CN104320179A - Point of tangency of tangent ring remote node device in wavelength division multiplexing passive optical network system - Google Patents

Abstract

The invention relates to a tangent ring tangent point remote node device in a wavelength division multiplexing passive optical network system, belonging to the technical field of optical fiber communication. The tangent ring tangent point remote node device in the wavelength division multiplexing passive optical network system of the present invention includes a first optical coupler for dividing optical signals into three paths and an arrayed waveguide for connecting with an optical network unit ONU grating AWG, the input end of the first optical coupler is connected to the main ring fiber through an optical switch, one output end of the first optical coupler is connected to the arrayed waveguide grating AWG, and the other two transmission branches are respectively passed through the corresponding optical ring The switch is connected to the main ring fiber and the sub-ring fiber. The present invention realizes the clockwise or counterclockwise transmission of signals on the main ring and sub-rings to the remote nodes of each main ring and sub-rings through the combination of optical switch connection, on-off optical switch and optical circulator, thereby realizing the protection and protection of nodes at all levels of the network. Network scale expansion.

Description

Tangent ring tangent point remote node device in wavelength division multiplexing passive optical network system

technical field

The invention relates to a tangent ring tangent point remote node device in a wavelength division multiplexing passive optical network system, belonging to the technical field of optical fiber communication.

Background technique

Wavelength division multiplexing passive optical network (WDM-PON) technology can upgrade the system bandwidth by increasing the number of wavelengths carried by a single optical fiber without changing the physical equipment of the network, greatly improve the network transmission capacity, and realize virtual Point-to-point transmission, and each user uses a dedicated wavelength allocated by the network for information transmission, and does not share information between users, thereby effectively preventing information leakage, with better security, and has broad application prospects in the field of optical access networks , is considered to be the final choice of fiber-to-the-home in the future. The current research on WDM-PON is mainly based on the type of static wavelength allocation. The wavelength in the RN is fixed to the optical network unit ONU side. When the user demand changes, the dynamic scheduling of the wavelength inside the system cannot be realized through adjustment. Therefore, when users change or increase or decrease, it brings inconvenience to the bandwidth reallocation of the system. At the same time, the WDM-PON system topology is mainly based on basic topologies such as star and tree. When a fault occurs, the network system of the above topology cannot find a new transmission route and automatic transmission route for the interrupted service in a short period of time. If there is no recovery solution, the transmission will fail and the reliability of the system will be affected.

Contents of the invention

The purpose of the present invention is to provide a tangent ring tangent point remote node device in a wavelength division multiplexing passive optical network system to solve the problem that the current wavelength division multiplexing passive optical network system is difficult to expand due to its topology and low reliability issues.

The technical solution of the present invention is: a tangent ring tangent point remote node device in a wavelength division multiplexing passive optical network system, the tangent point remote node device includes an optical splitter for dividing optical signals into three paths and the arrayed waveguide grating AWG used to connect with the optical network unit ONU, the input end of the optical splitter is connected to the main ring fiber through an optical switch, one output end of the optical splitter is connected to the arrayed waveguide grating AWG, and the other two The output ends are respectively connected to the main ring fiber and the sub-ring fiber through corresponding optical circulators or optical couplers.

At least one output branch of the three output ends of the optical splitter is provided with a wavelength blocking blocker for filtering signals that do not belong to the required wavelength of the optical splitter.

Two parallel optical circulators are arranged on the transmission branch between the optical splitter and the sub-ring fiber, and the first ports of the two parallel optical circulators pass through the second optical coupler and the optical splitter The output terminals of the optical circulator are connected to each other, and the second ports are respectively connected to the sub-ring optical fibers through corresponding optical switches. An on-off optical switch is connected in series between the first port of one optical circulator and the second optical coupler.

A second optical circulator is arranged between the first optical coupler and the arrayed waveguide grating AWG, the first port of the second optical circulator is connected to the output end of the first optical coupler, and the second port of the optical circulator Connected to the arrayed waveguide grating AWG.

The optical splitter is a first optical coupler, and the input end of the first optical coupler is connected to the optical switch through the first optical circulator.

The optical splitter includes a first coarse wavelength division multiplexer CWDM and a first optical coupler, the input end of the first coarse wavelength division multiplexer CWDM is connected to an optical switch through a first optical circulator, and the optical signal is The band is divided into two paths, one path is used to connect with the main ring fiber, the other path is connected to the first optical coupler, the first optical coupler is divided into two paths according to the power, one path is connected to the arrayed waveguide grating AWG, and the other path is used to connect to sub-ring fiber.

A third optical circulator is arranged on the output branch connected to the main ring fiber, the first port of the optical circulator is connected to the output end of the first optical coupler, and the second port is connected to the main ring fiber through an optical switch .

A third optical coupler is arranged on the output branch between the first coarse wavelength division multiplexer CWDM and the main ring fiber, and the input end of the third optical coupler is connected to the output end of the first coarse wavelength division multiplexer CWDM The output end of the third optical coupler is connected to the main ring fiber through an optical switch.

The beneficial effects of the present invention are: the tangent ring tangent point remote node device in the wavelength division multiplexing passive optical network system of the present invention includes a first optical coupler for dividing optical signals into three paths and a first optical coupler for connecting with optical The arrayed waveguide grating AWG connected to the network unit ONU, the input end of the first optical coupler is connected to the main ring fiber through the optical switch, one output end of the first optical coupler is connected to the arrayed waveguide grating AWG, and the other two transmission branches The paths are respectively connected to the main ring fiber and the sub-ring fiber through corresponding optical circulators. The present invention realizes the clockwise or counterclockwise transmission of signals on the main ring and sub-rings to reach the remote nodes of each main ring and sub-rings through the combination of the optical switch connection state, the on-off optical switch and the optical circulator, thereby realizing the protection of nodes at all levels of the network and network expansion.

Description of drawings

1 is a structural diagram of a remote node device at a tangent ring tangency point in a wavelength division multiplexing passive optical network system in Embodiment 1 of the present invention;

2 is a structural diagram of a remote node device at a tangent ring tangency point in a wavelength division multiplexing passive optical network system in Embodiment 2 of the present invention;

3 is a structural diagram of a remote node device at a tangent ring tangency point in a wavelength division multiplexing passive optical network system in Embodiment 3 of the present invention;

Fig. 4 is a structural diagram of a wavelength division multiplexing passive optical network system based on a single fiber;

Fig. 5 is a structural diagram of a wavelength division multiplexing passive optical network system based on dual fibers.

Detailed ways

The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

The tangent ring tangent point remote node device in the wavelength division multiplexing passive optical network system of the present invention is suitable for a passive optical network system with a tangent ring structure. The passive optical network system is composed of a tangent ring structure. The main ring is formed by the optical line terminal OLT29 connecting M remote nodes RN _a 31, 32, 1, 34, and 35 of the main ring through a single-mode optical fiber, that is, the main ring feeder fiber, and the sub-ring is formed by a remote node on the main ring. The point is formed by connecting the sub-ring feeder fiber with N sub-ring remote nodes RN _b 36, 37, 38, 39, 40 through single-mode fiber, and each main ring remote node RN _a 31, 32, 34 on the main ring , 35 are respectively connected to q ONUs through distribution fibers, and each sub-ring remote node RN _b 36, 37, 38, 39, 40 is connected to q ONUs through distribution fibers. Here, depending on the selection of the remote node at the tangent point, the single-mode optical fiber on the main ring and the sub-ring can be one or two, as shown in Figure 4 and Figure 5, the wavelength division multiplexing passive optical fiber of the present invention The remote node device in the network system includes a first optical coupler 8 for dividing optical signals into three paths and an arrayed waveguide grating AWG21 for connecting to an optical network unit ONU23. The input end of the first optical coupler 8 passes through the optical The switch is connected to the main ring fiber, one output branch of the first optical coupler 8 is connected to the arrayed waveguide grating AWG, and the other two output branches are respectively connected to the main ring fiber and the sub-ring fiber through corresponding optical circulators. The composition and working method of the tangent ring tangent point remote node device in the wavelength division multiplexing passive optical network system of the present invention will be described below in conjunction with specific structural diagrams.

Embodiment one

In this embodiment, the wavelength division multiplexing passive optical network system where the remote node device of the tangent ring tangent point is located is shown in Figure 4. The network system is composed of two ring tangent structures, wherein the main ring is composed of an optical line terminal OLT29 M remote nodes RN _a 31, 32, 34 and 35 of the main ring are connected through a single-mode fiber, that is, the feeder fiber ₄₁ of the main ring. Sub-ring feeder fiber 43 is connected with N sub-ring remote nodes RN _b 36, 37, 39 and 40 to form, and each main-ring remote node RN _a on the main ring is connected to q optical network units through distributed optical fibers. Each sub-ring remote node RN _b on the ring is connected to q optical network units through distributed optical fibers.

The tangent ring tangent point remote node device RN _m 1 in the wavelength division multiplexing passive optical network system in this embodiment is shown in Figure 1, including a 2×2 optical switch 2 and an on-off optical switch 13. 2 wavelength blockers WB11, 12, the first to fifth optical circulators 3, 4, 5, 6, 7, the first to third optical couplers 8, 9, 10 and 1 1×k Arrayed Waveguide Grating AWG21. The input end of the first optical coupler 8 is connected to the main ring optical fiber feeder through the first optical circulator 3 and the 2×2 optical switch 2 . The first optical coupler 8 divides the optical signal into three paths, the first branch is the sub-ring output branch, and the branch includes the first optical wavelength blocker WB11, the second optical coupler 9, and the third optical coupler 10 , the third optical circulator 5 and the fourth optical circulator 6, the input end of the third optical coupler 10 is connected with an output end of the first optical coupler 8 through the first optical wavelength blocker WB11, the third optical coupling The two output terminals of the device 10 are respectively connected to the third optical circulator 5 and connected to the first port of the fourth optical circulator 6 through the on-off optical switch 13, the third optical circulator 5 and the fourth optical circulator 6 The second port is respectively connected to the two directions of the sub-ring feeder fiber, the on-off optical switch 13 is connected in series between the output end of the third optical coupler 10 and the first port of the fourth optical circulator 6, the third optical The third port of the circulator 5 and the fourth optical circulator 6 are respectively connected to the two input ends of the second optical coupler 9, and the output end of the second optical coupler 9 is connected to the first port of the first optical circulator 3 ; The second branch is an output branch of the optical network unit ONU23, which includes a second optical circulator 4 and a 1*k arrayed waveguide grating AWG21, the first port of the second optical circulator 4 is connected to the first optical An output end of the coupler 8 is connected, the second port of the second optical circulator 4 is connected with the arrayed waveguide grating AWG21, the third port of the second optical circulator 4 is connected with an input end of the second optical coupler 9, and the array The waveguide grating AWG21 is connected to q optical network units ONU23 through the distributed optical fiber 22, each optical network unit ONU includes an optical coupler 24, a receiver RX25 and a reflective semiconductor optical amplifier RSOA26, in the optical network unit ONU23 The downlink signal is sent to the optical receiver RX25 and the reflective semiconductor optical amplifier RSOA26 respectively through the optical coupler 24; the third branch is the main ring transmission branch, which includes the second wavelength blocker WB12 and the second wavelength blocker WB12. Five optical circulators 7, the input end of the second optical wavelength blocker WB12 is connected with an output end of the first optical coupler 8, the output end of the second optical wavelength blocker WB12 is connected with the fifth optical circulator 7's output end One port is connected, the second port of the fifth optical circulator 7 is connected to the main ring feeder fiber through the other port of the 2×2 optical switch 2, and the third port of the fifth optical circulator 7 is connected to the second optical coupler 9 an input terminal of .

The working mode of the tangent ring tangent point remote node device in the wavelength division multiplexing passive optical network system in this embodiment is as follows, when the main ring feeder fiber and the sub-ring feeder fiber connected to the remote node device are normal , the 2×2 optical switch 2 will be placed in the parallel connection state, the on-off optical switch 13 is disconnected, the downlink signal is transmitted in the clockwise direction in the main ring feeder fiber, the downlink signal enters from the 2×2 optical switch 2, and passes through the first After the optical circulator 3, it is divided into three parts by the first optical coupler 8 according to the power ratio, and the signals of these three parts are referred to as signal A, signal B, and signal C here. After the signal A is filtered by the first wavelength blocker WB11 to filter out the wavelengths used by the users of the main ring, it then passes through the third optical coupler 10 and the third optical circulator 5 and then enters the feeder fiber of the sub-ring; the signal B passes through the second optical ring The arrayed waveguide grating AWG21 splits according to the wavelength after the shaper 4, and the corresponding downlink signal is output from the k ports below the arrayed waveguide grating AWG21, and reaches the corresponding optical network unit ONU23 through the distribution optical fiber 22, and passes through the optical network unit ONU23 The coupler 24 sends part of the signal to the optical receiver RX25 after demultiplexing according to the power, and sends the other part of the signal to the reflective semiconductor optical amplifier RSOA26. After the signal is erased and remodulated, it returns to the remote node of the main ring along the original path In RN _m 1, it passes through the arrayed waveguide grating AWG21, the second optical circulator 4, the second optical coupler 9, the first optical circulator 3 and the 2×2 optical switch in the remote node RN _m 1 of the main ring in sequence 2, return to the feeder fiber of the main ring and carry out upstream transmission in the counterclockwise direction; the signal C is filtered by the second wavelength blocker WB12 and used by users belonging to the remote node of the main ring and users on the sub-ring connected to it After the wavelength, it passes through the fifth optical circulator 7 and the 2×2 optical switch 2 in turn, and then returns to the main ring feeder fiber, and continues the downlink signal transmission in a clockwise direction.

When the main ring feeder fiber 41 breaks, the 2×2 optical switch 2 in the remote node device RN _m 1 at the tangent ring tangent point will be placed in the cross-connect state, so that the signal transmission direction in the main ring will change.

The direction of downlink signal transmission in the main ring is counterclockwise:

OLT→RN _M →...→RN _m+1 →RN _m →RN _m-1 →...→RN ₁

The direction of uplink signal transmission in the main ring is clockwise:

RN ₁ →...→RN _m-1 →RN _m →RN _m+1 →...→RN _M →OLT

The rest of the transmission process remains unchanged. Through the change of the connection state of the 2×2 optical switch 2, the change of the optical fiber transmission direction of the main ring feeder is realized, and a new path is found for signal transmission in time to realize the protection of the system.

When the sub-ring feeder fiber 43 breaks down, the on-off optical switch 13 is closed, and the signal A is filtered by the first wavelength blocker WB11 after the wavelength used by the main ring user, and then passes through the third optical coupler 10, on-off and on-off. The optical switch 13 and the fourth optical circulator 6 then enter the feeder fiber of the sub-ring to change the transmission direction of the signal in the sub-ring.

The direction of sub-ring downlink signal transmission is counterclockwise:

OLT→RN ₁ →...→RN _m-1 →RN _m →RN _*N →...→RN * _n+1 →RN _*n →RN _*n-1 →... ...→RN _*1

The uplink signal transmission direction of the sub-ring is clockwise:

RN _*1 →...→RN _*n-1 →RN _*n →RN _*n+1 →...→RN _*N →RN _m →RN _m-1 →.... ..→RN ₁ →OLT

When both the main ring and the sub-ring feeder fibers fail, the 2×2 optical switch 2 will be placed in the cross-connect state, and the on-off optical switch 13 will be closed to change the transmission direction in both the main ring and the sub-ring. Through the change of the transmission direction of the main ring feeder fiber and the sub-ring feeder fiber, a new path is found for signal transmission in time to realize the protection of the system.

The direction of downlink signal transmission in the main ring is counterclockwise (solid arrow):

OLT→RN _M →...→RN _m+1 →RN _m →RN _m-1 →...→RN ₁

The direction of uplink signal transmission in the main ring is clockwise:

RN ₁ →...→RN _m-1 →RN _m →RN _m+1 →...→RN _M →OLT

The direction of sub-ring downlink signal transmission is counterclockwise:

OLT→RN _M →......→RN _m+1 →RN _m →RN _*N →...→RN * _n+1 →RN _*n →RN _*n-1 →... ...→RN _*1

The uplink signal transmission direction of the sub-ring is clockwise:

RN _*1 →...→RN _*n-1 →RN _*n →RN _*n+1 →...→RN _*N →RN _m →RN _m+1 →.... ..→RN _M →OLT

Embodiment two

In this embodiment, the wavelength division multiplexing passive optical network system where the remote node device of the tangent ring tangency point is located is shown in Figure 4. The specific structure of the system has been described in detail in Embodiment 1. The wavelength in this embodiment The tangent ring tangent point remote node device in the division multiplexing passive optical network system is shown in Figure 2, including a 2×2 optical switch 2, an on-off optical switch 13, and a wavelength blocker WB11 , 4 optical circulators 3, 4, 5, 6, 6 optical couplers 8, 9, 10, 14, 15, 16 and 1 1×k arrayed waveguide grating AWG21. The input end of the first optical coupler 8 is connected to one end of the 2×2 optical switch 2 through the first optical circulator 3 , and connected to the main ring optical fiber feeder through the 2×2 optical switch 2 . The first optical coupler 8 divides the optical signal into three paths, and the first branch is a sub-ring transmission branch, which includes the first optical wavelength blocker WB11, the second optical coupler 9, and the third optical coupler 10 , the fourth optical coupler 14, the fifth optical coupler 16, the third optical circulator 5 and the fourth optical circulator 6, the input end of the third optical coupler 10 is connected with the first optical coupler through the wavelength blocker WB11 8, the two output ends of the third optical coupler 10 are respectively connected to the third optical circulator 5 and the first port of the fourth optical circulator 6 through the on-off optical switch 13, the third optical coupler The second ports of the circulator 5 and the fourth optical circulator 6 are respectively connected to the two directions of the sub-ring feeder fiber, and the on-off optical switch 13 is connected in series with the output end of the third optical coupler 10 and the fourth optical circulator 6, the third port of the third optical circulator 5 and the third port of the fourth optical circulator 6 are respectively connected to the two input ends of the fourth optical coupler 14, and through the sixth optical coupler 16 and the second Two optical couplers 9 are connected to the first port of the first optical circulator 3; the second branch is the transmission branch of the optical network unit ONU, and the transmission branch includes the second optical circulator 4 and a 1×k array waveguide Grating AWG21, the first port of the second optical circulator 4 is connected with an output end of the first optical coupler 8, the second port of the second optical circulator 4 is connected with the arrayed waveguide grating AWG21, the second optical circulator 4 The third port is connected to the input end of six optical couplers 16, connected to the first port of the first optical circulator 3 through the second optical coupler 9, and the arrayed waveguide grating AWG21 is connected to q optical network units ONU23 through the distribution fiber 22, each An optical network unit ONU includes an optical coupler 24, a receiver RX25 and a reflective semiconductor optical amplifier RSOA26. In the optical network unit ONU23, the downlink signal is sent to the optical receiver RX25 through the optical coupler 24 and in the reflective semiconductor optical amplifier RSOA26; the third branch is the main ring transmission branch, which includes the fifth optical coupler 15, a port of the fifth optical coupler 15 and one of the first optical coupler 8 The output ends are connected, and the other port of the third optical coupler 15 is connected to the other direction of the main ring feeder fiber through the 2×2 optical switch 2 .

The working mode of the tangent ring tangent point remote node device in the wavelength division multiplexing passive optical network system in this embodiment is as follows. When the optical fibers are all normal, the 2×2 optical switch 2 will be placed in the parallel connection state, and the on-off optical switch 13 will be disconnected. After the downlink signal arrives, it will pass through the 2×2 optical switch 2 and the first optical circulator 3 in turn, and will be transmitted by the first optical circulator 3. The optocoupler 8 is divided into three parts according to power, referred to as signal U, signal V and signal W here. Among them, after the signal U is filtered by the wavelength blocker WB11 and belongs to the wavelength signal used by the main ring ONU, after passing through the third optical coupler 10 and the third optical circulator 5, it enters the sub-ring feeder fiber and proceeds clockwise. Downlink transmission: after passing through the second optical circulator 4, the signal V is split by the arrayed waveguide grating AWG21 with the wavelength as the parameter, and the split signal is output from the corresponding port, enters the corresponding optical network unit ONU23 through the distribution fiber 22, and passes through the optical network The optical coupler 24 in the unit ONU sends part of the signal to the optical receiver RX25 after demultiplexing, and the other part of the optical signal is sent to the reflective semiconductor optical amplifier RSOA26. The signal is erased by the reflective semiconductor optical amplifier RSOA26 and then re-modulated along the original The road returns to the far-end node RN _m 1 of the tangency point, passing through the arrayed waveguide grating AWG21, the second optical circulator 4, the sixth optical coupler 16, the second optical coupler 9, the first optical circulator 3 and 2× 2 After the optical switch, 2 returns to the main ring feeder fiber, and transmits upstream in the counterclockwise direction; the signal W passes through the fifth optical coupler 15 and the 2×2 optical switch 2 in the far-end node RN _m 1 of the cut point, and then returns to The main ring feeds the optical fiber and continues the downstream transmission in the clockwise direction. When the main ring feeder fiber fails, the 2×2 optical switch 2 in the remote node RN _m 1 will be placed in the cross-connect state, and the rest of the transmission process remains unchanged. Through the change of the connection status of the 2×2 optical switch 2, the main ring feeder The change of the optical fiber transmission direction can find a new path for signal transmission in time to realize the protection of the system. When the sub-ring feeder fiber fails, the on-off optical switch 13 is closed, and the signal A is filtered out by the first wavelength blocker WB11 after the wavelength used by the main ring user, and then passes through the third optical coupler 10 and the on-off optical switch in turn. After the switch 13 and the fourth optical circulator 6 enter the sub-ring feeder fiber. When both the main ring and sub-ring feeder fibers fail, the 2×2 optical switch 2 will be placed in the cross-connect state, and the on-off optical switch 13 will be closed to realize the change of the transmission direction of the signal in the main ring feeder fiber and the sub-ring feeder fiber, and provide the signal in time. The transmission looks for a new path to realize the protection of the system.

Embodiment three

In this embodiment, the wavelength division multiplexing passive optical network system where the remote node device is located is shown in Figure 5. The network system is composed of two tangent ring structures, wherein the main ring is formed by the optical line terminal OLT29 through two single-mode The optical fiber is the main ring feeder fiber 41 and 51 connected to M remote nodes RN _a 31, 32, 34 and 35 of the main ring to form a sub-ring with a remote node RN _m 1 on the main ring as the tangent point through two single-mode optical fibers That is, the sub-ring feeder fibers 43 and 53 are connected with N sub-ring remote nodes RN _b 36, 37, 38, 39 and 40, and each main-ring remote node RN _a on the main ring is connected to q An optical network unit, each sub-ring remote node RN _b on the sub-ring is connected to q optical network units through distributed optical fibers.

The remote node device in the wavelength division multiplexing passive optical network system in this embodiment is shown in Figure 3, the device includes a 2×2 optical switch 2, and four 1×2 optical switches 19, 20, 27 , 28, 1 on-off optical switch 13, 1 wavelength blocker WB11, 2 coarse wavelength division multiplexers CWDM17, 18, 4 optical circulators 3, 4, 5, 6, 5 optical couplers 8 , 10, 14, 15, 16 and a 1×q arrayed waveguide grating AWG21. The two left ports of the first 1×2 optical switch 19 are respectively connected to the outer and inner optical fibers of the main ring feeder fiber, and the right port is connected to the left upper port of the 2×2 optical switch 2; the left side of the second 1×2 optical switch 20 The two ports on the side are respectively connected to the inner and outer optical fibers of the main ring feeder fiber, and the right port is connected to the lower left port of the 2×2 optical switch 2; the left port of the third 1×2 optical switch 27 is connected to the third optical circulator 5 The second port is connected, and the two ports on the right side are respectively connected to the outer and inner optical fibers of the sub-ring feeder fiber; the left port of the fourth 1×2 optical switch 28 is connected to the second port of the fourth optical circulator 6, and the two ports on the right The two ports are respectively connected to the inner and outer fibers of the feeder fiber of the sub-ring. The second port of the first optical circulator 3 is connected to the upper right side of the 2×2 optical switch 2, and the first port and the third port of the first optical circulator 3 are connected to the first coarse wavelength division multiplexer CWDM117 and the first coarse wavelength division multiplexer CWDM117 respectively. 2. Coarse wavelength division multiplexer CWDM218, the first wavelength division multiplexer 17 divides the signal into two paths according to the band to which it belongs, one path is the main ring transmission branch, and the other path is connected to the first optical coupler 8, and the signal passes through the first optical coupler The coupler 8 is divided into two parts according to power, one part is the transmission branch of the sub-ring, and the other part is the transmission branch of the optical network unit ONU. The sub-ring transmission branch includes a wavelength blocker WB11, a second optical coupler 10, a third optical coupler 14, a fifth optical coupler 16, a second coarse wavelength division multiplexer CWDM218, a third optical circulator 5 and In the fourth optical circulator 6, the input end of the second optical coupler 10 is connected to an output end of the first optical coupler 8 through a wavelength blocker WB11, and the two output ends of the second optical coupler 10 are connected to the first optical coupler 8 respectively. The three optical circulators 5 are connected to the first port of the fourth optical circulator 6 through an on-off optical switch 13, and the second ports of the third optical circulator 5 and the fourth optical circulator 6 are respectively connected to the third 1× 2 the left port of the optical switch 27 and the fourth 1×2 optical switch 28, the on-off optical switch 13 is connected in series between the output end of the second optical coupler 10 and the first port of the fourth optical circulator 6, The third port of the third optical circulator 5 and the fourth optical circulator 6 are respectively connected to the two input ends of the third optical coupler 14, and through the fifth optical coupler 16 and the second coarse wavelength division multiplexer CWDM218 Connect to the first port of the first optical circulator 3; the optical network unit ONU transmission branch includes a second optical circulator 4 and a 1×k arrayed waveguide grating AWG21, the first port of the second optical circulator 4 is connected to the first port of the second optical circulator 4 The other output end of an optical coupler 8 is connected, the second port of the second optical circulator 4 is connected with the arrayed waveguide grating AWG21, and the third port of the second optical circulator 4 is connected with the input end of five optical couplers 16, through The second coarse wavelength division multiplexer CWDM218 is connected to the first port of the first optical circulator 3, and the arrayed waveguide grating AWG21 is connected to q optical network units ONU23 through the distribution fiber 22, and each optical network unit ONU includes an optical coupler 24. One receiver RX25 and one reflective semiconductor optical amplifier RSOA26, the downlink signal in the optical network unit ONU23 is sent to the optical receiver RX25 and reflective semiconductor optical amplifier RSOA26 respectively through the optical coupler 24; the main ring The transmission branch includes a fourth optical coupler 15 and a second coarse wavelength division multiplexer CWDM218, one port of the fourth optical coupler 15 is connected with the other output end of the first coarse wavelength division multiplexer CWDM117, and the fourth optical coupler One port of the coupler 15 is connected to the main ring feeder fiber via the 2×2 optical switch 2 and the 1×2 optical switches 19 and 20 .

The working mode of the remote node device in the wavelength division multiplexing passive optical network system in this embodiment is as follows, when the main ring feeder fiber 41, 51 and the sub-ring feeder fiber 43, 53 are all normal , as shown in Figure 5.

The direction of downlink signal transmission in the main ring is clockwise:

OLT→ _RN1 →...→RNm _-1 → _RNm → _RNm+1 →...→ _RNm

The direction of uplink signal transmission in the main ring is counterclockwise:

RN _M →...→RN _m+1 →RN _m →RN _m-1 →...→RN ₁ →OLT

The direction of sub-ring downlink signal transmission is clockwise:

OLT→RN ₁ →...→RN _m-1 →RN _m →RN _*1 →...→RN * _n-1 →RN _*n →RN _*n+1 →... ...→RN _*N

The uplink signal transmission direction of the sub-ring is counterclockwise:

RN _*N →...→RN _*n+1 →RN _*n →RN _*n-1 →...→RN _*1 →RN _m →RN _m-1 →.... ..→RN ₁ →OLT

The 2×2 optical switch 2 will be placed in the parallel connection state, and the on-off optical switch 13 is disconnected. After the downlink signal arrives, it enters from the upper port on the left side of the first 1×2 optical switch 19, and passes through the 2×2 optical switch 2, After the first optical circulator 3 and the first coarse wavelength division multiplexer CWDM117, the signal output from the upper port of the first coarse wavelength division multiplexer CWDM117 is divided into two parts by the first optical coupler 8 according to power, which is called here For signal U and signal V. Wherein, after passing through the second optical circulator 4, the signal U is split by the arrayed waveguide grating AWG21 with the wavelength as a parameter, and the split signal is output from the corresponding port and enters the corresponding optical network unit ONU23, and the signal passes through the optical network unit ONU23. After demultiplexing by the optical coupler 24, a part of the signal is sent to the optical receiver RX25, and another part of the optical signal is sent to the reflective semiconductor optical amplifier RSOA26. The signal is erased and then remodulated, and then returns to the remote node RN _m of the tangency point along the original path 1, through the second optical circulator 4, the fifth optical coupler 16, the second coarse wavelength division multiplexer CWDM218, the first optical circulator 3, the 2×2 optical switch 2 and the first 1×2 optical switch After 19, return to the main ring feeder fiber for uplink transmission. After the signal V is filtered by the wavelength blocker WB11 and belongs to the wavelength signal used by the main ring ONU, after passing through the second optical coupler 10, the third optical circulator 5 and the third 1×2 optical switch 27, it enters the sub-ring feeder The outer fiber of the fiber transmits in a clockwise direction. The signal output from the lower port on the right side of the first coarse wavelength division multiplexer CWDM117 is called signal W here, and this part of the signal passes through the third optical coupler 15, the 2×2 optical switch 2 and the second 1×2 optical switch 20 Then return to the main ring feeder fiber to continue downward transmission.

When the feeder fiber 41 on one side of the main ring breaks, the signal transmission between the optical line terminal OLT29 and the far-end remote node of the main ring is completed through the inner feeder fiber 51, and the transmission direction of the main ring and the sub-ring is the same as that under normal conditions. The transmission direction is the same, the first 1×2 optical switch 19 is dialed down, the signal is transmitted along the optical fiber 51 inside the main ring, and enters the remote node RN _m 1 through the lower port on the left side of the first 1×2 optical switch 19, and the remote node The processing process of the signal by RN _m 1 is the same as under normal circumstances, and the description will not be repeated here. When the feeder optical fibers 41 and 51 on both sides of the main ring are broken, the signal transmission direction in the main ring needs to be changed to avoid signal transmission along the broken optical fiber.

The direction of downlink signal transmission in the main ring is clockwise:

OLT→ _RN1 →...→RNm _-1 → _RNm → _RNm+1 →...→ _RNm

The direction of uplink signal transmission in the main ring is counterclockwise:

RN _M →...→RN _m+1 →RN _m →RN _m-1 →...→RN ₁ →OLT

At this time, the 2×2 optical switch 2 in the far-end node RN _m 1 of the tangency point is placed in a parallel connection state, and the rest of the transmission process remains unchanged, thereby realizing the protection of the system.

When the two feeder optical fibers 41 and 51 on one side of the main ring are broken, the signal transmission between the optical line terminal OLT29 and the remote node at the main ring needs to change the transmission direction to complete. The transmission directions of the main ring and the sub-ring are the same Contrary to the transmission direction under normal conditions, it enters the remote node RN _m 1 through the lower port on the left side of the second 1×2 optical switch 20, and the processing process of the signal at the remote node RN _m 1 is similar to that under normal conditions. Repeat the instructions again. When the two feeder optical fibers 41 and 51 on one side of the main ring are both broken, the signal transmission direction in the main ring needs to be changed at this time, so as to prevent the signal from being transmitted along the broken optical fiber.

The direction of downlink signal transmission in the main ring is counterclockwise:

OLT→RN _M →...→RN _m+1 →RN _m →RN _m-1 →...→RN ₁

The direction of uplink signal transmission in the main ring is clockwise:

RN ₁ →...→RN _m-1 →RN _m →RN _m+1 →...→RN _M →OLT

At this time, the 2×2 optical switch 2 in the far-end node RN _m 1 of the cut point is placed in the cross-connection state, and the rest of the transmission process remains unchanged. Through the change of the connection state of the 2×2 optical switch 2, the transmission direction of the main ring feeder fiber is changed. , find a new path for signal transmission in time, and realize the protection of the system.

Similarly, when the outer optical fiber 43 of the sub-ring feeder breaks, the signal transmission between the far-end node RN _m 1 of the cut point and the remote nodes of each sub-ring is completed through the inner feeder optical fiber 53, and the transmission direction of the main ring and the sub-ring is the same as the normal situation The lower transmission direction is the same, the third 1×2 optical switch 27 is dialed down, the signal is transmitted along the inner optical fiber 53 of the sub-ring, and enters the remote node RN _m 1 through the upper port on the left side of the first 1×2 optical switch 19, and the remote The processing process of the signal by the end node RN _m 1 is the same as that under normal conditions, and the description will not be repeated here. When the feeder optical fibers 43 and 53 on both sides of the sub-ring are broken, the signal transmission direction in the sub-ring needs to be changed to avoid transmission along the broken optical fiber.

The direction of sub-ring downlink signal transmission is counterclockwise:

OLT→RN ₁ →...→RN _m-1 →RN _m →RN _*N →...→RN * _n+1 →RN _*n →RN _*n-1 →... ...→RN _*1

The uplink signal transmission direction of the sub-ring is clockwise:

RN _*1 →...→RN _*n-1 →RN _*n →RN _*n+1 →...→RN _*N →RN _m →RN _m-1 →.... ..→RN ₁ →OLT

At this time, the on-off optical switch 13 in the far-end node RN _m 1 of the tangency point is closed, and the rest of the transmission process remains unchanged. By changing the state of the on-off optical switch 13, the transmission direction of the sub-ring feeder fiber can be changed, and a new signal transmission can be found in time. path to protect the system.

Therefore, the remote node RN _m 1 of the tangent ring tangency point of the present invention realizes the clockwise or counterclockwise transmission and arrival of signals on the main ring and the sub-ring through the combination of the 2×2 optical switch 2 connection state, the on-off optical switch 13 and the optical circulator. The remote nodes of each main ring and sub-ring, so as to realize the protection of nodes at all levels of the network and the expansion of the network scale.

Claims (8)

1. A tangent ring tangent point remote node device in a wavelength division multiplexing passive optical network system, characterized in that the tangent point remote node device includes an optical splitter and an optical splitter for dividing optical signals into three paths The arrayed waveguide grating AWG used to connect with the optical network unit ONU, the input end of the optical splitter is connected to the main ring fiber through the optical switch, one output end of the optical splitter is connected to the arrayed waveguide grating AWG, and the other two outputs The ends are respectively connected to the main ring fiber and the sub-ring fiber through corresponding optical circulators or optical couplers. 2. The tangent ring tangent point remote node device in the wavelength division multiplexing passive optical network system according to claim 1, wherein at least one output branch in the three output ends of the optical splitter A wavelength blocking device is provided to filter out signals that do not belong to the wavelength required by this channel. 3. the tangent ring tangent point remote node device in the wavelength division multiplexing passive optical network system according to claim 2, characterized in that, the transmission branch between the optical splitter and the sub-ring optical fiber is set There are two parallel optical circulators, the first ports of the two parallel optical circulators are connected to the output end of the optical splitter through the second optical coupler, and the second ports are respectively connected through corresponding optical switches To the sub-ring fiber, an on-off optical switch is connected in series between the first port of one optical circulator and the second optical coupler. 4. The tangent ring tangent point remote node device in the wavelength division multiplexing passive optical network system according to claim 3, characterized in that, between the first optical coupler and the arrayed waveguide grating AWG A second optical circulator, the first port of the second optical circulator is connected to the output end of the first optical coupler, and the second port of the optical circulator is connected to the arrayed waveguide grating AWG. 5. The tangent ring tangent point remote node device in the wavelength division multiplexing passive optical network system according to any one of claims 1-4, wherein the optical splitter is a first optical A coupler, the input end of the first optical coupler is connected to the optical switch through the first optical circulator. 6. The tangent ring tangent point remote node device in the wavelength division multiplexing passive optical network system according to any one of claims 1-4, wherein the optical splitter includes a first coarse The wavelength division multiplexer CWDM and the first optical coupler, the input end of the first coarse wavelength division multiplexer CWDM is connected to the optical switch through the first optical circulator, and the optical signal is divided into two paths according to the wavelength band, and one path is used for communication with The main ring fiber is connected, the other is connected to the first optical coupler, and the first optical coupler is divided into two according to the power, one is connected to the arrayed waveguide grating AWG, and the other is used to connect to the sub-ring fiber. 7. The tangent ring tangent point remote node device in the wavelength division multiplexing passive optical network system according to claim 5, wherein a third An optical circulator, the first port of the optical circulator is connected to the output end of the first optical coupler, and the second port is connected to the main ring fiber through an optical switch. 8. The tangent ring tangent point remote node device in the wavelength division multiplexing passive optical network system according to claim 6, the output branch between the first coarse wavelength division multiplexer CWDM and the main ring optical fiber A third optical coupler is arranged on the road, the input end of the third optical coupler is connected with the output end of the first coarse wavelength division multiplexer CWDM, and the output end of the third optical coupler is connected with the main ring fiber through an optical switch.