolator 38, WDM by optical fiber 37
It is guided to the optical switch 42 through the coupler 39, the optical isolator 40, and the EDF 41 for amplifying the signal light.
Since the optical switch is connected to the terminal 42a side, the ED
The signal light amplified by F41 reaches the optical fiber 32 through the terminal 42a. Since the optical switch 30 is connected to the terminal 30b side, the signal light transmitted by the optical fiber 32 reaches the optical circulator 23 through the optical switch 30, is guided to the port 12 by the optical fiber 21, and is output from the port 12. To be done.

Each optical switch has port 1 as described above.
4 and the drive signal input via the interface 49. However, by performing remote switching by another communication means such as a telephone or a radio, even if a large number of relay devices exist, the target relay devices can be sequentially targeted. By switching, it becomes possible to check the state of the transmission line in a very short time.

As described above, the optical transmission module 10 of the present embodiment is provided with the pumping light source 28 for pumping the remotely arranged EDF, and further as an optical circuit as a receiving section, an optical circuit as a transmitting section, and as a repeater. Since the optical circuit of FIG. 3 is included, the optical transmission module 10 alone can form a transmitting / receiving unit, a transmitting unit, a receiving unit, and a relay device for long-distance optical transmission. That is, the optical transmission module 10 can be applied without distinction among the transmitting / receiving unit, the transmitting unit, the receiving unit, and the relay device. Therefore, by using the optical transmission module 10, it is possible to increase the maintainability and expandability of the system without complicating the construction of the long-distance optical transmission system. Further, by using one kind of multi-functional optical transmission module as described above, it is not necessary to classify backup modules into a transmission unit, a reception unit, and a relay device, which is economical. Further, since it has a function as an optical receiving device that is indispensable for optical communication, that is, a function of amplifying input signal light and converting into an electric signal, it is necessary to give the function of the receiving device to other parts. Absent.

The present invention is not limited to the above embodiment and can be variously modified. For example, in the above-described embodiment, the optical isolator, the EDF for optical amplification, and the O / E converter that converts an optical signal into an electric signal are included, and these functions as an optical receiving device. Need not always be present, and the received optical information may be amplified by other components and converted into electric signals. In the above embodiment, the optical fiber is used as the optical circuit of the optical transmission module, but the optical circuit is not limited to this.
For example, each component in the optical transmission module may be directly connected to form an optical circuit. Furthermore, in actual use, the combination of switching the optical switches is not limited to the above-mentioned embodiment, and it is also possible to provide another function. Furthermore, the arrangement of the optical components such as the optical switch, the optical circulator, and the optical coupler is not limited to this embodiment.

[0038]

As described above, according to the present invention,
Since the configuration has the receiving circuit, the transmitting circuit, and the relay circuit, and also has the pumping optical circuit for pumping the remotely arranged optical amplifier, only the optical transmission module of the present invention is used for the transmitting / receiving section for optical transmission. , A transmitter, a receiver, and a relay device can be configured. Therefore, by using the optical transmission module of the present invention, there is no complexity in constructing an optical transmission system, particularly a long-distance optical transmission system,
In addition, the maintainability and expandability of the system can be improved. Further, by using one type of optical transmission module having multiple functions as described above, it is not necessary to classify backup modules into a transmitter, a receiver, and a relay device, which is extremely economical.

Furthermore, by providing the function of amplifying the input signal light and converting it into an electric signal as the receiving circuit, it is not necessary to provide the function of the receiving device to other parts, and thus the long-distance optical transmission system can be realized. The construction can be further simplified.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of an optical transmission system to which an optical transmission module of the present invention can be applied.

FIG. 2 is a schematic configuration diagram showing an optical transmission module according to an embodiment of the present invention.

FIG. 3 is a diagram for explaining a circuit when performing remote excitation of EDF using the optical transmission module of FIG.

FIG. 4 is a diagram for explaining a circuit when performing reception using the optical transmission module of FIG.

FIG. 5 is a diagram for explaining a circuit when transmitting is performed using the optical transmission module of FIG.

FIG. 6 is a diagram for explaining a circuit for relaying using the optical transmission module of FIG.

7 is a diagram for explaining a circuit when performing reception at a relay point using the optical transmission module of FIG.

FIG. 8 is a diagram for explaining a circuit when performing loopback using the optical transmission module of FIG.

[Explanation of Codes] 1a, 1b; Transmission / Reception Unit 2; Optical Fiber 3; EDF 4; Transmission Unit 5; Reception Units 6, 6a, 6b; Repeater 10; Optical Transmission Module 11; Module Main Body 12, 13, 14, 15, 16; Ports 21, 25, 27, 29, 31, 32, 34, 35, 3
7, 45; Optical fiber 22, 39; WDM optical coupler 23; Optical circulator 24, 30, 36, 42; Optical switch 26; 10 dB optical coupler 28, 44; Excitation light source 38, 40; Optical isolator 41; EDF 46; Variable wavelength Filter 47; O / E converter 48; signal line 49; interfaces 50, 51, 52; drivers 61, 62; optical fiber 71; excitation light circuit 72; reception circuit 73; transmission circuit 74; relay circuit 75; relay / reception circuit 76; Loopback circuit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04B 10/26 10/28 (72) Inventor Shoji Fujitomi 1-2-1 Shibaura, Minato-ku, Tokyo In Ocy Sea (72) Inventor Fumio Mao 1-2-1 Shibaura, Minato-ku, Tokyo F-Term in Oshi Sea Co., Ltd. (reference) 5K102 AA10 AB02 AD01 MA01 MA02 MA03 MB03 NA02

Claims (7)

[Claims] 1. An optical transmission module used in a system for transmitting optical information using an optical fiber, comprising: a module main body; and a first port provided in the module main body, to which a first optical fiber is connected. A second port provided on the module body to which a second optical fiber is connected, a third port provided on the module body for inputting transmission information, and a reception information provided on the module body. A fourth port for outputting, a receiving circuit for receiving the optical information transmitted through the first optical fiber through the first port, and outputting the received information from the fourth port, and an input for the third port A transmission circuit for transmitting the transmitted transmission information to the first optical fiber; and the second circuit for transmitting the information input from the first optical fiber.
A relay circuit for outputting to the optical fiber, a pumping optical circuit for sending pumping light to an optical amplifier provided in the first optical fiber, and an optical component group for switching an optical path to configure each circuit. Characteristic optical transmission module. 2. The receiving circuit, an optical circuit for guiding optical information through the first port, an optical amplifier for amplifying optical information guided to the optical circuit, and the amplified optical information for converting to electrical information. The optical transmission module according to claim 1, further comprising an O / E converter for converting and a signal line for guiding the electric information converted by the O / E converter to the fourth port. 3. The transmission information input from the third port is optical information, and the transmission circuit has an optical circuit that guides the transmission information input via the third port to the first port. The optical transmission module according to claim 1 or 2, which is characterized in that. 4. The optical transmission module according to claim 1, wherein the relay circuit has an optical circuit that connects the first port and the second port. . 5. The pumping light circuit has a pumping light source, a driver for driving the pumping light source, and an optical circuit for guiding the pumping light from the pumping light source to the first port. Item 5. The optical transmission module according to any one of items 4. 6. The loopback circuit for outputting the optical information input from the first port from the first port, further comprising: a loopback circuit according to claim 1. Optical transmission module. 7. The relay / reception circuit according to claim 1, further comprising a relay / reception circuit that branches the optical information transmitted through the relay circuit by the reception circuit and guides it to the fourth port. The optical transmission module according to claim 1.