Optical switching device and optical switching method
By designing an optical switching device including a local parent optical transceiver, a local analog-to-digital conversion unit, a switching unit, etc., the problem of delay processing in the routing device in the wide-area optical network and the local optical network is solved, and the direct storage of the local optical network signal directly enters the wide-area optical network, eliminating the processing delay and reducing the use of the router, which has energy-saving effects.
Patent Information
- Application Number
- CN202280099051.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2022-08-19
- Publication Date
- 2025-03-25
AI Technical Summary
In a network composed of a wide-area optical network and a local-area optical network, the interpretation of destination control information by the routing device results in a large electrical processing load, resulting in a processing delay when sending multiple categories and large-capacity data.
An optical switching device is designed, which includes a local parent optical transceiver, a local analog-to-digital conversion unit, a switching unit, a digital analog conversion unit, a wide-area transmission digital signal processing unit, a wide-area digital analog conversion unit, a wide-area optical modulation unit, etc. Through direct detection and sampling, the finite-length signal of the local optical network can be directly entered into the wide-area optical network, avoiding processing delays of the routing device.
The wide-area optical network can directly accommodate finite-length signals from the local optical network, eliminate processing delays in the routing device, and reduce the use of routers in the network, thereby helping to save energy.
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Figure CN119698781A_ABST
Abstract
Description
Technical Field
[0001] The disclosed technology relates to an optical switching device and an optical switching method. Background Art
[0002] In the fifth generation mobile communication system, so-called 5G, it is known to utilize an optical transport network (OTN).
[0003] For example, in non-patent document 1, many examples of OTN networks connected to 5G networks are shown (refer to Figures 8-4 to 8-10 of non-patent document 1). Here, in this specification, a wide area optical network is referred to as a "wide area optical network". In addition, in this specification, a local area optical network is referred to as a "local area optical network".
[0004] As exemplified in non-patent document 1, usually, the limited-length traffic sent from the local optical network is managed separately for each service category, converted into a continuous signal by an electrical routing device, and then optically transmitted over a long distance and with a large capacity through the wide-area optical network. That is, usually, a network composed of a wide-area optical network and a local-area optical network has a routing device on the local-area optical network side, and the routing device interprets the destination information and implements routing. In addition, it can be said that on the wide-area optical network side, a wide-area optical switching device is prepared for each service category or each destination.
[0005] Prior art literature
[0006] Non-patent literature
[0007] Non-patent document 1: Information and Communications Technology Council, “Technical Report on Application of OTN to 5th Generation Mobile Communication Systems,” TR-1084, Version 1.0, March 11, 2020. Summary of the invention
[0008] Problem that the invention aims to solve
[0009] Such a network composed of conventional wide area optical networks and local area optical networks has a heavy load on the electrical processing of interpreting control information such as destinations and performing routing in a routing device. When transmitting large amounts of data of various types, processing delays that depend on the processing capabilities of the routing device occur.
[0010] In the technical field of networks composed of a wide area optical network and a local area optical network, a mechanism for enabling the wide area optical network to directly receive a finite length signal from the local area optical network without causing a processing delay is sought.
[0011] The purpose of the disclosed technology is to provide a structure for "a wide area optical network to directly accommodate a finite length signal from a local area optical network".
[0012] Means used to solve problems
[0013] The optical switching device of the disclosed technology is an optical switching device that connects a local optical network with a wide area optical network, and includes: a local mother optical transceiver, which directly detects an input intensity modulated optical signal and outputs it as a local reception analog electrical signal; a local mother analog-to-digital conversion unit, which samples the local reception analog electrical signal and outputs it as a local reception digital signal; a switching unit, which distributes the local reception digital signal into a local transmission digital signal and a wide area transmission digital signal and outputs them; a local mother digital-to-analog conversion unit, which converts the local transmission digital signal into an analog signal; a wide area transmission digital signal processing unit, which performs digital signal processing on the wide area transmission digital signal to generate a transmission subcarrier signal for coherent optical communication; a wide area digital-to-analog conversion unit, which performs frequency multiplexing on the transmission subcarrier signal and converts it into a wide area transmission analog electrical signal; and a wide area optical modulation unit, which modulates the optical carrier based on the wide area transmission analog electrical signal, and the local mother analog-to-digital conversion unit performs sampling according to the signal form with the most stringent sampling conditions among the assumed signal forms.
[0014] Effects of the Invention
[0015] Since the optical switching device of the disclosed technology has the above-mentioned structure, the wide area optical network can directly accommodate the limited length signal from the local area optical network. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 This is a block diagram showing the functional structure of the optical switching device according to the first embodiment.
[0017] FIG. 2 is an explanatory diagram showing an example of processing of a signal received from the local mother analog-to-digital converter 14 by the switching unit 20 of the optical switching device according to the first embodiment.
[0018] FIG. 3 is an explanatory diagram showing an example of processing of a signal received from the wide area reception digital signal processing unit 38 by the switching unit 20 of the optical switching device according to the first embodiment.
[0019] Figure 4 This is an explanatory diagram showing a connection example of an optical switching device according to the disclosed technology. DETAILED DESCRIPTION
[0020] Implementation method 1.
[0021] Figure 1 2 is a block diagram showing the functional structure of the optical switching device 200 according to Embodiment 1. Figure 1As shown, the optical switching device 200 is a device that connects the local optical network 100 to the wide area optical network 300. Figure 1 As shown, the optical switching device 200 of embodiment 1 has N (N is a natural number) local mother optical transceivers 13, N local mother analog-to-digital conversion units 14, N local mother digital-to-analog conversion units 15, a switching unit 20, M (M is a natural number) wide area transmission digital signal processing units 31, wide area digital-to-analog conversion units 32, wide area optical modulation units 33, wide area optical detection units 36, wide area analog-to-digital conversion units 37, and M wide area reception digital signal processing units 38.
[0022] The local optical network 100 assumed by the optical switching device 200 of the first embodiment includes a plurality of local optical sub-transceivers 11 and an optical transmission path 12 connecting the plurality of local optical sub-transceivers 11 and N local optical mother transceivers 13 .
[0023] Furthermore, the wide area optical network 300 assumed by the optical switching device 200 of the first embodiment includes a transmission optical switch 34 and a reception optical switch 35 .
[0024] The names of main signals processed by the optical switching device 200 according to Embodiment 1 are described in the following table in this specification.
[0025] Table 1 Signal names
[0026]
[0027] Local Area Optical Network 100
[0028] In the technical field of information communication, the term "local side" is used to indicate the client side. In addition, the term "wide area side" paired with the local side is used to indicate the line side or the transmission path side. The term "local" used in the name of the local optical network 100 indicates a limited place as defined in the dictionary.
[0029] In the local optical network 100 assumed by the optical switching device 200 of the first embodiment, a plurality of sub-optical transceivers are connected to one main optical transceiver. Figure 1 In the example shown, a plurality of local sub-optical transceivers 11 (11-1-1, 11-1-2, ..., 11-1-K[1]) are connected to the first local mother optical transceiver 13 (13-1) via the first optical transmission path 12 (12-1). As used in this specification, the number "-n" (n is a variable that can be 1 to N) added after the number indicates a functional block related to the nth transmission sequence. Figure 1 In the example shown, the total number of local sub-optical transceivers 11 is K[1]+K[2]+…+K[n]+…+K[N].
[0030] like Figure 1 As shown, each of the n-th optical transmission paths 12-n is partially shared. In addition, each of the optical transmission paths 12-n can be connected to a local side interface of another optical switching device (not shown, 200-other).
[0031] An intensity modulated signal of a finite length, more specifically, an intensity modulated signal in the form of a burst signal, is output from the local sub-optical transceiver 11. A burst signal means that when an observation is made in a time region, a signal exists only in a small portion, and no signal exists in other portions. In addition, the intensity modulated signal output from the local sub-optical transceiver 11 emphasizes that it is an optical signal, and is sometimes referred to as an "intensity modulated optical signal."
[0032] The intensity modulated signals output from the local sub-optical transceivers 11 are time-division multiplexed.
[0033] In addition, it is desirable to appropriately adjust the power of light transmitted from the local optical sub-transceiver 11 so as to suppress the resolution required in the local mother analog-to-digital converter 14 - n described later and ensure a power margin (Power Jet).
[0034] The optical transmission path 12-n is usually composed of a single-core optical fiber, and realizes bidirectional communication between the local sub-optical transceiver 11-nk (k is a variable that can be 1 to K[n]) and the local mother optical transceiver 13-n. In order to prevent the conflict between the upstream direction (from the sub-to-mother direction) and the downstream direction (from the mother to the sub-direction) in the optical transmission path 12-n, research has been conducted on changing the value of the optical wavelength.
[0035] The local optical sub-transceiver 11-nk located at the terminal of the local optical network 100 directly detects the intensity modulated optical signal transmitted from the local optical mother transceiver 13-n and input via the optical transmission path 12-n, determines the symbol, and demodulates it into the original data.
[0036] Here, a symbol refers to the duration or time that a certain state in digital modulation lasts. As a related term, the symbol rate is the number of symbols that change per unit time, and the unit is [symbol / s]. The symbol rate is also called the baud rate (unit [Baud]) or the modulation rate.
[0037] The symbol rate is related to the occupied frequency band. When the symbol rate is large, the occupied frequency band becomes wider. Therefore, it is a powerful means to transmit more information while saving limited frequency resources, that is, multi-value modulation with the same symbol rate and large bit rate is a powerful means.
[0038] In this way, the local optical network 100 assumed by the optical switching device 200 of embodiment 1 has the following properties: multiple local sub-optical transceivers 11 are connected to one local mother optical transceiver 13; the optical transmission path 12 between the local mother optical transceiver 13 and the local sub-optical transceiver 11 is partially shared; an intensity modulated signal of a finite length is output from the local sub-optical transceiver 11; and the intensity modulated signal is time-division multiplexed.
[0039] Wide Area Optical Network 300
[0040] The term "wide area" used in the name of the wide area optical network 300 means a wide area as defined in the dictionary. Generally, a wide area network connects a wide area within a city, between cities, or between countries.
[0041] The wide area optical network 300 assumed by the optical switching device 200 of the first embodiment can accommodate multiple virtual optical channels through one optical transceiver. The virtual optical channels can be processed as independent optical wavelengths. Here, the term "virtual" means that although it is physically an interface such as one optical transceiver, it can actually output simultaneously on multiple optical channels.
[0042] Through this function, the wide area optical network 300 can accommodate a large amount of different types of services with low latency and can communicate with different locations.
[0043] The signal processed by the wide area optical network 300 is a signal after polarization multiplexing, orthogonal amplitude modulation or subcarrier multiplexing. The receiving side of the wide area optical network 300 performs coherent detection and performs corrections such as waveform distortion compensation and symbol error correction through digital signal processing.
[0044] The details of the transmission optical switch 34 and the reception optical switch 35 included in the wide area optical network 300 will become clear from the following description.
[0045] 《Optical switching device 200》
[0046] As described above, the optical switching device 200 connects the local optical network 100 and the wide area optical network 300. The details of the optical switching device 200 will become clear from the description of each functional block described later.
[0047] <<Local mother optical transceiver 13 constituting the optical switching device 200>>
[0048] The local master optical transceiver 13 constituting the optical switching device 200 is a component that generates and detects an intensity modulated optical signal.
[0049] The local mother optical transceiver 13-n constituting the optical switching device 200 directly detects the intensity modulated optical signal sent from the local daughter optical transceiver 11-nk and input via the optical transmission path 12-n, but does not determine the symbol. The signal obtained by direct detection in the local mother optical transceiver 13 is referred to as the "local reception analog electrical signal" in this specification. The local reception analog electrical signal is sent to the local mother analog-to-digital conversion unit 14-n.
[0050] For the signal sent to the local mother analog-to-digital converter 14-n, that is, the local reception analog electrical signal, in the assumption of the disclosed technology, it is possible that signals of finite length with different baud rates or different degrees of multi-value modulation (sometimes referred to as "modulation multi-value degree") are multiplexed in time. It is possible that the local reception analog electrical signal assumed by the disclosed technology is a signal obtained by, for example, temporally multiplexing a 10 [Gb / s] on-off keying signal and a 50 [Gb / s] four-value PAM signal.
[0051] The technical feature of the optical switching device 200 of the disclosed technology is that sampling is performed regardless of the signal form and traffic is accommodated independently of the protocol. The case of accommodating traffic regardless of the signal form and independently of the protocol is referred to as "direct accommodation" in this specification.
[0052] <Local mother analog-to-digital converter 14 constituting optical switching device 200>
[0053] The local mother analog-to-digital converter 14-n constituting the optical switching device 200 is a component that samples the local reception analog electrical signal transmitted from the local mother optical transceiver 13-n. The signal obtained by sampling in the local mother analog-to-digital converter 14 is referred to as a "local reception digital signal" in this specification.
[0054] The local area received digital signal is sent to the switching unit 20 .
[0055] As described above, the technical feature of the optical switching device 200 of the disclosed technology is that sampling is performed regardless of the signal form, and traffic is accommodated independently of the protocol. Therefore, as a price, the local mother analog-to-digital conversion unit 14 needs to perform sampling according to the signal form with the most stringent conditions. The local mother analog-to-digital conversion unit 14 performs sampling at, for example, the most stringent sampling rate of 50 [Gsample / s] or 100 [Gsample / s] which is twice as high as the sampling rate in consideration of the safety rate. In addition, in this example, the local mother analog-to-digital conversion unit 14 performs sampling at a resolution of at least 2 [bit] or more, that is, the number of quantization bits. For example, in the case where a multi-value signal is not used (only a binary signal), there is a case where the sampling can be as small as 1 [bit], but in any case, the local mother analog-to-digital conversion unit 14 needs to have a resolution that can cope with any assumed signal form.
[0056] Thus, it can be said that the signal condition, such as the range of signals within which the traffic can be accommodated without relying on the protocol, and the conditions for the local mother analog-to-digital converter 14, such as the sampling rate and the number of quantization bits, are in a trade-off relationship. The disclosed technology accepts the most stringent conditions for the sampling rate and the number of quantization bits in the local mother analog-to-digital converter 14, thereby achieving traffic accommodation without relying on the protocol.
[0057] <Local mother digital-to-analog converter 15 constituting the optical switching device 200>
[0058] The local mother digital-to-analog converter 15 constituting the optical switching device 200 is a structural element that converts a digital signal (hereinafter referred to as a "switched digital signal") transmitted from the switching unit 20 into an analog signal. In the local mother digital-to-analog converter 15, the analog signal obtained by digital-to-analog conversion is referred to as a "local transmission analog electrical signal" in this specification.
[0059] The local area transmission analog electrical signal is sent to the local area mother optical transceiver 13-n.
[0060] In addition, from the viewpoint of achieving both resolution and power margin, it is desirable that the local mother digital-to-analog converter 15 appropriately performs amplitude adjustment in the digital domain before conversion.
[0061] <<Switching Unit 20 Constituting Optical Switching Device 200>>
[0062] In short, the switching unit 20 constituting the optical switching device 200 is a component that distributes and outputs input signals. The processing performed by the switching unit 20 is referred to as "switching processing" in this specification. The switching unit 20 constituting the optical switching device 200 is implemented as hardware by a processing circuit.
[0063] The signals input to the switching unit 20 are the local area reception digital signal from the local area mother analog-to-digital conversion unit 14-n (n=1, 2, ..., N) and the wide area reception digital signal from the wide area reception digital signal processing unit 38-m (m=1, 2, ..., M). The details of the wide area reception digital signal processing unit 38-m and the wide area reception digital signal will become clear from the following description.
[0064] The signal output from the switching unit 20 is a wide area transmission digital signal transmitted to the wide area transmission digital signal processing unit 31-m2 (m2=1, 2, ..., M), and a local area transmission digital signal transmitted to the local area mother digital analog conversion unit 15-n2 (n2=1, 2, ..., N). The details of the wide area transmission digital signal processing unit 31-m2 and the wide area transmission digital signal will become clear through the following description.
[0065] Various paths are generated by the switching process performed in the switching unit 20, but the paths can be roughly divided into four types. The four types of paths generated by the switching process are local→local area, local→wide area, wide area→local area, and wide area→wide area.
[0066] FIG2 is an explanatory diagram showing an example of processing of a signal received from the local mother analog-to-digital converter 14 by the switching unit 20 of the optical switching device 200 according to the first embodiment. Figure 2A The dotted lines indicate the local→wide area among the four types of paths generated by the switching process of the switching unit 20. Figure 2B Among the four types of paths generated by the switching process of the switching unit 20 , local→local paths are indicated by dotted lines.
[0067] FIG3 is an explanatory diagram showing an example of processing of a signal received from the wide area reception digital signal processing unit 38 by the switching unit 20 of the optical switching device 200 according to the first embodiment. Figure 3A The dotted lines indicate the wide area → local area among the four types of paths generated by the switching process of the switching unit 20. Figure 3B Among the four types of paths generated by the switching process of the switching unit 20 , wide area→wide area is indicated by a dotted line.
[0068] The switching process performed in the switching unit 20 can realize, for example, the distribution of signals to multiple paths, the distribution from multiple local optical networks 100 to a single virtual optical channel (also called "signal aggregation"), and the switching of physical frequencies related to the virtual optical channel. Here, the distribution of signals to multiple paths includes both the case of dividing the signal into parts and distributing it, and the case of duplicating the same signal and distributing it (multicasting).
[0069] The switching process is implemented according to the switching rules. The switching unit 20 of the optical switching device 200 of embodiment 1 is configured to be able to change the switching rules by instructions from the outside (hereinafter referred to as "monitoring control signals"). That is, the switching rules are processed in the optical switching device 200 of the disclosed technology so that they can be changed over time. In addition, in Figures 2 and 3, the parts represented as "external control devices, etc." represent the outside that changes the switching rules by monitoring control signals. In addition, in the disclosed technology, the monitoring control signal can also be implemented by external software. How to implement the monitoring control signal is not an essential matter for the disclosed technology.
[0070] The switching unit 20 of the optical switching device 200 of the first embodiment is configured to output information such as the short-time average power of the input signal, the bit error rate on the wide area side, or the amount of information (hereinafter referred to as "monitoring control information") to the outside.
[0071] The processing performed in the switching unit 20 includes a portion for maintaining the signal from the local optical network 100 as a digital value, but this portion of processing can also be said to be a concept similar to RoF (Radio-over-Fiber). If the naming method of RoF is followed, this portion of processing is a process for loading the signal of the access network into a coherent signal, so it can be said to be AoC (Access-over-Coherent: access based on coherent technology).
[0072] <Wide area transmission digital signal processing unit 31 constituting the optical switching device 200>
[0073] The wide area transmission digital signal processing unit 31 constituting the optical switching device 200 is a component that performs digital signal processing such as encoding and spectrum shaping.
[0074] More specifically, the wide area transmission digital signal processing unit 31-m constituting the optical switching device 200 is a structural element that generates a transmission subcarrier signal for coherent optical communication based on the wide area transmission digital signal transmitted from the switching unit 20. The m (m=1, 2, ..., M) in the number representing the wide area transmission digital signal processing unit 31-m is sometimes referred to as a "subcarrier number" for identifying a subcarrier. M represents the total number of subcarriers. Specifically, it is assumed that the total number of subcarriers (M) is 4 or more.
[0075] The transmission subcarrier signal generated by the wide area transmission digital signal processing unit 31 is sent to the wide area digital-to-analog converter 32 .
[0076] The wide area transmission digital signal processing unit 31 may also perform various processes such as transmission path side frame generation, partial scrambling processing, coding for probability shaping of signal point arrangement, error correction coding, symbol generation, spectrum shaping, etc. The transmission subcarrier signal processed by the wide area transmission digital signal processing unit 31 is sent to the wide area digital-to-analog converter 32.
[0077] Between a certain finite length of data sent from the local optical network 100 and other finite length of data, most of the data is near zero power value. Therefore, the optical switching device 200 of the disclosed technology can also implement simple compression processing in the wide area transmission digital signal processing unit 31 to obtain efficient signal transmission. The compression processing implemented by the wide area transmission digital signal processing unit 31 of the optical switching device 200 can also apply the method described in International Publication No. 2020 / 174574, for example.
[0078] 《Wide area digital-to-analog converter 32 constituting the optical switching device 200》
[0079] In short, the wide area digital-to-analog converter 32 constituting the optical switching device 200 is a component that multiplexes a plurality of subcarriers and converts them into analog electrical signals at once.
[0080] In more detail, the wide area digital-to-analog converter 32 constituting the optical switching device 200 is a structural element that implements the following two processes. First, the wide area digital-to-analog converter 32 frequency multiplexes M transmission subcarrier signals transmitted from M wide area transmission digital signal processing units 31 (31-1, 31-2, ..., 31-M). Here, the M transmission subcarrier signals are digital signals. As described above, M, which is also the total number of subcarriers, is assumed to be greater than 4. Second, the wide area digital-to-analog converter 32 converts the digital signal after frequency multiplexing into an analog signal. The analog signal converted by the wide area digital-to-analog converter 32 is referred to as a "wide area transmission analog electrical signal" in this specification.
[0081] Generally, for wide-area transmission analog electrical signals, two systems of wide-area transmission analog electrical signals are prepared for orthogonal polarization multiplexing, and two systems of wide-area transmission analog electrical signals are prepared for orthogonal amplitude modulation, and a total of four systems of wide-area transmission analog electrical signals are prepared (shown in the figure). Figure 1 4 right arrows starting from the wide area digital-to-analog converter 32 in FIG. 1 ).
[0082] Here, the operation speed of the wide area digital-to-analog converter 32 exceeds 100 [Gsample / s], for example.
[0083] All of the wide area transmission analog electrical signals corresponding to four systems are sent to the wide area optical modulation unit 33 .
[0084] 《Wide area light modulation unit 33 constituting the optical switching device 200》
[0085] The wide area optical modulation unit 33 constituting the optical switching device 200 is a component that modulates an optical carrier based on a wide area transmission analog electric signal.
[0086] Here, the electrical frequency band of the wide area optical modulation unit 33 is assumed to be several tens [GHz] or more.
[0087] The signal processed in the wide area optical modulation unit 33 , that is, the modulated optical signal, is sent to the wide area optical network 300 .
[0088] The transmission optical switch 34 included in the wide area optical network 300 is a structural element that receives various optical signals as input and distributes and outputs modulated optical signals to multiple paths. Specifically, the optical signals input to the transmission optical switch 34 are modulated optical signals sent from the wide area optical modulation unit 33 and optical signals sent from other external optical switching devices (not shown, 200-other).
[0089] The transmission optical switch 34 can transfer the subcarriers generated in the wide area transmission digital signal processing unit 31-m (m=1, 2, ..., M) to a specific destination. The transmission optical switch 34 of the first embodiment performs the same path selection as the path selection performed in the conventional optical wavelength channel. In addition to performing the processing content of the path selection functioning as a wavelength selection switch, the transmission optical switch 34 of the first embodiment can also perform switching related to, for example, optical fiber cores in a spatial multiplexing optical network.
[0090] The receiving optical switch 35 included in the wide area optical network 300 is a component that receives various optical signals as input and multiplexes the input optical signals.
[0091] The optical signal multiplexed in the reception optical switch 35 is sent to the wide area light detection unit 36 of the optical switching device 200 and other external optical switching devices (not shown, 200-other).
[0092] <<Wide-area light detection unit 36 constituting the optical switching device 200>>
[0093] The wide area light detection unit 36 constituting the optical switching device 200 is a component that performs coherent detection on the optical signal transmitted from the receiving optical switch 35. The signal obtained by the wide area light detection unit 36 is referred to as a "wide area reception analog electric signal" in this specification.
[0094] Generally, for the wide area receiving analog electrical signal, similarly to the wide area transmitting analog electrical signal, two systems of wide area receiving analog electrical signals are prepared for orthogonal polarization multiplexing, and two systems of wide area receiving analog electrical signals are prepared for orthogonal amplitude modulation, so that a total of four systems of wide area receiving analog electrical signals are prepared (shown in FIG. Figure 1 4 left arrows with the wide area light detection unit 36 as the starting point).
[0095] Here, the electrical frequency band of the wide area light detection unit 36 is assumed to be several tens [GHz] or more, similarly to the wide area light modulation unit 33 .
[0096] The wide area received analog electrical signal is sent to the wide area analog-to-digital converter 37 .
[0097] 《Wide area analog-to-digital converter 37 constituting the optical switching device 200》
[0098] In short, the wide area analog-to-digital converter 37 constituting the optical switching device 200 is a component that samples the analog electrical signal transmitted from the wide area optical detection unit 36 and performs subcarrier separation.
[0099] More specifically, the wide area analog-to-digital converter 37 constituting the optical switching device 200 is a component that performs the following two processes. First, the wide area analog-to-digital converter 37 samples the analog electrical signal sent from the wide area optical detection unit 36 and converts it into a digital signal. Second, the wide area analog-to-digital converter 37 separates the digital signal obtained by sampling into subcarriers in the frequency domain.
[0100] Here, the operation speed of the wide area analog-to-digital converter 37 exceeds 100 [Gsample / s], for example.
[0101] The M reception subcarrier signals obtained through the separation processing of the wide area analog-to-digital converter 37 are respectively sent to the wide area reception digital signal processing unit 38-1, the wide area reception digital signal processing unit 38-2, ..., the wide area reception digital signal processing unit 38-M.
[0102] 《Wide area reception digital signal processing unit 38 constituting the optical switching device 200》
[0103] The wide area reception digital signal processing unit 38 constituting the optical switching device 200 is a component that performs digital signal processing such as waveform distortion compensation and error correction.
[0104] More specifically, the wide area reception digital signal processing unit 38-m constituting the optical switching device 200 is a structural element that performs digital signal processing on the m-th reception subcarrier sent from the wide area analog-to-digital conversion unit 37. The digital signal processing performed by the wide area reception digital signal processing unit 38-m includes, for example, waveform equalization, clock regeneration, carrier recovery, symbol recovery, error correction decoding, decoding processing related to probability shaping of signal point configuration, partial scrambling processing, and transmission path frame termination processing. In addition, when the wide area transmission digital signal processing unit 31-m on the transmission side performs a simple compression process, the wide area reception digital signal processing unit 38-m also performs the termination processing.
[0105] The signal subjected to the digital signal processing in the wide area reception digital signal processing unit 38 - m is referred to as a “wide area reception digital signal” in this specification. The wide area reception digital signal is sent to the switching unit 20 .
[0106] It is also possible to use multiple optical switching devices 200 of embodiment 1 in collaboration. Consider that an optical switching device 200-a as a certain individual (individual a) receives an intensity modulated optical signal sent from an optical switching device 200-b as another individual (individual b). Specifically, the local mother optical transceiver 13-n of the optical switching device 200-a as individual a can also receive the intensity modulated optical signal sent from the local mother optical transceiver 13-n3 (n3 = 1, 2, ...) of the optical switching device 200-b as individual b.
[0107] Figure 4 1 is an explanatory diagram showing a connection example of the optical switching device 200 according to the disclosed technology.
[0108] like Figure 4 As shown, the optical switching device 200 (200a) of the disclosed technology can also be connected to a local sub-optical transceiver that is not connected to the loop via an optical coupler, an optical switch, an optical circulator or a routing device (hereinafter referred to as "optical coupler, etc.").
[0109] like Figure 4 As shown, the optical switching device 200 (200b) of the disclosed technology may be connected to a local sub-optical transceiver connected to the loop via an optical coupler or the like.
[0110] like Figure 4 As shown, the optical switching device 200 (200c) of the disclosed technology can also be implemented as a part of the function of a local sub-optical transceiver. Alternatively, the optical switching device 200 (200c) can be implemented as a part of the function of a local sub-optical transceiver, and the optical coupler etc. of the local sub-optical transceiver is connected to the optical coupler etc. of other local sub-optical transceivers.
[0111] As described above, since the optical switching device 200 of the first embodiment has the above structure, the wide area optical network 300 can directly accommodate the finite length signal from the local area optical network 100. Since it can be directly accommodated, the disclosed technology can eliminate the processing delay generated in the routing device of the prior art. In addition, the disclosed technology can minimize the routers used in the previous network, which also helps save energy from the perspective of the entire network.
[0112] 《Supplementary Note: Application of the Disclosed Technology to the Diagram Example of Non-Patent Document 1》
[0113] “Fronthaul” appearing in FIG. 8-1 of Non-Patent Document 1 is a local optical network (100) assumed by the disclosed technology.
[0114] The "DCI" in FIG8-1 is a wide area optical network (300) assumed by the disclosed technology. Here, DCI is an abbreviation of Data Center Interconnection, which refers to a connection between data centers or a connection between data centers.
[0115] It is considered that "DU" appearing in FIG. 8-1 of Non-Patent Document 1 includes a local optical switching device of the related art. Here, DU is an abbreviation of Distribution Unit and refers to a remote station.
[0116] The “Cloud edge” and “Cloud core” appearing in FIG. 8-1 are considered to include wide area optical switching devices in the related art.
[0117] The "Mid / Backhaul" shown in FIG. 8-1 of the non-patent document 1 exists between the local optical network (100) and the wide area optical network (300) assumed by the disclosed technology. Therefore, whether the Mid / Backhaul shown in the non-patent document 1 is set as local or wide area should be determined according to the specific situation.
[0118] As described above, the optical switching device 200 of the disclosed technology can be applied as a device that connects fronthaul and DCI in the network configuration illustrated in FIG. 8-1 of Non-Patent Document 1.
[0119] The "Metro-edge Fronthaul" shown in FIG8-2 of the non-patent document 1 is also the local optical network (100) assumed by the disclosed technology. The orange box (equivalent to the routing device) directly connected to the AAU (Active Antenna Unit) in the "Metro-edge Fronthaul" shown in FIG8-2 is the local optical network (100) in a narrow sense.
[0120] From the “New Core” appearing in FIG. 8-2 of Non-Patent Document 1 onwards (not shown) is the wide area optical network (300) assumed by the disclosed technology.
[0121] The "New Core" appearing in FIG. 8-2 of Non-Patent Document 1 is considered to include a wide area optical switching device of the related art.
[0122] FIG8-2 of Non-Patent Document 1 shows an example of a path from AAU to DU that passes through three (three-stage) routing devices. The line shown by the rainbow color that changes stepwise from red to blue in FIG8-2 of Non-Patent Document 1 is an optical transmission path (12).
[0123] In this way, the optical switching device 200 of the disclosed technology can be used in place of any routing device in the path from the AAU to the DU in the network architecture illustrated in FIG. 8-2 of Non-Patent Document 1.
[0124] The local area optical network (100) from AAU to DU+CU (Distribution Unit and Central Unit) appearing in FIG. 8-3 of Non-Patent Document 1 is assumed by the disclosed technology.
[0125] The wide area optical network (300) assumed by the disclosed technology is also shown from "New Core" appearing in FIG. 8-3 of Non-Patent Document 1 onwards (not shown).
[0126] In this way, the technology disclosed in the present invention can also be applied to the network architecture illustrated in FIG. 8-3 of Non-Patent Document 1.
[0127] "Metro-Edge" (cloud graph) commonly appearing in FIG. 8-4 to FIG. 8-10 of Non-Patent Document 1 is a local area optical network (100) assumed by the disclosed technology.
[0128] Although Figures 8-4 to 8-10 of Non-Patent Document 1 do not explicitly show the wide area optical network (300) assumed by the disclosed technology, the disclosed technology can also be applied to a network architecture including a local area optical network (100) in such a connection relationship.
[0129] The OLT (Optical Line Terminal) that appears in Figures 8-11 to 8-14 of Non-Patent Document 1 can be said to be a type of local mother optical switching device assumed by the disclosed technology. Although it does not appear in the figure of Non-Patent Document 1, the child device is called ONU (Optical Network Unit) relative to the OLT as the mother device. In addition, OLT and ONU are not distinguished in Japanese and are called optical line terminal devices.
[0130] The OTN that appears in common in FIGS. 8-11 to 8-14 of Non-Patent Document 1 refers to an optical transmission network as described above, but is considered here to refer to a wide area optical switching device in particular.
[0131] The OADM commonly shown in FIGS. 8-11 to 8-14 of Non-Patent Document 1 is an Optical Add Drop Multiplexer, i.e., an optical branching and insertion device, and functions as an optical switch in a wide area optical network (300).
[0132] In this way, the disclosed technology can also be applied to the connected networks illustrated in FIGS. 8-11 to 8-14 of Non-Patent Document 1.
[0133] Industrial Applicability
[0134] The technology disclosed in the present invention can be applied, for example, to technology for connecting a 5G network to an OTN network, and therefore has industrial applicability.
[0135] Description of Reference Numerals
[0136] 11 local sub-optical transceiver, 12 optical transmission path, 13 local mother optical transceiver, 14 local mother analog-to-digital conversion unit, 15 local mother digital-to-analog conversion unit, 20 switching unit, 31 wide-area transmission digital signal processing unit, 32 wide-area digital-to-analog conversion unit, 33 wide-area optical modulation unit, 34 transmission optical switch, 35 reception optical switch, 36 wide-area optical detection unit, 37 wide-area analog-to-digital conversion unit, 38 wide-area reception digital signal processing unit, 100 local optical network, 200 optical switching device, 300 wide-area optical network.
Claims
1. An optical switching device that connects a local area optical network to a wide area optical network, wherein: The optical switching device comprises: A local mother optical transceiver, which directly detects the input intensity modulated optical signal and outputs it as a local received analog electrical signal; A local area mother analog-to-digital conversion unit, which samples the local area reception analog electrical signal and outputs it as a local area reception digital signal; a switching unit that distributes the local area reception digital signal into a local area transmission digital signal and a wide area transmission digital signal and outputs the signals; A local area mother digital-to-analog conversion unit, which converts the local area transmission digital signal into an analog signal; a wide area transmission digital signal processing unit, which performs digital signal processing on the wide area transmission digital signal to generate a transmission subcarrier signal for coherent optical communication; a wide area digital-to-analog converter that performs frequency multiplexing on the transmission subcarrier signal and converts it into a wide area transmission analog electrical signal; and a wide area optical modulation unit that modulates an optical carrier based on the wide area transmission analog electrical signal, The local mother analog-to-digital conversion unit performs sampling according to a signal format with the most stringent sampling conditions among the assumed signal formats.
2. The optical switching device according to claim 1, wherein: The optical switching device also includes: a wide area optical detection unit that performs coherent detection on an optical signal transmitted from a receiving optical switch of the wide area optical network and outputs a wide area receiving analog electrical signal; a wide area analog-to-digital conversion unit that samples the wide area received analog electrical signal, converts it into a digital signal, and separates it into subcarriers in the frequency domain; and The wide area reception digital signal processing unit performs digital signal processing on the signal sent from the wide area analog-to-digital conversion unit, and outputs the signal as a wide area reception digital signal to the switching unit.
3. An optical switching method, which is an optical switching method of an optical switching device connecting a local area optical network to a wide area optical network, wherein: The local optical transceiver directly detects the input intensity modulated optical signal and outputs it as a local receiving analog electrical signal. The local area analog-to-digital conversion unit samples the local area reception analog electrical signal and outputs it as a local area reception digital signal. The switching unit distributes the local area reception digital signal into a local area transmission digital signal and a wide area transmission digital signal and outputs the signals. The local mother digital-to-analog converter converts the local transmission digital signal into an analog signal. The wide area transmission digital signal processing unit performs digital signal processing on the wide area transmission digital signal to generate a transmission subcarrier signal for coherent optical communication. The wide area digital-to-analog converter performs frequency multiplexing on the transmission subcarrier signal and converts it into a wide area transmission analog electrical signal. The wide area optical modulation unit modulates the optical carrier based on the wide area transmission analog electrical signal. The local mother analog-to-digital conversion unit performs sampling according to a signal format with the most stringent sampling conditions among the assumed signal formats.
4. The optical switching method according to claim 3, wherein: The wide area optical detection unit performs coherent detection on the optical signal transmitted from the receiving optical switch of the wide area optical network, and outputs a wide area receiving analog electrical signal. The wide area analog-to-digital converter samples the wide area received analog electrical signal, converts it into a digital signal, and separates it into subcarriers in the frequency domain. The wide area reception digital signal processing unit performs digital signal processing on the signal transmitted from the wide area analog-to-digital conversion unit, and outputs the signal to the switching unit as a wide area reception digital signal.