CN112088501A

CN112088501A - Single-fiber looped network structure

Info

Publication number: CN112088501A
Application number: CN201980030048.8A
Authority: CN
Inventors: 王磊; 邓彬林
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-03-29
Filing date: 2019-03-29
Publication date: 2020-12-15
Anticipated expiration: 2039-03-29
Also published as: CN112088501B; WO2020199041A1

Abstract

A single fiber ring network structure is used for simultaneously protecting a plurality of channels in a WDM system. The method comprises the following steps: the main node and the access node are configured with a main signal flow direction and a standby signal flow direction which have opposite flow directions; the main node comprises a first protection module and two groups of devices consisting of an optical amplifier, a multiplexer/demultiplexer and a single-fiber-double-fiber converter; the access node comprises a third single-fiber-double-fiber converter, a fourth single-fiber-double-fiber converter and a second protection module; in the main signal flow direction of the downlink signal, a first protection module, a multiplexer/demultiplexer, an optical amplifier and a single-fiber-double-fiber converter are sequentially connected; the third single-fiber-double-fiber converter is connected with the second protection module in sequence; in the spare signal flow direction of the downlink signal, the first protection module, the multiplexer/demultiplexer, the optical amplifier and the single-fiber-double-fiber converter are sequentially connected; the fourth single-fiber-double-fiber converter is connected with the second protection module in sequence.

Description

Single-fiber looped network structure

Technical Field

The embodiment of the application relates to the field of optical fiber communication, in particular to a single-fiber ring network structure.

Background

The optical communication technology is one of the fastest-developing technical fields at present, and the Wavelength Division Multiplexing (WDM) technology is a preferred technology for realizing high-speed large-capacity data transmission in an optical communication network. Meanwhile, as a basic bearer network for various telecommunication services, the optical transmission network transmits a large amount of information, and once the optical fiber channel of the optical transmission network fails or the optical transmission system fails, the influence is wide and the loss is hard to imagine. On the other hand, in practical applications, network failures are difficult to avoid, and therefore, protection of the optical transmission network is very necessary for the optical transmission network.

At present, most single-fiber bidirectional ring networks in WDM systems usually adopt a traditional protection mode of 1+1 protection or 1: 1 protection, and usually can only realize single-channel protection. Fig. 1 shows a schematic of the principle of using 1+1 protection in a single-fiber bidirectional ring network, in which an optical 2x1 switch 45 and an optical splitter 47 provide protection for the transceiver units of the optical channels. The optical receiver unit 43 is connected to the optical 2x1 switch 45 and the optical transmitter unit 41 is connected to the optical splitter 47. The two output ports of the optical splitter 47 are respectively connected to the first optical diplexer 38 and the second optical diplexer 39, wherein the first optical diplexer 38 corresponds to the channel port 9a, and the second optical diplexer 39 corresponds to the channel port 9 b. In this solution, 1+1 protection of the optical 2 × 1 switch 45 and the optical splitter 47 is performed between the optical transmitter unit 41 (i.e., the multiplexer/demultiplexer) and the first optical duplexer 38 and the second optical duplexer 39 (i.e., the transmission module), and the protected unit is a single transmission module and cannot perform 1+1 protection on a multi-path transmission unit including the multiplexer/demultiplexer.

Disclosure of Invention

The embodiment of the application provides a single-fiber ring network structure which is used for simultaneously protecting a plurality of channels in a WDM system.

A first aspect of the embodiments of the present application provides a single fiber ring network structure, wherein the single fiber ring network structure includes: the access node is connected with the master node through the master node, wherein a master signal flow direction and a standby signal flow direction are configured between the master node and the access node, and the master signal flow direction is opposite to the standby signal flow direction; the main node comprises a first protection module, a first group of optical amplifiers, a second group of optical amplifiers, a first multiplexer/demultiplexer, a second multiplexer/demultiplexer, a first single-fiber-double-fiber converter and a second single-fiber-double-fiber converter; the access node comprises a third single-fiber-double-fiber converter, a fourth single-fiber-double-fiber converter and a second protection module; in the main signal flow direction of the signal (namely, the downlink signal) sent by the main node to the access node, the first protection module, the first multiplexer/demultiplexer, the first group of optical amplifiers and the first single-fiber-dual-fiber converter are connected in sequence; the third single-fiber-double-fiber converter is connected with the second protection module in sequence; in the standby signal flow direction of the signal (namely, the downlink signal) sent by the main node to the access node, the first protection module, the second multiplexer/demultiplexer, the second group of optical amplifiers and the second single-fiber-dual-fiber converter are connected in sequence; the fourth single-fiber-double-fiber converter is connected with the second protection module in sequence; in the main signal flow direction of the signal (i.e. uplink signal) sent from the access node to the main node, the first single-fiber-dual-fiber converter, the first group of optical amplifiers, the first multiplexer/demultiplexer and the first protection module are connected in sequence; the second protection module is connected with the third single-fiber-double-fiber converter in sequence; in the standby signal flow direction of the signal (namely, the uplink signal) sent by the access node to the main node, the second single-fiber-dual-fiber converter, the second group of optical amplifiers, the second multiplexer/demultiplexer and the first protection module are connected in sequence; the second protection module and the fourth single-fiber-double-fiber converter are connected in sequence.

It is to be understood that, in the present embodiment, the number of the master nodes and the access nodes is not limited, but may have the same structure as that of the embodiment.

In this embodiment, the main node in the single-fiber ring network places the protection module behind the multiplexer/demultiplexer, so as to ensure that the multichannel optical signal can be multiplexed by the multiplexer/demultiplexer and amplified by the optical amplifier, and the converted single-fiber/dual-fiber converter is sent to the access node by the single fiber, and after receiving the multichannel optical signal, the access node selects the optical signal corresponding to the drop wave by the single-fiber/dual-fiber converter, thereby ensuring that the optical signal can be transmitted in multiple channels at the same time. Meanwhile, as the main/standby signal flow direction is configured between the main node and the access node in the single-fiber ring network, the main signal can be switched to the standby signal by the protection modules of the main node and the access node when a route fails, thereby ensuring the stability of data transmission.

Optionally, the first protection module is a 2 × 4 optical switch or an optical splitter and a 1 × 2 optical switch, so that the master node can selectively receive between the master signal and the slave signal.

Optionally, the first single-fiber-to-dual-fiber converter is a red-blue band filter or an optical cross wavelength division multiplexer; the second single-fiber-to-double-fiber converter is a red-blue band filter or an optical cross wavelength division multiplexer.

Optionally, the second protection module includes a 1 × 2 coupler, a 1 × 2 splitter, and a multiplexer/demultiplexer; or, the second protection module comprises a 2x 4 optical switch and a multiplexer/demultiplexer; or, the second protection module comprises an optical splitter, a 1 x 2 optical switch and a multiplexer/demultiplexer. The access node may thus selectively receive between the primary signal and the backup signal.

Optionally, the third single-fiber-to-dual-fiber converter includes a band-pass filter; or, the third single-fiber-to-dual-fiber converter comprises a band-pass filter and an optical cross wavelength division multiplexer;

the fourth single-fiber-to-dual-fiber converter comprises a band-pass filter; alternatively, the fourth single-fiber-to-dual-fiber converter includes a band-pass filter and an optical cross-wavelength division multiplexer.

Based on the above scheme, the single fiber ring network structure may specifically include, but is not limited to, the following cases:

in a possible implementation manner, the master node in the single fiber ring network includes N optical splitters and 1 × 2 optical switches, a first multiplexer/demultiplexer, a first group of optical amplifiers, a first red-blue band filter, a second multiplexer/demultiplexer, a second group of optical amplifiers, and a second red-blue band filter, where a value of N is determined by upper and lower wavelength ports of the first multiplexer/demultiplexer and the second multiplexer/demultiplexer, and N is greater than or equal to the number of the upper and lower wavelength ports of the first multiplexer/demultiplexer and the second multiplexer/demultiplexer; the access node includes an optical splitter and 1 × 2 optical switch, a multiplexer/demultiplexer (referred to as a third multiplexer/demultiplexer in this embodiment for distinction), and two sets of bandpass filters (referred to as a first bandpass filter and a second bandpass filter in this embodiment for distinction). The specific connection relationship of each device in the single fiber ring network is as follows: in the main signal flow direction of the downlink signals, the optical splitter and the 1 x 2 optical switch in the main node are sequentially connected with the first multiplexer/demultiplexer, the first group of optical amplifiers and the first red-blue band filter; the first band-pass filter, the optical splitter, the 1 x 2 optical switch and the third multiplexer/demultiplexer in the access node are connected in sequence; in the standby signal flow direction of the downlink signal, the optical splitter and the 1 x 2 optical switch in the main node are sequentially connected with the second multiplexer/demultiplexer, the second group of optical amplifiers and the second red-blue band filter; the second band-pass filter, the optical splitter, the 1 x 2 optical switch and the third combiner-splitter in the access node are connected in sequence. In this scheme, the signal flow direction in the single fiber ring network structure may be as follows:

during downlink signals, taking a channel A as an example, the signals are upwaved by an optical splitter in the main node and an optical splitter part of a 1 x 2 optical switch, and the main signal flow direction and the standby signal flow direction are sent to the main node; in the main signal flow direction, the optical signal of the channel A is combined with the optical signals on other channels through a wave combining part in the first wave combiner-splitter, amplified through an optical amplifier connected with the wave combining part and output to a first red-blue band filter, and converted into a single fiber by the first red-blue band filter for transmission; and when the main signal flows upwards, the combined optical signal of the channel A reaches the access node through a single fiber, then is down-wave through a down wave port of the first band-pass filter, and is selected to be down-wave of the wavelength division part of the third combined wave separator through an optical splitter of the access node and an optical switch of the 1 x 2 optical switch. In the standby signal flow direction, the optical signal of the channel A is combined with the optical signals on other channels through a wave combining part in the second wave combiner-splitter, amplified through an optical amplifier connected with the wave combining part and output to a second red-blue band filter, and converted into a single fiber by the second red-blue band filter for transmission; after the standby signal flows upwards, the combined optical signal of the channel A reaches the access node through a single fiber, then the combined optical signal passes through the lower wave port of the second band-pass filter for being subjected to down wave, and then the combined optical signal passes through the optical splitter of the access node and the optical switch selection of the 1 x 2 optical switch, and the optical signal in the standby signal flow direction is not selected any more because the access node selects the optical signal in the main signal flow direction. When the main signal flow between the main node and the access node goes up to have a fault, the optical splitter of the access node and the optical switch of the 1 x 2 optical switch cannot detect the main signal transmitted upwards by the original main signal flow, so that the main signal flow is switched to the standby signal flow, and the standby signal transmitted upwards by the standby signal flow is selected to be received. And when the standby signal flow between the main node and the access node fails upwards, the optical splitter of the access node and the optical switch of the 1 x 2 optical switch still keep receiving the main signal.

When uplink signals are transmitted, taking a channel B as an example, the uplink signals are subjected to the upper wave through a wave-combining part of a wave-combining and wave-splitting device in the access node and are transmitted to an optical splitter and a 1 x 2 optical switch, and then the optical signals of the channel B are subjected to light splitting through the optical splitter part of the optical splitter and the 1 x 2 optical switch and are transmitted to a main signal flow direction and a standby signal flow direction; in the main signal flow direction, the optical signal of the channel B is converted into a single fiber for transmission through an up wave port of the first band-pass filter; after the optical signal of the channel B reaches the main node through a single fiber, the optical signal is converted into a dual-fiber bidirectional signal through the first red-blue band filter, then is amplified through the optical amplifier and then is sent to the first multiplexer-demultiplexer, and then is down-wave through the wavelength division part of the first multiplexer-demultiplexer and is selectively received through the optical splitter of the main node and the optical switch of the 1 x 2 optical switch. In the standby signal flow direction, the optical signal of the channel B is converted into a single fiber for transmission through an upper wave port of the second band-pass filter; after the optical signal of the channel B reaches the main node through a single fiber, the optical signal is converted into a dual-fiber bidirectional signal through the second red-blue band filter, the dual-fiber bidirectional signal is transmitted to the second multiplexer-demultiplexer after being amplified by the optical amplifier, the dual-fiber bidirectional signal is down-wave through the wavelength division part of the second multiplexer-demultiplexer, and then is selected through the optical splitter of the main node and the optical switch of the 1 x 2 optical switch. When the main signal flow between the main node and the access node has a fault upwards, the optical splitter of the main node and the optical switch of the 1 x 2 optical switch cannot detect the main signal transmitted upwards by the original main signal flow, so that the main signal flow is switched to the standby signal flow, and the standby signal transmitted upwards by the standby signal flow is selected to be received. And when the backup signal flow between the main node and the access node fails upwards, the optical splitter of the main node and the optical switch of the 1-by-2 optical switch still receive the main signal.

It will be appreciated that the access node may also include a Variable Optical Attenuator (VOA), such that real-time control of Optical signals transmitted by the access node may be achieved by attenuating the transmitted Optical power.

In another possible implementation manner, the master node in the single fiber ring network includes N optical splitters and 1 × 2 optical switches, a first multiplexer/demultiplexer, a first group of optical amplifiers, a first optical cross-wavelength demultiplexer, a second multiplexer/demultiplexer, a second group of optical amplifiers, and a second optical cross-wavelength demultiplexer, where a value of N is determined by upper and lower wavelength ports of the first multiplexer/demultiplexer and the second multiplexer/demultiplexer, and N is greater than or equal to the number of the upper and lower wavelength ports of the first multiplexer/demultiplexer and the second multiplexer/demultiplexer; the access node includes an optical splitter and 1 × 2 optical switch, a multiplexer-demultiplexer (for distinction, referred to as a third multiplexer-demultiplexer in this embodiment), and two sets of bandpass filters and optical cross-wavelength-division multiplexers (for distinction, referred to as a first bandpass filter and a third optical cross-wavelength-division multiplexer in this embodiment, and a second bandpass filter and a fourth optical cross-wavelength-division multiplexer). The specific connection relationship of each device in the single fiber ring network is as follows: in the main signal flow direction of the downlink signal, the optical splitter and the 1 × 2 optical switch in the main node are sequentially connected with the first multiplexer-demultiplexer, the first group of optical amplifiers and the first optical cross wavelength division multiplexer; the first band-pass filter, the third optical cross wavelength division multiplexer, the optical splitter, the 1 x 2 optical switch and the third multiplexer/demultiplexer in the access node are connected in sequence; in the standby signal flow direction of the downlink signal, the optical splitter and the 1 × 2 optical switch in the main node are sequentially connected with the second multiplexer/demultiplexer, the second group of optical amplifiers and the second optical cross wavelength division multiplexer; the second band-pass filter, the fourth optical cross wavelength division multiplexer, the optical splitter, the 1 x 2 optical switch and the third multiplexer/demultiplexer in the access node are connected in sequence. In this scheme, the signal flow direction in the single fiber ring network structure may be as follows:

during downlink signals, taking a channel A as an example, the signals are upwaved by an optical splitter in the main node and an optical splitter part of a 1 x 2 optical switch, and the main signal flow direction and the standby signal flow direction are sent to the main node; in the main signal flow direction, the optical signal of the channel A is combined with the optical signals on other channels through a wave combining part in the first wave combining and splitting device, amplified through an optical amplifier connected with the wave combining part and output to a first red-blue band filter, and converted into a single fiber by the first optical cross wavelength division multiplexer for transmission; and when the main signal flows upwards, the combined optical signal of the channel A reaches the access node through a single fiber, then is down-waved through the first band-pass filter and the lower wave port of the third optical cross wavelength division multiplexer, and is down-waved through the optical splitter of the access node and the optical switch of the 1 × 2 optical switch to the wavelength division part of the third optical cross wavelength division multiplexer. In the standby signal flow direction, the optical signal of the channel A is combined with the optical signals on other channels through a wave combining part in the second wave combining and splitting device, amplified through an optical amplifier connected with the wave combining part and output to the second optical cross wavelength division multiplexer, and converted into a single fiber by the second optical cross wavelength division multiplexer for transmission; after the standby signal flows upwards, the combined optical signal of the channel A reaches the access node through a single fiber, then is down-waved through the lower wave port of the second band-pass filter and the fourth optical cross wavelength division multiplexer, and then is selected through the optical splitter of the access node and the optical switch of the 1 x 2 optical switch, and the optical signal in the standby signal flow direction is not selected any more because the access node selects the optical signal in the main signal flow direction. When the main signal flow between the main node and the access node goes up to have a fault, the optical splitter of the access node and the optical switch of the 1 x 2 optical switch cannot detect the main signal transmitted upwards by the original main signal flow, so that the main signal flow is switched to the standby signal flow, and the standby signal transmitted upwards by the standby signal flow is selected to be received. And when the standby signal flow between the main node and the access node fails upwards, the optical splitter of the access node and the optical switch of the 1 x 2 optical switch still keep receiving the main signal.

When uplink signals are transmitted, taking a channel B as an example, the uplink signals are subjected to the upper wave through a wave-combining part of a wave-combining and wave-splitting device in the access node and are transmitted to an optical splitter and a 1 x 2 optical switch, and then the optical signals of the channel B are subjected to light splitting through the optical splitter part of the optical splitter and the 1 x 2 optical switch and are transmitted to a main signal flow direction and a standby signal flow direction; in the main signal flow direction, the optical signal of the channel B is converted into a single fiber for transmission through the first band-pass filter and the upper wave port of the third optical cross wavelength division multiplexer; after the optical signal of the channel B reaches the main node through a single fiber, the optical signal is converted into a double-fiber bidirectional signal through the first optical cross wavelength division multiplexer, is amplified through the optical amplifier and then is sent to the first multiplexer-demultiplexer, is down-wave through the wavelength division part of the first multiplexer-demultiplexer, and is selectively received through the optical splitter of the main node and the optical switch of the 1 x 2 optical switch. In the standby signal flow direction, the optical signal of the channel B is converted into a single fiber for transmission through the second band-pass filter and the upper wave port of the fourth optical cross wavelength division multiplexer; after the optical signal of the channel B reaches the main node through a single fiber, the optical signal is converted into a double-fiber bidirectional signal through the second optical cross wavelength division multiplexer, the double-fiber bidirectional signal is transmitted to the second multiplexer/demultiplexer after being amplified by the optical amplifier, the optical signal is down-wave through the wavelength division part of the second multiplexer/demultiplexer, and the optical signal is selected through the optical splitter of the main node and the optical switch of the 1 x 2 optical switch. When the main signal flow between the main node and the access node has a fault upwards, the optical splitter of the main node and the optical switch of the 1 x 2 optical switch cannot detect the main signal transmitted upwards by the original main signal flow, so that the main signal flow is switched to the standby signal flow, and the standby signal transmitted upwards by the standby signal flow is selected to be received. And when the backup signal flow between the main node and the access node fails upwards, the optical splitter of the main node and the optical switch of the 1-by-2 optical switch still receive the main signal.

In another possible implementation manner, the master node in the single fiber ring network includes N optical splitters and 1 × 2 optical switches, a first multiplexer/splitter, a first group of optical amplifiers, a first red-blue band filter, a second multiplexer/splitter, a second group of optical amplifiers, and a second red-blue band filter, where a value of N is determined by upper and lower wavelength ports of the first multiplexer/splitter and the second multiplexer/splitter, and N is greater than or equal to the number of the upper and lower wavelength ports of the first multiplexer/splitter and the second multiplexer/splitter; the access node includes a 2x 4 optical switch, a combiner/splitter (referred to as a third combiner/splitter in this embodiment for the sake of distinction) and two sets of bandpass filters (referred to as a first bandpass filter and a second bandpass filter in this embodiment for the sake of distinction). The specific connection relationship of each device in the single fiber ring network is as follows: in the main signal flow direction of the downlink signals, the optical splitter and the 1 x 2 optical switch in the main node are sequentially connected with the first multiplexer/demultiplexer, the first group of optical amplifiers and the first red-blue band filter; the first band-pass filter, the 2x 4 optical switch and the third multiplexer/demultiplexer in the access node are connected in sequence; in the standby signal flow direction of the downlink signal, the optical splitter and the 1 x 2 optical switch in the main node are sequentially connected with the second multiplexer/demultiplexer, the second group of optical amplifiers and the second red-blue band filter; the second band-pass filter, the 2x 4 optical switch and the third multiplexer/demultiplexer in the access node are connected in sequence. In this scheme, the signal flow direction in the single fiber ring network structure may be as follows:

during downlink signals, taking a channel A as an example, the signals are upwaved by an optical splitter in the main node and an optical splitter part of a 1 x 2 optical switch, and the main signal flow direction and the standby signal flow direction are sent to the main node; in the main signal flow direction, the optical signal of the channel A is combined with the optical signals on other channels through a wave combining part in the first wave combiner-splitter, amplified through an optical amplifier connected with the wave combining part and output to a first red-blue band filter, and converted into a single fiber by the first red-blue band filter for transmission; and after the combined optical signal of the channel A reaches the access node through a single fiber, the combined optical signal passes through a lower wave port of the first band-pass filter for being down-wave, and then is selected to be down-wave of a wave splitting part of the third combined wave separator through a 2-by-4 optical switch of the access node. In the standby signal flow direction, the optical signal of the channel A is combined with the optical signals on other channels through a wave combining part in the second wave combiner-splitter, amplified through an optical amplifier connected with the wave combining part and output to a second red-blue band filter, and converted into a single fiber by the second red-blue band filter for transmission; after the combined optical signal of the channel a reaches the access node through a single fiber, the optical signal passes through the lower wave port of the second band-pass filter for being down-wave, and then is selected through the 2x 4 optical switch of the access node. When the main signal flow between the main node and the access node has a fault upwards, the 2x 4 optical switch of the access node cannot detect the main signal transmitted upwards by the original main signal flow, so that the access node is switched to the standby signal flow to select and receive the standby signal transmitted upwards by the standby signal flow. And when the standby signal flow between the main node and the access node fails upwards, the 2x 4 optical switch of the access node still receives the main signal.

In the uplink signal, taking channel B as an example, because the optical signal is up-converted by the multiplexer/demultiplexer in the access node and is sent to the 2x 4 optical switch, the sending optical switch state and the receiving optical switch state of the 2x 4 optical switch are kept the same, when the access node receives the main signal in the downlink signal, the 2x 4 optical switch sends the optical signal of channel B to the main signal flow direction; in the main signal flow direction, the optical signal of the channel B is converted into a single fiber for transmission through an up wave port of the first band-pass filter; after the optical signal of the channel B reaches the main node through a single fiber, the optical signal is converted into a dual-fiber bidirectional signal through the first red-blue band filter, is amplified through the optical amplifier and then is sent to the first multiplexer-demultiplexer, is down-waved through the wavelength division part of the first multiplexer-demultiplexer, and is selectively received through the optical splitter of the main node and the optical switch of the 1 x 2 optical switch. In the standby signal flow direction, no optical signal is transmitted in the standby signal flow direction because the transmitting optical switch state of the 2x 4 optical switch of the access node does not select the standby signal. When the main signal flow between the main node and the access node has a fault upwards, the optical splitter of the main node and the optical switch of the 1 x 2 optical switch cannot detect the main signal transmitted upwards by the original main signal flow, so that the main signal flow is switched to the standby signal flow, and the standby signal transmitted upwards by the standby signal flow is selected to be received. And when the backup signal flow between the main node and the access node fails upwards, the optical splitter of the main node and the optical switch of the 1-by-2 optical switch still receive the main signal.

In another possible implementation manner, the master node in the single fiber ring network includes N optical splitters and 1 × 2 optical switches, a first multiplexer/demultiplexer, a first group of optical amplifiers, a first optical cross-wavelength demultiplexer, a second multiplexer/demultiplexer, a second group of optical amplifiers, and a second optical cross-wavelength demultiplexer, where a value of N is determined by upper and lower wavelength ports of the first multiplexer/demultiplexer and the second multiplexer/demultiplexer, and N is greater than or equal to the number of the upper and lower wavelength ports of the first multiplexer/demultiplexer and the second multiplexer/demultiplexer; the access node includes a 2x 4 optical switch, two groups of combiner/splitters (referred to as a third combiner/splitter and a fourth combiner/splitter in this embodiment for distinction) and two groups of bandpass filters (referred to as a first bandpass filter and a second bandpass filter in this embodiment for distinction). The specific connection relationship of each device in the single fiber ring network is as follows: in the main signal flow direction of the downlink signal, the optical splitter and the 1 × 2 optical switch in the main node are sequentially connected with the first multiplexer-demultiplexer, the first group of optical amplifiers and the first optical cross wavelength division multiplexer; the first band-pass filter, the third multiplexer/demultiplexer and the 2x 4 optical switch in the access node are connected in sequence; in the standby signal flow direction of the downlink signal, the optical splitter and the 1 × 2 optical switch in the main node are sequentially connected with the second multiplexer/demultiplexer, the second group of optical amplifiers and the second optical cross wavelength division multiplexer; the second band-pass filter, the fourth multiplexer/demultiplexer and the 2x 4 optical switch in the access node are connected in sequence. In this scheme, the signal flow direction in the single fiber ring network structure may be as follows:

during downlink signals, taking a channel A as an example, the signals are upwaved by an optical splitter in the main node and an optical splitter part of a 1 x 2 optical switch, and the main signal flow direction and the standby signal flow direction are sent to the main node; in the main signal flow direction, the optical signal of the channel A is combined with the optical signals on other channels through a wave combining part in the first wave combining and splitting device, amplified through an optical amplifier connected with the wave combining part and output to a first red-blue band filter, and converted into a single fiber by the first optical cross wavelength division multiplexer for transmission; when the main signal flows upwards, the combined optical signal of the channel A reaches the access node through a single fiber, then is down-waved through the down-wave port of the first band-pass filter, then is down-waved through the wavelength division part of the third combining and splitting filter, and finally is selectively received through the 2x 4 optical switch. In the standby signal flow direction, the optical signal of the channel A is combined with the optical signals on other channels through a wave combining part in the second wave combining and splitting device, amplified through an optical amplifier connected with the wave combining part and output to the second optical cross wavelength division multiplexer, and converted into a single fiber by the second optical cross wavelength division multiplexer for transmission; when the standby signal flows upwards, the combined optical signal of the channel A reaches the access node through a single fiber, then is down-wave through the down-wave port of the second band-pass filter, then is down-wave through the wavelength division part of the fourth multiplexer/demultiplexer, and then is selected through the 2x 4 optical switch of the access node. When the main signal flow between the main node and the access node has a fault upwards, the 2x 4 optical switch of the access node cannot detect the main signal transmitted upwards by the original main signal flow, so that the access node is switched to the standby signal flow to select and receive the standby signal transmitted upwards by the standby signal flow. And when the standby signal flow between the main node and the access node fails upwards, the 2x 4 optical switch of the access node still receives the main signal.

In the uplink signal, taking channel B as an example, the sending optical switch state and the receiving optical switch state of the 2 × 4 optical switch are kept the same, so when the access node receives the main signal in the downlink signal, the 2 × 4 optical switch sends the optical signal of channel B to the main signal flow direction, and then sends the optical signal to the add-drop part of the third add-drop filter in the access node for add-drop; then the optical signal of the channel B is converted into a single fiber for transmission through an upper wave port of the first band-pass filter; after the optical signal of the channel B reaches the main node through a single fiber, the optical signal is converted into a double-fiber bidirectional signal through the first optical cross wavelength division multiplexer, is amplified through the optical amplifier and then is sent to the first multiplexer-demultiplexer, is down-wave through the wavelength division part of the first multiplexer-demultiplexer, and is selectively received through the optical splitter of the main node and the optical switch of the 1 x 2 optical switch. In the standby signal flow direction, no optical signal is transmitted in the standby signal flow direction because the transmitting optical switch state of the 2x 4 optical switch of the access node does not select the standby signal. When the main signal flow between the main node and the access node has a fault upwards, the optical splitter of the main node and the optical switch of the 1 x 2 optical switch cannot detect the main signal transmitted upwards by the original main signal flow, so that the main signal flow is switched to the standby signal flow, and the standby signal transmitted upwards by the standby signal flow is selected to be received. And when the backup signal flow between the main node and the access node fails upwards, the optical splitter of the main node and the optical switch of the 1-by-2 optical switch still receive the main signal.

In another possible implementation manner, the master node in the single fiber ring network includes N2 × 4 optical switches, a first multiplexer/demultiplexer, a first group of optical amplifiers, a first optical cross wavelength division multiplexer, a second multiplexer/demultiplexer, a second group of optical amplifiers, and a second optical cross wavelength division multiplexer, where a value of N is determined by upper and lower wavelength ports of the first multiplexer/demultiplexer and the second multiplexer/demultiplexer, and N is greater than or equal to the number of the upper and lower wavelength ports of the first multiplexer/demultiplexer and the second multiplexer/demultiplexer; the access node includes 1 × 2 couplers and 1 × 2 splitters, a combiner-splitter and two sets of bandpass filters and optical cross-wavelength-division multiplexers (for the sake of distinction, referred to as a first bandpass filter and a third optical cross-wavelength-division multiplexer, a second bandpass filter and a fourth optical cross-wavelength-division multiplexer in this embodiment). The specific connection relationship of each device in the single fiber ring network is as follows: in the main signal flow direction of the downlink signal, the 2x 4 optical switch in the main node is sequentially connected with the first multiplexer-demultiplexer, the first group of optical amplifiers and the first optical cross wavelength division multiplexer; the first band-pass filter, the third optical cross wavelength division multiplexer, the 1 x 2 coupler, the 1 x 2 optical splitter and the multiplexer-demultiplexer in the access node are connected in sequence; in the standby signal flow direction of the downlink signal, the 2x 4 optical switch in the main node is sequentially connected with the second multiplexer/demultiplexer, the second group of optical amplifiers and the second optical cross wavelength division multiplexer; the second band-pass filter, the fourth optical cross wavelength division multiplexer, the 1 x 2 coupler, the 1 x 2 optical splitter and the multiplexer-demultiplexer in the access node are connected in sequence. In this scheme, the signal flow direction in the single fiber ring network structure may be as follows:

when a downlink signal is sent, taking the channel A as an example, the optical signal of the channel A is sent in the main signal direction selected by the 2x 4 optical switch in the main node; in the main signal flow direction, the optical signal of the channel A is combined with the optical signals on other channels through a wave combining part in the first wave combining and splitting device, amplified through an optical amplifier connected with the wave combining part and output to a first optical cross wavelength division multiplexer, and converted into a single fiber by the first optical cross wavelength division multiplexer for transmission; and when the main signal flows upwards, the combined optical signal of the channel A reaches the access node through a single fiber, then is down-waved through the first band-pass filter and the lower wave port of the third optical cross wavelength division multiplexer, and then is down-waved through the wave-splitting part of the 1 x 2 coupler and the third combined wave-splitting device. In the backup signal flow direction, the master node does not send the optical signal of channel a to the backup signal, and thus the access node does not receive the backup signal. When the main signal flow between the main node and the access node fails upwards, the 2x 4 optical switch of the main node cannot detect the signal in the main signal flow, so that the main node is switched to the standby signal flow, and then the optical signal is sent upwards to the standby signal flow. The master node remains transmitting optical signals in the primary signal flow direction when the backup signal flow direction between the master node and the access node fails.

When uplink signals are received, taking a channel B as an example, an optical signal of the channel B is multiplexed with optical signals of other channels through a multiplexing part of a multiplexer/demultiplexer, then is sent to a main signal flow direction, and then is sent to a multiplexing part of a third multiplexer/demultiplexer in the access node for up-wave; then, the optical signal is sent to the main signal flow direction and the standby signal flow direction through a 1-by-2 optical splitter; in the main signal flow direction, the optical signal is converted into a single fiber for transmission through an upper wave port of a third optical cross wavelength division multiplexer and a first band-pass filter; after the optical signal of the channel B reaches the master node through a single fiber, the optical signal is converted into a dual-fiber bidirectional signal through the first optical cross wavelength division multiplexer, the dual-fiber bidirectional signal is transmitted to the first multiplexer-demultiplexer after being amplified by the optical amplifier, the dual-fiber bidirectional signal passes through the wavelength division part of the first multiplexer-demultiplexer for down-wave, and is selected through the 2x 4 optical switch of the master node, and because the state of the transmitting optical switch of the 2x 4 optical switch is the same as the state of the receiving optical switch, when the state of the transmitting optical switch of the master node in the down-going signal is the master signal, the master node also selects the master signal in the state of the receiving optical switch. In the standby signal flow direction, the optical signal is converted into a single fiber for transmission through the fourth optical cross wavelength division multiplexer and the upper wave port of the second band-pass filter; after the optical signal of the channel B reaches the main node through a single fiber, the optical signal is converted into a dual-fiber bidirectional signal through the second optical cross wavelength division multiplexer, the dual-fiber bidirectional signal is transmitted to the second multiplexer-demultiplexer after being amplified by the optical amplifier, the dual-fiber bidirectional signal is down-wave through the wavelength division part of the second multiplexer-demultiplexer and is selected through the 2-4 optical switch of the main node, and as the state of the transmitting optical switch of the 2-4 optical switch is the same as that of the receiving optical switch, when the state of the transmitting optical switch of the main node in the down-going signal is the main signal, the main node does not receive the standby signal any more. When the main signal flow between the main node and the access node has a fault upwards, the optical splitter of the main node and the optical switch of the 1 x 2 optical switch cannot detect the main signal transmitted upwards by the original main signal flow, so that the main signal flow is switched to the standby signal flow, and the standby signal transmitted upwards by the standby signal flow is selected to be received. And when the backup signal flow between the main node and the access node fails upwards, the optical splitter of the main node and the optical switch of the 1-by-2 optical switch still receive the main signal.

Drawings

Fig. 1 is a schematic diagram of single channel protection in a single fiber bidirectional ring network;

fig. 2 is a schematic view of an embodiment of a single fiber ring network structure in an embodiment of the present application;

fig. 3 is a schematic view of another embodiment of a single fiber ring network structure in the embodiment of the present application;

fig. 4 is a schematic view of another embodiment of a single fiber ring network structure in the embodiment of the present application;

fig. 5 is a schematic view of another embodiment of a single fiber ring network structure in the embodiment of the present application;

fig. 6 is a schematic view of another embodiment of a single fiber ring network structure in the embodiment of the present application;

fig. 7 is a schematic view of another embodiment of a single fiber ring network structure in the embodiment of the present application.

Detailed Description

The terms "first," "second," "third," "fourth," and the like in the description and in the claims of the present application and in the drawings described above, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be practiced otherwise than as specifically illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The optical communication technology is one of the fastest-developing technical fields at present, and the Wavelength Division Multiplexing (WDM) technology is a preferred technology for realizing high-speed large-capacity data transmission in an optical communication network. Meanwhile, as a basic bearer network for various telecommunication services, the optical transmission network transmits a large amount of information, and once the optical fiber channel of the optical transmission network fails or the optical transmission system fails, the influence is wide and the loss is hard to imagine. On the other hand, in practical applications, network failures are difficult to avoid, and therefore, protection of the optical transmission network is very necessary for the optical transmission network. At present, most single-fiber bidirectional ring networks in WDM systems usually adopt a traditional protection mode of 1+1 protection or 1: 1 protection, and usually can only realize single-channel protection. Fig. 1 shows a schematic of the principle of using 1+1 protection in a single-fiber bidirectional ring network, in which an optical 2x1 switch 45 and an optical splitter 47 provide protection for the transceiver units of the optical channels. The optical receiver unit 43 is connected to the optical 2x1 switch 45 and the optical transmitter unit 41 is connected to the optical splitter 47. The two output ports of the optical splitter 47 are respectively connected to the first optical diplexer 38 and the second optical diplexer 39, wherein the first optical diplexer 38 corresponds to the channel port 9a, and the second optical diplexer 39 corresponds to the channel port 9 b. In this solution, 1+1 protection of the optical 2 × 1 switch 45 and the optical splitter 47 is performed between the optical transmitter unit 41 (i.e., the multiplexer/demultiplexer) and the first optical duplexer 38 and the second optical duplexer 39 (i.e., the transmission module), and the protected unit is a single transmission module and cannot perform 1+1 protection on a multi-path transmission unit including the multiplexer/demultiplexer.

In order to solve the problem, an embodiment of the present application provides a single fiber ring network structure, which is specifically shown in fig. 2: the single fiber ring network structure 200 includes: a main node 201 and at least one access node 202, wherein a main signal flow direction and a standby signal flow direction are configured between the main node 201 and the access node 202, and the main signal flow direction and the standby signal flow direction are opposite; the master node 201 includes a first protection module 2011, a first group of optical amplifiers 2012, a second group of optical amplifiers 2013, a first multiplexer/demultiplexer 2014, a second multiplexer/demultiplexer 2015, a first single-fiber-to-double-fiber converter 2016 and a second single-fiber-to-double-fiber converter 2017; the access node 202 includes a third single-to-dual-fiber converter 2021, a fourth single-to-dual-fiber converter 2022, and a second protection module 2023; in the main signal flow direction of the signal (i.e., the downlink signal) transmitted from the main node 201 to the access node 202, the first protection module 2011, the first multiplexer/demultiplexer 2014, the first group of optical amplifiers 2012 and the first single-fiber/dual-fiber converter 2016 are sequentially connected; the third single-fiber-to-dual-fiber converter 2021 and the second protection module 2023 are connected in sequence; in the standby signal flow direction in which the master node sends a signal (i.e., a downlink signal) to the access node, the first protection module 2011, the second multiplexer/demultiplexer 2015, the second group of optical amplifiers 2013, and the second single-fiber/dual-fiber converter 2017 are sequentially connected; the fourth single-fiber-to-dual-fiber converter 2022 and the second protection module 2023 are connected in sequence; in the main signal stream direction in which the access node 202 sends a signal (i.e., an uplink signal) to the main node 201, the first single-fiber-to-dual-fiber converter 2016, the first group of optical amplifiers 2013, the first multiplexer/demultiplexer 2014, and the first protection module 2011 are connected in sequence; the second protection module 2023 and the third single-fiber-to-dual-fiber converter 2021 are connected in sequence; in the standby signal flow direction in which the access node 201 sends a signal (i.e., an uplink signal) to the master node 202, the second single-fiber-to-dual-fiber converter 2017, the second group of optical amplifiers 2013, the second multiplexer/demultiplexer 2015, and the first protection module 2011 are sequentially connected; the second protection module 2023 and the fourth single-fiber-to-double-fiber converter 2022 are connected in sequence.

Optionally, the first protection module 2011 is a 2 × 4 optical switch or an optical splitter and a 1 × 2 optical switch, so that the master node can selectively receive between the master signal and the slave signal.

Optionally, the first single-fiber-to-dual-fiber converter 2016 is a red-blue band filter or an optical cross wavelength division multiplexer; the second single-fiber-to-dual-fiber converter 2017 is a red-blue band filter or an optical cross-wavelength division multiplexer.

Optionally, the second protection module 2023 includes 1 × 2 couplers and 1 × 2 splitters and combiners; or, the second protection module 2023 includes a 2 × 4 optical switch and a multiplexer/demultiplexer; alternatively, the second protection module 2023 includes an optical splitter and 1 × 2 optical switches and a multiplexer/demultiplexer. The access node may thus selectively receive between the primary signal and the backup signal.

Optionally, the third single-fiber-to-dual-fiber converter 2021 includes a band-pass filter; or, the third single-fiber-to-dual-fiber converter 2021 includes a band-pass filter and an optical cross-wavelength division multiplexer;

the fourth single-to-double fiber converter 2022 includes a band pass filter; alternatively, the fourth single-to-dual fiber converter 2022 includes a band pass filter and an optical cross wavelength division multiplexer.

Based on the above scheme, the single fiber ring network structure 200 may specifically include, but is not limited to, the following cases:

in one possible implementation, as shown in fig. 3, an implementation manner of the first single-fiber-to-dual-fiber converter 2016 in the single-fiber ring network structure 200 is a first red-blue band filter 2016, an implementation manner of the second single-fiber-to-dual-fiber converter 2017 is a second red-blue band filter 2017, an implementation manner of the third single-fiber-to-dual-fiber converter 2021 is a first band-pass filter 2021, an implementation manner of the fourth single-fiber-to-dual-fiber converter 2022 is a second band-pass filter 2022, an implementation manner of the first protection module is an optical splitter and a 1 × 2 optical switch 2011, and an implementation manner of the second protection module 2023 is an optical splitter and a 1 × 2 optical switch and a combiner/splitter 2011. That is, the master node 201 of the single-fiber ring network structure includes N optical splitters and 1 × 2 optical switches 2011, a first multiplexer/demultiplexer 2014, a first group of optical amplifiers 2012, a first red-blue band filter 2016, a second multiplexer/demultiplexer 2015, a second group of optical amplifiers 2013, and a second red-blue band filter 2017, where a value of the N is determined by upper and lower wavelength ports of the first multiplexer/demultiplexer 2014 and the second multiplexer/demultiplexer 2015, and the N is greater than or equal to the number of the upper and lower wavelength ports of the first multiplexer/demultiplexer 2014 and the second multiplexer/demultiplexer 2015; the access node 202 includes an optical splitter and 1 × 2 optical switch, a combiner-splitter (referred to as a third combiner-splitter in this embodiment for the sake of distinction), and a first band-pass filter 2021 and a second band-pass filter 2022. The specific connection relationship of each device in the single fiber ring network is as follows: in the main signal flow direction of the downstream signal, the optical splitter and 1 × 2 optical switch in the main node are sequentially connected to the first multiplexer/demultiplexer 2014, the first group of optical amplifiers 2012 and the first red-blue band filter 2016; the first band-pass filter 2021, the optical splitter, the 1 x 2 optical switch and the third multiplexer/demultiplexer in the access node are connected in sequence; in the standby signal flow direction of the downlink signal, the optical splitter and the 1 × 2 optical switch 2011 in the master node are sequentially connected with the second multiplexer/demultiplexer 2015, the second group of optical amplifiers 2013 and the second red-blue band filter 2017; the second band-pass filter 2022, the optical splitter, and the 1 x 2 optical switch in the access node are connected in sequence to the third multiplexer/demultiplexer. In this scheme, the signal flow direction in the single fiber ring network structure may be as follows:

during downlink signals, taking channel a as an example, the signals are up-waved by the optical splitter in the master node and the optical splitter part of the 1 × 2 optical switch 2011, and the main signal flow direction and the standby signal flow direction sent to the master node 201 are up-waved; in the main signal flow direction, the optical signal of the channel a is combined with the optical signals on other channels through the wave combining part in the first wave combiner 2014, amplified by the optical amplifier connected to the wave combining part and output to the first red and blue band filter 2016, and converted into a single fiber by the first red and blue band filter 2016 for transmission; after the main signal flows upward, the combined optical signal of the channel a passes through a single fiber to reach the access node 202, and then passes through the drop port of the first band-pass filter 2021 to drop, and then passes through the optical splitter of the access node 202 and the optical switch of the 1 × 2 optical switch to select the drop of the wavelength division part of the third combiner/splitter. In the standby signal flow direction, the optical signal of the channel a is multiplexed with the optical signals on other channels through the multiplexing part in the second multiplexer/demultiplexer 2015, amplified by the optical amplifier connected with the multiplexing part and output to the second red-blue band filter 2017, and converted into a single fiber by the second red-blue band filter 2017 for transmission; after the backup signal flows upward, the combined optical signal of the channel a reaches the access node 202 through a single fiber, and then goes down through the add port of the second band-pass filter 2022, and then passes through the optical splitter of the access node 202 and the optical switch selection of the 1 × 2 optical switch, and the optical signal flowing upward in the backup signal flow is not selected any more because the optical signal flowing upward in the main signal flow is selected by the access node 202. When the main signal flow between the main node 201 and the access node 202 fails upwards, the optical splitter of the access node 202 and the optical switch of the 1 × 2 optical switch cannot detect the main signal transmitted upwards by the original main signal flow, so that the main signal flow is switched to the standby signal flow, and the standby signal transmitted upwards by the standby signal flow is selected to be received. However, when the backup signal flow between the master node 201 and the access node 202 fails upward, the optical splitter of the access node 202 and the optical switch of the 1 × 2 optical switch still receive the master signal.

In the uplink signal, taking channel B as an example, the optical signal is divided by the optical splitter part in the optical splitter and 1 × 2 optical switch, and then the optical signal of channel B is sent to the main signal flow direction and the standby signal flow direction; in the main signal flow direction, the optical signal of the channel B is converted into a single fiber for transmission through the upstream port of the first band-pass filter 2021; after the optical signal of the channel B reaches the master node through a single fiber, the optical signal is converted into a dual-fiber bidirectional signal through the first red-blue band filter 2016, amplified by the optical amplifier, sent to the first multiplexer/demultiplexer 2014, dropped by the wavelength splitting part of the first multiplexer/demultiplexer 2014, and selectively received by the optical splitter of the master node 201 and the optical switch in the 1 x 2 optical switch 2011. In the standby signal flow direction, the optical signal of the channel B is converted into a single fiber for transmission through the add port of the second band-pass filter 2022; after the optical signal of the channel B reaches the main node 201 through a single fiber, the optical signal is converted into a dual-fiber bi-directional signal through the second red-blue band filter 2017, the optical signal is amplified by the optical amplifier and then sent to the second multiplexer/demultiplexer 2015, the optical signal is down-wave through the wavelength division part of the second multiplexer/demultiplexer 2015, and then the optical signal is selected through the optical splitter of the main node 201 and the optical switch in the 1 x 2 optical switch 2011, and because the main node 201 selects the optical signal in the main signal flow direction, the optical signal in the standby signal flow direction is not selected any more. When the main signal flow between the main node 201 and the access node 202 fails in the upward direction, the optical splitter of the main node 201 and the optical switch of the 1 × 2 optical switch 2011 cannot detect the main signal transmitted in the upward direction of the original main signal flow, so that the main signal flow is switched to the standby signal flow, and the standby signal transmitted in the upward direction of the standby signal flow is selected to be received. However, when the backup signal flow between the master node 201 and the access node 202 fails in the upstream direction, the optical splitter of the master node 201 and the optical switch of the 1 × 2 optical switch 2011 still receive the master signal.

It is understood that the access node 202 may also include a Variable Optical Attenuator (VOA), such that real-time control of Optical signals transmitted by the access node may be achieved by attenuating the transmitted Optical power.

In another possible implementation, as shown in fig. 4, an implementation manner of the first single-fiber-to-dual-fiber converter 2016 in the single-fiber ring network structure 200 is a first optical cross wavelength division multiplexer 2016, an implementation manner of the second single-fiber-to-dual-fiber converter 2017 is a second optical cross wavelength division multiplexer 2017, an implementation manner of the third single-fiber-to-dual-fiber converter 2021 is a first band-pass filter plus a third optical cross wavelength division multiplexer 2021, an implementation manner of the fourth single-fiber-to-dual-fiber converter 2022 is a second band-pass filter and a fourth optical cross wavelength division multiplexer 2022, an implementation manner of the first protection module 2011 is an optical splitter and a 1 × 2 optical switch 2011, and an implementation manner of the second protection module 2023 is an optical splitter and a 1 × 2 optical switch and a multiplexer/demultiplexer. That is, the master node 201 in the single-fiber ring network structure 200 includes N optical splitters and 1 × 2 optical switches 2011, a first multiplexer/demultiplexer 2014, a first group of optical amplifiers 2012, a first optical cross-wavelength multiplexer 2016, a second multiplexer/demultiplexer 2015, a second group of optical amplifiers 2013, and a second optical cross-wavelength multiplexer 2017, where a value of the N is determined by upper and lower wavelength ports of the first multiplexer/demultiplexer 2014 and the second multiplexer/demultiplexer 2015, and the N is greater than or equal to the number of the upper and lower wavelength ports of the first multiplexer/demultiplexer 2014 and the second multiplexer/demultiplexer 2015; the access node 202 includes an optical splitter and 1 × 2 optical switch, a combiner-splitter (referred to as a third combiner-splitter in this embodiment for the sake of distinction) and first and third optical cross-wavelength-

division multiplexers

2021, 2022, and a second and fourth optical cross-wavelength-division multiplexer. The specific connection relationship of each device in the single fiber ring network is as follows: in the main signal flow direction of the downstream signal, the optical splitter and the 1 × 2 optical switch 2011 in the main node 201 are sequentially connected to the first multiplexer/demultiplexer 2014, the first group of optical amplifiers 2012 and the first optical cross wavelength division multiplexer 2016; the first band-pass filter, the third optical cross wavelength division multiplexer, the optical splitter, the 1 x 2 optical switch and the third multiplexer/demultiplexer in the access node 202 are connected in sequence; in the standby signal flow direction of the downlink signal, the optical splitter and the 1 × 2 optical switch 2011 in the master node 201 are sequentially connected with the second multiplexer/demultiplexer 2015, the second group of optical amplifiers 2013 and the second optical cross wavelength division multiplexer 2017; the second band-pass filter, the fourth optical cross wavelength division multiplexer, the optical splitter, the 1 × 2 optical switch, and the third multiplexer/demultiplexer in the access node 202 are connected in sequence. In this scheme, the signal flow direction in the single fiber ring network structure may be as follows:

during downlink signals, taking the channel a as an example, the signals are upwaved by the optical splitter in the master node 201 and the optical splitter part of the 1 × 2 optical switch, and the main signal flow direction and the standby signal flow direction are sent to the master node 201; in the main signal flow direction, the optical signal of the channel a is combined with the optical signals on other channels through the wave combining part in the first multiplexer/demultiplexer 2014, amplified by the optical amplifier connected to the wave combining part and output to the first red and blue band filter 2016, and converted into a single fiber by the first optical cross wavelength division multiplexer 2016 for transmission; after the main signal flows upward, the combined optical signal of the channel a reaches the access node 202 through a single fiber, and then is down-wave through the first band-pass filter and the down-wave port of the third optical cross wavelength division multiplexer, and then is down-wave through the optical splitter of the access node 202 and the optical switch of the 1 × 2 optical switch to the wavelength division part of the third optical cross wavelength division multiplexer. In the standby signal flow direction, the optical signal of the channel a is multiplexed with the optical signals on other channels through the multiplexing part in the second multiplexer/demultiplexer 2015, amplified by the optical amplifier connected with the multiplexing part and output to the second optical cross wavelength division multiplexer 2017, and converted into a single fiber by the second optical cross wavelength division multiplexer 2017 for transmission; after the backup signal flows upward, the combined optical signal of the channel a reaches the access node 202 through a single fiber, and then is down-wave through the lower wave port of the second band-pass filter and the fourth optical cross wavelength division multiplexer, and then passes through the optical splitter of the access node 202 and the optical switch selection of the 1 × 2 optical switch, and because the access node 202 selects the optical signal in the main signal flow direction, the optical signal in the backup signal flow direction is not selected any more. When the main signal flow between the main node 201 and the access node 202 fails upwards, the optical splitter of the access node 202 and the optical switch of the 1 × 2 optical switch cannot detect the main signal transmitted upwards by the original main signal flow, so that the main signal flow is switched to the standby signal flow, and the standby signal transmitted upwards by the standby signal flow is selected to be received. However, when the backup signal flow between the master node 201 and the access node 202 fails upward, the optical splitter of the access node 202 and the optical switch of the 1 × 2 optical switch still receive the master signal.

In the uplink signal, taking channel B as an example, the optical signal is divided by the optical splitter part in the optical splitter and 1 × 2 optical switch, and then the optical signal of channel B is sent to the main signal flow direction and the standby signal flow direction; in the main signal flow direction, the optical signal of the channel B is converted into a single fiber for transmission through the first band-pass filter and the upper wave port of the third optical cross wavelength division multiplexer; after the optical signal of the channel B reaches the host node 201 through a single fiber, the optical signal is converted into a dual-fiber bidirectional signal through the first optical cross wavelength division multiplexer 2016, amplified by the optical amplifier, sent to the first multiplexer/demultiplexer 2014, dropped through the wavelength division part of the first multiplexer/demultiplexer 2014, and selectively received through the optical splitter of the host node 201 and the optical switch of the 1 × 2 optical switch. In the standby signal flow direction, the optical signal of the channel B is converted into a single fiber for transmission through the second band-pass filter and the upper wave port of the fourth optical cross wavelength division multiplexer; after the optical signal of the channel B reaches the master node 201 through a single fiber, the optical signal is converted into a dual-fiber bi-directional signal through the second optical cross wavelength division multiplexer 2017, then is amplified by the optical amplifier and then is sent to the second multiplexer/demultiplexer 2015, the optical signal is down-wave through the wavelength division part of the second multiplexer/demultiplexer 2015, and then is selected through the optical splitter of the master node 201 and the optical switch of the 1 × 2 optical switch, and because the master node 201 selects the optical signal in the main signal flow direction, the optical signal in the standby signal flow direction is not selected any more. When the main signal flow between the main node 201 and the access node 202 has a failure in the upward direction, the optical splitter of the main node 201 and the optical switch of the 1 × 2 optical switch cannot detect the main signal transmitted in the upward direction of the original main signal flow, so that the main signal flow is switched to the standby signal flow, and the standby signal transmitted in the upward direction of the standby signal flow is selected to be received. However, when the backup signal flow between the master node 201 and the access node 202 fails in the upstream direction, the optical splitter of the master node 201 and the optical switch of the 1 × 2 optical switch still receive the master signal.

It is understood that the access node 202 may also include a Variable Optical Attenuator (VOA), such that real-time control of Optical signals transmitted by the access node 202 may be achieved by attenuating the transmitted Optical power.

In another possible implementation manner, as shown in fig. 5, an implementation manner of the first single-fiber-to-dual-fiber converter 2016 in the single-fiber ring network structure 200 is a first red-blue band filter 2016, an implementation manner of the second single-fiber-to-dual-fiber converter 2017 is a second red-blue band filter 2017, an implementation manner of the third single-fiber-to-dual-fiber converter 2021 is a first band-pass filter 2021, an implementation manner of the fourth single-fiber-to-dual-fiber converter 2022 is a second band-pass filter 2022, an implementation manner of the first protection module 2011 is an optical splitter and a 1 × 2 optical switch 2011, and an implementation manner of the second protection module 2023 is a 2 × 4 optical switch and a combiner/splitter. That is, the master node 201 in the single-fiber ring network includes N optical splitters and 1 × 2 optical switches 2011, a first multiplexer/demultiplexer 2014, a first group of optical amplifiers 2012, a first red-blue band filter 2016, a second multiplexer/demultiplexer 2015, a second group of optical amplifiers 2013, and a second red-blue band filter 2017, where a value of the N is determined by upper and lower wavelength ports of the first multiplexer/demultiplexer 2014 and the second multiplexer/demultiplexer 2015, and the N is greater than or equal to the number of the upper and lower wavelength ports of the first multiplexer/demultiplexer 2014 and the second multiplexer/demultiplexer 2015; the access node 202 includes a 2x 4 optical switch, a combiner/splitter (referred to as a third combiner/splitter in this embodiment for the sake of distinction), a first bandpass filter 2021, and a second bandpass filter 2022. The specific connection relationship of each device in the single fiber ring network is as follows: in the main signal flow direction of the downstream signal, the optical splitter and the 1 × 2 optical switch 2011 in the main node 201 are sequentially connected to the first multiplexer/demultiplexer 2014, the first group of optical amplifiers 2012 and the first red-blue band filter 2016; the first bandpass filter 2021, the 2x 4 optical switch and the third multiplexer/demultiplexer in the access node 202 are connected in sequence; in the standby signal flow direction of the downlink signal, the optical splitter and the 1 × 2 optical switch 2011 in the master node 201 are sequentially connected with the second multiplexer/demultiplexer 2015, the second group of optical amplifiers 2013 and the second red-blue band filter 2017; the second band-pass filter 2022, the 2x 4 optical switch and the third combiner/demultiplexer in the access node 202 are connected in sequence. In this scheme, the signal flow direction in the single fiber ring network structure may be as follows:

during downlink signals, taking the channel a as an example, the signals are upwaved by the optical splitter in the master node 201 and the optical splitter part of the 1 × 2 optical switch, and the main signal flow direction and the standby signal flow direction are sent to the master node 201; in the main signal flow direction, the optical signal of the channel a is combined with the optical signals on other channels through the wave combining part in the first wave combiner 2014, amplified by the optical amplifier connected to the wave combining part and output to the first red and blue band filter 2016, and converted into a single fiber by the first red and blue band filter 2016 for transmission; after the combined optical signal of the channel a reaches the access node 202 through a single fiber, it goes down through the drop port of the first bandpass filter 2021, and then goes down through the 2 × 4 optical switch of the access node 202 to the wavelength division part of the third multiplexer/demultiplexer. In the standby signal flow direction, the optical signal of the channel a is multiplexed with the optical signals on other channels through the multiplexing part in the second multiplexer/demultiplexer 2015, amplified by the optical amplifier connected with the multiplexing part and output to the second red-blue band filter 2017, and converted into a single fiber by the second red-blue band filter 2017 for transmission; after the combined optical signal of the channel a reaches the access node 202 through a single fiber, it is down-waved through the down wave port of the second band-pass filter 2022, and then is selected by the 2 × 4 optical switch of the access node 202, and since the access node 202 selects the optical signal in the main signal flow direction, the optical signal in the backup signal flow direction is not selected any more. When the main signal flow between the main node 201 and the access node 202 fails in the upward direction, the 2 × 4 optical switch of the access node 202 cannot detect the main signal transmitted in the upward direction from the original main signal flow, and therefore switches to the standby signal flow, and selects to receive the standby signal transmitted in the upward direction from the standby signal flow. The 2x 4 optical switch of the access node 202 remains receiving the primary signal when the backup signal flow between the primary node 201 and the access node 202 fails in the upstream direction.

In the uplink signal, taking channel B as an example, since the optical signal is up-converted by the multiplexer/demultiplexer in the access node 202 and sent to the 2 × 4 optical switch, the sending optical switch state and the receiving optical switch state of the 2 × 4 optical switch are kept the same, when the access node 202 receives the main signal in the downlink signal, the 2 × 4 optical switch sends the optical signal of channel B to the main signal flow direction; in the main signal flow direction, the optical signal of the channel B is converted into a single fiber for transmission through the upstream port of the first band-pass filter 2021; after the optical signal of the channel B reaches the host node 201 through a single fiber, the optical signal is converted into a dual-fiber bi-directional signal through the first red and blue band filter 2016, amplified by the optical amplifier, sent to the first multiplexer/demultiplexer 2014, dropped through the wavelength division part of the first multiplexer/demultiplexer 2014, and selectively received through the optical splitter of the host node 201 and the optical switch of the 1 × 2 optical switch. In the standby signal flow direction, no optical signal is transmitted in the standby signal flow direction because the transmit optical switch state of the 2x 4 optical switch of access node 202 does not select the standby signal. When the main signal flow between the main node 201 and the access node 202 fails in the upward direction, the optical splitter of the main node 201 and the optical switch of the 1 × 2 optical switch 2011 cannot detect the main signal transmitted in the upward direction of the original main signal flow, so that the main signal flow is switched to the standby signal flow, and the standby signal transmitted in the upward direction of the standby signal flow is selected to be received. However, when the backup signal flow between the master node 201 and the access node 202 fails in the upstream direction, the optical splitter of the master node 201 and the optical switch of the 1 × 2 optical switch 2011 still receive the master signal.

In another possible implementation manner, as shown in fig. 6, an implementation manner of the first single-fiber-to-dual-fiber converter 2016 in the single-fiber ring network structure 200 is a first optical cross wavelength division multiplexer 2016, an implementation manner of the second single-fiber-to-dual-fiber converter 2017 is a second optical cross wavelength division multiplexer 2017, an implementation manner of the third single-fiber-to-dual-fiber converter 2021 is a first band-pass filter 2021, an implementation manner of the fourth single-fiber-to-dual-fiber converter 2022 is a second band-pass filter 2022, an implementation manner of the first protection module 2011 is an optical splitter and a 1 × 2 optical switch 2011, and an implementation manner of the second protection module 2023 is a 2 × 4 optical switch and a combiner/splitter. That is, the master node 201 in the single-fiber ring network includes N optical splitters and 1 × 2 optical switches 2011, a first multiplexer/demultiplexer 2014, a first group of optical amplifiers 2012, a first optical cross-wavelength multiplexer 2016, a second multiplexer/demultiplexer 2015, a second group of optical amplifiers 2013, and a second optical cross-wavelength multiplexer/demultiplexer 2017, where a value of the N is determined by upper and lower wavelength ports of the first multiplexer/demultiplexer 2014 and the second multiplexer/demultiplexer 2015, and the N is greater than or equal to the number of the upper and lower wavelength ports of the first multiplexer/demultiplexer 2014 and the second multiplexer/demultiplexer 2015; the access node 202 includes a 2x 4 optical switch, two combiner/splitters (referred to as a third combiner/splitter and a fourth combiner/splitter in this embodiment for the sake of distinction), a first bandpass filter 2021, and a second bandpass filter 2022. The specific connection relationship of each device in the single fiber ring network is as follows: in the main signal flow direction of the downstream signal, the optical splitter and the 1 × 2 optical switch 2011 in the main node 201 are sequentially connected to the first multiplexer/demultiplexer 2014, the first group of optical amplifiers 2012 and the first optical cross wavelength division multiplexer 2016; the first bandpass filter 2021, the third combiner/splitter, and the 2x 4 optical switch in the access node 202 are connected in sequence; in the standby signal flow direction of the downlink signal, the optical splitter and the 1 × 2 optical switch 2011 in the master node 201 are sequentially connected with the second multiplexer/demultiplexer 2015, the second group of optical amplifiers 2013 and the second optical cross wavelength division multiplexer 2017; the second band-pass filter 2022, the fourth multiplexer/demultiplexer and the 2x 4 optical switch in the access node 202 are connected in sequence. In this scheme, the signal flow direction in the single fiber ring network structure may be as follows:

during downlink signals, taking the channel a as an example, the signals are upwaved by the optical splitter in the master node 201 and the optical splitter part of the 1 × 2 optical switch, and the main signal flow direction and the standby signal flow direction are sent to the master node 201; in the main signal flow direction, the optical signal of the channel a is combined with the optical signals on other channels through the wave combining part in the first multiplexer/demultiplexer 2014, amplified by the optical amplifier connected to the wave combining part and output to the first optical cross wavelength division multiplexer 2016, and converted into a single fiber by the first optical cross wavelength division multiplexer 2016 for transmission; after the main signal flows upward, the combined optical signal of the channel a reaches the access node 202 through a single fiber, then is down-wave through the down-wave port of the first band-pass filter 2021, then is down-wave through the wavelength division part of the third combining/splitting filter, and finally is selectively received through the 2 × 4 optical switch. In the standby signal flow direction, the optical signal of the channel a is multiplexed with the optical signals on other channels through the multiplexing part in the second multiplexer/demultiplexer 2015, amplified by the optical amplifier connected with the multiplexing part and output to the second optical cross wavelength division multiplexer 2017, and converted into a single fiber by the second optical cross wavelength division multiplexer 2017 for transmission; when the backup signal flows upward, the optical signal of the combined channel a reaches the access node 202 through a single fiber, then goes down through the down wave port of the second band-pass filter 2022, goes down through the wavelength division part of the fourth multiplexer/demultiplexer, and is selected through the 2 × 4 optical switch of the access node 202, and because the access node 202 selects the optical signal in the main signal flow direction, the optical signal in the backup signal flow direction is not selected any more. When the main signal flow between the main node 201 and the access node 202 fails in the upward direction, the 2 × 4 optical switch of the access node 202 cannot detect the main signal transmitted in the upward direction from the original main signal flow, and therefore switches to the standby signal flow, and selects to receive the standby signal transmitted in the upward direction from the standby signal flow. The 2x 4 optical switch of the access node 202 remains receiving the primary signal when the backup signal flow between the primary node 201 and the access node 202 fails in the upstream direction.

In the uplink signal, taking channel B as an example, the sending optical switch state and the receiving optical switch state of the 2 × 4 optical switch are kept the same, so when the access node 202 receives the main signal in the downlink signal, the 2 × 4 optical switch sends the optical signal of channel B to the main signal flow direction, and then sends the optical signal to the add-drop part of the third add-drop filter in the access node 202 for add-drop; then, the optical signal of the channel B is converted into a single fiber for transmission through the add port of the first band-pass filter 2021; after the optical signal of the channel B reaches the host node 201 through a single fiber, the optical signal is converted into a dual-fiber bidirectional signal by the first optical cross wavelength division multiplexer 2016, amplified by the optical amplifier, sent to the first multiplexer/demultiplexer 2014, dropped by the wavelength division part of the first multiplexer/demultiplexer 2014, and selectively received by the optical splitter of the host node 201 and the optical switch in the 1 × 2 optical switch 2011. In the standby signal flow direction, no optical signal is transmitted in the standby signal flow direction because the transmit optical switch state of the 2x 4 optical switch of access node 202 does not select the standby signal. When the main signal flow between the main node 201 and the access node 202 fails in the upward direction, the optical splitter of the main node 201 and the optical switch of the 1 × 2 optical switch 2011 cannot detect the main signal transmitted in the upward direction of the original main signal flow, so that the main signal flow is switched to the standby signal flow, and the standby signal transmitted in the upward direction of the standby signal flow is selected to be received. However, when the backup signal flow between the master node 201 and the access node 202 fails in the upstream direction, the optical splitter of the master node 201 and the optical switch of the 1 × 2 optical switch still receive the master signal.

In another possible implementation, as shown in fig. 7, an implementation manner of the first single-fiber-to-dual-fiber converter 2016 in the single-fiber ring network structure 200 is a first optical cross wavelength division multiplexer 2016, an implementation manner of the second single-fiber-to-dual-fiber converter 2017 is a second optical cross wavelength division multiplexer 2017, an implementation manner of the third single-fiber-to-dual-fiber converter 2021 is a first band-pass filter plus a third optical cross wavelength division multiplexer 2021, an implementation manner of the fourth single-fiber-to-dual-fiber converter 2022 is a second band-pass filter plus a fourth optical cross wavelength division multiplexer 2022, an implementation manner of the first protection module 2011 is a 2 & lt 4 & gt optical switch 2011, and an implementation manner of the second protection module 2023 is a 1 & lt 2 & gt coupler plus 1 & lt 2 & gt optical splitter and a multiplexer/demultiplexer. That is, the master node 201 in the single-fiber ring network includes N2 × 4 optical switches 2011, a first multiplexer/demultiplexer 2014, a first group of optical amplifiers 2012, a first optical cross wavelength division multiplexer 2016, a second multiplexer/demultiplexer 2015, a second group of optical amplifiers 2013, and a second optical cross wavelength division multiplexer 2017, where a value of the N is determined by upper and lower wavelength ports of the first multiplexer/demultiplexer 2014 and the second multiplexer/demultiplexer 2015, and the N is greater than or equal to the number of the upper and lower wavelength ports of the first multiplexer/demultiplexer 2014 and the second multiplexer/demultiplexer 2015; the access node 202 comprises 1 x 2 couplers and 1 x 2 splitters, combiners and first and third optical cross-multiplexers 2021, second and fourth optical cross-multiplexers 2022. The specific connection relationship of each device in the single fiber ring network is as follows: in the main signal flow direction of the downstream signal, the 2 × 4 optical switch 2011 in the main node 201 is connected to the first multiplexer/demultiplexer 2014, the first group of optical amplifiers 2012 and the first optical cross wavelength division multiplexer 2016 in sequence; the first band-pass filter, the third optical cross wavelength division multiplexer, the 1 x 2 coupler, the 1 x 2 splitter and the multiplexer-demultiplexer in the access node 202 are connected in sequence; in the standby signal flow direction of the downlink signal, the 2 × 4 optical switch 2011 in the master node 201 is sequentially connected with the second multiplexer/demultiplexer 2015, the second group of optical amplifiers 2013 and the second optical cross wavelength division multiplexer 2017; the second band-pass filter, the fourth optical cross wavelength division multiplexer, the 1 x 2 coupler, the 1 x 2 splitter and the multiplexer/demultiplexer in the access node 202 are connected in sequence. In this scheme, the signal flow direction in the single fiber ring network structure may be as follows:

in the case of a downlink signal, taking channel a as an example, the optical signal of channel a is sent in the main signal direction through the 2 × 4 optical switch 2011 in the master node 201; in the main signal flow direction, the optical signal of the channel a is combined with the optical signals on other channels through the wave combining part in the first multiplexer/demultiplexer 2014, amplified by the optical amplifier connected to the wave combining part and output to the first optical cross wavelength division multiplexer 2016, and converted into a single fiber by the first optical cross wavelength division multiplexer 2016 for transmission; after the main signal flows upward, the combined optical signal of the channel a reaches the access node 202 through a single fiber, and then is down-waved through the first band-pass filter and the down-wave port of the third optical cross wavelength division multiplexer, and then is down-waved through the coupler section of the 1 × 2 coupler and the 1 × 2 splitter and the wavelength division section of the third combiner/splitter. In the backup signal flow direction, the master node 201 does not transmit the optical signal of channel a to the backup signal, and thus the access node 202 does not receive the backup signal. When the main signal flow between the main node 201 and the access node 202 fails in the upward direction, the 2 × 4 optical switch of the main node 201 switches to the standby signal flow because it cannot detect the signal in the upward direction of the main signal flow, and then transmits the optical signal in the upward direction of the standby signal flow. When the backup signal flow between the master node 201 and the access node 202 fails in the upstream direction, the master node 201 remains transmitting optical signals in the upstream direction.

When an uplink signal is received, taking channel B as an example, the optical signal of channel B is multiplexed with the optical signals of other channels through the multiplexing part of the multiplexer/demultiplexer, and then sent to the main signal flow direction, and then sent to the multiplexing part of the third multiplexer/demultiplexer in the access node 202 for uplink; then, the optical signal is sent to a main signal flow direction and a standby signal flow direction through the optical splitter parts in the 1 x 2 coupler and the 1 x 2 optical splitter; in the main signal flow direction, the optical signal is converted into a single fiber for transmission through an upper wave port of a third optical cross wavelength division multiplexer and a first band-pass filter; after the optical signal of the channel B reaches the master node 201 through a single fiber, the optical signal is converted into a dual-fiber bidirectional signal through the first optical cross wavelength division multiplexer 2016, amplified by the optical amplifier, and then sent to the first multiplexer/demultiplexer 2014, and down-waves through the wavelength division part of the first multiplexer/demultiplexer 2014, and then selected through the 2x 4 optical switch of the master node 201, because the sending optical switch state and the receiving optical switch state of the 2x 4 optical switch are maintained the same, when the sending optical switch state of the master node 201 in the down-going signal is the master signal, the master node 201 also selects the master signal in the receiving optical switch state. In the standby signal flow direction, the optical signal is converted into a single fiber for transmission through the fourth optical cross wavelength division multiplexer and the upper wave port of the second band-pass filter; after the optical signal of the channel B reaches the master node 201 through a single fiber, the optical signal is converted into a dual-fiber bidirectional signal by the second optical cross wavelength division multiplexer 2017, amplified by the optical amplifier and then sent to the second multiplexer/demultiplexer 2015, the optical signal is down-wave by the wavelength division part of the second multiplexer/demultiplexer 2015 and then selected by the 2x 4 optical switch of the master node 201, and since the sending optical switch state and the receiving optical switch state of the 2x 4 optical switch are kept the same, when the sending optical switch state of the master node 201 in the downlink signal is the master signal, the master node 201 does not receive any standby signal. When the main signal flow between the main node 201 and the access node 202 has a failure in the upward direction, the optical splitter of the main node 201 and the optical switch of the 1 × 2 optical switch cannot detect the main signal transmitted in the upward direction of the original main signal flow, so that the main signal flow is switched to the standby signal flow, and the standby signal transmitted in the upward direction of the standby signal flow is selected to be received. However, when the backup signal flow between the master node 201 and the access node 202 fails in the upstream direction, the optical splitter of the master node 201 and the optical switch of the 1 × 2 optical switch still receive the master signal.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be substantially implemented or contributed to by the prior art, or all or part of the technical solution may be embodied in a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

A single fiber ring network structure, comprising:

the main node and the access node are configured with a main signal flow direction and a standby signal flow direction, and the main signal flow direction is opposite to the standby signal flow direction;

the main node is connected with the access node through a single fiber between the nodes;

the main node comprises a first protection module, a first group of optical amplifiers, a second group of optical amplifiers, a first multiplexer/demultiplexer, a second multiplexer/demultiplexer, a first single-fiber-double-fiber converter and a second single-fiber-double-fiber converter, wherein the first protection module is used for selecting;

the access node comprises a third single-fiber-double-fiber converter, a fourth single-fiber-double-fiber converter and a second protection module;

in a main signal flow direction in which the main node sends a signal to the access node, the first protection module, the first multiplexer/demultiplexer, the first group of optical amplifiers, and the first single-fiber/dual-fiber converter are sequentially connected; the third single-fiber-double-fiber converter is connected with the second protection module in sequence;

in a standby signal flow direction in which the master node sends a signal to the access node, the first protection module, the second multiplexer/demultiplexer, the second group of optical amplifiers, and the second single-fiber/dual-fiber converter are sequentially connected; the fourth single-fiber-double-fiber converter and the second protection module are connected in sequence.
The single fiber ring network structure of claim 1, wherein the first protection module is a two-way optical switch or an optical splitter and 1 x 2 optical switch, and the optical splitter and 1 x 2 optical switch comprise an optical switch and an optical splitter.
The single fiber ring network structure of claim 1, wherein the first single-to-dual fiber converter is a red-blue band filter or an optical cross-wavelength division multiplexer;

the second single-fiber-double-fiber converter is a red-blue band filter or an optical cross wavelength division multiplexer.
The single fiber ring network structure of claim 1, wherein the second protection module comprises 1 x 2 couplers and 1 x 2 splitters and combiners;

or the like, or, alternatively,

the second protection module comprises a 2x 4 optical switch and a multiplexer/demultiplexer;

or the like, or, alternatively,

the second protection module comprises an optical splitter, a 1 x 2 optical switch and a multiplexer/demultiplexer.
The single fiber ring network structure of claim 1, wherein the third single-to-dual fiber converter includes a band pass filter;

or the like, or, alternatively,

the third single-fiber-to-double-fiber converter comprises a band-pass filter and an optical cross wavelength division multiplexer;

the fourth single-fiber-to-dual-fiber converter comprises a band-pass filter;

or the like, or, alternatively,

the fourth single-fiber-to-dual-fiber converter includes a band-pass filter and an optical cross-wavelength division multiplexer.
The single fiber ring network structure of any one of claims 1 to 5, wherein the first protection module comprises an optical protection splitter and a 1 x 2 optical switch, and the first single-fiber-to-dual-fiber converter and the second single-fiber-to-dual-fiber converter are red-blue band filters;

the second protection module comprises an optical splitter, a 1 x 2 optical switch and a combiner-splitter, the third single-fiber-dual-fiber converter and the fourth single-fiber-dual-fiber converter are band-pass filters, wherein a main node sends a signal to the access node, the main signal flows upwards, the band-pass filters, the optical splitter, the 1 x 2 optical switch and the combiner-splitter are sequentially connected, the main node sends a signal to the access node, and the main node sends a signal to the access node, the signal flows upwards, the band-pass filters, the optical splitter, the 1 x 2 optical switch and the combiner-splitter are sequentially connected.
The single fiber ring network structure of any one of claims 1 to 5, wherein the first protection module comprises an optical splitter and a 1 x 2 optical switch, the first and second single-to-dual fiber converters being optical cross-wavelength division multiplexers;

the second protection module comprises an optical splitter, a 1 x 2 optical switch and a multiplexer/demultiplexer, the third single-fiber-dual-fiber converter and the fourth single-fiber-dual-fiber converter comprise a band-pass filter and an optical cross wavelength division multiplexer, wherein a main signal of a signal sent by the main node to the access node flows upwards, the band-pass filter, the optical cross wavelength division multiplexer, the optical splitter, the 1 x 2 optical switch and the multiplexer/demultiplexer are sequentially connected, and a standby signal of a signal sent by the main node to the access node flows upwards, the band-pass filter, the optical cross wavelength division multiplexer, the optical splitter, the 1 x 2 optical switch and the multiplexer/demultiplexer are sequentially connected.
The single fiber ring network structure of any one of claims 1 to 5, wherein the first protection module comprises an optical splitter and a 1 x 2 optical switch, and the first single-to-dual fiber converter and the second single-to-dual fiber converter are red-to-blue band filters;

the second protection module comprises a 2x 4 optical switch and a multiplexer-demultiplexer, the third single-fiber-dual-fiber converter and the fourth single-fiber-dual-fiber converter are band-pass filters, wherein a main signal flow of a signal sent by the main node to the access node is upward, the band-pass filters, the 2x 4 optical switch and the multiplexer-demultiplexer are sequentially connected, a standby signal flow of a signal sent by the main node to the access node is upward, and the band-pass filters, the 2x 4 optical switch and the multiplexer-demultiplexer are sequentially connected.
The single fiber ring network structure of any one of claims 1 to 5, wherein the first protection module comprises an optical splitter and a 1 x 2 optical switch, the first and second single-to-dual fiber converters being optical cross-wavelength division multiplexers;

the second protection module comprises a 2x 4 optical switch and a multiplexer/demultiplexer, the third single-fiber-dual-fiber converter and the fourth single-fiber-dual-fiber converter are band-pass filters, wherein a main signal of a signal sent by the main node to the access node flows upwards, the band-pass filters, the multiplexer/demultiplexer and the 2x 4 optical switch are sequentially connected, a standby signal of a signal sent by the main node to the access node flows upwards, and the band-pass filters, the multiplexer/demultiplexer and the 2x 4 optical switch are sequentially connected.
The single fiber ring network structure of any one of claims 1 to 5, wherein the first protection module comprises a 2x 4 optical switch, and the first and second single-to-dual fiber converters are optical cross-wavelength division multiplexers;

the second protection module comprises a 1 x 2 coupler, a 1 x 2 optical splitter and a combiner-splitter, the third single-fiber-dual-fiber converter and the fourth single-fiber-dual-fiber converter are band-pass filters, wherein a main signal flow of a signal sent by the main node to the access node is upward, the band-pass filters, the 1 x 2 coupler, the 1 x 2 optical splitter and the combiner-splitter are sequentially connected, and a standby signal flow of a signal sent by the main node to the access node is upward, and the band-pass filters, the 1 x 2 coupler, the 1 x 2 optical splitter and the combiner-splitter are sequentially connected.