KR102290902B1 - Optical module for telecommunication - Google Patents

Abstract

The present invention relates to an optical module for communication that enables optical communication in both directions. Two bidirectional optical sub-assemblies are included in one optical module for communication. Since each bidirectional optical sub-assembly has an optical path separating unit that separates optical paths of a transmitting optical signal and a receiving optical signal instead of a multiplexer or demultiplexer, the present invention is configured to enable transceiving of an optical signal with only one bidirectional optical sub-assembly.

Description

Optical module for communication {OPTICAL MODULE FOR TELECOMMUNICATION}

The present invention relates to an optical module for communication that facilitates 100 Gbps-class optical communication using a bidirectional transmission method and a PAM4 modulation method.

Currently, the 100G QSFP28 ER4 Lite transceiver is widely used as an optical module for communication to perform bidirectional optical communication over a distance of about 20 km at a speed of 100 Gbps. In general, a conventional optical module 1 for communication, such as a 100G QSFP28 ER4 Lite transceiver, is provided with a transmitter 10 and a receiver 20 as described below.

FIG. 1 is a diagram schematically showing a conventional optical module for communication, and FIG. 2 is a diagram schematically showing an optical communication network including the optical module for communication shown in FIG. 1 .

The optical communication network shown in FIG. 2 includes a plurality of optical modules for central office communication (1), a central station side network switch (2) installed on the central station side and communicatively connected to one end of the central station side communication optical module (1), the central station side A plurality of central station-side LC connectors 3 that are communicatively connected to the other end of the optical module for communication 1, a plurality of optical modules for subscriber-side communication (1'), are installed on the subscriber side, and of the optical module for subscriber-side communication (1') A subscriber-side network switch (2') communicatively connected to one end, a plurality of subscriber-side LC connectors (3') communicatively connected to the other end of the optical module for subscriber-side communication (1'), and the central office-side LC connector (3) and a network optical fiber (4) connecting the subscriber side LC connector (3).

Although FIG. 1 shows only the optical module 1 for communication at the central station of the optical communication network shown in FIG. 2, the details shown in FIG. 1 may be equally applied to the optical module 1' for communication at the subscriber side shown in FIG. have.

The optical module 1 for communication on the central station side shown in FIG. 1 includes a transmitter 10 and a receiver 20 .

The transmitting unit 10 includes a light emitting unit 11 , a plurality of transmitting lenses 12 , a multiplexer 13 , an isolator 14 , a first lens 15 , a first optical fiber 16 , and a first receptacle 17 . ) is included.

The light emitting unit 11 serves to electro-optically convert a transmission signal, and for this purpose, four EML (Electro-absorption Modulated Lasers) that output optical signals (wavelength IDs: L0, L1, L2, L3) of different wavelengths, respectively (11-1), a sub-mount 11-2 for seating the EML 11-1, and the wavelength of the optical signal emitted from the EML 11-1 under the control of a controller (not shown). It includes a thermoelectric element 11-3 fixed to a specific wavelength.

The optical signals L0, L1, L2, and L3 of different wavelengths output from the light emitting unit 11 are converted into parallel light by the transmission lens 12 and then input to the multiplexer 13 .

The multiplexer 13 bundles and outputs the optical signals L0, L1, L2, and L3 input to each channel, and the optical signal output from the multiplexer 13 is the isolator 14 and the first lens 15 ) and is incident on the first optical fiber 16 .

The optical signal incident to the first optical fiber 16 is transmitted to the receiver of the communication optical module 1' installed at the subscriber side through the network optical fiber 4 shown in FIG. Here, one side of the first receptacle 17 accommodates the first optical fiber 16 , and the other side of the first receptacle 17 receives the central office side LC connector 3 connected to the network optical fiber 4 .

The receiving unit 20 includes a light receiving unit 21 , a plurality of receiving lenses 22 , a demultiplexer 23 , a second lens 25 , a second optical fiber 26 , and a second receptacle 27 .

The light receiving unit 21 receives the received optical signal and performs photoelectric conversion. The light receiving unit 21 includes four light receiving elements 21-1 for receiving reception optical signals (wavelength IDs: L0, L1, L2, L3) of different wavelengths, and the receiving elements 21-1 receive. and a signal amplifier 21-2 for amplifying an optical signal.

The optical signal transmitted from the optical module 1' for communication on the subscriber side is emitted from the second optical fiber 26, and the optical signal emitted from the second optical fiber 26 is transformed into a parallel light by the second lens 25. It is then input to the demultiplexer 23 .

The demultiplexer 23 selectively outputs the optical signals L0, L1, L2, and L3 that are bundled together into one, and the optical signal output from the demultiplexer 23 is condensed by the receiving lens 22 and then the light receiving unit It is sent to the light receiving element 21-1 of (21). The optical signal sent to the light receiving element 21-1 may be amplified by the signal amplifier 21-2. Here, one side of the second receptacle 27 accommodates the second optical fiber 26 , and the other side of the second receptacle 27 receives the central office side LC connector 3 connected to the network optical fiber 4 .

As described above, the conventional optical module 1 for communication includes a light emitting unit 11 including four EMLs 11-1 and a light receiving unit 21 including four light receiving elements 21-1, It has 4 channels for transmitting and receiving optical signals having L0, L1, L2, and L3 wavelengths. And in the case of the conventional optical module 1 for communication, the modulation method of the transmission optical signal performed by the light emitting unit 11 is a NRZ (Non-Return-to-Zero) modulation method, and using the NRZ modulation method, It transmits and receives optical signals at high speed. That is, the conventional optical module 1 for communication transmits and receives optical signals at a total speed of 100 Gbps.

FIG. 3 is a table showing wavelength IDs and transmission/reception wavelengths used in the optical communication network of FIG. 2 .

In FIG. 3, "1Left" denotes an optical module for central station-side communication located at the leftmost among the four central station-side communication optical modules 1 located at a place indicated by "Left" in FIG. 1, and "2Left" is located in the second position from the left. The central station side communication optical module is indicated, "3Left" indicates the central station side communication optical module located 3rd from the left, and "4Left" indicates the central station side communication optical module located 4th from the left.

In FIG. 3, "1Right" denotes an optical module for subscriber-side communication located at the rightmost among the four subscriber-side communication optical modules 1' located at a place indicated by "Right" in FIG. 1, and "2Right" is second from the right. It indicates the optical module for communication on the subscriber side located, "3Right" indicates the optical module for communication on the subscriber side located 3rd from the right, and "4Right" indicates the optical module for communication on the subscriber side located 4th from the right.

In FIG. 3 , “Transmitter Optical Sub Assembly (TOSA)” refers to the transmitter 10 , and “Receiver Optical Sub Assembly (ROSA)” refers to the receiver 20 . And in FIG. 3 , L0, L1, L2, and L3 denote wavelength IDs, and “WL” denotes a wavelength of an optical signal.

For example, the optical module 1 for communication on the central station side corresponding to "1Left" is 1295.56 nm (L0), 1300.05 nm (L1), 1304.58 nm (L2) and 1309.14 nm (L3) through the light emitting unit 11 . It is possible to transmit a transmission optical signal having a wavelength. In this case, the transmission optical signal transmitted by the light emitting unit 11 is included in the multiplexer 13 included in the optical module 1 for communication on the central station side and the optical module 1' for communication on the subscriber side corresponding to “1Right”. Through the demultiplexer, it is input to the light receiving unit of the optical module 1' for communication on the subscriber side. At this time, the light receiving unit of the optical module 1' for communication on the subscriber side corresponding to "1Right" receives 1295.56 nm (L0), 1300.05 nm (L1), 1304.58 nm (L2) and 1309.14 nm (L3) as reception optical signals. .

As another example, the subscriber-side communication optical module 1' corresponding to "3Right" emits wavelengths of 1295.56 nm (L0), 1300.05 nm (L1), 1304.58 nm (L2) and 1309.14 nm (L3) through the light emitting unit. It is possible to transmit a transmit optical signal with In this case, the transmission optical signal transmitted by the light emitting unit of the optical module for communication on the subscriber side (1') is a multiplexer included in the optical module for communication on the subscriber side (1') and the optical module for communication on the central station (1) corresponding to “3Left” It is input to the light receiving unit 21 of the optical module 1 for communication on the central station side through the demultiplexer 23 included in the . At this time, the light receiving unit 21 of the optical module 1 for communication on the central station side corresponding to “3Left” inputs 1295.56 nm (L0), 1300.05 nm (L1), 1304.58 nm (L2) and 1309.14 nm (L3) as reception optical signals. will receive

As described above, the conventional optical module 1 for communication includes a multiplexer 13 that bundles and outputs optical signals L0, L1, L2, and L3 input to each channel, and optical signals L0, L1, It includes a demultiplexer 23 that selectively outputs L2 and L3.

For this reason, in order to transmit and receive data between the four optical communication modules 1 installed on the central station side and the four communication optical modules 1' installed on the subscriber side, the four transmission ( Tx_A) network optical fibers 4 and 4 receiving (Rx_B) network optical fibers 4, a total of 8 network optical fibers 4 are required.

Additionally, if data is transmitted/received between the 8 communication optical modules 1 installed on the central station side and the 8 communication optical modules 1' installed on the subscriber side, 8 transmission ( Tx_A) network optical fibers 4 and 8 receiving (Rx_B) network optical fibers 4, a total of 16 network optical fibers 4 are required.

The optical communication method as shown in FIG. 2 is referred to as a point-to-point method. However, in the point-to-point optical communication network shown in FIG. 2, when n optical modules for communication are installed on the central station side and the subscriber side, respectively, a total of 2n network optical fibers are required for transmission and reception of optical signals between the central station and the subscriber. Therefore, the cost of building a network is high. In addition, as shown in Fig. 1, in the case of a conventional optical module for communication, four EMLs and four light receiving elements are used to perform bidirectional optical communication at a speed of 100 Gbps, which is a manufacturing cost of an optical module for communication and a network construction cost. cause to increase

Publication No. 2011-0011123 (published date: 2011.02.08)

The present invention has been devised to solve the above problems, and an object of the present invention is to provide an optical module for communication capable of reducing network construction cost compared to the prior art.

Another object of the present invention is to provide an optical module for communication capable of performing two-way optical communication at the same speed as that of a conventional optical module for communication, but reducing the number of elements compared to a conventional optical module for communication.

In order to achieve the above object, an optical module for communication according to the present invention includes a first light emitting unit for transmitting a first transmission optical signal, a first light receiving unit for receiving a first reception optical signal, and the first light emitting unit a first port receiving the first transmission optical signal transmitted from a second port for receiving and a third port for outputting the first reception optical signal input through the second port toward the first light receiving unit, the optical path of the first transmission optical signal and the first reception A first optical path separating unit for separating an optical path of an optical signal, and a first optical fiber to which a first transmission optical signal output through the second port is incident, and a first optical fiber to emit a first reception optical signal toward the second port a first bidirectional optical sub-assembly comprising; and a second light emitting unit for transmitting a second transmission optical signal, a second light receiving unit for receiving a second reception optical signal, and a fourth port for receiving the second transmission optical signal transmitted from the second light emitting unit; a fifth port for outputting the second transmission optical signal input through the fourth port and receiving the second reception optical signal to be received by the second light receiving unit; a second optical path separating unit having a sixth port for outputting a received optical signal toward the second light receiving unit to separate an optical path of the second transmission optical signal and an optical path of the second received optical signal; and a second bidirectional optical sub-assembly including a second optical fiber to which a second transmission optical signal output through the fifth port is incident, and to which a second reception optical signal is emitted toward the fifth port.

The first light emitting unit transmits the first transmit optical signal modulated through a 4-level pulse amplitude modulation method, and the second light emitting unit transmits the second transmit optical signal modulated through the 4-level pulse amplitude modulation method, , the first light receiving unit receives the first reception optical signal modulated through the 4-level pulse amplitude modulation method, and the second light receiving unit receives the second reception optical signal modulated through the 4-level pulse amplitude modulation method can receive

The first transmission optical signal transmitted by the first light emitting unit and the first reception optical signal received by the first light receiving unit have different wavelengths within the same channel, and the second transmission signal transmitted by the second light emitting unit The optical signal and the second reception optical signal received by the second light receiving unit may have different wavelengths in the same channel as the channel.

The first optical path separating unit may be a first circulator, the first transmission optical signal is input to the first port of the first circulator, and the second optical signal is input to the second port of the first circulator. A first transmission optical signal may be output, the first reception optical signal may be input, and the first reception optical signal may be output to the third port of the first circulator. Here, the first light receiving unit further includes a first bandpass filter that passes only a wavelength band corresponding to the first received optical signal to be received by the first light receiving unit and blocks a wavelength band other than the wavelength band corresponding to the first received optical signal. The optical signal input to the third port of the first circulator may be blocked from being transmitted to the first port of the first circulator.

The second optical path separating unit may be a second circulator, the second transmission optical signal is input to the fourth port of the second circulator, and the fifth port of the second circulator is the A second transmission optical signal may be output, the second reception optical signal may be input, and the second reception optical signal may be output to the sixth port of the second circulator. Here, a second band-pass filter unit that passes only a wavelength band corresponding to the second reception optical signal to be received by the second light-receiving unit and blocks a wavelength band other than the wavelength band corresponding to the second reception optical signal is further included. The optical signal input to the sixth port of the second circulator may be blocked from being transmitted to the fourth port of the second circulator.

The first optical path splitter may be a first optical rotator, the first transmission optical signal is input to the first port of the first optical rotator, and the second optical signal is input to the second port of the first optical rotator. A first transmit optical signal may be output and the first receive optical signal may be input, and the first receive optical signal may be output to the third port of the first optical rotator. Here, the first light receiving unit further includes a first bandpass filter that passes only a wavelength band corresponding to the first received optical signal to be received by the first light receiving unit and blocks a wavelength band other than the wavelength band corresponding to the first received optical signal. The optical signal input to the third port of the first optical rotator may be blocked from being transmitted to the first port of the first optical rotator.

The second optical path splitter may be a second optical rotator, the second transmission optical signal is input to the fourth port of the second optical rotator, and the fifth port of the second optical rotator includes the A second transmit optical signal may be output and the second receive optical signal may be input, and the second receive optical signal may be output to the sixth port of the second optical rotator. Here, a second band-pass filter unit that passes only a wavelength band corresponding to the second reception optical signal to be received by the second light-receiving unit and blocks a wavelength band other than the wavelength band corresponding to the second reception optical signal is further included. The optical signal input to the sixth port of the second optical rotator may be blocked from being transmitted to the fourth port of the second optical rotator.

The first optical path separating unit may be a first interleaver filter, and the first port of the first interleaver filter may transmit only an optical signal of a wavelength band corresponding to a first period, and the first interleaver filter of the first interleaver filter Port 2 transmits optical signals in all bands, and in the third port of the first interleaver filter, only optical signals in the wavelength band corresponding to the second period are transmitted, and the wavelength band corresponding to the first period and The wavelength bands corresponding to the second period may be different. Here, the first light receiving unit further includes a first bandpass filter that passes only a wavelength band corresponding to the first received optical signal to be received by the first light receiving unit and blocks a wavelength band other than the wavelength band corresponding to the first received optical signal. The first transmit optical signal transmitted from the first light emitting unit is included in a wavelength band corresponding to the first period, and the first received light signal received from the first light receiving unit is included in the second period It may be included in the wavelength band corresponding to .

The second optical path separator may be a second interleaver filter, and the fourth port of the second interleaver filter may transmit only an optical signal of a wavelength band corresponding to a third period, and the second interleaver filter of the second interleaver filter Optical signals of all bands are transmitted through port 5, and only optical signals of the wavelength band corresponding to the fourth period are transmitted through the sixth port of the second interleaver filter, and the wavelength band corresponding to the third period and The wavelength bands corresponding to the fourth period may be different. Here, a second band-pass filter unit that passes only a wavelength band corresponding to the second reception optical signal to be received by the second light-receiving unit and blocks a wavelength band other than the wavelength band corresponding to the second reception optical signal is further included. The second transmit optical signal transmitted from the second light emitting unit is included in a wavelength band corresponding to the third period, and the second received light signal received from the second light receiving unit is included in the fourth period It may be included in the wavelength band corresponding to .

In the conventional optical module for communication, optical signals having a plurality of different wavelengths (for example, wavelengths under CWDM or LAN WDM conditions) are bundled by one multiplexer and then transmitted, and also optical signals having a plurality of different wavelengths are converted into one single multiplexer. Since it is received after being distributed by the demultiplexer, each of the transmitter and receiver has no choice but to use one network optical fiber exclusively. That is, when n communication optical modules are installed on the central station side and the subscriber side, respectively, a total of 2n network optical fibers are required for transmitting and receiving optical signals between the central station and the subscriber.

On the other hand, in the present invention, two bidirectional optical sub-assemblies are included in one optical module for communication, and each of the bi-directional optical sub-assemblies has a multiplexer (or demultiplexer) instead of a multiplexer (or demultiplexer), and optical paths of a transmission optical signal and a reception optical signal Since the optical path separation unit for separating the optical signals is provided, it is possible to transmit and receive optical signals with only one bidirectional optical sub-assembly.

According to the present invention, even when n communication optical modules are installed on the central station side and the subscriber side, as long as a multiplexer-demultiplexer is provided outside the communication optical module, only one network optical fiber is used for the central station Transmission and reception of optical signals between a subscriber and an optical signal are possible, and thus, according to the present invention, it is possible to reduce the network construction cost compared to the conventional optical module for communication.

In addition, the present invention is configured such that the first light emitting unit transmits the first transmission optical signal through the 4-level pulse amplitude modulation scheme, and the second light emitting unit also transmits the second transmission optical signal through the 4-level pulse amplitude modulation scheme. The first light receiving unit receives the first reception optical signal modulated through the 4-level pulse amplitude modulation method, and the second light receiving unit also receives the second reception optical signal modulated through the 4-level pulse amplitude modulation method. Consists of.

According to the present invention, a device included in the light emitting unit (ie, the first light emitting unit and the second light emitting unit) while performing bidirectional optical communication at the same speed (eg, 100 Gbps) as the conventional optical module for communication The number of and the number of elements included in the light receiving unit (ie, the first light receiving unit and the second light receiving unit) can be reduced compared to the conventional optical module for communication, and thus, according to the present invention, the manufacturing cost of the optical module for communication can be reduced.

1 is a diagram schematically showing a conventional optical module for communication.
FIG. 2 is a diagram schematically illustrating an optical communication network including the optical module for communication shown in FIG. 1 .
FIG. 3 is a table showing wavelength IDs and transmission/reception wavelengths used in the optical communication network of FIG. 2 .
4 is a diagram schematically showing an optical module for communication according to a first embodiment of the present invention.
FIG. 5 is a diagram schematically illustrating an optical communication network including the optical module for communication shown in FIG. 4 .
FIG. 6 is a table showing wavelength IDs and transmission/reception wavelengths used in the optical communication network shown in FIG. 5 .
7 is a diagram schematically showing an optical module for communication according to a second embodiment of the present invention.
FIG. 8A is a diagram illustrating an optical signal inputtable through a first port of the first interleaver filter shown in FIG. 7 according to wavelength;
FIG. 8B is a diagram illustrating an optical signal outputable to a third port of the first interleaver filter shown in FIG. 7 according to wavelength.
FIG. 9A is a diagram illustrating an optical signal inputtable through a fourth port of the second interleaver filter shown in FIG. 7 according to wavelength.
FIG. 9B is a diagram illustrating an optical signal outputable to a sixth port of the second interleaver filter shown in FIG. 7 according to wavelength.

Hereinafter, an optical module for communication according to the present invention will be described in detail with reference to the accompanying drawings. The accompanying drawings are provided as examples in order to sufficiently convey the spirit of the present invention to those skilled in the art, and the present invention is not limited to the drawings presented below and may be embodied in other forms.

4 is a diagram schematically showing an optical module for communication according to a first embodiment of the present invention. The optical module 1000 for communication according to the first embodiment of the present invention includes a first bidirectional optical subassembly 100 and a second bidirectional optical subassembly 200 . Although FIG. 4 shows only the optical module 1000 for communication on the central station side, the details shown in FIG. 4 may be equally applied to the optical module 1000' for communication on the subscriber side, which will be described later.

The first bidirectional light subassembly 100 includes a first light emitting unit 110 , a first light receiving unit 120 , a first optical path separating unit 130 , and a first optical fiber 140 .

The first light emitting unit 110 serves to electro-optically convert the first transmission optical signal and transmit it. The first light emitting unit 110 may include a first electro-absorption modulated laser (EML) 111 and a first sub-mount 112 on which the first EML 111 is mounted.

The first EML 111 may emit a first transmit optical signal, and may modulate the first transmit optical signal in a form suitable for high-speed transmission. More specifically, the first EML 111 modulates an optical signal to be emitted through a 4-level pulse amplitude modulation (PAM4) method, and then uses the modulated optical signal as the first transmission optical signal. send The PAM4 modulation method is a modulation method capable of transmitting 2 bits per symbol, and is twice as fast as the conventional NRZ modulation method. Accordingly, when the first light emitting unit 110 transmits the first transmission optical signal modulated through the PAM4 modulation method, the number of elements included in the light emitting unit may be reduced compared to the conventional optical module for communication.

That is, in the case of the conventional optical module for communication using the NRZ modulation method, in order to perform bidirectional optical communication at a speed of 100 Gbps, a total of four EMLs each capable of transmitting light at a speed of 25 Gbps are required. However, the first light emitting unit 110 transmits the optical signal modulated through the PAM4 modulation method as a first transmission optical signal, and the second light emitting unit 210, which will be described later, also transmits the optical signal modulated through the PAM4 modulation method to the second light. When transmitting as a transmission optical signal, since light can be transmitted at a speed of 50 Gbps per one EML, only two EMLs 111 and 211 in total need be used.

The first light emitting unit 110 may include a first thermistor 113, a first thermoelectric element 114, and a first control unit (not shown) to fix the wavelength of the first transmission optical signal within a relatively narrow wavelength range. have.

The first thermistor 113 is positioned in contact with or adjacent to the first EML 111 to sense the temperature of the first EML 111 , and the first controller controls the temperature sensed by the first thermistor 113 . to control the first thermoelectric element 114 . The first thermoelectric element 114 fixes the wavelength of the optical signal emitted from the first EML 111 to a specific wavelength under the control of the first controller.

The first light receiving unit 120 serves to photoelectrically convert and receive the first received optical signal. To this end, the first light receiving unit 120 may be composed of only the first light receiving element (eg, a photodiode) 121 , or may include the first light receiving element 121 and the first signal amplifier 122 . . The first light receiving element 121 of the first light receiving unit 120 receives the optical signal modulated through the 4-level pulse amplitude modulation method as the first received optical signal, and the first signal amplifier 122 includes the first light receiving element ( 121) amplifies the first received optical signal received. Here, a linear TIA may be used as the first signal amplifier 122 for smooth reception of the PAM4 signal.

When the first light emitting unit of the optical module 1000' for communication at the subscriber side transmits the first transmission optical signal, the first light receiving unit 120 of the optical module 1000 for communication at the central station transmits the first transmission optical signal to the first light emitting unit. Receive as a receive optical signal. At this time, when the first light emitting unit of the optical module 1000' for communication on the subscriber side transmits the first transmission optical signal modulated through the 4-level pulse amplitude modulation method, the number of elements included in the light receiving unit compared to the conventional optical module for communication can reduce

That is, in the case of a conventional optical module for communication using the NRZ modulation method, in order to perform bidirectional optical communication at a speed of 100 Gbps, a total of four EMLs each capable of transmitting light at a speed of 25 Gbps are required. You will need 4 in total. However, the first light emitting unit of the optical module 1000' for communication on the subscriber side transmits the optical signal modulated through the PAM4 modulation method as the first transmission optical signal, and the second light emitting unit of the optical module 1000' for communication on the subscriber side also transmits the optical signal modulated through the PAM4 modulation method. When the optical signal modulated through the PAM4 modulation method is transmitted as the second transmission optical signal, the optical module for communication according to the present invention includes a total of two light receiving elements ( 121, 221) only.

The first transmission optical signal transmitted from the first light emitting unit 110 passes through the first lens 161 , the first isolator 170 , the first optical path separation unit 130 , and the second lens 162 . It may be incident on the optical fiber 140 . Here, the first optical fiber 140 may be accommodated at one side of the first receptacle 150 , and the central station side LC connector 3000 connected to the central station side optical fiber 4000 may be accommodated at the other side of the first receptacle 150 . can

The first lens 161 converts the first transmit optical signal transmitted from the first light emitting unit 110 into a parallel light form, and the first isolator 170 converts the first transmit optical signal to the first light emitting unit 110 . ) to be transmitted only in a direction toward the first optical path separating unit 130 . In addition, the second lens 162 condenses the first transmission optical signal output from the first optical path splitter 130 and changes the first reception optical signal emitted from the first optical fiber 140 into a parallel light form. .

In the central station side communication optical module 1000, the first transmission optical signal incident on the first optical fiber 140 passes through the first optical fiber of the subscriber side communication optical module 1000' to the subscriber side communication optical module 1000'. is received as a first received light signal by the first light receiving unit of the And the first transmission optical signal transmitted from the first light emitting unit of the optical module 1000' for communication on the subscriber side is transmitted to the first light receiving unit 120 via the first optical fiber 140 of the optical module 1000 for communication on the central station side. 1 Received as an optical signal.

The first optical path separating unit 130 outputs a first port receiving the first transmission optical signal transmitted from the first light emitting unit 110 and the first transmission optical signal input through the first port, a second port for receiving a first reception optical signal to be received by the first light receiving unit 120 , and outputting the first reception optical signal received through the second port toward the first light receiving unit 120 . A third port is provided to separate the optical path of the first transmission optical signal and the optical path of the first reception optical signal.

As the first optical path splitter 130 has three ports as described above, the first transmit optical path and the first receive optical path may be completely separated, and thus the first transmit optical signal and the first receive optical signal The inter-guard band can be narrowed down to sub-nanometers, and there is no fear of loss of optical power, so that the link budget of the optical transmission network can be sufficiently secured.

In the first embodiment of the present invention, a bulk type first circulator 131 is used as the first optical path separating unit 130 . The first circulator 131 is an element that separates the optical path according to the traveling direction of light, and has three ports 131-1, 131-2, and 131-3 as shown in FIG. 4 .

A first transmission optical signal transmitted from the first light emitting unit 110 may be input to the first port 131-1 of the first circulator 131 . Thereafter, the first transmission optical signal input to the first port 131-1 may be transmitted only to the second port 131-2, and the first transmission optical signal transmitted to the second port 131-2 may be It is output toward the first optical fiber 140 . Accordingly, the first transmission optical signal output through the second port 131 - 2 is incident on the first optical fiber 140 , and the first transmission optical signal incident on the first optical fiber 140 is transmitted to the subscriber side. It is received as a first reception optical signal by the first light receiving unit provided on the subscriber side via the installed first optical fiber.

Meanwhile, the first transmission optical signal transmitted from the first light emitting unit installed on the subscriber side is transmitted as a first reception optical signal to the first optical fiber 140 installed on the central station side. The first optical fiber 140 emits the first reception optical signal toward the second port 131 - 2 , and the first reception optical signal is finally received by the first light receiving unit 120 .

The second port 131-2 may receive a first reception optical signal that is emitted from the first optical fiber 140 to be received by the first light receiving unit 120, and is input to the second port 131-2. The first received optical signal may be transmitted only to the third port 131-3. The third port 131-3 outputs the first reception optical signal input through the second port 131-2 toward the first light receiving unit 120, and the first light receiving unit 120 receives the first reception signal. An optical signal may be received and demodulated into an electrical signal.

As described above, in the first embodiment of the present invention, the first transmission optical signal input from the first light emitting unit 110 to the first port 131-1 is transmitted only to the second port 131-2, and the first optical fiber The first received optical signal input from 140 to the second port 131-2 is configured to be transmitted only to the third port 131-3. That is, in the first embodiment of the present invention, the first transmit optical path and the first receive optical path are completely separated through the three ports 131-1, 131-2, and 131-3 according to the propagation direction of light. As a result, the guard band between the first transmission optical signal and the first reception optical signal can be narrowed down to sub-nanometers, and there is no fear of loss of optical power, so that the link budget of the optical transmission network can be sufficiently secured.

On the other hand, an optical signal (a transmission optical signal, a reception optical signal, or a signal corresponding to other noise) input to the third port 131-3 of the first circulator 131 is transmitted to the first port 131-1 It is preferable in terms of improving the reception efficiency of the first light receiving unit 120 to configure the first circulator 131 so as to block it.

Furthermore, between the first circulator 131 and the first light receiving unit 120, only a wavelength band corresponding to the first received optical signal to be received by the first light receiving unit 120 passes, and the first received optical signal It is preferable to prevent the crosstalk phenomenon by providing the first bandpass filter 180 that blocks wavelength bands other than the corresponding wavelength band. In this way, it is possible to more reliably secure a guard band between the first transmit optical signal and the first receive optical signal.

The first received optical signal output through the third port 131-3 of the first circulator 131 may be focused by the third lens 163 through the first band-pass filter 180 . Thereafter, the first reception light signal focused by the third lens 163 is received by the first light receiving unit 120 .

Meanwhile, the second bidirectional optical subassembly 200 includes a second light emitting unit 210 , a second light receiving unit 220 , a second optical path separating unit 230 , and a second optical fiber 240 .

The second light emitting unit 210 serves to electro-optically convert and transmit the second transmission optical signal. The second light emitting unit 210 may include a second EML 211 and a second sub-mount 212 on which the second EML 211 is mounted.

The second EML 211 may emit a second transmit optical signal, and may modulate the second transmit optical signal into a form suitable for high-speed transmission. More specifically, the second EML 211 modulates an optical signal to be emitted using a 4-level pulse amplitude modulation (PAM4) method, and then transmits the modulated optical signal as a second transmission optical signal. The PAM4 modulation method is a modulation method capable of transmitting 2 bits per symbol, and is twice as fast as the conventional NRZ modulation method. Accordingly, when the second light emitting unit 210 transmits the second transmit optical signal modulated through the PAM4 modulation method, as described above, the number of elements included in the light emitting unit is reduced compared to the conventional optical module for communication. can

The second light emitting unit 210 may include a second thermistor 213 , a second thermoelectric element 214 , and a second controller (not shown) to fix the wavelength of the second transmission optical signal within a relatively narrow wavelength range. have.

The second thermistor 213 is positioned in contact with or adjacent to the second EML 211 to sense the temperature of the second EML 211 , and the second control unit controls the temperature sensed by the second thermistor 213 . to control the second thermoelectric element 214 . The second thermoelectric element 214 fixes the wavelength of the optical signal emitted from the second EML 211 to a specific wavelength under the control of the second controller.

The second light receiving unit 220 serves to photoelectrically convert and receive the second received optical signal. To this end, the second light receiving unit 220 may be composed of only the second light receiving element (eg, a photodiode) 221 , or may include the second light receiving element 221 and the second signal amplifier 222 . . The second light receiving element 221 of the second light receiving unit 220 receives the optical signal modulated through the 4-level pulse amplitude modulation method as the second receiving optical signal, and the second signal amplifier 222 includes the second light receiving element ( 221) amplifies the received second received optical signal. Here, as the second signal amplifier 122 , a linear TIA may be used for smooth reception of the PAM4 signal.

When the second light emitting unit of the optical module 1000' for communication at the subscriber side transmits the second transmission optical signal, the second light receiving unit 220 of the optical module 1000 for communication at the central station transmits the second transmission optical signal to the second light source. Receive as a receive optical signal. At this time, when the optical signal modulated through the 4-level pulse amplitude modulation method is transmitted as the second transmission optical signal by the second light emitting unit of the subscriber-side optical module 1000' for communication, as described above, the conventional optical module for communication As compared to , the number of elements included in the light receiving unit can be reduced.

The second transmission optical signal transmitted from the second light emitting unit 210 passes through the fourth lens 261 , the second isolator 270 , the second optical path separating unit 230 , and the fifth lens 262 to the second It may be incident on the optical fiber 240 . Here, the second optical fiber 240 may be accommodated at one side of the second receptacle 250 , and the subscriber side LC connector 3000 ′ connected to the subscriber side optical fiber 4000 ′ is provided at the other side of the second receptacle 250 . can be accepted.

The fourth lens 261 converts the second transmit optical signal transmitted from the second light emitting unit 210 into a parallel light form, and the second isolator 270 converts the second transmit optical signal to the second light emitting unit 210 . ) to transmit only in a direction toward the second optical path separating unit 230 . In addition, the fifth lens 262 condenses the second transmission optical signal output from the second optical path splitter 230 and changes the second reception optical signal emitted from the second optical fiber 240 into a parallel light form. .

In the central station side communication optical module 1000, the second transmission optical signal incident on the second optical fiber 240 passes through the second optical fiber of the subscriber side communication optical module 1000' to the subscriber side communication optical module 1000'. is received as a second reception optical signal in the second light receiving unit of the . And the second transmission optical signal transmitted from the second light emitting unit of the optical module 1000' for communication on the subscriber side is transmitted to the second light receiving unit 220 via the second optical fiber 240 of the optical module 1000 for communication on the central station side. 2 Received as an optical signal.

The second optical path separating unit 230 outputs a fourth port receiving the second transmission optical signal transmitted from the second light emitting unit 210 and the second transmission optical signal input through the fourth port, a fifth port for receiving a second reception optical signal to be received by the second light receiving unit 220, and outputting the second reception optical signal received through the fifth port toward the second light receiving unit 220 A sixth port serves to separate the optical path of the second transmission optical signal and the optical path of the second reception optical signal.

As the second optical path splitter 230 is provided with three ports as described above, the second transmit optical path and the second receive optical path may be completely separated, and thus the second transmit optical signal and the second receive optical signal The inter-guard band can be narrowed down to sub-nanometers, and there is no fear of loss of optical power, so that the link budget of the optical transmission network can be sufficiently secured.

In the first embodiment of the present invention, a bulk-type second circulator 231 is used as the second optical path separating unit 230 . The second circulator 231 is an element that separates the optical path according to the traveling direction of light, and has three ports 231-1, 231-2, and 231-3 as shown in FIG. 4 .

A second transmission optical signal transmitted from the second light emitting unit 210 may be input to the fourth port 231-1 of the second circulator 231 . Thereafter, the second transmit optical signal input to the fourth port 231-1 may be transmitted only to the fifth port 231-2, and the second transmit optical signal transmitted to the fifth port 231-2 is It is output toward the second optical fiber 240 . Accordingly, the second transmission optical signal output through the fifth port 231 - 2 is incident on the second optical fiber 240 , and the second transmission optical signal incident on the second optical fiber 240 is transmitted to the subscriber side. It is received as a second reception optical signal by a second light receiving unit provided on the subscriber side via the installed second optical fiber.

Meanwhile, the second transmission optical signal transmitted from the second light emitting unit installed on the subscriber side is transmitted as a second reception optical signal to the second optical fiber 240 installed on the central station side. The second optical fiber 240 emits the second reception optical signal toward the fifth port 231 - 2 , and the second reception optical signal is finally received by the second light receiving unit 220 .

The fifth port 231 - 2 may receive a second received optical signal that is emitted from the second optical fiber 240 to be received by the second light receiving unit 220 , and is input to the fifth port 231 - 2 . The second received optical signal may be transmitted only to the sixth port 231-3. The sixth port 231-3 outputs the second reception optical signal input through the fifth port 231-2 toward the second light receiving unit 220, and the second light receiving unit 220 receives the second reception signal. An optical signal may be received and demodulated into an electrical signal.

As described above, in the first embodiment of the present invention, the second transmission optical signal input from the second light emitting unit 210 to the fourth port 231-1 is transmitted only to the fifth port 231-2, and the second optical fiber The second reception optical signal input from 240 to the fifth port 231-2 is configured to be transmitted only to the third port 231-3. That is, in the first embodiment of the present invention, the second transmit optical path and the second receive optical path are completely separated through the three ports 231-1, 231-2, and 231-3 according to the propagation direction of light. As a result, the guard band between the second transmission optical signal and the second reception optical signal can be narrowed down to sub-nanometers, and there is no fear of loss of optical power, so that the link budget of the optical transmission network can be sufficiently secured.

On the other hand, an optical signal (transmission optical signal, reception optical signal, or other signal corresponding to noise) input to the sixth port 231-3 of the second circulator 231 is transmitted to the fourth port 231-1 It is preferable to configure the second circulator 231 so as to block the occurrence of the second circulator 231 from the viewpoint of improving the reception efficiency of the second light receiving unit 220 .

Furthermore, only a wavelength band corresponding to the second received optical signal to be received by the second light receiving unit 220 passes between the second circulator 231 and the second light receiving unit 220 , and the second received optical signal It is preferable to prevent the crosstalk phenomenon by providing the second bandpass filter 280 for blocking wavelength bands other than the corresponding wavelength band, and by doing so, the second transmit optical signal and the second receive optical signal more reliably It is possible to secure an inter-guard band.

The second reception optical signal output through the sixth port 231-3 of the second circulator 231 may be focused by the sixth lens 263 through the second band pass filter 280 . Thereafter, the second reception light signal focused by the sixth lens 263 is received by the second light receiving unit 220 .

Although the case in which the circulators 131 and 231 are used as the optical path separating units 130 and 230 has been described above, the optical rotator 131 instead of the circulators 131 and 231 as the optical path separating units 130 and 230 has been described. ', 231') can also be used. The optical rotators 131' and 231' are devices that separate the optical path according to the traveling direction of the light, like the circulators 131 and 231. As shown in FIG. 4, each optical rotator 131', 231' is It has 3 ports.

The first transmission optical signal transmitted from the first light emitting unit 110 may be input to the first port 131 ′ - 1 of the first optical rotator 131 ′. Thereafter, the first transmission optical signal input to the first port 131'-1 may be transmitted only to the second port 131'-2, and the first transmission optical signal transmitted to the second port 131'-2 may be transmitted. The optical signal is output toward the first optical fiber 140 . Accordingly, the first transmission optical signal output through the second port 131'-2 is incident on the first optical fiber 140, and the first transmission optical signal incident on the first optical fiber 140 is transmitted to the subscriber side. It is received as a reception optical signal by the first light receiving unit installed on the subscriber side via the first optical fiber installed in the .

Meanwhile, the first transmission optical signal transmitted from the first light emitting unit installed on the subscriber side is transmitted as a first reception optical signal to the first optical fiber 140 installed on the central station side. The first optical fiber 140 emits the first reception optical signal toward the second port 131 ′ - 2 , and the first reception optical signal is finally received by the first light receiving unit 120 .

The second port 131'-2 may receive a first reception optical signal that is emitted from the first optical fiber 140 and is to be received by the first light receiving unit 120, and the second port 131'-2 may receive an input. The first received optical signal input to , may be transmitted only to the third port 131'-3. The third port 131'-3 outputs the first received optical signal input through the second port 131'-2 toward the first light receiving unit 120, and the first light receiving unit 120 is 1 It can receive a received optical signal and demodulate it into an electrical signal.

As such, even when the first optical rotator 131 ′ is used instead of the first circulator 131 as the first optical path separating unit 130 , the first port 131 ′ - 1 in the first light emitting unit 110 . The first transmit optical signal input to the , is transmitted only to the second port 131'-2, and the first received optical signal input from the first optical fiber 140 to the second port 131'-2 is transmitted to the third port. It is configured to transmit only (131'-3). That is, even in the modified example of the first embodiment, the first transmit optical path and the first receive optical path are completely separated according to the propagation direction of light through the three ports 131'-1, 131-2', and 131-3'. . As a result, the guard band between the first transmission optical signal and the first reception optical signal can be narrowed down to sub-nanometers, and there is no fear of loss of optical power, so that the link budget of the optical transmission network can be sufficiently secured.

On the other hand, an optical signal (a transmission optical signal, a reception optical signal, or a signal corresponding to other noise) input to the third port 131'-3 of the first optical rotator 131' is transmitted to the first port 131'-1. ), it is preferable in terms of improving the reception efficiency of the first light receiving unit 120 to configure the first light rotator 131 ′ to block the transmission.

Furthermore, only a wavelength band corresponding to the first received optical signal to be received by the first light receiving unit 120 passes between the first optical rotator 131 ′ and the first light receiving unit 120 , and the first received optical signal It is preferable to prevent the crosstalk phenomenon by providing the first bandpass filter 180 that blocks the wavelength band other than the wavelength band corresponding to It becomes possible to secure a guard band between signals.

The first reception optical signal output through the third port 131 ′ - 3 of the first optical rotator 131 ′ may be focused by the third lens 163 through the first band pass filter 180 . . Thereafter, the first reception light signal focused by the third lens 163 is received by the first light receiving unit 120 .

Meanwhile, a second transmission optical signal transmitted from the second light emitting unit 210 may be input to the fourth port 231 ′ - 1 of the second optical rotator 231 ′. Thereafter, the second transmission optical signal input to the fourth port 231'-1 may be transmitted only to the fifth port 231'-2, and the second transmission optical signal transmitted to the fifth port 231'-2 may be transmitted. The optical signal is output toward the second optical fiber 240 . Accordingly, the second transmission optical signal output through the fifth port 231'-2 is incident on the second optical fiber 240, and the second transmission optical signal incident on the second optical fiber 240 is transmitted to the subscriber side. It is received as a reception optical signal by a second light receiving unit installed on the subscriber side via a second optical fiber installed in the .

The second transmission optical signal transmitted from the second light emitting unit installed on the subscriber side is transmitted as a second reception optical signal to the second optical fiber 240 installed on the central station side. The second optical fiber 240 emits the second reception optical signal toward the fifth port 231 ′ - 2 , and the second reception optical signal is finally received by the second light receiving unit 220 .

The fifth port 231'-2 may receive a second reception optical signal that is emitted from the second optical fiber 240 and is to be received by the second light receiving unit 220, and the fifth port 231'-2 The second reception optical signal input as , may be transmitted only to the sixth port 231'-3. The sixth port 231'-3 outputs the second received optical signal input through the fifth port 231'-2 toward the second light receiving unit 220, and the second light receiving unit 220 is 2 It can receive the received optical signal and demodulate it into an electrical signal.

As such, even when the second optical rotator 231 ′ is used instead of the second circulator 231 as the second optical path separating unit 230 , the fourth port 231 ′-1 in the second light emitting unit 210 is The second transmit optical signal inputted to is transmitted only to the fifth port 231'-2, and the second received optical signal input from the second optical fiber 240 to the fifth port 231'-2 is transmitted to the sixth port. It is configured to be transmitted only to (231'-3). That is, even in the modified example of the first embodiment, the second transmit optical path and the second receive optical path are completely separated according to the propagation direction of light through the three ports 231'-1, 231-2', 231-3'. . As a result, the guard band between the second transmission optical signal and the second reception optical signal can be narrowed down to sub-nanometers, and there is no fear of loss of optical power, so that the link budget of the optical transmission network can be sufficiently secured.

On the other hand, the optical signal (transmission optical signal, reception optical signal, or other signal corresponding to noise) input to the sixth port 231'-3 of the second optical rotator 231' is transmitted to the fourth port 231'-1. ), it is preferable to configure the second light rotator 231 ′ to block transmission to the second light receiving unit 220 in terms of improving the reception efficiency of the second light receiving unit 220 .

Furthermore, only a wavelength band corresponding to the second reception optical signal to be received by the second light receiving unit 220 passes between the second optical rotator 231 ′ and the second light receiving unit 220 , and the second reception optical signal It is preferable to prevent the crosstalk phenomenon by providing the second bandpass filter 280 that blocks the wavelength band other than the wavelength band corresponding to It becomes possible to secure a guard band between signals.

The second reception optical signal output through the sixth port 231 ′ - 3 of the second optical rotator 231 ′ may be focused by the sixth lens 263 through the second band pass filter 280 . . Thereafter, the second reception light signal focused by the sixth lens 263 is received by the second light receiving unit 220 .

FIG. 5 is a diagram schematically illustrating an optical communication network including the optical module for communication shown in FIG. 4 .

The optical communication network shown in FIG. 5 includes a plurality of optical modules 1000 for communication at the central office side, and a central station side network switch 2000 that is installed on the side of the central station and is communicatively connected to one end of the optical module 1000 for communication at the central station side, the central station side. A plurality of central station-side LC connectors 3000 that are communicatively connected to the other end of the optical module for communication 1000, the first optical fibers 140 of the central station-side communication optical module 1000 through the central office-side LC connector 3000, or the first 2 It includes a plurality of central office-side optical fibers 4000 communicatively connected to the optical fibers 240 , and a central office-side multiplexer-demultiplexer 5000 communicatively connected to the central office-side optical fibers 4000 .

In addition, the optical communication network shown in FIG. 5 includes a plurality of optical modules for subscriber-side communication 1000', a subscriber-side network switch 2000' installed on the subscriber side and communicatively connected to one end of the optical module 1000' for subscriber-side communication. ), a plurality of subscriber-side LC connectors 3000' that are communicatively connected to the other end of the subscriber-side communication optical module 1000', and the subscriber-side communication optical module 1000' through the subscriber-side LC connector 3000') and a plurality of subscriber-side optical fibers 4000' communicatively connected to the first optical fiber or the second optical fiber of

In addition, the optical communication network shown in FIG. 5 includes a network optical fiber 6000 communicatively connected to the central office-side multiplexer-demultiplexer 5000 and the subscriber-side multiplexer-demultiplexer 5000', respectively.

Under the control of the central station side network switch 2000, each of the plurality of central station side communication optical modules 1000 transmits and receives a transmission optical signal and a reception optical signal having different wavelengths within the same channel. In addition, under the control of the subscriber-side network switch 2000', each of the plurality of subscriber-side communication optical modules 1000' transmits and receives a transmission optical signal and a reception optical signal having different wavelengths in the same channel.

FIG. 6 is a table showing wavelength IDs and transmission/reception wavelengths used in the optical communication network shown in FIG. 5 .

In FIG. 6, "1Left" denotes an optical module for central station-side communication located at the leftmost among the four central station-side communication optical modules 1000 located at a place indicated by "Left" in FIG. 5, and "2Left" is located in the second position from the left. The central station side communication optical module is indicated, "3Left" indicates the central station side communication optical module located 3rd from the left, and "4Left" indicates the central station side communication optical module located 4th from the left.

In FIG. 6, "1Right" indicates an optical module for subscriber-side communication located at the rightmost among the four optical modules for subscriber-side communication 1000' located at a place indicated by "Right" in FIG. 5, and "2Right" is second from the right. It indicates the optical module for communication on the subscriber side located, "3Right" indicates the optical module for communication on the subscriber side located 3rd from the right, and "4Right" indicates the optical module for communication on the subscriber side located 4th from the right.

In FIG. 6, "BIDI" means bidirectional, and the first bidirectional optical subassembly 100 and the second bidirectional optical subassembly 200 included in the optical module 1000 for communication of FIG. 4 transmit optical signals in both directions, respectively. means that it can transmit and receive

That is, in the case of the conventional optical module 1 for communication of FIG. 1 , the transmitter 10 can only transmit an optical signal, and the receiver 20 can only receive the optical signal, and the transmitter 10 and the receiver (20) is not capable of transmitting and receiving optical signals in both directions, respectively. In contrast, the optical module 1000 for communication according to the present invention includes a first bidirectional optical subassembly 100 and a second bidirectional optical subassembly 200 capable of bidirectionally transmitting and receiving optical signals. It is different from the optical module (1).

6, S0, S1, S2, S3, L0, L1, L2, and L3 denote channels, S0L, S0H, S1L, S1H, S2L, S2H, S3L, S3H, L0L, L0H, L1L, L1H, L2L, L2H, L3L, and L3H represent wavelength IDs. And in FIG. 6, "WL" means the wavelength of an optical signal transmitted or received through each channel.

For example, the SO channel has a wavelength of 1273.55 nm as a center wavelength, and has a wavelength band of ±1 nm based on this. That is, the S0 channel has a wavelength band of 1272.55 nm or more and 1274.55 nm or less.

In this case, the optical module 1000 for communication on the central station side corresponding to “1Left” transmits a first transmission optical signal having a wavelength of 1273.55Lnm belonging to the S0 channel through the first light emitting unit 110, and the first light receiving unit 120 ), the first reception optical signal having a wavelength of 1273.55Hnm belonging to the S0 channel may be received. Here, 1273.55 nm is the center wavelength of the S0 channel, "L(Low)" means a wavelength in a band smaller than the center wavelength, and "H(High)" means a wavelength in a band larger than the center wavelength. For example, "1273.55Lnm" may mean a wavelength between 1272.55nm and 1273.55nm, and "1273.55Hnm" may mean a wavelength between 1273.55nm and 1274.55nm.

The subscriber-side communication optical module 1000 ′ corresponding to “1Right” transmits a first transmission optical signal having a wavelength of 1273.55Hnm belonging to the S0 channel through the first light emitting unit, and transmits the S0 channel through the first light receiving unit. It is possible to receive a first reception optical signal having a wavelength of 1273.55Lnm belonging to.

As described above, in the optical module 1000 for communication according to the present invention, the first transmission optical signal transmitted by the first light emitting unit 110 and the first reception optical signal received by the first light receiving unit 120 are transmitted through the same channel (eg, For example, in the S0 channel), optical signals may be transmitted and received with different wavelengths.

In addition, the S1 channel has a wavelength of 1277.89 nm as a center wavelength, and has a wavelength band of ±1 nm based on this. That is, the S1 channel has a wavelength band of 1276.89 nm or more and 1278.89 nm or less.

In this case, the central station side communication optical module 1000 corresponding to "1Left" transmits a second transmission optical signal having a wavelength of 1277.89Lnm belonging to the S1 channel through the second light emitting unit 210, and the second light receiving unit 220 ), a second reception optical signal having a wavelength of 1277.89Hnm belonging to the S1 channel may be received. Here, 1277.89 nm is the center wavelength of the S1 channel, "L(Low)" means a wavelength in a band smaller than the center wavelength, and "H(High)" means a wavelength in a band larger than the center wavelength. For example, “1277.89Lnm” may mean a wavelength between 1276.89nm and 1277.89nm, and “1277.89Hnm” may mean a wavelength between 1277.89nm and 1278.89nm.

In addition, the subscriber-side communication optical module 1000 ′ corresponding to “1Right” transmits a second transmission optical signal having a wavelength of 1277.89Hnm belonging to the S1 channel through a second light emitting unit, and through the second light receiving unit, the S1 channel A first reception optical signal having a wavelength of 1277.89Lnm belonging to can be received.

As described above, in the optical module 1000 for communication according to the present invention, the second transmission optical signal transmitted by the second light emitting unit 210 and the second reception optical signal received by the second light receiving unit 220 are transmitted to the above-described channel ( For example, optical signals having different wavelengths may be transmitted and received in the same channel (eg, S1 channel) different from the S0 channel.

Meanwhile, FIG. 7 is a diagram schematically illustrating an optical module for communication according to a second embodiment of the present invention. The optical module 1000 for communication according to the second embodiment of the present invention shown in FIG. 7 is also the first bidirectional optical subassembly 100 and the second bidirectional optical module, like the optical module for communication according to the first embodiment of the present invention described above. It includes a sub-assembly 200 .

In the optical module for communication according to the first embodiment of the present invention, optical circulators 131 and 231 or optical rotators 131' and 231' were used as the optical path separation units 130 and 230, but the second In the optical module for communication according to the embodiment, there is a difference only in that the interleaver filters 132 and 232 are used as the optical path separation units 130 and 230, and accordingly, the difference will be mainly described below. .

FIG. 7 shows an optical module for communication using bulk-type interleaver filters 132 and 232 as optical path separation units 130 and 230 . The interleaver filters 132 and 232 are devices that separate optical paths according to wavelengths, and have periodic transmission characteristics according to wavelengths. The wavelength band of the optical signal that can be transmitted from each port 132-1, 132-2, 132-3, 232-1, 232-2, 232-3 of the interleaver filter 132, 232 is the interleaver filter 132, 232. ) is determined by the internal elements constituting it.

FIG. 8A is a diagram illustrating an optical signal inputtable through a first port of the first interleaver filter shown in FIG. 7 according to wavelength; As shown in FIG. 8A , in the first port 132-1 of the first interleaver filter 132, an optical signal of a wavelength band corresponding to the first period, for example, SOL, S2L, S0L, S2L, Only optical signals of wavelength bands corresponding to L0L and L2L may be transmitted.

Optical signals of all bands may be transmitted through the second port 132 - 2 of the first interleaver filter 132 .

8B is a diagram illustrating an optical signal outputable to a third port of the first interleaver filter shown in FIG. 7 according to wavelength. As shown in FIG. 8B , in the third port 132-3 of the first interleaver filter 132, an optical signal of a wavelength band corresponding to the second period, for example, S0H, S2H, Only optical signals of wavelength bands corresponding to L0H and L2H may be transmitted. As can be seen from FIGS. 8A and 8B , the wavelength band corresponding to the first period and the wavelength band corresponding to the second period are different.

When the first optical path separating unit 130 is implemented as the first interleaver filter 132 , the first transmission optical signal transmitted from the first light emitting unit 110 is included in the wavelength band corresponding to the first period. can For example, the first light emitting unit 110 emits an optical signal having a specific wavelength band among the wavelength bands corresponding to the first cycle shown in FIG. 8A (eg, an optical signal having a wavelength band corresponding to SOL). It can be transmitted as a first transmission optical signal toward the first port 132-1.

The first port 132-1 of the first interleaver filter 132 may receive the first transmit optical signal transmitted from the first light emitting unit 110, and the first port 132-1 of the first interleaver filter 132 may receive the first transmit optical signal. The first transmission optical signal may be transmitted to the second port 132 - 2 . As described above, optical signals of all bands can be transmitted through the second port 132 - 2 , and the first transmission optical signal transmitted to the second port 132 - 2 is directed toward the first optical fiber 140 . is output Accordingly, the first transmission optical signal output through the second port 132-2 is incident on the first optical fiber 140, and the first transmission optical signal incident on the first optical fiber 140 is transmitted to the subscriber side. It may be received as a first reception optical signal by the first light receiving unit installed on the subscriber side via the installed first optical fiber.

Meanwhile, the first transmission optical signal transmitted from the first light emitting unit installed on the subscriber side is transmitted as a first reception optical signal to the first optical fiber 140 installed on the central station side. The first optical fiber 140 emits the first reception optical signal toward the second port 132 - 2 , and the first reception optical signal is finally received by the first light receiving unit 120 .

More specifically, the second port 132-2 is output from the first optical fiber 140 and may receive a first reception optical signal to be received by the first light receiving unit 120, and the second port 132- The first received optical signal input to 2) may be transmitted to the third port 132 - 3 . The third port 132-3 outputs the first reception optical signal input through the second port 132-2 toward the first light receiving unit 120, and the first light receiving unit 120 receives the first reception signal. An optical signal may be received and demodulated into an electrical signal.

In this case, the first reception optical signal received by the first light receiving unit 120 is preferably included in the wavelength band corresponding to the second period. For example, the first light receiving unit 120 first transmits an optical signal having a specific wavelength band among the wavelength bands corresponding to the second cycle shown in FIG. 8B (eg, an optical signal having a wavelength band corresponding to SOH). It can be received as a reception optical signal.

More specifically, referring to FIGS. 6, 8A, and 8B , the S0 channel has a wavelength of 1273.55 nm as a center wavelength, and has a wavelength band of ±1 nm based on this. That is, the S0 channel has a wavelength band of 1272.55 nm or more and 1274.55 nm or less.

In this case, the central station side communication optical module 1000 corresponding to “1Left” transmits a first transmission optical signal having a wavelength of 1273.55Lnm belonging to the S0 channel through the first light emitting unit 110, and the first light receiving unit ( 120), a first reception optical signal having a wavelength of 1273.55 Hnm belonging to the S0 channel may be received. Here, "1273.55Lnm" means a wavelength between 1272.55nm and 1273.55nm as shown in FIG. 8A, and "1273.55Hnm" may mean a wavelength between 1273.55nm and 1274.55nm as shown in FIG. 8B.

In addition, the subscriber-side communication optical module 1000 ′ corresponding to “1Right” transmits a first transmit optical signal having a wavelength between 1273.55 nm and 1274.55 nm belonging to the S0 channel through the first light emitting unit, and transmits the first light receiving unit. Through the S0 channel, a first reception optical signal having a wavelength between 1272.55 nm and 1273.55 nm may be received.

As described above, in the optical module 1000 for communication according to the present invention, the first transmission optical signal transmitted by the first light emitting unit 110 and the first reception optical signal received by the first light receiving unit 120 are transmitted through the same channel (eg, For example, it is possible to transmit and receive optical signals with different wavelengths within the S0 channel).

In the second embodiment of the present invention, only the transmit optical signal included in the wavelength band corresponding to the first period is transmitted through the first port 132-1 of the first interleaver filter 132, and the second port 132 In -2), optical signals of all bands are transmitted, and only the received optical signals included in the wavelength band corresponding to the second period are transmitted through the third port 132-3.

That is, in the second embodiment of the present invention, the first interleaver filter 132 having three ports 132-1, 132-2, 132-3 having different transmission characteristics according to wavelength bands is used, and thus Due to this, the first transmit optical path and the first receive optical path may be completely separated. As a result, the guard band between the first transmission optical signal and the first reception optical signal can be narrowed down to sub-nanometers, and there is no fear of loss of optical power, so that the link budget of the optical transmission network can be sufficiently secured.

Only a wavelength band corresponding to the first received optical signal to be received by the first light receiving unit 120 passes between the first interleaver filter 132 and the first light receiving unit 120 , and a wavelength corresponding to the first received optical signal is passed. It is preferable to prevent the crosstalk phenomenon by providing the first bandpass filter 180 that blocks the wavelength bands other than the band, and by doing so, the guard band between the first transmit optical signal and the first receive optical signal is more reliably can be obtained.

The first reception optical signal output through the third port 132 - 3 of the first interleaver filter 132 may be focused by the third lens 163 through the first band pass filter 180 . Thereafter, the first reception light signal focused by the third lens 163 is received by the first light receiving unit 120 .

Meanwhile, FIG. 9A is a diagram illustrating an optical signal inputted to a fourth port of the second interleaver filter shown in FIG. 7 according to wavelength. As shown in FIG. 9A , in the fourth port 232-1 of the second interleaver filter 232, an optical signal of a wavelength band corresponding to the third period, for example, S1L, S3L, S1L, S3L, Only optical signals of wavelength bands corresponding to L1L and L3L may be transmitted.

Optical signals of all bands may be transmitted through the fifth port 232 - 2 of the second interleaver filter 232 .

FIG. 9B is a diagram illustrating an optical signal outputable to a sixth port of the second interleaver filter shown in FIG. 7 according to wavelength. 9B, in the sixth port 232-3 of the second interleaver filter 232, an optical signal of a wavelength band corresponding to the fourth period, for example, S1H, S3H, S1H, S3H, Only optical signals of wavelength bands corresponding to L1H and L3H may be transmitted. As can be seen from FIGS. 9A and 9B , the wavelength band corresponding to the third period and the wavelength band corresponding to the fourth period are different. Furthermore, all wavelength bands corresponding to the first period, the second period, the third period, and the fourth period are different.

When the second optical path separation unit 230 is implemented as the second interleaver filter 232 , the second transmission optical signal transmitted from the second light emitting unit 210 is included in the wavelength band corresponding to the third period. can For example, the second light emitting unit 210 emits an optical signal (eg, an optical signal in a wavelength band corresponding to S1L) having any specific wavelength band among the wavelength bands corresponding to the third period shown in FIG. 9A . 4 may be transmitted as a second transmission optical signal toward the port 232-1.

The fourth port 232-1 of the second interleaver filter 232 may receive the second transmit optical signal transmitted from the second light emitting unit 210, and the fourth port 232-1 is inputted to the fourth port 232-1. The second transmission optical signal may be transmitted to the fifth port 232 - 2 . As described above, optical signals of all bands can be transmitted through the fifth port 232 - 2 , and the second transmission optical signal transmitted to the fifth port 232 - 2 is directed toward the second optical fiber 240 . is output Accordingly, the second transmission optical signal output through the fifth port 232-2 is incident on the second optical fiber 240, and the second transmission optical signal incident on the second optical fiber 240 is transmitted to the subscriber side. It may be received as a second reception optical signal by a second light receiving unit installed on the subscriber side via the installed second optical fiber.

On the other hand, the second transmission optical signal transmitted from the second light emitting unit installed on the subscriber side is transmitted as a second reception optical signal to the second optical fiber 240 installed on the central station side. The second optical fiber 240 emits the second reception optical signal toward the fifth port 232 - 2 , and the second reception optical signal is finally received by the second light receiving unit 220 .

More specifically, the fifth port 232-2 is output from the second optical fiber 240 and may receive a second reception optical signal to be received by the second light receiving unit 220, and the fifth port 232- The second reception optical signal input to 2) may be transmitted to the sixth port 232 - 3 . The sixth port 232-3 outputs a second reception optical signal input through the fifth port 232-2 toward the second light receiving unit 220, and the second light receiving unit 220 receives the second reception signal. An optical signal may be received and demodulated into an electrical signal.

In this case, the second reception optical signal received by the second light receiving unit 220 is preferably included in the wavelength band corresponding to the fourth period. For example, the second light receiving unit 220 transmits an optical signal (eg, an optical signal in a wavelength band corresponding to S1H) having a specific wavelength band among the wavelength bands corresponding to the fourth cycle shown in FIG. 9B . It can be received as a reception optical signal.

More specifically, referring to FIGS. 6, 9A and 9B , the S1 channel has a wavelength of 1277.89 nm as a center wavelength, and has a wavelength band of ±1 nm based on this. That is, the S0 channel has a wavelength band of 1276.89 nm or more and 1278.89 nm or less.

In this case, the central station side communication optical module 1000 corresponding to "1Left" transmits a second transmission optical signal having a wavelength of 1277.89Lnm belonging to the S1 channel through the second light emitting unit 210, and the second light receiving unit ( 220), a second reception optical signal having a wavelength of 1277.89Hnm belonging to the S1 channel may be received. Here, "1277.89Lnm" means a wavelength between 1276.89nm and 1277.89nm as shown in FIG. 9A, and "1277.89Hnm" may mean a wavelength between 1277.89nm and 1278.89nm as shown in FIG. 9B.

In addition, the subscriber-side communication optical module 1000 ′ corresponding to “1Right” transmits a second transmission optical signal having a wavelength between 1277.89 nm and 1278.89 nm belonging to the S1 channel through the second light emitting unit, and includes a second light receiving unit. Through the S1 channel, a second reception optical signal having a wavelength between 1276.89 nm and 1277.89 nm may be received.

As described above, in the optical module 1000 for communication according to the present invention, the second transmission optical signal transmitted by the second light emitting unit 210 and the second reception optical signal received by the second light receiving unit 220 are transmitted through the same channel (eg, For example, in the S0 channel), optical signals may be transmitted and received with different wavelengths.

In the second embodiment of the present invention, only the transmit optical signal included in the wavelength band corresponding to the third period is transmitted through the fourth port 232-1 of the second interleaver filter 232, and the fifth port 232 In -2), optical signals of all bands are transmitted, and only the received optical signals included in the wavelength band corresponding to the fourth period are transmitted through the sixth port 232-3.

That is, in the second embodiment of the present invention, a second interleaver filter 232 having three ports 232-1, 232-2, 232-3 having different transmission characteristics according to wavelength bands is used, and thus Due to this, the second transmit optical path and the second receive optical path may be completely separated. As a result, the guard band between the second transmission optical signal and the second reception optical signal can be narrowed down to sub-nanometers, and there is no fear of loss of optical power, so that the link budget of the optical transmission network can be sufficiently secured.

Only a wavelength band corresponding to the second received optical signal to be received by the second light receiving unit 220 passes between the second interleaver filter 232 and the second light receiving unit 220 , and a wavelength corresponding to the second received optical signal is passed. It is preferable to prevent the crosstalk phenomenon by providing a second bandpass filter 280 that blocks out wavelength bands other than the band, and by doing so, the guard band between the second transmission optical signal and the second reception optical signal is more reliable. can be obtained.

The second reception optical signal output through the sixth port 232 - 3 of the second interleaver filter 232 may be focused by the sixth lens 263 through the second band pass filter 280 . Thereafter, the second reception light signal focused by the sixth lens 263 is received by the second light receiving unit 220 .

As described above, although the present invention has been described with reference to the limited embodiments and drawings, the present invention is not limited to the above embodiments, and various modifications and variations can be made from these descriptions by those skilled in the art to which the present invention pertains. possible. Therefore, the technical spirit of the present invention should be understood only by the claims, and all equivalents or equivalent modifications thereof will fall within the scope of the technical spirit of the present invention.

100: first bidirectional light sub-assembly 110: first light emitting part
120: first light receiving unit 130: first light path separating unit
131: first circulator 131': first optical rotator
132: first interleaver filter 140: first optical fiber
150: first receptacle 160: first signal amplifier
180: first isolator 190: first band-pass filter
200: second bidirectional light sub-assembly 210: second light emitting unit
220: second light receiving unit 230: second light path separating unit
231: second circulator 231': second optical rotator
232: second interleaver filter 240: second optical fiber
250: second receptacle 260: second signal amplifier
280: second isolator 290: second bandpass filter
1000: optical module for communication

Claims (14)

a first light emitting unit for transmitting a first transmission optical signal;
a first light receiving unit for receiving the first received optical signal;
a first port for receiving the first transmission optical signal transmitted from the first light emitting unit; a second port for receiving a reception optical signal, and a third port for outputting the first reception optical signal received through the second port toward the first light receiving unit, the optical path of the first transmission optical signal and a first optical path separating unit separating an optical path of the first received optical signal;
a first bidirectional optical subassembly including a first optical fiber to which a first transmission optical signal outputted through the second port is incident and a first reception optical signal is emitted toward the second port; and
a second light emitting unit for transmitting a second transmission optical signal;
a second light receiving unit for receiving a second received light signal;
a fourth port for receiving the second transmit optical signal transmitted from the second light emitting unit; A fifth port for receiving a reception optical signal and a sixth port for outputting the second reception optical signal input through the fifth port toward the second light receiving unit, the optical path of the second transmission optical signal and a second optical path separating unit separating an optical path of the second received optical signal;
A second bidirectional optical subassembly including a second optical fiber to which a second transmission optical signal output through the fifth port is incident, and a second optical fiber for emitting a second reception optical signal toward the fifth port; .
According to claim 1,
The first transmission optical signal transmitted by the first light emitting unit and the first reception optical signal received by the first light receiving unit have different wavelengths in the same channel;
The second transmission optical signal transmitted by the second light emitting unit and the second reception optical signal received by the second light receiving unit have different wavelengths in the same channel different from the channel. .
According to claim 1,
The first optical path separation unit is a first circulator,
The first transmit optical signal is input to the first port of the first circulator, the first transmit optical signal is output to the second port of the first circulator, and the first receive optical signal is The optical module for communication, characterized in that the first received optical signal is output to the third port of the first circulator.
4. The method of claim 3,
and a first band-pass filter unit for passing only a wavelength band corresponding to the first reception optical signal to be received by the first light receiving unit, and blocking wavelength bands other than the wavelength band corresponding to the first reception optical signal,
The optical module for communication, characterized in that the transmission of the optical signal input to the third port of the first circulator to the first port of the first circulator is blocked.
According to claim 1,
The second optical path separation unit is a second circulator,
The second transmit optical signal is input to the fourth port of the second circulator, the second transmit optical signal is output to the fifth port of the second circulator, and the second receive optical signal is is input, and the second reception optical signal is output to the sixth port of the second circulator.
6. The method of claim 5,
Further comprising a second band-pass filter unit that passes only a wavelength band corresponding to the second reception optical signal to be received by the second light-receiving unit, and blocks wavelength bands other than the wavelength band corresponding to the second reception optical signal,
The optical module for communication, characterized in that the transmission of the optical signal input to the sixth port of the second circulator to the fourth port of the second circulator is blocked.
According to claim 1,
The first optical path separation unit is a first optical rotator,
The first transmit optical signal is input to the first port of the first optical rotator, the first transmit optical signal is output to the second port of the first optical rotator, and the first receive optical signal is The optical module for communication, characterized in that the first received optical signal is output to the third port of the first optical rotator.
8. The method of claim 7,
and a first band-pass filter unit for passing only a wavelength band corresponding to the first reception optical signal to be received by the first light receiving unit, and blocking wavelength bands other than the wavelength band corresponding to the first reception optical signal,
The optical module for communication, characterized in that the optical signal input to the third port of the first optical rotator is blocked from being transmitted to the first port of the first optical rotator.
According to claim 1,
The second optical path separating unit is a second optical rotator,
The second transmit optical signal is input to the fourth port of the second optical rotator, the second transmit optical signal is output to the fifth port of the second optical rotator, and the second receive optical signal is The optical module for communication, characterized in that the second reception optical signal is output to the sixth port of the second optical rotator.
10. The method of claim 9,
Further comprising a second band-pass filter unit that passes only a wavelength band corresponding to the second reception optical signal to be received by the second light-receiving unit, and blocks wavelength bands other than the wavelength band corresponding to the second reception optical signal,
The optical module for communication, characterized in that the optical signal input to the sixth port of the second optical rotator is blocked from being transmitted to the fourth port of the second optical rotator.
According to claim 1,
The first optical path separating unit is a first interleaver filter,
The first port of the first interleaver filter transmits only the optical signal of the wavelength band corresponding to the first period, and the second port of the first interleaver filter transmits the optical signal of all bands; 1, the third port of the interleaver filter can transmit only the optical signal of the wavelength band corresponding to the second period,
The optical module for communication, characterized in that the wavelength band corresponding to the first period and the wavelength band corresponding to the second period are different.
12. The method of claim 11,
and a first band-pass filter unit for passing only a wavelength band corresponding to the first reception optical signal to be received by the first light receiving unit, and blocking wavelength bands other than the wavelength band corresponding to the first reception optical signal,
The first transmission optical signal transmitted from the first light emitting unit is included in a wavelength band corresponding to the first period, and the first reception optical signal received by the first light receiving unit has a wavelength corresponding to the second period. Optical module for communication, characterized in that included in the band.
According to claim 1,
The second optical path separating unit is a second interleaver filter,
The fourth port of the second interleaver filter transmits only the optical signal of the wavelength band corresponding to the third period, and the fifth port of the second interleaver filter transmits the optical signal of all bands, 2 In the sixth port of the interleaver filter, only the optical signal of the wavelength band corresponding to the fourth period can be transmitted,
The optical module for communication, characterized in that the wavelength band corresponding to the third period and the wavelength band corresponding to the fourth period are different.
14. The method of claim 13,
Further comprising a second band-pass filter unit that passes only a wavelength band corresponding to the second reception optical signal to be received by the second light-receiving unit, and blocks wavelength bands other than the wavelength band corresponding to the second reception optical signal,
The second transmit optical signal transmitted from the second light emitting unit is included in a wavelength band corresponding to the third period, and the second received optical signal received by the second light receiving unit has a wavelength corresponding to the fourth period Optical module for communication, characterized in that included in the band.

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