Optical add / drop multiplexer and optical network

Abstract

One embodiment described herein provides an optical add / drop multiplexer and an optical network. The optical add / drop multiplexer may include a plurality of network interface modules and an optical cross-connect module coupling the plurality of network interface modules. The plurality of network interface modules may include at least: a first network interface module including a first optical component from a first supplier, and a second network interface module including a second optical component from a second supplier. The first optical component and the second optical component have different optical parameters. Another embodiment provides an optical network, which includes a plurality of interconnected optical add / drop multiplexers, including homogeneous optical add / drop multiplexers and heterogeneous optical add / drop multiplexers. The heterogeneous optical add / drop multiplexer may include at least a first network interface module including a first optical component from a first supplier, and a second network interface module including a second optical component from a second supplier.

Description

Technical Field

[0001] The present disclosure generally relates to optical transport networks (OTNs). More specifically, the present disclosure relates to open optical transport networks implementing heterogeneous reconfigurable optical add / drop multiplexers (ROADMs). Background Art

[0002] Optical transport systems and networks have historically been closed and proprietary systems due to the analog nature of optical signals. However, the continued surge in bandwidth demand, coupled with the increasing expectation to access data-intensive applications anywhere, with the lowest possible latency, requires service providers to be able to build networks using the latest innovations without being constrained by vendor lock-in. Open disaggregated optical transport networks are a hot technology for industry research and development, providing their operators with the freedom to deploy best-of-breed equipment at any time and the flexibility to upgrade equipment to meet new needs.

[0003] Current open disaggregated optical transport network technologies are mainly implemented in point-to-point communication systems, using an open line system architecture. In an open line system, the optical line system comes from one vendor and accepts "third-party" wavelengths; the control software, whether homemade or third-party, can manage equipment from different vendors. Different wavelengths on the same line system can come from different vendors, and the open line system does not require interoperability of optical transceivers (i.e., it does not need to support optical transceivers from different vendors / generations at the two ends of the connection).

[0004] Although the open line system separates the optical line system and the terminal equipment, it still requires the optical line system to come from the same supplier, which imposes serious constraints on the owners and operators of large-scale mesh optical networks and limits their freedom and ability to upgrade and expand their transmission networks according to their own development needs. Summary of the invention

[0005] One embodiment described herein provides an optical add / drop multiplexer. The optical add / drop multiplexer may include a plurality of network interface modules and an optical cross-connect module coupling the plurality of network interface modules to each other. The plurality of network interface modules may include at least a first network interface module including at least one first optical component from a first supplier, and a second network interface module including at least one second optical component from a second supplier. The first optical component and the second optical component may have different optical parameters.

[0006] In a variation of this embodiment, each network interface module is reconfigurable and includes an input wavelength selective switch and an output wavelength selective switch.

[0007] In another variation, at least one port of the wavelength selective switch is coupled to a multiplexer or demultiplexer, thereby increasing the number of ports associated with the wavelength selective switch.

[0008] In a variation of this embodiment, each network interface module is fixed and includes a wavelength multiplexer and a wavelength demultiplexer.

[0009] In a variation of this embodiment, the plurality of network interface modules may include at least a reconfigurable network interface module and a fixed network interface module. The reconfigurable network interface module includes input and output wavelength selective switches, and the fixed network interface module includes a wavelength multiplexer and a wavelength demultiplexer.

[0010] In a variation of this embodiment, when the add / drop multiplexer is deployed in a heterogeneous optical network including a first optical multiplex section (OMS) link built using optical components from a first supplier and a second OMS link built using optical components from a second supplier, the first network interface module is coupled to the first OMS link and the second network interface module is coupled to the second OMS link.

[0011] In a variation of this embodiment, the optical cross-connect module may include a first adapter that interfaces with the first network interface module and a second adapter that interfaces with the second network interface module.

[0012] In a variation on this embodiment, the plurality of network interface modules includes additional network interface modules constructed using optical components from the first or second supplier.

[0013] In a variation on this embodiment, the plurality of network interface modules includes an additional network interface module including at least one third optical component from the first or second supplier or from a third supplier.

[0014] In a variation of this embodiment, the add / drop multiplexer may further include local add / drop modules, and the local add / drop modules and / or the optical cross-connect modules may include components from any supplier.

[0015] One embodiment may provide an optical network. The optical network may include a plurality of interconnected optical add / drop multiplexers, which may include several homogeneous optical add / drop multiplexers and one or more heterogeneous optical add / drop multiplexers. Each heterogeneous optical add / drop multiplexer may include a plurality of network interface modules and an optical cross-connect module that couples the plurality of network interface modules to each other. The plurality of network interface modules include at least a first network interface module including at least one first optical component from a first supplier, and a second network interface module including at least one second optical component from a second supplier. The first optical component and the second optical component may have different optical parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1A A schematic diagram illustrating an exemplary heterogeneous optical mesh network according to one embodiment is presented.

[0017] Figure 1B An exemplary optical transmission link between adjacent OADMs according to one embodiment is shown.

[0018] Figure 2A An exemplary conventional reconfigurable optical add / drop multiplexer (ROADM) according to the prior art is shown.

[0019] Figure 2B An exemplary heterogeneous ROADM according to one embodiment is shown.

[0020] Figure 2C An exemplary heterogeneous ROADM as part of a heterogeneous optical mesh network is shown in more detail according to one embodiment.

[0021] Figure 3A An exemplary heterogeneous FOADM is shown according to one embodiment.

[0022] Figure 3B An exemplary heterogeneous OADM having hybrid ROADM and FOADM functionality is shown according to one embodiment.

[0023] Figure 4 An exemplary heterogeneous ROADM as part of a heterogeneous meshed optical network is shown according to one embodiment.

[0024] Figure 5 An exemplary heterogeneous OADM having hybrid ROADM and FOADM functionality is shown according to one embodiment.

[0025] Figure 6 A flow chart illustrating an exemplary process for expanding or upgrading an existing optical transmission network according to one embodiment is presented.

[0026] In the drawings, like reference numerals denote the same drawing elements. DETAILED DESCRIPTION

[0027] The following description is presented to enable those skilled in the art to make and use the embodiments, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present disclosure. Therefore, the present invention is not limited to the embodiments shown, but should be consistent with the widest scope consistent with the principles and features disclosed herein.

[0028] Overview

[0029] In the present disclosure, an open decoupled optical transport network is provided. The open network implements a heterogeneous reconfigurable optical add / drop multiplexer (ROADM) to facilitate the decoupling of optical line systems within a meshed optical network. More specifically, the heterogeneous ROADM may include wavelength selective switches from different vendors. A wavelength selective switch (WSS) from a particular vendor may be used to interface with a portion of a network that uses equipment from the particular vendor. Thus, a heterogeneous meshed network including optical line system equipment from different vendors may be implemented without requiring interoperability of the ROADM.

[0030] Heterogeneous Mesh Optical Network

[0031] As discussed earlier, the open line system architecture allows for decoupling between the optical line system and the terminal equipment, but still requires a closed optical line system, which makes it a less than ideal open system solution for mesh optical networks. Another approach to open optical transport networks is the open ROADM system, which requires ROADM and optical transceiver interoperability between vendors. However, open ROADM technology is not mature and does not support vendor-provided proprietary optical line system features (e.g., automatic management of optical layer equipment, amplifier spontaneous emission (ASE) noise loading, etc.), which reduces network performance and hinders the development of network control systems.

[0032] In order to provide an open optical transport network solution for meshed optical networks, in some embodiments, heterogeneous ROADMs can be constructed using WSSs from different vendors. Such heterogeneous ROADMs can provide interoperability of network parts from different vendors without requiring interoperability of the actual hardware in the ROADM.

[0033] Figure 1A A schematic diagram illustrating an exemplary heterogeneous mesh optical network according to one embodiment is presented. Figure 1A In the figure, only optical add / drop multiplexers (OADMs) are shown. The optical mesh network 100 may include several OADMs, labeled as OADM A, B, C, ..., N.

[0034] Optical mesh network 100 is a heterogeneous network, which means that different parts of the network are built using equipment from different vendors. Figure 1A In the example shown, network 100 can be divided into multiple domains (e.g., domains 1, 2, and 3), and the devices in each domain are manufactured by a specific vendor. Each domain can also be referred to as a vendor domain. For example, domain 1 can be built using devices from a first vendor, domain 2 can be built using devices from a second vendor, and domain 3 can be built using devices from a third vendor. For better illustration, in Figure 1AIn the figure, the optical links between OADMs in different domains are drawn using different line patterns, and different domains are separated by dashed lines 102. Note that in each domain, the optical components are from the same vendor, which means that the internal equipment of each domain does not need to interact with the equipment of other vendors. This retains many proprietary functions provided by specific vendors (e.g., automatic management of optical layer equipment, ASE noise loading, etc.), thereby achieving optimization of network functions and simplification of network management and control. However, the equipment in different domains comes from different vendors, which means that they may have different specifications and may require different management tools.

[0035] Different domains of the network 100 (i.e., portions of the optical layer of different vendors) are adjacent to each other at OADM nodes. Figure 1A In the example shown, OADM C is located at the boundary between domain 1 and domain 2, OADMs F and G are located at the boundary between domain 1 and domain 3, and OADM I is located at the boundary between domain 2 and domain 3. These boundary OADM nodes can be configured to bridge different domains.

[0036] Note that the principle used to divide the network into different domains is that the same optical multiplex section (OMS) needs to remain in the same domain, using the optical layer equipment from the same vendor. In other words, only when the OMS changes (i.e., when one or more wavelengths are added or removed) can the network operator choose to use equipment from a different vendor to build a part of the network. Figure 1B FIG. 2 shows an exemplary optical transmission link between adjacent OADMs according to one embodiment. Figure 1B In FIG. 1 , the optical transmission link between adjacent OADMs 112 and 114 may belong to the same OMS 110 because the optical wavelength on the link between OADMs 112 and 114 remains unchanged. OMS 110 may include several optical transmission sections (OTSs), each of which terminates in an optical amplifier module (e.g., amplifier 116). Note that, for simplicity of illustration, Figure 1A Only the OMS layer of the network is shown. Optical devices (eg, amplifiers) belonging to the same OMS (eg, OMS 110) are from the same vendor and may be operated and managed using the same vendor's proprietary software.

[0037] There is no need to consider the interoperability of equipment within each domain because all equipment comes from the same supplier. However, at the boundary between domains (i.e., OADM), a solution is needed that can operate and manage optical signals generated by equipment from different suppliers. As discussed above, open ROADM solutions face many challenges, such as availability and limitations in supporting proprietary optical line system functions. In order to provide an OADM solution that supports heterogeneous networks without the need for interoperability between OADMs, some embodiments use heterogeneous OADMs to replace traditional OADMs at the boundaries of different domains.

[0038] Figure 2A An exemplary conventional reconfigurable optical add / drop multiplexer (ROADM) according to the prior art is shown. Figure 2A In the embodiment, ROADM 200 may include three ports (e.g., ports 202, 204, and 206) in three switching directions (i.e., three dimensions), and a local add / drop module 208 including a plurality of add / drop ports. To simplify the description, the interconnection between ROADM network interfaces 202-206 and local add / drop modules 208 is represented by optical cross-connects (OXCs) 210.

[0039] Each dimension of the ROADM 200 is associated with a network interface and a pair of transmission fibers for inbound and outbound transmission. More specifically, the network interface on each ROADM dimension may include a pair of wavelength selective switches (WSS) to achieve colorless and directionless switching, which means that any wavelength from any dimension can be routed to any other dimension, including local add / drop ports. For example, the network interface 202 may include an input WSS 212 for switching input signals and an output WSS 214 for switching output signals. Here, both the input and output are relative to the ROADM 200. The switching operation of the WSS can be controlled using software, making the ROADM programmable and reconfigurable. Each WSS can also be coupled to an amplifier (e.g., a preamplifier or a booster amplifier).

[0040] In the traditional approach, all ROADMs are homogeneous, which means that every component in the ROADM comes from the same vendor and the operation of the ROADM is managed by proprietary management software. Such ROADMs cannot be used at the boundaries of different domains in a heterogeneous network. Instead, heterogeneous ROADMs are required at the boundaries of different domains in a heterogeneous network.

[0041] Figure 2B 2 shows an exemplary heterogeneous ROADM according to one embodiment. At first glance, the heterogeneous ROADM 220 may be similar to Figure 2A The homogeneous ROADM 200 shown in FIG. 1 and may include three dimensions and a local add / drop port. However, unlike the homogeneous ROADM 200, where each component is from the same vendor, the heterogeneous ROADM 220 may be built using equipment from different vendors.

[0042] More specifically, each ROADM network interface (also called a network-side module because the signals from the mesh network enter and exit the ROADM 220 from the network interface) can be from different vendors, depending on the OMS connected to the ROADM interface. Each ROADM network interface can include a WSS and amplifiers in both the input and output directions. Figure 1AAs an example, two of the three dimensions of OADM F interface with the OMS in domain 1, and the third dimension interfaces with the OMS in domain 3. Therefore, if the heterogeneous ROADM 220 is used as Figure 1A For the OADM F shown in FIG. 1 , two of the ROADM network interfaces (e.g., interfaces 222 and 224) need to be able to process optical signals from domain 1, while the other network interface (e.g., interface 226) needs to be able to process optical signals from domain 3. Figure 2B In the embodiment, network interfaces 222 and 224 may be constructed using optical equipment (e.g., amplifiers and WSS) from the same first vendor that provides equipment in domain 1. Similar to network interface 202, interface 222 may include an input WSS for switching input optical signals and an output WSS for switching output optical signals. Here both the input and output are relative to ROADM 220. On the other hand, network interface 226 may be constructed using optical equipment (e.g., amplifiers and WSS) from the same third vendor that provides equipment in domain 3. The optical equipment (e.g., amplifiers and WSS) in network interfaces of different domains (e.g., domain 1 and domain 3) may have different specifications (e.g., different optical parameters) and may be managed using different management tools. Note that ROADM network interfaces from different vendors are configured in different management tools. Figure 2B are shown with different background patterns (shaded vs. non-shaded). Figure 2B Also shown is a heterogeneous ROADM 220 including local add / drop modules 228 and an OXC 230 that interconnects the ROADM network interfaces. Note that the OXC 230 and the add / drop modules 228 can be domain independent, meaning that they can be built using equipment from any vendor, including but not limited to vendors that provide equipment for domains 1, 2, and 3. In some embodiments, the OXC 230 can be designed to include various types of adapters to allow the OXC 230 to interface with WSSs from different vendors. Note that WSSs from different vendors may have different numbers of ports and different port sequences.

[0043] Back to Figure 1A, the mesh optical network 100 includes several OADMs, some of which are located in a specific domain (e.g., OADM A and B or OADM K and L), and some of which are located at the boundaries between different domains (e.g., OADM C, F, and I). For OADMs located in a specific domain, they only interact with optical signals in the same domain. Therefore, such OADMs can be implemented using traditional homogeneous OADMs, and all components in the OADMs come from the same supplier that provides other optical devices in the corresponding domain. For example, OADM A and B are in domain 1; therefore, they can be built using equipment provided by the domain 1 supplier (i.e., the first supplier). Similarly, OADM K and L are located in domain 3 and can be built using equipment provided by the domain 3 supplier (i.e., the third supplier). On the other hand, OADM C is located between domains 1 and 2, where two of the three dimensions of OADM C interact with domain 1 signals and the third dimension interacts with domain 2 signals; and OADM F is located between domains 1 and 3, where two of the three dimensions of OADM F interact with domain 1 signals and the third dimension interacts with domain 3 signals. These border OADMs need to be heterogeneous, meaning they are built using equipment from different vendors. In the case of OADM C, it is built using equipment from both vendor 1 and vendor 2. OADM F, on the other hand, is built using equipment from both vendor 1 and vendor 3.

[0044] Figure 2C An exemplary heterogeneous ROADM as part of a heterogeneous optical mesh network according to one embodiment is shown in more detail. Figure 2C In FIG. 1 , ROADM 240 may include three dimensions (i.e., three network interfaces 242, 244, and 246) and a local add / drop module 248. OXC 250 connects the network interfaces and the add / drop module 248. ROADM 240 may be similar to Figure 2B The ROADM 220 shown, Figure 2C ROADM 240 is shown as being used Figure 1A The OADM F in the network is shown to interface with other elements in the network (eg, OTS).

[0045] exist Figure 2C In FIG. 1 , network interfaces 242 and 244 interface with the portion of the network belonging to domain 1. As discussed previously, the various optical components in domain 1 come from the same first vendor. Therefore, the optical components (e.g., WSS and amplifiers) used to build network interfaces 242 and 244 also need to come from the same first vendor in order to work with these optical components. Similarly, network interface 246 interfaces with the portion of the network belonging to domain 3, and it is built using equipment from domain 3. In FIG. Figure 2C In the , different padding patterns are used to indicate devices from different vendors.

[0046] Figure 2C It is also shown that network interface 242 is part of OMS252, network interface 244 is part of OMS254, and network interface 246 is part of OMS256. Using equipment from corresponding vendors to build network interfaces can ensure that all optical components on the same OMS are from the same vendor, thereby providing guaranteed operability and retaining vendor-specific management functions. On the other hand, the optical equipment on different OMSs can be from different vendors and can have different optical parameters. This enables network operators to flexibly expand their networks, one OMS at a time, using equipment from the vendor that best suits their needs. For example, OMS252 and OMS254 only include equipment from domain 1 vendors, while OMS256 only includes equipment from domain 3 vendors. Note that OXC 250 and add-drop modules 248 can be domain independent, meaning that they can be built using components or equipment from any vendor, including but not limited to vendors that provide equipment for domains 1, 2, and 3.

[0047] Figure 2B and Figure 2C The structure of a heterogeneous ROADM is illustrated. In practice, other types of OADMs can also be used in heterogeneous mesh networks to facilitate interoperability between different parts (or domains) of a network built using equipment from different vendors. For example, fixed OADMs (FOADMs) can also be used in heterogeneous mesh networks to bridge different domains of a network built using equipment from different vendors, replacing ROADMs that can be dynamically reconfigured to allow dynamic wavelength placement. FOADMs can only be used to drop optical signals of fixed wavelengths, and reconfiguration of the OXC usually requires manual adjustments (e.g., by adjusting a manual fiber patch panel).

[0048] Figure 3A An exemplary heterogeneous FOADM according to one embodiment is shown. FOADM 300 is a three-dimensional OADM that may include three network interfaces (e.g., interfaces 302, 304, and 306) and multiple local add / drop ports. Each network interface in FOADM 300 simply includes a wavelength multiplexer (MUX) for multiplexing output optical signals and a wavelength demultiplexer (DEMUX) for demultiplexing input optical signals, rather than a WSS for implementing wavelength switching. Similar to Figure 2B In the example shown, both dimensions of the FOADM 300 are connected to an OMS within a specific domain, which means that the components within the corresponding network interfaces (e.g., MUX, DEMUX, amplifiers, etc.) are from the same vendor that provides equipment for that specific domain. Figure 1AOADM F in the network shown, network interfaces 302 and 304 will be configured to interact with domain 1 optical signals, which means that the optical components in network interfaces 302 and 304 need to be from the same domain 1 vendor. On the other hand, network interface 306 will be configured to interact with domain 3 optical signals and will be built using optical components from a domain 3 vendor. OXC 310 and local add / drop ports can use equipment from any vendor, including but not limited to vendors that provide equipment for domains 1, 2, and 3. In some embodiments, OXC 310 can be customized to include various types of adapters to allow OXC 310 to interface with multiplexers and demultiplexers from different vendors. Note that MUX / DEMUX from different vendors may have different numbers of ports and different port sequences.

[0049] Other variations are possible. For example, it is possible to mix FOADM and ROADM functionality into a single OADM, in addition to different network interfaces for OADMs built using equipment from different vendors.

[0050] Figure 3B An exemplary heterogeneous OADM with hybrid ROADM and FOADM functionality according to one embodiment is shown. OADM 320 is a three-dimensional OADM that may include three network interfaces (e.g., interfaces 322, 324, and 326) and multiple local add / drop ports. Network interfaces 322 and 324 may be reconfigurable and may include WSS, while network interface 326 may be fixed and may include MUX and DEMUX. In addition, in Figure 3B In the example shown, network interfaces 322 and 324 may be part of the OMS in domain 1 and may be built using equipment (e.g., WSS and amplifiers) from a domain 1 vendor. On the other hand, network interface 326 may be part of the OMS in domain 3 and may be built using equipment (e.g., MUX, DEMUX, and amplifiers) from a domain 3 vendor. OXC 330 and local add / drop ports may use equipment from any vendor, including but not limited to vendors that provide equipment for domains 1, 2, and 3. In some embodiments, OXC 330 may be customized to include various types of adapters to allow OXC 330 to interface with WSS, multiplexers, and demultiplexers from different vendors.

[0051] In some embodiments, different network interfaces in the OADM can be upgraded individually according to network needs. Figure 3A FOADM 300 or Figure 3B The fixed interfaces in the illustrated hybrid OADM 320 can be upgraded to reconfigurable interfaces.

[0052] In the above example, the OADM (which can be a ROADM, FOADM, or hybrid OADM) is located on the boundary between two different domains, and two of the three dimensions of the OADM belong to the same domain (e.g., Figure 1A In practical applications, the OADM can also be configured to act as a three-way bridge, located at the intersection of three different domains. Figure 4 An exemplary heterogeneous ROADM as part of a heterogeneous optical mesh network is shown according to one embodiment.

[0053] exist Figure 4 In FIG. 4 , ROADM 400 may include three dimensions (ie, three network interfaces 402, 404, and 406) and a local add / drop module 408. OXC 410 interconnects the network interfaces and the local add / drop module 408. Figure 4 , three network interfaces in three dimensions, each belonging to a different domain, as shown by the different fill patterns (e.g., hatched, cross-hatched, non-hatched) of the interfaces. More specifically, network interface 402 may be part of an OMS belonging to domain 1, network interface 404 may be part of an OMS belonging to domain 2, and network interface 406 may be part of an OMS belonging to domain 3. Therefore, each network interface will be constructed using equipment (e.g., WSS, amplifiers, etc.) from different vendors, such as domain 1, domain 2, or domain 3 vendors, depending on the domain to which the network interface belongs. As discussed previously, when a particular OMS is composed of equipment or optical devices from the same vendor, interoperability between the equipment or optical devices does not need to be considered, and various vendor-specific functions can be retained to optimize network functions and simplify network management and control. Other variations are also possible. For example, a three-way, three-dimensional OADM may be a FOADM, or an OADM with hybrid ROADM and FOADM functions, where some interfaces are reconfigurable and include WSS, and some interfaces are fixed and include wavelength MUXs and DEMUXs.

[0054] Figure 5 An exemplary heterogeneous OADM with hybrid ROADM and FOADM functionality is shown in accordance with one embodiment. Figure 5 In FIG. 5 , OADM 500 may include three dimensions (i.e., three network interfaces 502, 504, and 506) and multiple local add / drop ports. OXC 510 interconnects the network interfaces and the local add / drop ports. Figure 5In the example shown, network interfaces 502 and 504 are reconfigurable interfaces including WSS, while network interface 506 is a fixed interface including MUX and DEMUX. In addition, one or more WSS ports in network interfaces 502 and 504 can be expanded to multiple wavelength ports using a multiplexer or demultiplexer, thereby increasing the total number of ports of the WSS. The increased number of WSS ports can provide more add / drop channels for a specific dimension of OADM 500. In addition, considering that the number of input / output ports of MUX / DEMUX is generally greater than the number of ports of WSS, extending the WSS ports also facilitates port matching between a network interface including WSS (e.g., interface 502 or 504) and a network interface including MUX and DEMUX (e.g., interface 506).

[0055] For example, in Figure 5 In the example, the port of WSS 512 in interface 502 can be expanded to multiple ports through MUX 514. Other WSS ports can remain the same and can be interconnected with the WSS port of interface 504 or the MUX / DEMUX in interface 506. Figure 5 In the example shown, only one WSS port is extended. In actual applications, multiple WSS ports can be extended (for example, by connecting each WSS port to a MUX / DEMUX). If a WSS has eight ports, and four of the eight ports are respectively coupled to the output of a 4-to-1 MUX, then the equivalent number of ports of the WSS can be 20.

[0056] As an example, OADM 500 may be used as Figure 1A OADM F in the network shown. In this case, network interfaces 502 and 504 are part of the OMS in domain 1 and can be built using components (e.g., WSS, MUX, DEMUX, amplifiers) from domain 1 suppliers. Figure 1A As shown, the network interface 502 of OADM F can be coupled to the corresponding network interface on ROADM G via an optical link including several OTSs to form an OMS; the network interface 504 of OADM F can be coupled to the corresponding network interface on ROADM C via an optical link including multiple OTSs to form an OMS. Each component on these two OMSs is a domain 1 component, which means that it is provided by a domain 1 vendor. Using equipment from a single vendor to build an OMS simplifies network management and control because wavelength management can be accomplished using management tools provided by the vendor.

[0057] As mentioned earlier, the implementation of heterogeneous OADM in the network provides network operators with the flexibility to expand or upgrade their networks without being constrained by their initial vendor selection. The only remaining constraint is that all devices or components within the same OMS need to come from the same vendor. This scheme partially decomposes the optical transport network without requiring interoperability between all OADM nodes in the network. Instead, a heterogeneous OADM node can bridge two OMS links built using equipment from two different vendors. Because each OMS belongs to a certain vendor, the various management and control functions provided by the vendor can be retained.

[0058] Figure 6 A flow chart of an exemplary process for expanding or upgrading an existing optical transport network according to one embodiment is shown. During operation, an operator of the network identifies a portion of the network that needs to be upgraded or expanded (operation 602). This can be determined based on the increased bandwidth requirements of its customers. The operator can then select equipment from one or more suppliers that can be used to build several OMSs (operation 604), and then use the selected equipment to build the OMS (operation 606). The topology of the OMS layer of the network can be similar to Figure 1A The mesh network shown. When building these OMSs, operators are not bound by a specific vendor that provides equipment for existing networks. Instead, operators are free to choose one or more different vendors to provide equipment based on various factors such as network requirements, technological innovation, price, etc. This flexibility allows network operators to optimize their networks. The only restriction in building an OMS is that the equipment belonging to the same OMS needs to be from the same vendor to ensure the operability of that OMS.

[0059] Based on the choice of the supplier and the topology of the OMS layer of the network, a heterogeneous OADM can be constructed (operation 608). When constructing a heterogeneous OADM node, it is necessary to ensure that the network interface on a specific dimension of the OADM node that interfaces with a specific OMS is formed using equipment from the same supplier that provides equipment for the specific OMS. In other words, depending on the OMS link connected to the heterogeneous OADM node, different network interfaces of the heterogeneous OADM can be constructed using equipment from different suppliers. More specifically, the heterogeneous OADM node can be a ROADM, a FOADM, or an OADM node with a mix of fixed and reconfigurable interfaces.

[0060] Heterogeneous nodes may be placed between OMS links constructed using devices from different vendors to bridge these different OMS links (operation 610). This may facilitate the construction of a heterogeneous network.

[0061] In general, embodiments of the present invention provide a scheme for decomposing optical transmission networks, in particular, mesh optical networks. More specifically, heterogeneous optical mesh networks may include multiple domains (also referred to as supplier domains). A domain may be defined as a portion of a network having devices from the same supplier. By including different supplier domains in the same network, the instant solution at least partially opens the optical layer of the network. The only constraint is that all devices on the same OMS link need to be in the same domain. The OADM nodes located on the boundaries between different domains may be heterogeneous. More specifically, heterogeneous OADMs may include different network interfaces for interfacing with different types of OMS links. The network interface of the OADM and the OMS link connected to the interface are both built using the equipment of the same supplier. Ensuring supplier consistency on the same OMS can ensure the operability of the OMS and retain various supplier-specific network management functions, thereby helping to optimize the network structure and simplify the management and control of the network. In the above example, heterogeneous OADMs are used to implement the construction of heterogeneous optical mesh networks. In fact, in addition to mesh networks, heterogeneous OADMs can also be used to build optical networks with other types of topologies, such as ring topologies or star topologies. Systems and methods for implementing heterogeneous OADMs in these types of networks will be similar to the disclosed embodiments and will not be described in detail here.

[0062] The methods and processes described in the detailed description section may be embodied as code and / or data, which may be stored in a computer-readable storage medium as described above. When a computer system reads and executes the code and / or data stored on a computer-readable storage medium, the computer system executes the methods and processes embodied as data structures and code and stored in the computer-readable storage medium.

[0063] In addition, the above methods and processes can be implemented in digital electronic circuits; or in computer software, firmware or hardware. Hardware modules or devices may include, but are not limited to, application specific integrated circuit (ASIC) chips, field programmable gate arrays (FPGAs), dedicated or shared processors that execute specific software modules or code segments at specific times, and other programmable logic devices now known or later developed. When the hardware modules or devices are activated, they perform the methods and processes included therein.

[0064] The above technology can be implemented using one or more computer program products. Programmable processors and computers can be included in or packaged as mobile devices. Processes and logic flows can be performed by one or more programmable processors or one or more programmable logic circuits. General and special computing devices and storage devices can be interconnected through communication networks.

[0065] The above descriptions of various embodiments are presented for the purpose of illustration and description only. They are not intended to be exhaustive or to limit the invention to the disclosed forms. Therefore, many modifications and variations will be apparent to those skilled in the art. In addition, the above disclosure is not intended to limit the invention.

Claims

1. An optical add / drop multiplexer, wherein: include: Multiple network interface modules; and an optical cross-connect module for coupling the plurality of network interface modules to each other; The plurality of network interface modules include at least: a first network interface module including at least one first optical component from a first supplier, and a second network interface module including at least one second optical component from a second supplier, wherein the first optical component and the second optical component have different optical parameters.

2. The optical add / drop multiplexer according to claim 1, wherein: Each network interface module is reconfigurable and includes an input wavelength selective switch and an output wavelength selective switch.

3. The optical add / drop multiplexer according to claim 2, wherein: At least one port of the wavelength selective switch is coupled to a multiplexer or a demultiplexer, thereby increasing the number of ports associated with the wavelength selective switch.

4. The optical add / drop multiplexer according to claim 1, wherein: Each network interface module is fixed and includes a wavelength multiplexer and a wavelength demultiplexer.

5. The optical add / drop multiplexer according to claim 1, wherein: The plurality of network interface modules include at least a reconfigurable network interface module and a fixed network interface module, wherein the reconfigurable network interface module includes an input wavelength selective switch and an output wavelength selective switch, and wherein the fixed network interface module includes a wavelength multiplexer and a wavelength demultiplexer.

6. The optical add / drop multiplexer according to claim 1, wherein: When the add / drop multiplexer is deployed in a heterogeneous optical network including a first optical multiplex section OMS link constructed using optical components from the first supplier and a second OMS link constructed using optical components from the second supplier, the first network interface module is coupled to the first OMS link and the second network interface module is coupled to the second OMS link.

7. The optical add / drop multiplexer according to claim 1, wherein: The optical cross-connect module includes a first adapter that interfaces with the first network interface module and a second adapter that interfaces with the second network interface module.

8. The optical add / drop multiplexer according to claim 1, wherein: The plurality of network interface modules includes an additional network interface module including at least one third optical component from the first or second vendor or from a third vendor.

9. The optical add / drop multiplexer according to claim 1, further comprising a local add / drop module, wherein: The local add / drop modules and / or the optical cross-connect modules may include components from any supplier.

10. An optical network, wherein: include: A plurality of interconnected optical add / drop multiplexers, including several homogeneous optical add / drop multiplexers and one or more heterogeneous optical add / drop multiplexers; Among them, each heterogeneous optical add / drop multiplexer includes: a plurality of network interface modules; and an optical cross-connect module for coupling the plurality of network interface modules to each other; The plurality of network interface modules include at least: a first network interface module including at least one first optical component from a first supplier, and a second network interface module including at least one second optical component from a second supplier, wherein the first optical component and the second optical component have different optical parameters.

11. An optical network according to claim 10, comprising a plurality of domains, wherein The optical layer devices in each domain are from the same supplier, and the optical add / drop multiplexers in each domain are homogeneous optical add / drop multiplexers.

12. The optical network according to claim 11, wherein: Adjacent domains are adjacent to each other at one or more heterogeneous optical add / drop multiplexers.

13. The optical network according to claim 11, wherein: The respective heterogeneous optical add / drop multiplexers are located at a boundary between a first domain and a second domain, wherein optical layer devices in the first domain are from the first supplier, and wherein optical layer devices in the second domain are from the second supplier.

14. The optical network according to claim 10, wherein: Each network interface module is reconfigurable and includes an input wavelength selective switch and an output wavelength selective switch.

15. The optical network according to claim 14, wherein: At least one port of the wavelength selective switch is coupled to a multiplexer or a demultiplexer, thereby increasing the number of ports associated with the wavelength selective switch.

16. The optical network according to claim 10, wherein: Each network interface module is fixed and includes a wavelength multiplexer and a wavelength demultiplexer.

17. The optical network according to claim 10, wherein: The plurality of network interface modules include at least a reconfigurable network interface module and a fixed network interface module, wherein the reconfigurable network interface module includes an input wavelength selective switch and an output wavelength selective switch, and wherein the fixed network interface module includes a wavelength multiplexer and a wavelength demultiplexer.

18. The optical network according to claim 10, wherein: The optical cross-connect module includes a first adapter that interfaces with the first network interface module and a second adapter that interfaces with the second network interface module.

19. The optical network according to claim 10, wherein: The plurality of network interface modules includes an additional network interface module including at least one third optical component from the first or second vendor or from a third vendor.

20. The optical network of claim 10, wherein: Each of the heterogeneous optical add / drop multiplexers further includes a local add / drop module, wherein the local add / drop module and / or the optical cross-connect module include components from any supplier.

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