High-efficiency fiber utilization with a wide range of parallel optical interfaces

Abstract

This disclosure relates to efficient utilization of optical fibers with a wide range of parallel optical interfaces. Apparatus, systems, and methods are disclosed for example, to efficiently utilize optical media by performing bidirectional BiDi dense wavelength division multiplexing (DWDM) according to a wavelength plan. Some wavelength plans prioritize or consider cardinality, energy efficiency, and / or fiber utilization. Some apparatuses may be network devices, such as switches, routers, and / or the like. Some apparatuses may be computers, servers, and / or the like.

Description

Technical Field

[0001] This disclosure generally relates to the transmission of data via optical media, and more specifically, to the efficient use of optical media for data transmission. Background Technology

[0002] In optical communications, Energy Efficient Interfaces (EEIs) typically operate the link (transmitting and / or receiving data) at a lower baud rate than conventional interfaces, often using relatively simple modulation formats such as Non-Return-to-Zero (NRZ). This operation significantly reduces the overall power consumption of the link by minimizing or eliminating the need for high-power digital signal processors (DSPs), which are typically required to process higher baud rate data encoded using more complex modulation formats (e.g., Pulse Amplitude Modulation Level 4 (PAM4)).

[0003] However, the shift to lower baud rates may conflict with the existing trend of increasing bandwidth demands from servers and network devices such as switches. The optical fibers connecting two nodes in a network must support a certain amount of bandwidth, and therefore lower baud rates require additional wavelengths to carry data in order to maintain the overall bandwidth of the fiber optic link. In many cases, such wavelengths traveling on a single fiber are necessary or desirable.

[0004] Adding wavelengths to an optical fiber, with each wavelength carrying an independent data stream, is a common method for increasing fiber bandwidth and is known as wavelength division multiplexing (WDM). Dense WDM (DWDM) refers to a technique that closely arranges wavelengths together.

[0005] Optical networks are commonly used to support artificial intelligence (AI) and / or machine learning (ML) workloads. These workloads impose additional constraints on the backend cluster networks supporting them. Such networks typically require a single switch-level mesh architecture to provide full-pair full connectivity between the compute nodes forming the cluster. The term "radix" refers to the ability of a switch or other network device to operate or support a non-blocking network, which can connect multiple inputs to multiple outputs in a mesh pattern without collisions; the radix refers to the number of non-blocking connections that the network device can support within this mesh.

[0006] Using a large number of optical fibers to increase the cardinality presents problems because it consumes valuable shoreline on the chip's package edge (e.g., photonic integrated circuits (PICs) that operate switches), thereby reducing the chip's shoreline bandwidth density and making such chips more difficult to manufacture (e.g., lower yield per chip and higher cost). Multiplexing or demultiplexing a large number of wavelength channels over a single fiber also presents problems because it increases optical power requirements and also increases the complexity of the light source, which must support the increased number of wavelengths.

[0007] A technology is needed to solve these problems. Summary of the Invention

[0008] In one aspect, this disclosure relates to an apparatus comprising: an optical interface; and logic for efficiently utilizing an optical medium by performing bidirectional (BiDi) dense wavelength division multiplexing (DWDM), wherein performing BiDi DWDM includes: transmitting data via the optical interface at a first plurality of wavelengths centered at a first center wavelength via a single optical fiber; and receiving data via the optical interface at a second plurality of wavelengths centered at a second center wavelength via the single optical fiber.

[0009] In another aspect, this disclosure relates to a method comprising: efficiently utilizing an optical medium by performing bidirectional (BiDi) dense wavelength division multiplexing (DWDM), wherein performing BiDi DWDM comprises: transmitting data via a single optical fiber at a first plurality of wavelengths centered at a first center wavelength via an optical interface; and receiving data via the single optical fiber at a second plurality of wavelengths centered at a second center wavelength via the optical interface.

[0010] In another aspect, this disclosure relates to an apparatus comprising: logic for implementing a (BiDi) dense wavelength division multiplexing (DWDM) wavelength scheme that takes into account energy efficiency, cardinality, and fiber utilization; logic for transmitting data on a single optical fiber and according to the BiDi DWDM wavelength scheme on at least one set of transmission wavelengths centered at at least one transmission center wavelength; and logic for receiving data on the single optical fiber on at least one set of receiving wavelengths centered at at least one receiving center wavelength. Attached Figure Description

[0011] Figures 1A to 1C Illustrated explanation of wavelength plans according to various embodiments.

[0012] Figure 2 This is a functional block diagram illustrating a system comprising two optical interfaces communicating via a single optical fiber, according to various embodiments.

[0013] Figure 3 This is a flowchart illustrating an optical communication method according to some embodiments.

[0014] Figures 4A to 4D This is a block diagram of an apparatus according to some embodiments. Detailed Implementation

[0015] A set of embodiments combines DWDM to implement bidirectional (BiDi) technology to increase fiber utilization efficiency, for example, by increasing bandwidth and reducing fiber count (compared to conventional methods) without sacrificing cardinality. While BiDi technology has been implemented in specific environments (e.g., fiber to the home (FTTH)) and DWDM in various environments, the inventors have discovered that the combination of these technologies (including but not limited to data center settings) can provide high bandwidth (e.g., 200 Gb / s to 1.6 Tb / s) on a single fiber, while employing less complex hardware (e.g., DSP) and consuming less power than conventional technologies. Solutions achieved through this technology can provide more wavelengths on a single fiber compared to conventional systems. Furthermore, by efficiently using a single fiber to transmit and receive this greater number of wavelengths on a single fiber, various embodiments can save cardinality by eliminating the need for multiple fibers to transmit data between two stations (e.g., a switch and a compute node in a data center).

[0016] Some embodiments center each DWDM channel group (e.g., spaced apart on a 200 GHz or 400 GHz grid) around each of a plurality of coarse wavelength division multiplexing (CWDM) wavelength ranges. For example, in some embodiments, the center wavelength (λ) of the different channel groups c The wavelengths may be located at 1271 nm, 1291 nm, 1311 nm, and / or 1331 nm, thus effectively spanning the O-band of the fiber. In some embodiments, each channel group may include, for example, four to eight wavelengths. In some embodiments, the center wavelengths of adjacent CWDM bands are spaced 20 nm apart (e.g., as indicated above). The arrangement of the operating wavelengths on the fiber is referred to herein as a “wavelength scheme” and is discussed below. Figures 1A to 1C The illustration illustrates an exemplary wavelength plan according to such an embodiment.

[0017] Some embodiments utilize the fact that, due to the large spacing between CWDM bands, a set of DWDM channels (residing in one CWDM band) can be transmitted on the same optical fiber while another set of DWDM channels (residing in different CWDM bands) can be received simultaneously. In other words, certain embodiments perform both transmission and reception (BiDi) on the same optical fiber. Instead of using a single wavelength corresponding to a CWDM wavelength, some embodiments transmit and receive a set of DWDM channels centered on different CWDM bands.

[0018] Exemplary Examples

[0019] Specific exemplary embodiments are described below. As those skilled in the art will appreciate, each of the described embodiments can be implemented individually or in any combination. Therefore, no single embodiment or combination of embodiments should be considered limiting.

[0020] Figures 1A to 1C The diagram illustrates wavelength planning according to some embodiments, which can be implemented by devices such as optical interface 200 (described in further detail below), device 400 (described in further detail below), and / or components thereof, such as optical interface 415, laser device 420, etc. Wavelength planning according to some embodiments may include at least one center wavelength for transmitting data and at least one center wavelength for receiving data. According to some embodiments, these center wavelengths correspond to CWDM wavelengths, and they can form the basis of a channel arranged according to DWDM. Therefore, in some embodiments, wavelength planning may employ CWDM to establish both a transmission center frequency and a reception center frequency on the same optical fiber, thereby providing BiDi communication, while also employing DWDM for the channel centered on the center frequency.

[0021] For example, Figure 1A The diagram illustrates a wavelength plan 100 for a single optical fiber, wherein a device transmits on a first plurality of wavelengths 105a to 105d centered around a first center wavelength (e.g., uniformly spaced around the first center wavelength), and the device receives on a second plurality of wavelengths 110a to 110d centered around a second center wavelength. As used herein, the term "channel" refers to an operating wavelength for transmitting or receiving data (e.g., according to the wavelength plan), and a plurality of such wavelengths are referred to as a "group" of wavelengths or channels, or simply a "channel group."

[0022] therefore, Figure 1A The wavelength plan 100 includes two channel groups: group 105, consisting of transmission channels 105a to 105d, and group 110, consisting of receiving channels 110a to 110d. Transmission group 105 uses a center wavelength (λ) of 1271 nm. c Centered on ), while receiver group 110 uses a center wavelength of 1331 nm (λ). c Centered on ), those skilled in the art will understand that, based on the disclosure herein, the center wavelength (λ) can also be obtained by dividing the speed of light (c) by the wavelength. c ) is expressed as center frequency (f c ):

[0023]

[0024] This will give transmission group 105 approximately 2.358 × 10 14 The center frequency (f) of Hz (235.8 THz)c And receiver group 110 will have approximately 2.251 × 10⁻⁶. 14 The center frequency (f) of Hz (225.1 THz) c ).

[0025] Wavelength plans are typically spaced across one or more wavelength grids. As used herein, the term "wavelength grid" refers to a grid defined by one or more center wavelengths (defined in meters) and channel spacing (defined in Hz), the channel spacing corresponding to the grid spacing (defined in meters). For example, wavelengths 105a to 105d and 110a to 110d in channel groups 105 and 110 are spaced across a 400 GHz grid, as shown by... Figure 1A The diagram illustrates this. Therefore, for example, in... Figure 1A In wavelength plan 100, the channel may have the following characteristics as shown in Table 1:

[0026]

[0027] Table 1 – Figure 1A channel

[0028] As shown in Table 1, each of the transmission channels 105a to 105d in the transmission channel group 105 is separated by 0.4 THz (400 GHz), and the transmission channel group 105 itself is centered at a wavelength of 1271 nm, which is the CWDM wavelength (λ) of the channel group. c Accordingly, each of channels 110a to 110d in the receiving channel group 110 is spaced 400 GHz apart, and the receiving channel group 110 is centered at a wavelength of 1331 nm. Therefore, each of channels 105a to 105d and 110a to 110d is spaced apart according to a 400 GHz grid.

[0029] It should be understood that the embodiments are not limited to a specific number of transmit and receive channel groups; nor are specific channel groups limited to a specific number of channels. For example, Figure 1B The diagram illustrates a wavelength scheme 130 according to some embodiments; this scheme 130 is characterized by two transmission groups 105 and 115, each transmission group including four channels 105a to 105d and 115a to 115d respectively. The first transmission group 105 is centered at 1271 nm, while the second transmission group 115 is centered at 1291 nm. Similarly, Figure 1B Plan 130 is characterized by two receive channel groups 110 and 120, which respectively include channels 110a to 110d and 120a to 120d. The first receive group 110 is centered at 1331 nm, and the second receive group 120 is centered at 1311 nm. Table 2 shows... Figure 1BThe characteristics of the channel as described in wavelength plan 130:

[0030]

[0031] Table 2 – Figure 1B channel

[0032] Technical personnel in this field should understand that Figure 1B Wavelength plan 130 and Figure 1A Similar to Plan 100, except that it includes an additional channel group in each of the transmission and reception modes and is therefore similar to Figure 1A Compared to Plan 100, which supports twice as many channels in each mode. It should also be understood that in CWDM, adjacent center wavelengths are spaced 20 nm apart, but this spacing is not mandatory. For example, in some embodiments, the first center wavelength may fall between approximately 1265 nm and approximately 1275 nm (e.g., for channel group 105), the second center wavelength (e.g., for channel group 110) may fall between approximately 1325 nm and approximately 1335 nm, the third center wavelength (e.g., for channel group 115) may fall between approximately 1285 nm and 1295 nm, and the fourth center wavelength (e.g., for channel group 120) may fall between approximately 1305 nm and approximately 1315 nm.

[0033] In some embodiments, wavelength planning specifies channels and / or center wavelengths to meet specific constraints. For example, if channels are selected on a grid that is too narrow, there is a risk of crosstalk between channels. Similarly, if adjacent center wavelengths are too close, crosstalk can occur between adjacent channel groups. Therefore, in some embodiments, center wavelength spacing is selected (e.g., according to CWDM principles) to avoid this crosstalk; for example, the center wavelength (λ) c The channels are spaced approximately 20 nm apart. Conversely, if channels are selected on a grid that is too wide, they may encroach on the bands of neighboring channels.

[0034] In other respects, wavelength planning may prioritize the cardinality of the switches implementing the plan, for example, by using media efficiently (e.g., DWDM transmission and reception over a single fiber between two stations) to allow the switches to operate at a high cardinality, thereby enabling non-blocking connections between the switches and a relatively large number of nodes connected to the switches. Another consideration when implementing wavelength planning is prioritizing the energy efficiency of the switches or other devices implementing the plan. For example, as mentioned above, wavelength planning provided by some embodiments allows for relatively simple coding algorithms (e.g., NRZ) that can be operated using less complex and / or more energy-efficient signal processors.

[0035] Optical fibers can typically be characterized as having multiple “bands”; for example, the following bands are common in many optical fibers, but should not be considered unique:

[0036] • O-band (1260 nm to 1360 nm)

[0037] • E-band (1360 nm to 1460 nm)

[0038] • S-band (1460 nm to 1530 nm)

[0039] • C-band (1530 nm to 1565 nm)

[0040] • L-band (1565 nm to 1625 nm)

[0041] As respectively by Figure 1A and 1B The wavelength plans 100 and 130 illustrate that, in some embodiments, all center frequencies λ c (And in fact, all channel groups) fall within the O-band. This is advantageous because devices transmitting in the O-band can typically employ simpler (less complex) amplification than those in other bands, offering lower cost and simpler system design, consuming less power, and allowing for higher fiber counts compared to devices transmitting in other bands. Although the O-band is generally limited to shorter transmission distances than other bands, many implementations can be used in data centers, especially in high-cardinality applications such as AI or ML processing where long transmission distances are not typically required. Therefore, many implementations utilize O-band wavelength plans that leverage optical fibers.

[0042] However, the embodiments are not so limited. For example, some embodiments implement wavelength plans in which all center wavelengths and / or channel groups fall within the C-band (for example, which can support longer transmission distances) and / or any other suitable band of the optical fiber. The selection of the center wavelength and / or the band it falls into may depend on specific implementation details and / or planning constraints and objectives.

[0043] The wavelength scheme, according to various embodiments, is not limited to a 400 GHz grid. For example, Figure 1C The diagram illustrates wavelength scheme 150 according to some embodiments, which spaces channels across a 200 GHz grid. Although Figure 1C Plan 150 has the same Figure 1B The plan is to have the same channel groups 105, 110, 115, and 120, but the channels are spaced apart on a 200 GHz grid, therefore Figure 1C The planned 150 can support eight channels per group, with exemplary features shown in Table 3:

[0044]

[0045]

[0046] Table 3 – Figure 1C channel

[0047] For a narrower 200 GHz grid, Figure 1C The wavelength plan 150 can support eight channels per group, thus providing a total of 16 channels in both transmission and reception modes, with a channel capacity of Figure 1B The illustrated plan 130 has twice the channel capacity and is Figure 1A The illustrated plan 100 has four times the channel capacity. Despite Figures 1A to 1C Each of the wavelength plans described herein is exemplary and none is limiting; however, these plans should be explained to those skilled in the art, as different implementations may be carried out depending on specific implementation needs and / or equipment capabilities. By way of example, in some embodiments, each channel may support 50 Gb / s, enabling the use of four transmit channels 105a to 105d and four receive channels 110a to 110d. Figure 1A The planned 100 can support 200 Gb / s throughput in each direction; Figure 1B The planned 130 could correspondingly support 400 Gb / s in each direction, and Figure 1C The planned 150 could correspondingly support 800 Gb / s in each direction. Based on the disclosure herein, those skilled in the art will understand that some embodiments may support 1.6 Tb / s or higher throughput in each direction.

[0048] Figure 2 The diagram illustrates a system 200 according to some embodiments, the system including a single optical fiber 205 providing optical communication between a pair of optical interfaces 210. Each optical interface 210 includes similar functional components 215, 220 and operates in a similar manner, except that the transmission channel groups 105, 115 of the first interface 210a correspond to the receive channel groups 105, 115 of the second interface 210b, and the receive channel groups 110, 120 of the first interface 210a correspond to the transmission channel groups of the second interface 210b. (For illustrative purposes, each of the channel groups 105 to 120 corresponds to...) Figure 1B and 1C The channel groups illustrated in the wavelength plan are not required. Furthermore, for simplicity, only... Figure 2The diagram illustrates channel groups 105 to 120, not the actual channels 105a to 105h, 110a to 110h, 115a to 115h, and 120a to 120h.

[0049] An exemplary first interface 210a includes a polarization splitter rotator (PSR) 215a that splits the polarization of an incoming channel (represented by groups 110, 120) into transverse magnetic (TM) 220a and transverse electrical (TE) 225a components. Each of these components 220a, 225a of each optical channel in each group 110, 120 is routed to a corresponding photodiode (PD) 230a, 230b for the corresponding wavelength, where the electrical signal is recovered from the optical signal on the channel in each group 110, 120. (Although for simplicity only two PDs 230a, 230b corresponding to channel groups 110, 120 are illustrated, many embodiments will feature one PD per channel rather than one PD per channel group.) On the transmission side, the transmitters (represented by transmitters 235a and 235b) for each channel in channel groups 105 and 115 generate optical signals from the incoming electrical signals (only the TE component 225a of the optical signals exists during transmission) and transmit those optical signals on channels 105 and 115 on the same optical fiber 205 where data is received on channel groups 110 and 120.

[0050] In the second interface 210b (which again communicates with the end of the fiber optic cable 205 opposite to the first interface 210a), a similar process is performed to receive signals on channels 105, 115 and convert those signals into electrical signals using PDs represented by 230c, 230d respectively, while using transmitters 235c, 235d to convert the electrical signals into optical signals to be transmitted on the channels in groups 110, 120.

[0051] Figure 3 The diagram illustrates a method 300 for optical communication according to some embodiments. In some embodiments, method 300 may be provided by, for example... Figure 2 The optical interface, such as interface 210 illustrated in the figure, the device, such as device 400 illustrated in FIG. 4 and described below, and / or one or more components of this device are used to perform the functions. However, it should be understood that the embodiments are not limited to any particular structural implementation.

[0052] At block 305, method 300 includes efficiently utilizing an optical medium. According to various embodiments, several techniques can be employed to efficiently utilize the optical medium. For example, in some embodiments, efficiently utilizing the optical medium may include implementing a BiDi DWDM wavelength plan (block 310), such as with... Figures 1A to 1CThe illustrated scheme is similar to one of the schemes described in detail above. In some embodiments, implementing a wavelength scheme may include configuring one or more optical interfaces to transmit and / or receive optical signals according to the wavelength scheme, for example by installing, programming, configuring, and / or operating appropriate interfaces to transmit and / or receive on a channel specified by the wavelength scheme. As previously mentioned, wavelength schemes according to various embodiments are characterized by BiDi DWDM. Therefore, in some embodiments, implementing a wavelength scheme may include performing BiDi DWDM (block 315).

[0053] For example, in some embodiments, implementing a wavelength plan may include (and / or method 300 may include) transmitting data via optical fiber (box 320) and / or receiving data via optical fiber (box 325). Reference Figure 2 In certain embodiments, transmitting optical data (block 320) and receiving optical data (block 325) may include, for example, transmitting data via a single optical fiber 205 on multiple wavelengths (e.g., channel group 105) centered at a first center wavelength (e.g., 1271 nm), and / or, for example, receiving data via the same single optical fiber 205 on a second multiple wavelengths (e.g., channel group 110) centered at a second center wavelength (e.g., 1311 nm), thereby performing BiDi DWDM in data transmission and reception. In some embodiments, as described in further detail, the above-described transmission and reception of optical data may further include, for example, transmitting data via the single optical fiber 205 on a third multiple wavelengths (e.g., channel group 115) centered at a third center wavelength (e.g., 1291 nm), centered at the same optical interface 210a. In some embodiments, and / or further include receiving data via a single optical fiber 205 on a fourth plurality of wavelengths (e.g., channel group 120) centered at a fourth center wavelength (e.g., 1311 nm), for example via optical interface 210a.

[0054] Figures 4A to 4DThe illustrations illustrate various embodiments of apparatus 400 according to a set of embodiments. In some embodiments, apparatus 400 may be: a network device, such as a network switch (e.g., an Ethernet switch) or router; a server, compute node (which may have additional network devices, optical network interface cards, etc.), leaf node, spine node, etc.; or any other type of computer network device, storage network device, and / or communication device or communication node. In some embodiments, as described above, network apparatus 400 may be implemented in a data center. In particular embodiments, network apparatus 400 may prioritize cardinality (e.g., as described above) and may be used to provide optical communication and / or connectivity between various nodes (e.g., compute nodes, storage nodes, etc.) within the network to support AI and / or ML operations.

[0055] In certain embodiments, device 400 may operate in a variety of networks, including networks conforming to various standards and / or protocols. For example, in some embodiments, device 400 communicates according to IEEE Ethernet standards (e.g., IEEE 802.3). However, it should be noted that while this disclosure may refer to various aspects of these standards, the disclosed embodiments are in no way limited to these standards. Some standards may relate to storage area networks (SANs) for connecting computer data storage devices to servers in commercial data centers. SANs may use Fibre Channel (FC) standards / protocols, Small Computer System Interface (SCSI) standards / protocols, Asynchronous Transfer Mode (ATM) protocols, and / or Synchronous Optical Network Protocol (SONET), to name just a few.

[0056] In the Figures 4A to 4D In the illustrated embodiment, device 400 includes a switching unit 405, which includes a switching circuit 410 and a plurality of optical interface devices 415 (also referred to herein as "optical interfaces"). In some cases, the optical interface devices 415 may be incorporated on-chip into the switching unit 405, while in other cases, the optical interface devices 415 may be external to the switching unit 405. Examples of these two scenarios are described in further detail below. The optical interface devices 415 may function as optical interfaces, for example, as described above in conjunction with... Figure 2The optical interface 210a is described herein. As used herein, the term "optical interface" or "optical interface device" broadly refers to any device that receives optical signals and provides electrical signals and / or is provided with electrical signals and transmits optical signals. In some embodiments, the optical interface device receives an unmodulated laser signal, uses the laser signal to modulate and provide a first optical signal in response to an electronic signal from a processor (e.g., a switching circuit), and receives a second optical signal (e.g., a modulated optical signal) and provides an electronic signal to the processor in response to the second optical signal. Examples of this functionality are described in conjunction with the optical interfaces 210a and 210b above. The device 400 will also typically include the functionality of one or more laser devices and / or one or more ports.

[0057] In some embodiments, as described in further detail below, the optical interface 415 may optically communicate with the laser device 420 and / or incorporate the functionality of the laser device. The term "laser device" is used broadly herein to refer to any device comprising at least one laser or other light source that provides at least one optical signal suitable for optical communication (e.g., high-speed optical communication of 1 Gb / s or higher). In some embodiments, the optical signal is a laser signal or other optical signal suitable for optical communication. In some embodiments, the laser device 420 may be configured to transmit single-wavelength or multi-wavelength signals (and / or a combination thereof), and the corresponding optical interface 415 may similarly be configured to process single-wavelength signals, multi-wavelength signals, or a combination thereof. In some embodiments, each laser device may each comprise more than one laser (e.g., a Q number of lasers or light sources).

[0058] In some embodiments, such as as described in further detail below, the optical interface may also communicate with port 425 and / or incorporate the functionality of said port. The port provides a physical interface to which external optical cables (including one or more optical fibers, such as those described above) can be connected to provide optical communication between network device 400 and another device or node. Examples of optical ports according to various embodiments include, but are not limited to, small form factor pluggable (SFP) ports, SFP+, quad SFP (QSFP), and QSPF+ ports. In some embodiments, the functionality of laser device 420 and / or port 425 may be incorporated into optical interface 415, while in other embodiments, such as Figure 3 As shown, the laser device 420 (e.g., RLM or PLS) and / or port 425 can be detached from and / or optically communicate with the corresponding optical interface 415.

[0059] According to various embodiments, device 400 may include any number of optical interfaces 415, laser devices 420, and / or ports 425. In one aspect, device 400 communicates with other nodes or devices using optical signals, which are transmitted and received using optical interface devices 415. In some cases, as described in further detail below, optical interface devices 415 operate in conjunction with separate corresponding laser devices 420 and / or ports 425, while in other cases, the functionality of laser devices 420 and ports 425 may be combined, and / or some or all of the functionality of laser devices 420 and ports 425 may be integrated with the optical interface device 415 itself.

[0060] In some embodiments, each of the optical interface devices 415a to 415h is configured as a universal switching interface that supports some or all of the interface types associated with the respective laser devices 420a to 420h. In some embodiments, the optical interface devices 415a to 415h are electrically coupled to a switching circuit 410, which may be implemented in any suitable form, such as a photonic integrated circuit (PIC), an application-specific integrated circuit (ASIC), etc. In some embodiments, the optical interface devices 415a to 415h are co-packaged optical interfaces (CPO) provided in the same package or housing as the switching circuit 410. In some embodiments, the optical interface devices 415a to 415h are physically separate from the switching circuit 410 and / or the switching unit 405. In some embodiments, the switching circuit 410 is a 51.2 Tb / s Ethernet switching circuit.

[0061] Different embodiments can be configured in multiple ways as features. For example, Figure 4A The illustration illustrates an implementation according to a set of embodiments, wherein each optical interface 415 communicates with a corresponding laser device 420, which is incorporated with a corresponding port 425 and / or includes port functionality. For example, in some cases, a specific laser device 420 may be provided within a laser module, which broadly refers to any device comprising one or more laser devices that may, but do not necessarily, be housed or contained in a separate structure; for example, a laser module may include a packaged device configured to provide laser light. In some embodiments, a laser module may include heat dissipation components (e.g., heat sinks, Peltier assemblies, etc.), optical components, optical connectors (e.g., port 425), and / or electrical components. In some embodiments, the laser module may be a remote laser module (RLM) or a pluggable light source (PLS), either of which may be packaged within a multi-chip module. In some embodiments, the RLM or PLS may be a remote module detachable or separable from the corresponding optical interface device 415 and includes at least one laser.

[0062] As by Figure 4A As illustrated, laser device 420 may be integrated with port 425 and / or may include a receive and transmit optical multiplexer with optical pass-through (OPT) capability, which is used to provide light between a corresponding optical interface 415 and one or more external input / output (I / O) optical fibers (i.e., fibers at the external I / O of laser device 420) according to various configurations (e.g., single wavelength per fiber, M fibers each carrying P wavelengths, etc.). In one aspect, laser device 420 may support N transmit and / or receive channels, M external I / O fibers, and P wavelengths per external I / O fiber. In a particular embodiment where each optical interface provides BiDi DWDM (e.g., according to the wavelength scheme described above, for example) on a single fiber, M may be 1, and P and N may each be equal and have values ​​such as 4, 8, 16, 32, etc. (i.e., a configuration in which the laser device, for example, uses the technique described above to transmit / receive the same number of channels via a single fiber using a specific number of wavelengths).

[0063] In other embodiments, such as those by Figure 4B As illustrated, optical interface 415 includes the functionality of a laser device and port, and / or optical device 415 can receive optical signals from an external optical I / O cable (e.g., according to wavelength plans, using the above-mentioned...). Figure 4A (as described elsewhere in BiDi DWDM, etc.), converting those signals into electrical signals and providing those electrical signals to the switching circuit 410. Similarly, the optical interface 415 can receive electrical signals from the switching circuit 410, convert those signals into optical signals, and output the optical signals to an external optical I / O cable (e.g., according to a wavelength plan, using the above-described...). Figure 4A (and other places that describe BiDi DWDM, etc.).

[0064] In other embodiments, such as those by Figure 4C As illustrated, each optical interface can optically communicate with the corresponding laser device 420 and the corresponding port 425. In such a case, the optical device may receive electrical signals from the switching circuit 410 and light from the corresponding laser device 420, convert the electrical signals into optical signals modulated onto the received light, and transmit the modulated optical signals via the corresponding port 425 through an external I / O cable (e.g., according to a wavelength plan, using the above description). Figure 4A (And BiDi DWDM, etc., as described elsewhere). Similarly, optical interface 415 may receive optical signals via port 425 and convert the optical signals into electrical signals (e.g., according to the wavelength plan, using the above-mentioned...). Figure 4A(as described elsewhere, such as BiDi DWDM, etc.), and provides electrical signals to the switching circuit 410.

[0065] In other embodiments (e.g., by) Figure 4D In the illustrated embodiment, optical device 415 may include the functionality of a laser device and optically communicate with a corresponding port 425. In such cases, the optical device can transmit and receive optical signals (e.g., according to a wavelength scheme, using the information above regarding...). Figure 4A (as described elsewhere, such as BiDi DWDM), converting optical signals into electrical signals and converting electrical signals into optical signals, and transmitting / receiving electrical signals from the switching circuit 410.

[0066] based on Figures 4A to 4D As illustrated by these examples, those skilled in the art should understand that different embodiments may employ a variety of different architectures and / or structural implementations. Those skilled in the art should also understand that these examples are provided for illustrative purposes only and that some embodiments may operate in different ways, and / or include additions or differences from those provided. Figures 4A to 4D The structure of those structures described in the text.

[0067] The device 400 may also include logic, including but not limited to logic for configuring the device 400 and / or its components to perform operations according to methods provided by various embodiments, said operations including but not limited to Figure 3 Method 300 includes some or all of the operations and those used to implement them, for example, in combination. Figures 1A to 1C The operation of the described wavelength plan. This logic may take the form of hardware circuitry, firmware instructions, and / or software instructions executed by a processor, such as a switching circuit 410, a microcontroller, a communication controller, and / or any other suitable hardware.

[0068] It should be noted that although Figure 4 illustrates the optical interface 415, laser device 420 and port 425 in a specific arrangement for illustrative purposes, this arrangement is not limiting and many such arrangements are possible, including but not limited to arrangements in which the functionality of laser device 420 and / or port 425 is incorporated into the optical interface so that separate laser device 420 and / or port 425 is not required.

[0069] Other examples

[0070] The following examples describe various features of specific embodiments. All such features of each example described below can be combined in any way, and therefore different embodiments may include any set or subset of the features described below, as well as the various features of the embodiments described above. It should not be assumed that all embodiments require a particular feature or set of features. Rather, in view of this disclosure, some embodiments may combine some or all of these features in any way that is understood by one of ordinary skill in the art.

[0071] A set of embodiments provides an apparatus. Exemplary apparatus may include an optical interface. In some embodiments, the apparatus includes logic for efficiently utilizing the optical medium by performing bidirectional (BiDi) dense wavelength division multiplexing (DWDM). In some embodiments, the apparatus includes a network switch. In some embodiments, the network switch is an Ethernet switch. In some embodiments, the logic for efficiently utilizing the optical medium prioritizes the cardinality of the network switch.

[0072] In some embodiments, performing BiDi DWDM includes transmitting data via a single optical fiber at a first plurality of wavelengths centered on a first center wavelength via an optical interface. In some embodiments, performing BiDi DWDM includes receiving data via a single optical fiber at a second plurality of wavelengths centered on a second center wavelength via an optical interface. In some embodiments, performing BiDi DWDM includes transmitting data via a single optical fiber at a third plurality of wavelengths centered on a third center wavelength via an optical interface. In some embodiments, performing BiDi DWDM includes receiving data via a single optical fiber at a fourth plurality of wavelengths centered on a fourth center wavelength via an optical interface.

[0073] In some embodiments, the first center wavelength and the second center wavelength are sufficiently spaced to avoid crosstalk between the transmission path and the reception path in the optical interface. In some embodiments, the first plurality of wavelengths and the second plurality of wavelengths each comprise four to eight wavelengths spaced apart on a grid between approximately 200 GHz and 400 GHz. In some embodiments, adjacent center wavelengths are spaced approximately 20 nm apart.

[0074] In some embodiments, the first center wavelength is between about 1265 nm and about 1275 nm. In some embodiments, the second center wavelength is between about 1325 nm and about 1335 nm. In some embodiments, the third center wavelength is between about 1285 nm and 1295 nm. In some embodiments, the fourth center wavelength is between about 1305 nm and about 1315 nm.

[0075] In some embodiments, each of the first plurality of wavelengths and each of the second plurality of wavelengths falls within the O-band of a single optical fiber. In some embodiments, each of the first plurality of wavelengths and each of the second plurality of wavelengths falls within the C-band of a single optical fiber.

[0076] The apparatus according to another set of embodiments may include logic for implementing a BiDi (BiDWDM) dense wavelength division multiplexing (DWDM) wavelength scheme. In some embodiments, the BiDi DWDM scheme takes into account energy efficiency, cardinality, and fiber utilization. In some embodiments, the apparatus includes logic for transmitting data over a single fiber on at least one set of transmission wavelengths centered at at least one transmission center wavelength, according to the BiDi DWDM wavelength scheme. In some embodiments, the apparatus includes logic for receiving data over a single fiber on at least one set of receive wavelengths centered at at least one receive center wavelength. In some embodiments, the at least one set of transmission wavelengths includes multiple sets of transmission wavelengths, each set centered on a corresponding one of a plurality of transmission center frequencies. In some embodiments, the at least one set of receive wavelengths includes multiple sets of receive wavelengths, each set centered on a corresponding one of a plurality of receive center frequencies.

[0077] Another set of embodiments provides a method. An exemplary method may include efficiently utilizing an optical medium by performing bidirectional (BiDi) dense wavelength division multiplexing (DWDM). In some embodiments, performing BiDi DWDM includes transmitting data via a single optical fiber at a first plurality of wavelengths centered on a first center wavelength via an optical interface. In some embodiments, performing BiDi DWDM includes receiving data via a single optical fiber at a second plurality of wavelengths centered on a second center wavelength via an optical interface.

[0078] In some embodiments, performing BiDi DWDM includes transmitting data via a single optical fiber at a third plurality of wavelengths centered at a third center wavelength via an optical interface. In some embodiments, performing BiDi DWDM includes receiving data via a single optical fiber at a fourth plurality of wavelengths centered at a fourth center wavelength via an optical interface.

[0079] In some embodiments, the first center wavelength and the second center wavelength are sufficiently spaced to avoid crosstalk between the transmission path and the reception path in the optical interface. In some embodiments, the first plurality of wavelengths and the second plurality of wavelengths each comprise four to eight wavelengths spaced apart on a grid between approximately 200 GHz and 400 GHz. In some embodiments, adjacent center wavelengths are spaced approximately 20 nm apart.

[0080] In some embodiments, the first center wavelength is between about 1265 nm and about 1275 nm. In some embodiments, the second center wavelength is between about 1325 nm and about 1335 nm. In some embodiments, the third center wavelength is between about 1285 nm and 1295 nm. In some embodiments, the fourth center wavelength is between about 1305 nm and about 1315 nm.

[0081] In some embodiments, each of the first plurality of wavelengths and each of the second plurality of wavelengths falls within the O-band of a single optical fiber. In some embodiments, each of the first plurality of wavelengths and each of the second plurality of wavelengths falls within the C-band of a single optical fiber.

[0082] in conclusion

[0083] In the foregoing description, numerous details are set forth for illustrative purposes to provide a thorough understanding of the described embodiments. However, those skilled in the art will appreciate that other embodiments can be practiced without some of these details. In other instances, structures and apparatuses are shown in block diagram form, without all details for the sake of brevity. Several embodiments are described herein, and although various features pertain to different embodiments, it should be understood that features described with respect to one embodiment may also be incorporated into other embodiments. However, for the same reason, no single feature or features of any of the described embodiments should be considered essential to every embodiment of the invention, as such features may be omitted in other embodiments of the invention.

[0084] Therefore, the foregoing description provides an illustrative and descriptive account of some features and various embodiments, but the description is not intended to be exhaustive or generally does not limit the embodiments to the precise forms disclosed. Those skilled in the art will recognize that modifications can be made in light of the foregoing disclosure or can be obtained from the practice of implementing the embodiments, all of which fall within the scope of the various embodiments. For example, as described above, the methods and processes described herein can be implemented using software components, firmware and / or hardware components (including but not limited to processors, other hardware circuit systems, custom integrated circuits (ICs), programmable logic, etc.) and / or any combination thereof.

[0085] Furthermore, although the various methods and processes described herein may be described with respect to specific structural and / or functional components for ease of description, the methods provided by the various embodiments are not limited to any particular structural and / or functional architecture, but may instead be implemented in any suitable hardware configuration. Similarly, although some functionality may belong to one or more system components, unless the context otherwise indicates, this functionality may be distributed among various other system components according to several embodiments.

[0086] Similarly, although the procedures of the methods and processes described herein are presented in a particular order for ease of description, various procedures may be reordered, added, and / or omitted according to various embodiments unless the context otherwise requires. Furthermore, procedures described with respect to a method or process may be incorporated into other described methods or processes; similarly, system components described with respect to a particular architecture and / or a system may be organized in an alternative architecture and / or incorporated into other described systems. Therefore, although those embodiments are described as having or lacking certain features for ease of description and to illustrate various aspects of the embodiments, various components and / or features described herein with respect to particular embodiments may be replaced, added, and / or omitted in other described embodiments unless the context otherwise requires.

[0087] As used herein, the term "component" is intended to be broadly understood as hardware, firmware, software, or any combination thereof. It will be understood that the systems and / or methods described herein may be implemented in various forms of hardware, firmware, and / or combinations of hardware and software. The actual dedicated control hardware or software code used to implement these systems and / or methods does not limit any embodiment, except as specifically cited in the appended claims. Therefore, when the operation and behavior of the systems and / or methods are not described herein with reference to specific software code, those skilled in the art will understand that software and hardware can be used to implement the systems and / or methods described herein.

[0088] In this disclosure, when an element is referred to herein as “connected” or “coupled” to another element, it will be understood that an element may be directly connected to another element or that there may be an intervening element between these elements. Conversely, when an element is referred to as “directly connected” or “directly coupled” to another element, it should be understood that there is no intervening element in the “direct” connection between said elements. However, the presence of a direct connection does not preclude the presence of other connections in which an intervening element may be present. Similarly, although the methods and processes described herein may be described in a particular order for ease of description, it should be understood that, unless the context otherwise specifies, the intervention process may occur before and / or after any part of the described process, and as mentioned above, the described procedures may be reordered, added, and / or omitted according to various embodiments.

[0089] In this application, unless otherwise specifically stated, the singular is used to encompass the plural, and unless otherwise indicated, the term “and” means “and / or”. Furthermore, as used herein, the term “or” is intended to be inclusive when used in a series and may also be used interchangeably with “and / or” unless otherwise explicitly stated (e.g., in conjunction with “any one” or “only one of…”). Additionally, the use of the term “including” and other forms (e.g., “includes” and “included”) should be considered non-exclusive. And, unless otherwise specifically stated, terms such as “element” or “component” cover both elements and components comprising one unit and elements and components comprising more than one unit. As used herein, the phrase “at least one of…” following a series of items (where the terms “and” or “or” are used to separate any of the items) modifies the list as a whole, not each member of the list (i.e., each item). The phrase “at least one of…” does not require selection of at least one of each of the listed items; rather, the phrase allows for the meaning of at least one of any of the items and / or at least one of any combination of the items. By way of example, the phrases “at least one of A, B, and C” or “at least one of A, B, or C” each refer to only A, only B, or only C; and / or any combination of A, B, and C. In instances where the intended selection is “at least one of each of A, B, and C” or alternatively “at least one of A, at least one of B, and at least one of C”, it will be explicitly described as such.

[0090] Unless otherwise indicated, all numbers used herein to express quantity, size, etc., should be understood to be modified by the term “about” in all instances. As used herein, the article “a (a and an)” is intended to include one or more items and is used interchangeably with “one or more”. Similarly, as used herein, the article “described” is intended to include one or more items mentioned in conjunction with the article “described” and is used interchangeably with “described one or more”. As used herein, the term “group” is intended to include one or more items (e.g., related items, unrelated items, a combination of related and unrelated items, etc.) and is used interchangeably with “one or more”. When intended to refer to only one item, the phrase “only one” or similar language is used. As used herein, the terms “has (has, have, having)”, etc., are intended to be open-ended terms. Furthermore, unless otherwise expressly stated, the phrase “based on” is intended to mean “at least partially based on”. In the foregoing description, depending on the context, satisfying the threshold can refer to a value greater than the threshold, a value greater than or equal to the threshold, a value less than the threshold, a value less than or equal to the threshold, a value equal to the threshold, and so on.

[0091] While specific combinations of features are cited in the claims and / or disclosed in the description, these combinations are not intended to limit the disclosure of the various embodiments. In fact, many of these features can be combined in several ways not specifically cited in the claims or disclosed in the description. Therefore, although each dependent claim listed below may directly refer to only one claim, the disclosure of the various embodiments includes every dependent claim in combination with every other claim in the claim set. Elements, actions, or instructions used herein should not be construed as critical or essential unless explicitly stated otherwise.

Claims

1. An apparatus comprising: Optical interface; Logic for efficiently utilizing optical media by performing bidirectional BiDi dense wavelength division multiplexing (DWDM), wherein performing BiDi DWDM includes: Data is transmitted via a single optical fiber at a first plurality of wavelengths centered on a first center wavelength via the optical interface; and Data is received via the optical interface at a second plurality of wavelengths centered on the second center wavelength via the single optical fiber.

2. The apparatus of claim 1, wherein the first center wavelength and the second center wavelength are sufficiently spaced apart to avoid crosstalk between the transmission path and the receiving path in the optical interface.

3. The apparatus of claim 1, wherein the first plurality of wavelengths and the second plurality of wavelengths each comprise four to eight wavelengths spaced apart on a grid between about 200 GHz and 400 GHz.

4. The apparatus of claim 1, wherein performing BiDi DWDM further comprises: Data is transmitted via a single optical fiber at a third plurality of wavelengths centered on a third center wavelength via the optical interface; and Data is received via the optical interface at a fourth plurality of wavelengths centered on the fourth center wavelength via the single optical fiber.

5. The apparatus according to claim 4, wherein: The first center wavelength is between approximately 1265 nm and approximately 1275 nm; The second center wavelength is between approximately 1325 nm and approximately 1335 nm; The third center wavelength is between approximately 1285 nm and 1295 nm; and The fourth center wavelength is between approximately 1305 nm and approximately 1315 nm.

6. The apparatus of claim 4, wherein adjacent center wavelengths are spaced about 20 nm apart.

7. The apparatus of claim 1, wherein each of the first plurality of wavelengths and each of the second plurality of wavelengths falls within the O-band of the single optical fiber.

8. The apparatus of claim 1, wherein each of the first plurality of wavelengths and each of the second plurality of wavelengths falls within the C-band of the single optical fiber.

9. The apparatus of claim 1, wherein the apparatus comprises a network switch.

10. The apparatus of claim 9, wherein the network switch is an Ethernet switch.

11. The apparatus of claim 9, wherein the logic for efficiently utilizing the optical medium prioritizes the number of network switches.

12. A method comprising: Efficient utilization of optical media is achieved by performing bidirectional BiDi dense wavelength division multiplexing (DWDM), wherein performing BiDiDWDM includes: Data is transmitted via an optical interface over a first plurality of wavelengths centered on a first center wavelength via a single optical fiber; and Data is received via the optical interface at a second plurality of wavelengths centered on the second center wavelength via the single optical fiber.

13. The method of claim 12, further comprising prioritizing the number of switches that transmit and receive the data.

14. The method of claim 12, wherein the first plurality of wavelengths and the second plurality of wavelengths each comprise four to eight wavelengths spaced apart on a grid between about 200 GHz and 400 GHz.

15. The method of claim 12, wherein performing BiDi DWDM further comprises: Data is transmitted via a single optical fiber at a third plurality of wavelengths centered on a third center wavelength via the optical interface; and Data is received via the optical interface at a fourth plurality of wavelengths centered on the fourth center wavelength via the single optical fiber.

16. The method of claim 15, wherein: The first center wavelength is between approximately 1265 nm and approximately 1275 nm; The second center wavelength is between approximately 1325 nm and approximately 1335 nm; The third center wavelength is between approximately 1285 nm and 1295 nm; and The fourth center wavelength is between approximately 1305 nm and approximately 1315 nm.

17. The method of claim 16, wherein adjacent center wavelengths are spaced about 20 nm apart.

18. The method of claim 12, wherein each of the first plurality of wavelengths and each of the second plurality of wavelengths falls within the O band of the single optical fiber or the C band of the single optical fiber.

19. An apparatus comprising: The logic used to implement BiDi dense wavelength division multiplexing (DWDM) wavelength plans that take into account energy efficiency, cardinality, and fiber utilization. Logic for transmitting data on a single optical fiber and on at least one set of transmission wavelengths centered on at least one transmission center wavelength, according to the BiDi DWDM wavelength plan; and Logic for receiving data on the single optical fiber at at least one set of receiving wavelengths centered at at least one receiving center wavelength.

20. The apparatus according to claim 19, wherein: The at least one set of transmission wavelengths includes multiple sets of transmission wavelengths, each set of transmission wavelengths being centered on a corresponding one of multiple transmission center frequencies; and The at least one set of receiving wavelengths includes multiple sets of receiving wavelengths, each set of receiving wavelengths being centered on a corresponding one of multiple receiving center frequencies.

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