Method for Tuning an Optical-Electrical Transceiver in an Optical Network

Abstract

The present disclosure relates to a method for tuning an optical and electrical transceiver in an optical network. The method may include: powering on a first optical and electrical transceiver; receiving a first request command at the first optical and electrical transceiver; responding to the first request command; setting a channel wavelength of the first optical and electrical transceiver; sending a second request command including the set channel wavelength of the first optical and electrical transceiver from the first optical and electrical transceiver to a second optical and electrical transceiver; and waiting to receive an acknowledgment command from the second optical and electrical transceiver.

Description

[0001] This application is a divisional application of the invention patent application with the application date of January 9, 2019, the application number of "201910020012.3", and the invention title of "Method for Tuning an Optical and Electrical Transceiver in an Optical Network". Technical Field

[0002] The present disclosure generally relates to signal transmission using optoelectronic devices. Background Art

[0003] In some cases, optoelectronic devices can be used to transmit signals or data in a multiplexed network. Multiplexing is a technique that enables multiple signals to be transmitted simultaneously over the same transmission medium. Wavelength Division Multiplexing ("WDM") enables multiple optical signals to be transmitted through the same optical fiber. This is achieved by having each signal have a different wavelength. At the transmitting side, the individual signals with different wavelengths are transmitted in the same optical fiber. At the receiving end of the transmission, the wavelengths are typically separated. The advantage of a WDM system is that it effectively provides virtual optical fibers by having a single optical fiber carry multiple optical signals with different carrier wavelengths.

[0004] Dense Wavelength Division Multiplexing ("DWDM") systems can use carrier wavelengths where the spacing between the carrier wavelengths is less than a nanometer. In a DWDM system, more carrier wavelengths can be used to increase the capacity of the DWDM system. The wavelength emitted by an optoelectronic module can be adjusted as needed based on the emission wavelength and the target wavelength. The ability to adjust the wavelength is useful in optical systems, particularly in DWDM systems.

[0005] Some optical networks can implement a unidirectional optical system. Such a system is configured to transmit optical signals in one direction through a single first optical cable and to transmit signals in the opposite second direction through a second optical cable different from the first optical cable. Such a system can be considered "unidirectional" because each optical cable is only used to transmit optical signals in one direction. A unidirectional optical system can implement a duplex transceiver coupled to two optical fibers, one optical fiber for transmitting data in the first direction and the second optical fiber for transmitting data in the opposite second direction. In some cases, these two directions can be referred to as the east direction and the west direction. Other optical networks implement a bidirectional system that uses one optical fiber to transmit data in two directions (e.g., east and west). A bidirectional system transmits signals in the first direction and the opposite second direction through the same optical cable.

[0006] The subject matter claimed herein is not limited to implementations that solve any disadvantages or operate only in environments such as those described above. Rather, this background is only provided to illustrate an example technical field in which some of the implementations described herein may be practiced. Summary of the Invention

[0007] The present disclosure generally relates to signal transmission using optoelectronic devices.

[0008] In one aspect, a method of tuning an optoelectronic transceiver in an optical network having a wavelength selection component includes: powering on a first optoelectronic transceiver; setting a channel wavelength of the first optoelectronic transceiver; sending a first request command from the first optoelectronic transceiver to a second optoelectronic transceiver through the optical network; and non-iteratively changing the channel wavelength of the first optoelectronic transceiver until a second request command is received from the second optoelectronic transceiver, wherein the second request command indicates to the first optoelectronic transceiver that the channel wavelength set by the first optoelectronic transceiver can propagate between the first optoelectronic transceiver and the second optoelectronic transceiver through the optical network.

[0009] In another aspect, a method of tuning an optoelectronic transceiver in an optical network includes: powering on a first optoelectronic transceiver; receiving a first request command at the first optoelectronic transceiver; responding to the first request command; setting a channel wavelength of the first optoelectronic transceiver; sending a second request command including the set channel wavelength of the first optoelectronic transceiver from the first optoelectronic transceiver to a second optoelectronic transceiver; and waiting to receive an acknowledgment command from the second optoelectronic transceiver.

[0010] In an example embodiment, a method of tuning an optoelectronic transceiver in an optical network may include: powering on the optoelectronic transceiver; setting a channel wavelength of the optoelectronic transceiver; sending a request command from the optoelectronic transceiver to another optoelectronic transceiver through the optical network; and waiting to receive a second request command from the other optoelectronic transceiver.

[0011] In some aspects, the optical network may include a wavelength selection component. The request command sent from the optoelectronic transceiver to another optoelectronic transceiver through the optical network may include channel establishment information. The request command and the second request command may be sent as out-of-band optical signals. The second request command may indicate to the optoelectronic transceiver that the particular wavelength can propagate between the optoelectronic transceiver and another optoelectronic transceiver through the optical network.

[0012] In some aspects, the optoelectronic transceiver and another optoelectronic transceiver located on opposite sides of the optical network may be substantially the same.

[0013] The method may include: changing the channel wavelength of the optoelectronic transceiver in response to elapse of a predetermined amount of time. The method may include: iteratively incrementing the wavelength channel of the optoelectronic transceiver by one iteration until the second request command is received.

[0014] In some aspects, the operating wavelengths of an optical network can be divided into wavelength pairs, where a wavelength pair has a first wavelength for one direction and a further wavelength for the opposite second direction, and the optical-electrical transceiver can alternate between the wavelengths of the wavelength pair.

[0015] The method can include: sending a reply in response to receiving a second request command from another optical-electrical transceiver. The request command can be used to send channel information and / or wavelength information.

[0016] In some aspects, the optical-electrical transceiver can be configured to send and receive messages of a predetermined type, and the types of messages include channel notifications during scanning and message types for channel detection replies.

[0017] In another example, a method of tuning an optical-electrical transceiver in an optical network can include: powering on a first optical-electrical transceiver; receiving a first request command at the first optical-electrical transceiver; responding to the first request command; setting the channel wavelength of the first optical-electrical transceiver; sending a second request command that includes the channel wavelength of the first optical-electrical transceiver and / or the first request command; and waiting to receive a reply command from a second optical-electrical transceiver.

[0018] In some aspects, the optical-electrical transceiver may not have information about the channels and wavelengths on which the optical-electrical transceiver should operate when powered on.

[0019] The method can include: changing the channel wavelength of the first optical-electrical transceiver if a reply command is not received after a predetermined amount of time has elapsed; and sending a third request command that includes the changed channel wavelength.

[0020] The method can include: iteratively incrementing the wavelength channel of the first optical-electrical transceiver by one iteration until a reply command is received. The method can include: starting normal operation of the first optical-electrical transceiver in response to receiving a reply command from the second optical-electrical transceiver.

[0021] In some aspects, responding to the request command can include: sending an acknowledgement if the optical-electrical transceiver can operate at the wavelength of the request command; or, if the request command relates to a remote paired optical-electrical transceiver, the optical-electrical transceiver forwards the request command to the remote paired transceiver.

[0022] In some aspects, the request command can be received from a network management system or another optical-electrical transceiver via the optical network. The second request command can be received at a second optical-electrical transceiver, and the method can include: setting the second optical-electrical transceiver to an appropriate operating wavelength based on the information received in the second request command.

[0023] In another example, a method for tuning an optical - electrical transceiver in an optical network may include: powering on a first optical - electrical transceiver; receiving a first request command at the first optical - electrical transceiver; in response to the first optical - electrical transceiver being able to operate at the wavelength of the first request command, responding to the first request command with a first reply; sending a second request command to a corresponding second optical - electrical transceiver; and receiving a second reply from the corresponding second optical - electrical transceiver.

[0024] In some aspects, the second reply may include confirmation that the corresponding second optical - electrical transceiver is set to operate at the channel wavelength specified in the second request command. The optical - electrical transceiver may not have information about the channels and wavelengths at which the optical - electrical transceiver should operate when powered on. The optical - electrical transceiver may be configured to send and receive predetermined types of messages, and the types of messages may include channel notifications for scanning and message types for channel detection replies.

[0025] In some cases, an optical network implementing the concepts described herein may include wavelength - selecting components and / or wavelength - selecting optical links. In such a configuration, when a specified channel is sent through the wavelength - selecting optical link, the receiver side can receive the optical signal based on the configuration of the wavelength - selecting component and can respond to establish an optical link with a corresponding local wavelength that can be sent through the wavelength - selecting optical link.

[0026] This summary introduces some concepts in a simplified form that will be further described in the detailed description below. This summary is not intended to identify key features or essential characteristics of the claimed subject matter, nor is it intended to be used to help determine the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of an example of a two - way system.

[0028] Figure 2 is a schematic diagram of an example of a two - way dense wavelength division multiplexing system.

[0029] Figure 3A and Figure 3B is a schematic diagram of an example configuration of a filter.

[0030] Figure 4 is a schematic diagram of an example of a multi - point system.

[0031] Figure 5 is a flowchart of an example method for tuning a transceiver in an optical network.

[0032] Figure 6 is a flowchart of an example method for tuning a transceiver in an optical network including a network management system (NMS).

[0033] Figure 7 FIG. 1 is a flow chart of another example method for tuning a transceiver in an optical network including a network management system (NMS).

[0034] Figures 8A to 8B FIG. 2 shows a flow chart of another example method for tuning a transceiver in an optical network including a network management system (NMS). DETAILED DESCRIPTION

[0035] Aspects of the present disclosure will be described with reference to the drawings and in specific language. The use of the drawings and description in this manner should not be construed as limiting its scope. Other aspects may be apparent from the present disclosure including the claims, or may be learned by practice.

[0036] The present disclosure generally relates to signal transmission using optoelectronic modules. As used herein, the term "optoelectronic module" includes a module having optical components and electrical components. Examples of optoelectronic modules include, but are not limited to, transponders, transceivers, transmitters, and / or receivers.

[0037] In particular, the present disclosure relates to optical wavelength tuning of optical transceiver wavelength division multiplexing ("WDM") or dense wavelength division multiplexing ("DWDM") systems. In some configurations, aspects of the present disclosure may be implemented in a bidirectional DWDM system, but the concepts described herein may also be implemented in other systems.

[0038] The present disclosure includes a wavelength band polling configuration that may be implemented using an out-of-band communication signal to automatically tune the wavelength of a bidirectional tunable transceiver in an optical network. The automatic tuning and selection of the transceiver wavelength may facilitate the implementation of optical transceivers in WDM or DWDM systems. In particular, the described configuration may reduce the steps required to deploy optical transceivers in WDM or DWDM systems because the transceiver does not have to be tuned by the user during or after installation.

[0039] Such a configuration may be referred to as "plug and play" because the steps required to complete installation are limited after the transceiver is inserted to interface with the system. Additionally, the described configuration may be relatively low cost and may be implemented in the transceiver without significantly increasing the cost of the transceiver or the system implementing such a transceiver.

[0040] In previous configurations of DWDM systems, wavelength tuning was typically performed manually using a master transceiver and a slave transceiver. The wavelength of the master transceiver was selected by a network management system. Based on the information sent from the master transceiver, the wavelength of the slave transceiver was tuned to match the predefined wavelength of the master transceiver. In some configurations, the master transceiver may be included in the head-end equipment (HEE) of the system, and the slave transceiver may be included in the tail-end equipment (TEE). In one example configuration, the HEE and TEE are defined in ITU-T G.698.4 (previously known as G.metro).

[0041] In some configurations, the disclosed concepts may be implemented in a cellular network. For example, the disclosed concepts may be implemented in a C-RAN architecture for mobile network infrastructure for LTE-A and 5G wireless applications. In some configurations, the disclosed concepts may be implemented in ultra-dense WDM applications enabled by coherent detection and tunable transceiver functionality. For example, the disclosed concepts may be implemented for WDM standards such as G.698.4.

[0042] Colorless or fixed-wavelength bi-directional transceivers may be a suitable C-RAN architecture for LTE-A and 5G wireless systems because DWDM systems provide higher bandwidth, and at the same time implementing colorless bi-directional transceivers can help reduce network deployment and maintenance costs.

[0043] The described automatic wavelength tuning configuration can help eliminate wavelength-related installation and maintenance costs because the wavelength of the transceiver is automatically tuned. Therefore, wavelength tuning may not be required during transceiver setup. In addition, maintenance regarding the wavelength of the transceiver may not have to be performed because the transceiver is automatically tuned to the appropriate wavelength.

[0044] Additionally, the described configuration allows the use of the same transceivers on both sides of a bidirectional system, which can reduce costs and simplify inventory since the same components (e.g., part numbers) can be used on both sides of the system. In contrast, in a typical bidirectional system configuration, transceivers on one side and transceivers on the other side are usually sold as a matching pair, where the transceivers on each side include different configurations (and thus different part numbers). Such a matching pair is acceptable to system vendors when the network includes a star architecture such as a headend or hub site and multiple tail or remote sides because it is relatively easy to match the type of transceiver to the type of node, but it can result in additional maintenance costs if the network has a ring-based architecture. Because the unpaired transceivers at both ends of a link within the ring may not be able to correctly transmit optical signals, it may be necessary to insert a matching pair of transceivers at both ends of the link within the ring, which in turn increases the maintenance cost due to the difficulty of pairing the transceivers at both ends of the link and matching the node type or link direction to the type of transceiver. This matching difficulty may increase the deployment cost of bidirectional transceivers in ring-based networks such as metropolitan area network applications.

[0045] The described embodiments may include optical interface specifications for a horizontally compatible bidirectional DWDM system, which can be implemented in metropolitan area network applications. Tail-end equipment (TEE) transmitters can have the ability to automatically adapt their DWDM channel frequencies to the optical demultiplexer / optical multiplexer (OD / OM) or optical add / drop multiplexer (OADM) ports to which they are connected using feedback from a head-end equipment (HEE) via a head-to-tail message channel (HTMC). In some configurations, the optical link for a point-to-point DWDM application can be a single-mode fiber that is shared end-to-end in both propagation directions by the same optical fiber. The link between the TEE and the HEE can be a passive link and may not include an optical amplifier.

[0046] Figure 1Schematic diagram of an example of a bidirectional system 100. System 100 is an example of a system that can implement the concepts described herein. System 100 includes a head-end device 102 and a tail-end device 104 optically coupled to a DWDM link 106. The head-end device 102 includes transceivers 112a to 112n optically coupled to an optical multiplexer or optical demultiplexer (OD / OM) 114. Each of the transceivers 112a to 112n may include a corresponding transmitter TX and a corresponding receiver RX. The OD / OM 114 may combine optical signals from the transmitters TX of the transceivers 112a to 112n for transmission via an optical link 116. In addition, the OD / OM 114 may separate optical signals received via the optical link 116 and direct the corresponding signals to the receivers RX of the transceivers 112a to 112n. In some configurations, the optical link 116 may be a single bidirectional optical fiber, but other configurations may also be implemented.

[0047] The tail-end 104 includes transceivers 114a to 114n, each transceiver including a corresponding transmitter TX and a corresponding receiver RX. Each of the transceivers 114a to 114n is optically coupled to the DWDM link 106 via a corresponding optical link 118a to 118n to transmit and receive optical signals.

[0048] System 100 also includes transceivers 120a to 120n on the tail-end 104, each transceiver including a corresponding transmitter TX and a corresponding receiver RX. Each of the transceivers 120a to 120n is optically coupled to the DWDM link 106 via a corresponding optical link 122a to 122n to transmit and receive optical signals. The optical links 122a to 122n may be bidirectional. In some configurations, the transceivers 120a to 120n may be part of the primary side of the tail-end 104.

[0049] The DWDM link 106 is optically coupled to the head-end 102, the tail-end 104, and the transceivers 120a to 120n. The DWDM link 106 includes a DWDM network element 110, which may include an optical add-drop multiplexer (OADM) 124 and an OD / OM 126. In other configurations, the OADM 124 may not be included in the DWDM link 106.

[0050] The OD / OM 126 can combine optical signals from the transmitters TX of the transceivers 120a to 120n for transmission via the optical link 128, which can be bidirectional. Additionally, the OD / OM 126 can separate the optical signals received via the optical link 128 and direct the corresponding signals to the receivers RX of the transceivers 120a to 120n. The OADM 124 can be optically coupled to the OD / OM 126 via the optical link 128, optically coupled to the headend 102 via the optical link 116, and optically coupled to the transceivers 114a to 114n via the optical links 118a to 118n. In some configurations, the optical links 118a to 118n can be bidirectional optical fibers, but other configurations can also be implemented.

[0051] The OADM 124 can act as a passive link between the transceivers 112a to 112n of the headend 102 and the transceivers 114a to 114n of the tailend 104. Specifically, the OADM 124 can direct optical signals having a specific wavelength from the transceivers 112a - 112n to the corresponding transceivers of the transceivers 114a to 114n, or vice versa.

[0052] In the illustrated configuration, the transceivers 112a to 112n of the headend 102 can operate as master transceivers in wavelength band A, and the transceivers 114a to 114n of the tailend 104 can operate as slave transceivers in wavelength band B, which is a paired wavelength band corresponding to wavelength band A. As used herein, a wavelength band can refer to a group of wavelengths or a group of wavelength ranges.

[0053] The transceivers 114a to 114n of the tailend 104 can have the ability to automatically adapt their DWDM channel frequencies to specific ports of the OD / OM126 or the OADM 124. Such an implementation can allow the transceivers 112a to 112n of the headend to communicate with the transceivers 114a to 114n of the tailend 104 without having to exchange any additional information at startup. Some implementations can send data at a rate of up to 10 gigabits per second (Gbit / s) with a channel frequency spacing of 50 gigahertz (GHz) and / or 100 GHz. Additionally, some implementations can include a transmission distance of up to 20 kilometers (km) with a capacity of up to 40 bidirectional channels.

[0054] The optical signals propagating from the headend 102 to the DWDM link 106 via the optical link 116 can be multi-channel data signals transmitted by the transceivers 112a to 112n of the headend 102. The optical signals propagating from the DWDM link 106 to the headend 102 via the optical link 116 can be multi-channel data signals received by the transceivers 112a to 112n of the headend 102.

[0055] The optical signals propagating from the tail end 104 to the DWDM link 106 through the optical links 118a to 118n can be single-channel data signals. The optical signals propagating from the DWDM link 106 to the transceivers 114a to 114n at the tail end 104 through the optical links 118a to 118n can be single-channel data signals. At the S S interface, the single-channel signals can be transmitted by the transceivers in the transceivers 114a to 114n at the tail end 104 whose wavelengths are suitable for the wavelengths of the OD / OM 126 or OADM 124 ports to which they are connected.

[0056] For each optical channel, different frequency ranges are used in the head-end to tail-end direction and the tail-end to head-end direction. The channel frequencies in both directions can be paired such that their difference is equal to the minimum value compatible with the frequency range.

[0057] In one example, the optical channel frequencies can be paired according to Table 1 with a channel frequency spacing of 100 GHz:

[0058] Table 1:

[0059] HE to TE TE to HE 194.1 191.5 194.2 191.6 … … 196 193.4

[0060] In another example, the optical channel frequencies can be paired according to Table 2 with a channel frequency spacing of 50 GHz:

[0061] Table 2:

[0062] HE to TE TE to HE 194.05 191.45 194.1 191.5 … … 196 193.4

[0063] Figure 2 is a schematic diagram of an example of a bidirectional dense wavelength division multiplexing (“DWDM”) system 150. The system 150 includes a plurality of transceivers 154 on one side of the optical fiber 152 and a plurality of transceivers 156 on the other side of the optical fiber 152. Each transceiver 154 includes a transmitter 160, a receiver 162, and a filter 164, and each transceiver 156 includes a transmitter 170, a receiver 172, and a filter 174, and the filter 174 is configured to exchange optical signals via the optical fiber 152.

[0064] In some configurations, each channel of system 150 has a different wavelength. In such a configuration, each of transceivers 154, 156 can be configured to transmit and receive optical signals having different wavelengths. In particular, each of transceivers 154, 156 can be configured to transmit an optical signal at a first wavelength or wavelength range and receive an optical signal at a second wavelength or wavelength range different from the first wavelength or wavelength range. In such a configuration, each channel can operate at two different wavelengths, one wavelength for a first direction (e.g., east direction) and another wavelength for a second direction (e.g., west direction).

[0065] System 150 also includes an optical multiplexer / demultiplexer (mux / demux) 180 on one side of optical fiber 152 and a mux / demux 182 on the other side of optical fiber 152. The mux / demux 180 receives different optical signals (e.g., different channels) from transmitter 160 of transceiver 154 and combines the optical signals for transmission through optical fiber 152. The mux / demux 182 receives the combined optical signals from transceiver 154 and separates the optical signals for reception by corresponding receiver 172 of transceiver 154. Similarly, the mux / demux 182 receives different optical signals (e.g., different channels) from transmitter 170 of transceiver 154 and combines the optical signals for transmission through optical fiber 152. The mux / demux 180 receives the combined optical signals from transceiver 156 and separates the optical signals for reception by corresponding receiver 162 of transceiver 154. In some configurations, the mux / demux 180 and the mux / demux 182 can be 100 gigahertz (GHz) mux / demuxes. Additionally or alternatively, the mux / demux 180 and the mux / demux 182 can include one or more thin film filters, or an arrayed waveguide grating (AWG), such as a circulator or a general AWG.

[0066] As Figure 2 shown, system 150 conveys optical signals from different optical transceivers 154, 156 through optical fiber 152. System 150 includes optical multiplexers / demultiplexers 180, 182 that direct optical signals between different transceivers 154, 156. Although Figure 2 four transceivers 154, 156 are shown in detail, system 150 can include any suitable number of transceivers, where each pair of transceivers corresponds to one optical signal channel that can propagate through the optical fiber. Additionally, the illustrated system 150 can include any suitable number of channels, and each channel can be associated with a different wavelength or wavelength range of light.

[0067] System 150 can be a bidirectional system, which means that system 150 is configured to send signals in a first direction and an opposite second direction over the same optical cable (i.e., optical fiber 152). This is in contrast to a unidirectional system, which includes a dedicated optical cable for signals in one direction and another optical cable for signals in the opposite direction. Thus, optical fiber 152 can be a bidirectional optical fiber. Additionally, system 150 can be a bidirectional dense wavelength division multiplexing system or a bidirectional colorless system, and system 150 can be configured to send data signals and time synchronization signals in a first direction and an opposite second direction over optical fiber 152.

[0068] Filter 164 can be configured to transmit the wavelength of the optical signal from transmitter 160 such that the optical signal from transmitter 160 propagates to multiplexer / demultiplexer 180. Additionally, filter 164 can be configured to reflect or otherwise direct the wavelength of the optical signal from multiplexer / demultiplexer 180 to receiver 162. Similarly, filter 174 can be configured to transmit the wavelength of the optical signal from transmitter 170 such that the optical signal from transmitter 170 propagates to multiplexer / demultiplexer 182. Additionally, filter 174 can be configured to reflect or otherwise direct the wavelength of the optical signal from multiplexer / demultiplexer 182 to receiver 172. In some configurations, filters 164, 174 can be tunable filters, narrowband circulator filters, periodic filters, edge filters, or other suitable filters.

[0069] Filters 164, 174 can be configured to transmit optical signals having a certain wavelength or wavelength range and reflect optical signals having another wavelength or wavelength range. Additionally, if filters 164, 174 are tunable filters, the configuration can be changed such that optical transceivers 154, 156 can operate at different channels and on different sides of optical fiber 152. In other configurations, instead of or in addition to filters 164, 174, mirrors or other suitable optical components can be implemented to direct optical signals.

[0070] In some configurations, system 150 may include a wavelength locker, a power detector, and / or a network management system (NMS). For example, as shown, system 150 may include an external wavelength locker, an optical channel monitor (OCM), and / or a power detector 190 as part of the NMS. The NMS may be implemented to send wavelength tuning information and / or power tuning information to transceivers in an optical network. In some embodiments, the NMS may be coupled to the wavelength locker and the power detector 190, and may collect information from the wavelength locker and the power detector 190 to determine information about the optical network. Then, this information may be used to configure components in the optical network, e.g., transceivers in the optical network. However, in other configurations such as those described below, the NMS and the wavelength locker and the power detector 190 may not be included.

[0071] Figure 3A and Figure 3B is a schematic diagram of an example configuration of a filter. In particular, Figure 3A is a schematic diagram of configuration 200, Figure 3B is a schematic diagram of configuration 220. As Figure 3A shown, in configuration 200, filter 202 transmits optical signals in a first wavelength range 204 and reflects optical signals in a second wavelength range 206. In such a configuration, a transmitter may send an optical signal in the first wavelength range 204, and the optical signal propagates through filter 202 in a first direction (e.g., eastward). In addition, filter 202 receives optical signals propagating in a second direction (e.g., westward) opposite to the first direction, and reflects optical signals in the second wavelength range 206, which may be sent to a receiver. Thus, filter 202 directs optical signals to the transmitter and the receiver based on wavelength.

[0072] As Figure 3B shown, in configuration 220, filter 202 transmits optical signals in the second wavelength range 206 and reflects optical signals in the first wavelength range 204. In such a configuration, a transmitter may send an optical signal in the second wavelength range 206, and the optical signal propagates through filter 202 in a first direction (e.g., eastward). In addition, filter 202 receives optical signals propagating in a second direction (e.g., westward) opposite to the first direction, and reflects optical signals in the first wavelength range 204, which may be sent to a receiver. Thus, filter 202 directs optical signals to the transmitter and the receiver based on wavelength.

[0073] In some cases, configuration 200 may be implemented on one side of a bidirectional DWDM system (see, for example, Figure 2), and the configuration 220 can be implemented on the other side of the bidirectional DWDM system to transmit and receive an optical signal channel according to the direction through different wavelengths. Since the filter 202 can be a tunable filter, the same filter can be implemented on both sides of the bidirectional DWDM system. Therefore, the transceivers and related hardware on both sides of the bidirectional DWDM system can be the same (e.g., only different in the tuning configuration of the filter 202). In addition, the tuning of the filter 202 can be changed (e.g., tuned) to accommodate different wavelengths or channels used in the bidirectional DWDM system. In particular, the tuning of the filter 202 can be changed to reflect or transmit optical signals of different wavelengths or wavelength ranges to direct optical signals of different channels. In some configurations, the filter 202 can be tuned by changing the temperature of the filter 202, but other suitable configurations and types of tunable filters can also be implemented.

[0074] In some cases, the concepts described herein can be implemented in a multi-point system having a bidirectional DWDM system. Figure 4 is a schematic diagram of an example of the multi-point system 300. The system 300 includes a head end 302, which can support 40 optical signal channels 1 to 40 (or any other suitable number of optical channels), where corresponding transceivers TRX01a to TRX40a are used for each optical signal channel. The head end 302 is optically coupled to a multiplexer / demultiplexer 304, which can multiplex and / or demultiplex the optical signals propagating to or from the transceivers TRX01a to TRX40a. The multiplexer / demultiplexer 304 can be optically coupled to a bidirectional optical fiber 306, which enables the transmission of the multiplexed optical signals to other parts of the system 300, e.g., sent to the tail ends 310a to 310f. The tail ends 310a to 310f can be optically coupled to other components of the system 300 via any suitable components such as an OADM or a multiplexer / demultiplexer.

[0075] For example, OADM 312a is optically coupled to the tail end 310a via corresponding transceivers TRX01b to TRX03b to insert / drop optical channels 1 to 3. Similarly, OADM 312b is optically coupled to the tail end 310b via corresponding transceivers TRX04b to TRX06b to insert / drop optical channels 4 to 6. Multiplexer / demultiplexer 314 drops a portion of the remaining optical channels (e.g., optical channels 7 to 40) and directs optical channels 7 to 12 to the tail end 310c. Multiplexer / demultiplexer 316 is optically coupled between multiplexer / demultiplexer 314 and the tail end 310c to direct optical channels 7 to 12 to the corresponding transceivers TRX07b to TRX12b. OADM 312c is optically coupled to the tail end 310d via corresponding transceivers TRX13b to TRX14b to insert / drop optical channels 13 to 14. OADM 312d is optically coupled to the tail end 310e via corresponding transceivers TRX16b to TRX16b to insert / drop optical channels 16 to 18. Multiplexer / demultiplexer 317 drops the remaining optical channels (e.g., optical channels 21 to 40) and directs optical channels 21 to 40 to the tail end 310f. In particular, multiplexer / demultiplexer 318 directs optical channels 21 to 40 to the corresponding transceivers TRX21b to TRX40b.

[0076] As described above, the disclosed embodiments relate to a wavelength band polling configuration that can be implemented to automatically tune the wavelengths of bidirectional tunable transceivers in an optical network. In some aspects, the wavelength band polling configuration can include an out-of-band communication signal that tunes the wavelength of a transceiver. The automatic tuning and selection of transceiver wavelengths can facilitate the implementation of optical transceivers in a WDM or DWDM system.

[0077] Figure 5 is a flowchart of an example method 500 for tuning a transceiver in an optical network. Method 500 can be implemented, for example, in the above-described system, such as in Figure 1 , Figure 2 and Figure 4 systems 100, 150, and / or 300. In some configurations, method 500 can be performed by a transceiver that can be part of a bidirectional DWDM system, such as the transceivers described above. Although shown as discrete blocks, various blocks can be divided into additional blocks, combined into fewer blocks, or removed depending on the desired implementation.

[0078] Method 500 may begin at step 502, where a transceiver may be powered on. When the transceiver is powered on, it may not have information about the channels and wavelengths on which it should operate. The transceiver may need to pair with another corresponding transceiver optically coupled via an optical network, but the transceiver may not know the specific channels that should be used. Additionally, the transceiver may not have information about whether it should operate in a master configuration or a slave configuration.

[0079] In some configurations, the operating wavelengths of an optical network may be divided into wavelength pairs, where a first wavelength is for one direction (e.g., the east direction) and another wavelength is for the opposite second direction (e.g., the west direction). For each transceiver, the first wavelength may correspond to the transceiver's transmitter, and the second wavelength may correspond to the receiver, or if the transceiver is on the other side of the optical network, the first wavelength may correspond to the transceiver's receiver, and the second wavelength may correspond to the transmitter. In some aspects, the first wavelength may correspond to a main frequency band, and the second wavelength may correspond to a slave frequency band, although other configurations may also be implemented.

[0080] In a configuration implementing wavelength pairs, the transceiver may not have information about which side of the optical network it is located on when it is powered on, and thus, it may also not have information about which specific wavelength of the wavelength pair it should use (e.g., the wavelength for the east direction for a given channel, or the wavelength for the west direction for that channel).

[0081] Thus, after startup, the transceiver may begin scanning to identify on which channels and / or which wavelengths it should operate. Although, as described, method 500 is performed by a transceiver located on one side of the optical network, it should be understood that method 500 may also be performed by a corresponding transceiver on the other side of the optical network. Additionally, each transceiver that is part of the optical network may perform method 500 to identify on which channels and / or which wavelengths it should operate.

[0082] At step 504, the transceiver may set its channel wavelength. In some configurations, the channel wavelength may be set to a random value, and the random value may be selected from a list of possible wavelength channels compatible with the transceiver. In other configurations, the transceiver may set its channel wavelength to a predefined value determined before the transceiver was powered on.

[0083] At step 506, the transceiver may send a request command. In some configurations, the request command may include the transceiver's channel wavelength and / or the request command (e.g., the set channel wavelength from step 504), which may be a random value selected from a list of possible wavelength channels. In other configurations, the request command may not include the transceiver's channel wavelength.

[0084] The request command can be sent as an optical signal from the transmitter of the transceiver. The request command can propagate from the transceiver through an optical network such as a bidirectional DWDM system to the corresponding transceiver that receives the request command. In particular, the request command can be received at the receiver of the corresponding transceiver. In some configurations, the request command can include channel establishment information or other aspects related to the optical network.

[0085] In some embodiments, the request command can be sent as an out-of-band optical signal. In some cases, the optical signals exchanged by the transceiver (or corresponding transceiver pair) can include in-band optical signals and out-of-band (OOB) optical signals. In-band optical signals can generally be used to send high-speed data and can include electronic files or programs sent over a computer network, commands and status signals sent between two buildings on a campus or servers in a server farm, or the transfer of various files. In contrast, OOB optical signals can include data related to the management and status of the optical network, optical signals, and / or the optical channels carrying the optical signals. For example, OOB optical signals can include data indicating the optical signal intensity, commands to reduce the optical signal intensity, and / or commands to increase the optical signal intensity, and / or transceiver memory mapping information.

[0086] OOB optical signals can be sent in a different manner from in-band optical signals. For example, OOB optical signals can be frequency or amplitude modulated and sent together with in-band optical signals without disrupting or interfering with the in-band optical signals. In some cases, the in-band optical signal can be a relatively high-speed data signal, while the OOB optical signal can be a relatively low-speed data signal (or at least slower than the in-band optical signal).

[0087] At step 508, the transceiver can wait to receive an optical signal from the corresponding transceiver, such as a second request command. As described above, in some embodiments, the transceivers on both sides of the system can be substantially the same. And in some embodiments, the corresponding transceiver on the other side of the system can perform method 500 for tuning the transceiver in the optical network. In such a configuration, as described with respect to step 504, the corresponding transceiver on the other side of the system can send an optical signal and / or a request command (e.g., a second request command) at the channel wavelength of the corresponding transceiver. Thus, the second request command from the corresponding transceiver can propagate through the system to the transceiver, and the transceiver can receive the second request command. Additionally or alternatively, step 508 can include receiving an optical signal or receiving the second request command as an optical signal from the corresponding transceiver and / or through the optical network. In some configurations, the second request command can be received as an out-of-band optical signal.

[0088] The received second request command can indicate to the transceiver that the particular wavelength can propagate through the optical system, e.g., between the transceiver and a corresponding transceiver on the other side of the optical system. As described above, in some cases, the second request command can include wavelength information. In such a case, the transceiver can determine the wavelength of the optical signal that can be transmitted between the two transceivers.

[0089] If the second request command is not received after a certain amount of time, the transceiver can proceed to step 510, in which the transceiver changes the channel wavelength. In some configurations, the transceiver can wait for a predetermined amount of time before proceeding to step 510. In some cases, the amount of time the transceiver waits can be the timeout length, and this length can be adjustable or configurable. In some embodiments, the transceiver can be configured to increase the channel wavelength by one iteration (e.g., one wavelength range). Then, method 500 can return to step 506, in which the transceiver can send a request command at the new channel wavelength. Method 500 can continue by iteratively increasing the wavelength channel by one iteration until the second request command is received, or until the maximum wavelength channel is reached. If the maximum wavelength channel is reached, the transceiver can change the channel wavelength to the lowest channel wavelength, and the iterative increase of the channel wavelength can continue until the second request command is received. In this way, the transceiver can scan all possible wavelength channels until a suitable channel is identified.

[0090] Although in one example embodiment the channel wavelength is iteratively increased until the second request command is received, in other configurations, the suitable wavelength can be identified in other ways. For example, the channel wavelength can be changed randomly instead of increased. In such a configuration, the channel wavelength can be changed with or without repeating the previous channel wavelength until a message is received from the corresponding transceiver.

[0091] If the operating wavelength of the optical network is divided into a wavelength pair having a first wavelength for one direction and another wavelength for the opposite second direction, the transceiver can alternate between the wavelengths of the wavelength pair. Additionally or alternatively, the transceiver can receive alternating wavelength pairs from the corresponding transceiver. The transceiver can use the alternating wavelength pairs to determine on which side of the optical network they are located.

[0092] If a second request command is received, method 500 may proceed to step 512, in which the transceiver may send a response and / or update its channel wavelength based on the received second request command, e.g., via an optical network, to a corresponding transceiver. In some configurations, the second request command received from the corresponding transceiver may include the channel wavelength of the corresponding transceiver. In such a configuration, if necessary, the transceiver may update its channel wavelength based on the channel wavelength of the corresponding transceiver. Whether or not the second request command includes the channel wavelength of the corresponding transceiver, the transceiver may send a response. In some configurations, the response may be sent as an OOB optical signal. Additionally or alternatively, the response may include local channel information.

[0093] As described above, the operating wavelengths of the optical network may be divided into wavelength pairs having a first wavelength for one direction and another wavelength for the opposite second direction. In such a configuration, the transceiver may receive the second request command and determine its wavelength, and then the transceiver may switch to the other wavelength in the corresponding wavelength pair for transmission.

[0094] Once the channel pairing is confirmed by both the transceiver and the corresponding transceiver on the other side of the network, one or both of the transceivers may switch to the channel pairing mode.

[0095] At step 514, the transceiver and / or the corresponding transceiver may terminate tuning and / or may begin normal transceiver operation. Normal transceiver operation may include sending data signals via the optical network and / or exchanging data signals with the corresponding transceiver. In some configurations, the data signals exchanged may be inbound optical signals.

[0096] In some configurations, step 514 may be regarded as the normal operating state of the transceiver. Additionally or alternatively, steps 504 to 510 may be regarded as the tuning steps or discovery state of the transceiver. Step 502 may be regarded as the startup state of the transceiver, or may be included in the tuning steps or discovery state.

[0097] If the transceiver stops receiving data signals from the corresponding transceiver, or if the transceiver otherwise detects improper or undesirable operation, method 500 may return to step 510, and the transceiver may initiate a tuning step or discovery state.

[0098] As described above, the transceiver can scan to identify on which channel and / or at which wavelength it should operate. In some configurations, the channel and / or wavelength can be sent together with the request command, and as described with respect to step 506, the request command (and the channel and / or wavelength) can be sent as an OOB optical signal. In other configurations, the request command may not include channel information and / or wavelength information, and in such configurations, the request command may not be sent as an OOB optical signal. In some cases, scanning with channel information and / or wavelength information can be faster than scanning without the channel and / or wavelength, because the corresponding station can use the received channel information to determine the local channel wavelength and skip the scanning of potentially unnecessary local wavelengths to save scanning time. In particular, skipping the scanning of local wavelengths to save scanning time can be achieved in a configuration in which the wavelengths in two directions (e.g., the east direction and the west direction) of the optical network are paired, and for a specific port in the design of passive components based on a bidirectional system, the specific link in both directions is designed to be transparent to the wavelength pair for facilitating bidirectional optical transmission. In other words, when scanning with channel information and / or wavelength information, only one successful attempt may be needed to obtain the required channel information in any direction, which also saves scanning time.

[0099] In one example configuration, the transceiver can be powered on without wavelength and band information. The transceiver can divide all wavelengths into two bands (e.g., band A as the main band and band B as the secondary band). In one aspect, for a pair of bidirectional transceivers, band A can be used for the transmit direction and band B can be used for the receive direction, or band A can be used for the receive direction and band B can be used for the transmit direction. One transceiver in the transceiver pair can start a full-channel fast scan alternately with band A and band B (e.g., without sending channel information and / or wavelength information via an OOB optical signal). Once the transceiver receives optical power from the corresponding transceiver on the other side of the optical network, the transceiver can lock the current band as the target band, and the transceiver can send a full-channel fast scan of the target band. When the corresponding transceiver receives optical power from the first transceiver, it can lock the current band as the target band and send a full-channel fast scan of the target band.

[0100] In some aspects, a transceiver operating on band A can be the master transceiver, and a transceiver operating on band B can be the slave transceiver. The master transceiver can start a full-channel slow scan in the target band and can send the current channel number via an OOB optical signal (e.g., to the corresponding transceiver). The slave transceiver can receive the sent OOB optical signal and, once it receives the target channel information via the OOB optical signal, can lock the target channel and send an acknowledgment to the master transceiver. Then, the slave transceiver can start operating on the target channel. The master transceiver can receive the acknowledgment from the slave transceiver and, once it receives the acknowledgment from the slave transceiver, can stop the full-channel slow scan and lock the current channel as the target channel. Then, the master transceiver can start operating on the target channel. Once the channel pairing is confirmed, the slave transceiver and the master transceiver can switch to the channel pairing mode.

[0101] In a configuration without using an external wavelength locker, optical channel monitor, and / or power detector, paired transceivers can poll the master and the slave as needed as described above. However, in other configurations, a wavelength locker and a power detector can be implemented. Additionally, in some configurations, a network management system (NMS) can be implemented, and the NMS can issue wavelength tuning information and / or power tuning information to transceivers in the optical network. In some embodiments, the NMS can be coupled to the wavelength locker and the power detector and can collect information from the wavelength locker and the power detector to determine information about the optical network. Then, this information can be used to configure components in the optical network, such as transceivers in the optical network.

[0102] In some configurations, the NMS can determine which transceivers in the optical network are master transceivers or slave transceivers and / or can determine which end of the optical network a transceiver is located at. Then, the NMS can use this information to configure the transceivers based on whether the transceiver is a master transceiver or a slave transceiver and / or based on the location of the transceiver in the optical network.

[0103] Figure 6 is a flowchart of an example method 600 for tuning transceivers in an optical network including a network management system (NMS). Method 600 can be implemented, for example, in the above-described systems, such as in Figure 1 , Figure 2 and Figure 4 systems 100, 150, and / or 300. In some configurations, method 600 can be executed by a transceiver that can be part of a bidirectional DWDM system, such as the above-described transceivers. Although shown as discrete blocks, the individual blocks can be divided into additional blocks, combined into fewer blocks, or removed according to the desired implementation.

[0104] Method 600 may start at step 602, where a transceiver may be powered on. When the transceiver is powered on, it may not have information about the channels and wavelengths on which it should operate. The transceiver may need to pair with another corresponding transceiver optically coupled via an optical network, but the transceiver may not know the specific channels to be used. Additionally, the transceiver may not have information about whether it should operate in a master configuration or a slave configuration or its location in the optical network (e.g., which side of the optical network it is on). In some configurations, the transceiver may default to operating in a slave configuration unless it receives a request command indicating otherwise, although other configurations may be implemented.

[0105] In some configurations, the NMS may identify which transceivers are on which side of the optical network. For example, for two corresponding transceivers, the NMS may identify that one of the transceivers is on one side of the optical network and the other transceiver is on the other side of the optical network. Additionally or alternatively, the NMS may identify one of the transceivers as the master transceiver and the other transceiver as the slave transceiver. Further, the NMS may send a request command to one or both of the transceivers in a pair of transceivers. The request command may include wavelength tuning information and / or power tuning information. In some embodiments, the request command may identify whether the transceiver is a master transceiver or a slave transceiver. In some configurations, the request command may be sent as an OOB optical signal.

[0106] At step 604, a request command may be received at the transceiver, e.g., from the NMS or a corresponding transceiver on the other side of the optical network.

[0107] At step 606, the transceiver may respond to the NMS's request command. For example, if the transceiver can operate at the wavelength requested by the NMS, the transceiver may respond to the tuning request with a reply or confirmation, or if the request is related to a remote paired transceiver, the transceiver may forward the request command to the remote paired transceiver. For example, if the transceiver is identified as the master transceiver, it may forward the request command for the slave transceiver to the corresponding slave transceiver, or if the transceiver is identified as the slave transceiver, it may forward the request command for the master transceiver to the corresponding master transceiver. Responding to the request command may include the transceiver setting itself to a master configuration or a slave configuration according to the content of the request command received from the NMS.

[0108] Since the transceiver receives information about its operating state (e.g., master or slave) from the NMS. The transceiver may not need to determine whether it is a master transceiver or a slave transceiver and / or on which side of the optical network it is located. In a configuration where the operating wavelengths of the optical network are divided into wavelength pairs, the transceiver may have information about the direction in which it transmits the optical signal (e.g., east direction or west direction), but it may not have information about which specific wavelength should be used. Therefore, after identifying whether it is master or slave, the transceiver can start scanning to identify which channel and / or which wavelength it should operate on.

[0109] Since the transceiver has information about the direction in which it transmits the optical signal (e.g., east direction or west direction), it may not need to scan half of the possible optical wavelengths. For example, if the transceiver has received information from the NMS that it is a master transceiver and / or information that it transmits signals in the east direction, the transceiver may only need to scan the wavelengths corresponding to the east direction and not need to scan any wavelengths corresponding to the west direction. Such a configuration can result in a relatively faster scan, but may require additional components such as an NMS, an external wavelength locker, and / or a power detector.

[0110] Although as described, method 600 is performed by a transceiver located on one side of the optical network, it should be understood that method 600 can also be performed by a corresponding transceiver on the other side of the optical network. Additionally, each transceiver that is part of the optical network can perform method 600 to identify which channel and / or which wavelength it should operate on.

[0111] At step 608, the transceiver can set its channel wavelength. In some configurations, the channel wavelength can be set to a random value, and the random value can be selected from a list of possible wavelength channels that are compatible with the transceiver and correspond to a frequency band specified for one direction (e.g., east direction or west direction) in the optical network.

[0112] At step 610, the transceiver can send a request command. The request command can include the channel wavelength of the transceiver and / or the request command (e.g., the set channel wavelength from step 608), and the channel wavelength can be a random value selected from a list of possible wavelength channels. The request command can be sent as an optical signal from the transmitter of the transceiver. The request command can propagate from the transceiver and through the optical network to the corresponding transceiver that receives the request command. In particular, the request command can be received at the receiver of the corresponding transceiver. In some configurations, the request command can include channel establishment information or other aspects related to the optical network. In some embodiments, the request command can be sent as an out-of-band optical signal.

[0113] In some cases, the corresponding transceiver that receives the request command can be a slave transceiver. In response to receiving the request command, the corresponding transceiver can set itself to an appropriate operating wavelength, for example, based on the information received in the request command. Additionally or alternatively, the corresponding transceiver can send a response command to the transceiver that sent the request command via the optical network. In some configurations, the response command can be sent as an out-of-band optical signal.

[0114] At step 612, the transceiver can wait to receive an optical signal, such as a response command from the corresponding transceiver. The received response command can indicate to the transceiver that the particular wavelength can propagate through the optical system, for example, between the transceiver and the corresponding transceiver on the other side of the optical system. In some cases, the response command can include wavelength information. In such a case, the transceiver can determine the wavelength of the optical signal that can be transmitted between the two transceivers based on the response command.

[0115] If no response command is received after a certain amount of time, the transceiver can proceed to step 614, where the transceiver changes the channel wavelength. In some configurations, the transceiver can wait for a predetermined amount of time before proceeding to step 614. In some cases, the amount of time the transceiver waits can be a timeout length, and this time length can be adjustable or configurable. In some embodiments, the transceiver can be configured to increase the channel wavelength by one iteration (e.g., one wavelength range). Then, method 600 can return to step 610, where the transceiver can send a request command with the new channel wavelength.

[0116] Method 600 can continue by iteratively increasing the wavelength channel by one iteration until a response command is received, or until the maximum wavelength channel is reached. If the maximum wavelength channel is reached, the transceiver can change the channel wavelength to the lowest channel wavelength, and the iterative increase of the channel wavelength can continue until a second request command is received. In this way, the transceiver can scan all possible wavelength channels until a suitable channel is identified. However, as described above, since the transceiver has information about whether it is a master transceiver or a slave transceiver and / or information about its location in the wireless network, the number of wavelength channels scanned can be reduced compared to method 500.

[0117] Once the channel pairing is confirmed by the transceiver and the corresponding transceiver on the other side of the network, one or both of the transceivers can switch to the channel pairing mode.

[0118] At step 616, the transceiver and / or corresponding transceiver may terminate tuning and / or may begin normal transceiver operation. The transceiver may terminate tuning and / or may begin normal transceiver operation in response to receiving an acknowledgment command from another transceiver. Normal transceiver operation may include transmitting data signals over the optical network and / or exchanging data signals with the corresponding transceiver. In some configurations, the exchanged data signals may be inbound optical signals.

[0119] In some configurations, step 616 may be considered the normal operating state of the transceiver. Additionally or alternatively, steps 604 to 612 may be considered the tuning steps or discovery state of the transceiver. Step 602 may be considered the startup state of the transceiver, or step 602 may be included in the tuning steps or discovery state.

[0120] If the transceiver stops receiving data signals from the corresponding transceiver, or if the transceiver otherwise detects improper or undesirable operation, method 600 may return to step 614, and the transceiver may initiate the tuning steps or discovery state of the transceiver.

[0121] As described above, in some configurations, a wavelength locker, a power detector, and an NMS may be used to determine information about the optical network. Then, this information may be used to configure the transceiver as, for example, a master transceiver or a slave transceiver. Additionally or alternatively, in some configurations, the NMS may collect information from the wavelength locker and the power detector to determine on which channel wavelength the transceiver in the optical network should operate.

[0122] Figure 7 is a flowchart of an example method 700 for tuning a transceiver in an optical network including a network management system (NMS). Method 700 may be implemented, for example, in the systems described above, such as in Figure 1 , Figure 2 and Figure 4 systems 100, 150, and / or 300. In some configurations, method 700 may be performed by a transceiver, which may be part of a bidirectional DWDM system, such as the transceiver described above. Although shown as discrete blocks, the individual blocks may be divided into additional blocks, combined into fewer blocks, or removed according to the desired implementation.

[0123] Method 700 may begin at step 702, in which a transceiver may be powered on. When the transceiver is powered on, the transceiver may not have information about the channels and wavelengths on which it should operate. The transceiver may need to pair with another corresponding transceiver optically coupled via an optical network, but the transceiver may not know the specific channels that should be used. Additionally, the transceiver may not have information about whether it should operate in a master configuration or a slave configuration or its location in the optical network (e.g., which side of the optical network it is located on). In some configurations, the transceiver may default to operating in a slave configuration unless it receives a request command indicating otherwise, although other configurations may be implemented.

[0124] As described above, in some configurations, the NMS may identify which transceivers are on which side of the optical network and / or may identify which transceivers should be set as master or slave transceivers. Additionally or alternatively, the NMS may identify which channel wavelength the transceivers in the optical network should operate on. The NMS may send a request command to one or both transceivers in a pair of transceivers. The request command may include wavelength tuning information and / or power tuning information, including the specific wavelength on which the transceiver should operate. In some configurations, the request command may be sent as an OOB optical signal.

[0125] At step 704, a request command may be received at the transceiver, such as from the NMS or a corresponding transceiver on the other side of the optical network.

[0126] At step 706, the transceiver may respond to the NMS's request command. For example, if the transceiver can operate at the wavelength requested by the NMS, the transceiver may respond to the tuning request with an acknowledgment or confirmation. Responding to the request command may include the transceiver setting itself to a master configuration or a slave configuration according to the content of the request command received from the NMS. Additionally or alternatively, responding to the request command may include the transceiver setting itself to the correct operating wavelength channel based on the content of the request command received from the NMS.

[0127] Since the transceiver receives information from the NMS about the operating state of the transceiver (e.g., master or slave), the direction in which the transceiver sends optical signals (e.g., east direction or west direction), and which wavelength the transceiver should operate on, the transceiver may not need to scan to determine which wavelength it should operate on.

[0128] After the transceiver sets itself to the appropriate operating channel, the transceiver may proceed to tune the corresponding transceiver to the appropriate wavelength channel. For example, if the transceiver is identified as the master transceiver, the transceiver may send a second request command to the corresponding slave transceiver.

[0129] Accordingly, at step 708, the transceiver may send a second request command to the corresponding slave transceiver. The second request command may include wavelength tuning information and / or power tuning information. For example, the second request command may include an identification that the corresponding transceiver is a slave transceiver. Additionally or alternatively, the second request command may include a specific wavelength at which the transceiver should operate. In some configurations, the second request command may be sent as an OOB optical signal.

[0130] The corresponding transceiver may respond to the tuning request with an acknowledgment or confirmation. Specifically, if the corresponding transceiver can operate at the channel wavelength specified in the second request, the corresponding transceiver may respond to the tuning request. Additionally or alternatively, the corresponding transceiver may set itself to operate at the channel wavelength specified in the second request.

[0131] At step 710, the transceiver may receive an acknowledgment from the corresponding transceiver. The acknowledgment may include a confirmation related to the corresponding transceiver being set to operate at the channel wavelength specified in the second request.

[0132] Once the channel pairing is confirmed by the transceiver and the corresponding transceiver on the other side of the network, one or both of the transceivers may switch to the channel pairing mode.

[0133] At step 712, the transceiver and / or the corresponding transceiver may terminate the tuning and / or may start normal transceiver operation. Normal transceiver operation may include sending data signals over the optical network and / or exchanging data signals with the corresponding transceiver. In some configurations, the exchanged data signals may be inbound optical signals.

[0134] In some configurations, the transceiver may be configured to send or receive a specific type of message (TOM). Such a TOM may be specified, for example, in the specification of the physical layer interface for a DWDM system. Such a specification may be standardized by an industry group. In certain cases, additional TOMs may be implemented to apply the configurations described above. For example, a discovery type TOM may be used to indicate the discovery of a remote transceiver. In another example, a channel notification TOM during a scan may be used to indicate a local channel notification when wavelength and band information have not been defined (e.g., corresponding to method 500). In yet another example, a channel detection acknowledgment TOM may be used to indicate an acknowledgment with local channel information based on the received channel information; or an acknowledgment indicating that it has received a signal. In other aspects, other TOMs may be implemented to achieve the configurations described herein.

[0135] In some configurations, the behavior of the TEE can be defined as a state machine that operates on the value of the TOM field in a head-to-tail message channel (HTMC). The state machine can include states such as: the TEE transmitter is off in standby mode; the TEE transmitter is off but ready to start the tuning procedure; the TEE transmitter scans frequencies, transmits a pilot tone at the required tuning power and at the tuning modulation depth; the TEE transmitter transmits within the required channel, transmits a pilot tone at the operating modulation depth and adjusts the output power and frequency; the TEE transmits at the required power and center frequency, transmits a pilot tone at the operating modulation depth and transmits traffic (i.e., normal operation). The TEE transmits at the required power and center frequency, transmits the THMC and transmits traffic (i.e., normal operation). Additionally, to implement the configurations described above, the state machine can include additional states indicating that channel pairing is complete, which can correspond to a channel detection response TOM that can be used to indicate a response such as: a response with local channel information based on the received channel information or a response indicating that it has received a signal. However, other configurations can also be implemented. In other aspects, other state machines can be implemented to achieve the configurations described herein.

[0136] Figures 8A to 8B A flowchart of a wavelength tuning configuration 800 for a remote site end equipment (TEE) is shown. In some cases, at least some aspects of the wavelength tuning configuration can be defined in industry-specified standards such as ITU-T G.698.4. As shown, the configuration 800 can include various states or steps S0, S1, S2, S3, S4, S5, S3a, S4a, S5a for tuning the transceiver. Such states can be specified, for example, in ITU-T G.698.4. However, for the self-tuning of the wavelengths of the master transceiver and the slave transceiver as described above, an additional configuration state S0a can be added for channel pairing. The state S0a can include any suitable aspects of the tuning described above.

[0137] Figures 8A to 8B Also included are various TOMs corresponding to the states of the configuration 800, which can also be defined in industry-specified standards such as ITU-T G.698.4. Table 3 shows a list of TOMs including TOM values, message types, and message contents.

[0138] Table 3

[0139]

[0140]

[0141] A TOM having values from 1 to 11 can be specified in ITU-T G.698.4. However, additional TOMs can be implemented for automatic wavelength tuning. For example, additional TOMs for discovery, channel notification during scanning, and channel detection response can be included for wavelength tuning. In one example, a TOM value 12 can be assigned to the TOM for discovery, however other configurations can be implemented. Accordingly, Table 3 includes TOM 12 for discovery, which corresponds to the discovery of a remote transceiver. Additional TOMs to be assigned can include channel notification during scanning and channel detection response as shown in Table 3. The channel notification TOM during scanning can be a local channel notification when wavelength and band information has not been defined (e.g., as described in method 500). The channel detection response TOM can be a response indicating that local channel information has been received based on channel information or can be a response indicating that a transceiver has received a signal (e.g., as described in method 500).

[0142] In some cases, an optical network implementing the concepts described herein can include wavelength selection components and / or wavelength selection optical links. In such a configuration, when a specified channel is transmitted through a wavelength selection optical link, the receiver side can be able to receive an optical signal based on the configuration of the wavelength selection component, and can respond to establish an optical link having a corresponding local wavelength that can be transmitted through the wavelength selection optical link.

[0143] This application also includes the following technical solutions:

[0144] Solution 1. A method for tuning an optoelectronic transceiver in an optical network having a wavelength selection component, the method comprising:

[0145] Power on the optoelectronic transceiver;

[0146] Set the channel wavelength of the optoelectronic transceiver;

[0147] Send a request command from the optoelectronic transceiver to another optoelectronic transceiver through the optical network; and

[0148] Wait to receive a second request command from the other optoelectronic transceiver.

[0149] Solution 2. The method according to Solution 1, wherein the request command sent from the optoelectronic transceiver to the other optoelectronic transceiver through the optical network includes channel establishment information.

[0150] Solution 3. The method according to Solution 1, wherein the request command and the second request command are sent as out-of-band optical signals.

[0151] Solution 4. The method according to Solution 1, wherein the second request command instructs the optoelectronic transceiver that the specific wavelength can be propagated through the optical network between the optoelectronic transceiver and the other optoelectronic transceiver.

[0152] Solution 5. The method according to Solution 1, wherein the optoelectronic transceiver and the other optoelectronic transceiver located on opposite sides of the optical network are substantially the same.

[0153] Solution 6. The method according to Solution 1, further comprising: changing the channel wavelength of the optoelectronic transceiver in response to a predetermined amount of time elapsing.

[0154] Solution 7. The method according to Solution 1, further comprising: iteratively increasing the wavelength channel of the optoelectronic transceiver by one iteration until the second request command is received.

[0155] Solution 8. The method according to Solution 1, wherein the operating wavelength of the optical network is divided into wavelength pairs, the wavelength pairs having a first wavelength for one direction and an additional wavelength for the opposite second direction, and the optoelectronic transceiver alternates between the wavelengths of the wavelength pairs.

[0156] Solution 9. The method according to Solution 1, further comprising: sending a reply in response to receiving the second request command from the other optoelectronic transceiver.

[0157] Solution 10. The method according to Solution 1, wherein channel information and / or wavelength information is sent using the request command.

[0158] Solution 11. The method according to Solution 1, wherein the optoelectronic transceiver is configured to send and receive predetermined types of messages, and the types of the messages include a channel notification during scanning and a message type for a channel detection reply.

[0159] Solution 12. A method for tuning an optoelectronic transceiver in an optical network having a wavelength selection component, the method comprising:

[0160] Powering on a first optoelectronic transceiver, wherein the optoelectronic transceiver does not have information about the channel and wavelength on which the optoelectronic transceiver should operate when powered on;

[0161] Receiving a first request command at the first optoelectronic transceiver;

[0162] Responding to the first request command;

[0163] Setting the channel wavelength of the first optoelectronic transceiver;

[0164] Send a second request command, where the second request command includes the channel wavelength of the first optical transceiver and / or the first request command; and

[0165] Wait to receive an acknowledgment command from the second optical transceiver.

[0166] Solution 13. The method according to Solution 12 further includes: if the acknowledgment command is not received after a predetermined amount of time has elapsed, change the channel wavelength of the first optical transceiver; and send a third request command including the changed channel wavelength.

[0167] Solution 14. The method according to Solution 12 further includes: iteratively incrementing the wavelength channel of the first optical transceiver by one iteration until the acknowledgment command is received.

[0168] Solution 15. The method according to Solution 12 further includes: in response to receiving the acknowledgment command from the second optical transceiver, start the normal operation of the first optical transceiver.

[0169] Solution 16. The method according to Solution 12, wherein responding to the request command includes:

[0170] If the optical transceiver can operate at the wavelength of the request command, send an acknowledgment; or

[0171] If the request command is related to a remote paired optical transceiver, the optical transceiver forwards the request command to the remote paired transceiver.

[0172] Solution 17. The method according to Solution 12, wherein the request command is received from a network management system or another optical transceiver via the optical network.

[0173] Solution 18. The method according to Solution 12, wherein the second request command is received at the second optical transceiver, and the method further includes: setting the second optical transceiver to an appropriate operating wavelength based on the information received in the second request command.

[0174] Solution 19. A method for tuning an optical transceiver in an optical network, the method including:

[0175] Power on a first optical transceiver, where the optical transceiver does not have information about the channel and wavelength at which the optical transceiver should operate when powered on;

[0176] Receive a first request command at the first optical transceiver;

[0177] In response to the first optical transceiver being able to operate at the wavelength of the first request command, respond to the first request command with a first reply;

[0178] Send a second request command to the corresponding second optical transceiver; and

[0179] Receive a second reply from the corresponding second optical transceiver, the second reply including confirmation that the corresponding second optical transceiver is set to operate at the channel wavelength specified in the second request command.

[0180] Scheme 20. The method according to Scheme 19, wherein the optical transceiver is configured to send and receive messages of a predetermined type, and the types of the messages include a channel notification during a scan and a message type for a channel detection reply.

[0181] Those skilled in the art will understand that for this process and method and other processes and methods disclosed herein, the functions performed in the process and method can be implemented in a different order. In addition, the outlined steps and operations are provided only as examples, and some of the steps and operations can be optional, combined into fewer steps and operations, or extended into additional steps and operations without departing from the essence of the disclosed embodiments.

[0182] The terms and words used in the specification and claims are not limited to the written meanings, but are only used to enable a clear and consistent understanding of the present disclosure. It is to be understood that unless the context clearly dictates otherwise, the singular forms "a", "an", and "the" include plural referents. Thus, for example, a reference to "a component surface" includes a reference to one or more such surfaces.

[0183] By means of the term "substantially", it means that the recited features, parameters, or values need not be precisely achieved, but rather include, for example, tolerances, measurement errors, measurement precision limitations, and deviations or variations due to other factors known to those skilled in the art that can occur in an amount that does not impede the effect that the feature is intended to provide.

[0184] Aspects of the present disclosure can be implemented in other forms without departing from the spirit or essential characteristics of the invention. The described aspects are considered illustrative in all respects and not restrictive. The claimed subject matter is indicated by the appended claims rather than the foregoing description. All changes within the meaning and scope of equivalents of the claims are included in the scope of the claims.

Claims

1. A method for tuning a photoelectric transceiver in an optical network having a wavelength selection component, the method comprises: Powering on a first photoelectric transceiver; Setting a channel wavelength of the first photoelectric transceiver; Sending a first request command from the first photoelectric transceiver to a second photoelectric transceiver through the optical network; and Non-iteratively changing the channel wavelength of the first photoelectric transceiver until a second request command is received from the second photoelectric transceiver, wherein the second request command indicates to the first photoelectric transceiver that the channel wavelength set by the first photoelectric transceiver can propagate between the first photoelectric transceiver and the second photoelectric transceiver through the optical network.

2. The method according to claim 1, wherein Non-iteratively changing the channel wavelength of the first photoelectric transceiver includes randomly changing the channel wavelength of the first photoelectric transceiver.

3. The method according to claim 1, wherein The first request command identifies whether the first photoelectric transceiver is a master transceiver or a slave transceiver.

4. The method according to claim 1, wherein The first request command or the second request command is sent as an out-of-band optical signal.

5. The method according to claim 1, further comprising changing the channel wavelength of the first photoelectric transceiver in response to a predetermined amount of time elapsing.

6. The method according to claim 1, wherein The operating wavelength of the optical network is divided into wavelength pairs, the wavelength pairs having a first wavelength for one direction and an additional wavelength for the opposite second direction, and the first photoelectric transceiver alternates between the wavelengths of the wavelength pair.

7. The method according to claim 1, further comprising sending a response in response to receiving the second request command from the second photoelectric transceiver.

8. The method according to claim 1, wherein The first request command is used to send channel information and / or wavelength information.

9. The method according to claim 1, wherein The first photoelectric transceiver is configured to send and receive messages of a predetermined type, and the types of the messages include a channel notification during scanning and a message type for a channel detection response.

10. A method for tuning a photoelectric transceiver in an optical network, the method comprises: Powering on a first photoelectric transceiver; Receiving a first request command at the first photoelectric transceiver; Responding to the first request command; Setting a channel wavelength of the first photoelectric transceiver; Sending a second request command including the set channel wavelength of the first photoelectric transceiver from the first photoelectric transceiver to a second photoelectric transceiver; and Waiting to receive an answer command from the second photoelectric transceiver.

11. The method according to claim 10, wherein The first request command identifies whether the first photoelectric transceiver is a master transceiver or a slave transceiver.

12. The method according to claim 10, further comprising receiving a second response from the second photoelectric transceiver, the second response including confirmation that the second photoelectric transceiver is set to operate at the channel wavelength specified in the second request command.

13. The method according to claim 10, further comprises: if the response command is not received after a predetermined amount of time, randomly or iteratively changing the channel wavelength of the first optical-electrical transceiver, and transmitting a third request command including the changed channel wavelength.

14. The method according to claim 10, further comprising randomly or iteratively changing the wavelength channel of the first optical-electrical transceiver until the response command is received.

15. The method according to claim 10, further comprises: in response to receiving the response command from the second optical-electrical transceiver, starting the normal operation of the first optical-electrical transceiver at the operating wavelength channel.

16. The method according to claim 10, wherein, responding to the first request command includes: if the request command is related to the second optical-electrical transceiver, the first optical-electrical transceiver forwards the first request command to the second optical-electrical transceiver.

17. The method according to claim 10, wherein, the first request command is received from a network management system or another optical-electrical transceiver through the optical network.

18. The method according to claim 10, wherein, the second request command instructs that the second optical-electrical transceiver will be set at the main operating wavelength or the slave operating wavelength.

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