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OPTICAL SWITCH DEVICE

Foreign code F180009332
File No. S2016-0327-C0
Posted date Feb 27, 2018
Country WIPO
International application number 2017JP002832
International publication number WO 2017131125
Date of international filing Jan 26, 2017
Date of international publication Aug 3, 2017
Priority data
  • P2016-015710 (Jan 29, 2016) JP
Title OPTICAL SWITCH DEVICE
Abstract The number of servers in data centers and the amount of data traffic exchanged between storage devices are increasing sharply, and thus in order to reduce power consumption there is a need for large-scale optical switch devices having up to 1000 or more input/output ports. Wavelength routing switches exist as conventional large-scale optical switch devices, but these require the same number of wavelength tunable light sources as the number of input/output ports. A complicated control mechanism is required to enable a stable oscillation action to be achieved over a wide wavelength range using wavelength tunable light sources, and this has been an obstacle to providing large-scale optical switch devices, in terms of cost and circuit size. A wavelength routing switch according to the present disclosure is configured from N wavelength group generators, a splitting/selecting unit, and MN tunable filters. Each wavelength group generator is provided with M fixed wavelength light sources. For the fixed wavelength light sources it is possible to utilize inexpensive general purpose devices that do not require a control mechanism for wavelength tuning. It is also possible to reduce optical switch device path losses by utilizing wavelength tunable light sources having a limited narrow range, and an output port selection function using an arrayed waveguide grating (AWG) wavelength.
Outline of related art and contending technology BACKGROUND ART
Various types of information on a global scale the device to a person or an object by all of the terminal, the wireless communication network is wired or not and continues to expand, the amount of data flowing through it is a great deal. In this situation, the information communication system and a great deal of power consumption, the core network, metro/LAN, such as access network system, information communication networks in the various tiers of a reduction in power consumption being energetically made. 1 Reduction of power consumption of an information communication system 1 for one of the one key technique is, instead of processing an electrical signal layer routing technique that carries out the optical signal layer. Optical routing technique is used, light can be routed by the passive device is performed, the processing of the communication nodes in the electrical layer of the whole communication network is significantly reduced to a significant low power consumption is considered to be advanced.
The importance of the information communication network infrastructure element is one of the data center 1. The data center, a server or an Internet communication, fixed, mobile, such as IP telephone equipment is installed, the operation object is a generic name of the building. A plurality of data center and the communication line is retracted, a vast number of inside of the building such as a server computer and may be aggregated, in a data center is a very important reduction of power consumption has been a problem. Especially in recent years, not only the increase of the user, the application server, data storage, the database server the function of differentiation, distributed processing, parallel processing such as the use of a plurality of servers for processing is increased in between, in the IP traffic in the data center is expected to increase considerably. The amount of traffic is allowed to circulate in the data center of the total traffic of the Internet 4 will be approximately twice the estimated. Further, many of the traffic in the data center data center may remain within the traffic, the amount is 4.8 to 2015 year zettabyte (4.8x1021) are also said to achieve. As a result, the power consumption of the large-scale data centers 100MW (10 million kW) and the situation above, the traffic in the data center to reduce the power consumption due to rapid and the Avian.
Such as a web search or an e-mail in the data center occurs in a high frequency of small capacity and the Mice flow, such as data storage and movement of the virtual machine occurs in a large memory capacity and Elephant data flows generated with a low frequency. Therefore low power consumption of the processing flow for an electrical switch Mice, Elephant to occupy most of the traffic flow to the optical switch processing has been proposed a hybrid network.
Fig. 1 is, in the data center is a schematic diagram showing the traffic processing. In the data center 10, the rack (TOR) is referred to as top-of-configuration has been adopted. A large number of a server computer or a storage unit such as a rack, a plurality of racks 1-1, 1-2, 1-n are disposed. TOR configuration, each upper part of the rack 2-1, 2-2, the switch (SW) 2-n may be connected to the rack is provided, containing a server in the rack, the rack 1 and the minimum unit constituting a high degree of freedom and management facility. 10 Is a data center, a server computer or other storage, not shown and the devices of the core layer, core layer and between the external network 8 in a large-capacity communication line 7 is connected.
Mice with regard to the flow of traffic between each rack, the rack 5 using the electrical path between the SW3 and switches, while the flow is Elephant, for low power consumption of the light path between the rack SW4 using the switch 6 so that the traffic can be processed in the data center. And a rapid increase in communication traffic in recent years, the number n is in the data center rack and exceeds the 1000, 1000 is set to an arbitrary path between the racks, can change the optical switch device is demanded. Specifically, a large-scale over 1000x1000 need for large line switching the optical switch device.
Fig. 2C is Fig. 2A -, illustrating a configuration and function of the optical switch of the present invention. Fig. 2A is a conceptual diagram showing a configuration of the optical switch. The optical switch 20, depicted on the left side N input ports to one of the input optical signal 1, which is illustrated in the right side of any one of N output ports is operable to output to one 1. The optical switch 20 is, in Fig. 1 in a plurality of (n one) of the two racks of the rack from the TOR 1, any of the other of the paths to the TOR part of the rack can be formed, if necessary another new path is switched at high speed. Is the simplest configuration of the optical switch, as shown in Fig. 2B, arranged in a matrix of two-dimensional 2 element SW 22 a SW element in the matrix space. MEMS(Micro Electro Mechanical Systems) 3 using a two-dimensional space matrix SW can also be constructed. However, element SW in the SW-space matrix elements is, as shown in Fig. 2C the number of elements N and the number of ports of the SW element in the conceptual illustration of the relationship between, the number of ports increases N, N2 SW element 22 is required in proportion to increasing the number of elements has been known. Therefore, in the data center 1000 is interconnected over the number of the server rack, the number of input ports and output ports of the optical switch device 1000 are greater than N in such a situation, SW elements is enormous and the number of elements, SW-space matrix in terms of circuit scale and the cost is not realistic.
A plurality of multi-stage cascade-connected to the matrix SW by configuring, a certain number of elements and the entire SW SW element can be reduced. However the effect is limited, as shown in Fig. 2C, the increase in the number of ports N, N1.5 SW element 22 in proportion to the increase in the number of necessary elements. N is the number of ports of the optical switch device 1000 over such a case, with multiple stages of the SW element of the elements is still a significant problem and the increase in the number of, in order to more completely satisfy the condition of the SW on the configuration applied is also limited. N is the number of ports of the SW element increases when the increase in the number of elements, as indicated by the dotted line in Fig. 2C, an approximately linear (square of N) is suppressed as the configuration of the spatial optical switch, wavelength routing SW has been known.
Fig. 3 is, wavelength routing SW is a view showing the concept of the structure. SW30 Is an exemplary wavelength routing, the input SW 100 is switched to the output space in the 100, 100 to the input port side of the wavelength-variable light source (LD: laser diode) and 31-1-31-100, the two output ports 100 to the output port side of the duplexer 35 a having 36-1-36-100 respectively. 100 Each of the wavelength tunable LD, λ1 -λ100 different wavelengths can be set to any one of or, each of the output light of LD 32-1-32-100 modulated by the information signal. From tunable LD31-1-31-100 modulated light of different wavelengths, are multiplexed by a coupler 33, and if necessary is amplified by optical amplifier 34. The optical amplifier 34 from the combined modulated light, a demultiplexer 35 by λ1 -λ100 100 corresponding to the wavelength of the output ports of the demultiplexer to either 36-1-36-100. As the demultiplexer 35, an arrayed waveguide grating (AWG) for example can be used, combined λ1 -λ100 maximum of 100 different wavelength in the wavelength multiplexing light can be demultiplexed into each wavelength.
The operation of the wavelength routing described in the following manner. For example, the second wavelength corresponding to the input port 1 of the oscillation wavelength of the variable λ LD31-1100 set. At this time, the wavelength λ100 1 of the output light of the second input to the input port of the information signal is modulated by 32-1. The modulation wavelength λ100 of the optical signal, by a demultiplexer 35, the output port corresponding to the output port of the 100 th output to the 36-100. Therefore, the second input port 1 of the information signal is input, the first 100 will be connected to the output port. The oscillation wavelength of the tunable λ LD31-11 if set, the second output port 35 of demultiplexer 1 is outputted to the output port corresponding to 36-1. Similarly, the oscillation wavelength of the tunable λ LD31-150 if set, the optical demultiplexer 35 50 of the output port corresponding to the output port of the second output to the 36-50.
As described above, each of the wavelength tunable LD 100 of the oscillation wavelength can arbitrarily set, the modulated optical signal output port can be arbitrarily selected. 100 Different information signals, an arbitrary position of the two output ports 100 can be output and, to implement SW of 100x100 wavelength routing. Wavelength routing in the SW, SW SW from the difference of the principles of the space matrix element of the configuration of the elements is completely different, the hardware scale of the input ports, N being substantially proportional to the number of output ports increases. Therefore, compared to SW-space matrix, a small-scale hardware than the cost of the optical switch device are considered to be implemented.
Optical communication, the propagation loss of a small amount of C from the band (width of about 4400GHz) has been widely used, associated equipment, and the widely available components. The C-band bandwidth of two communication channels 1 and 50GHz, slightly beyond the C band is used in the same frequency band, generally about 100 (100 wave) of the communication channel can be used. 1 Of one half the bandwidth of communications channels if the 25GHz, 200 (200 wave) to the channel C band can also be configured, resulting in half bandwidth of the information signal. The accuracy of the wavelength control of the associated components also becomes a problem, the number of ports of the wavelength routing of the increase in the number of SW 100 is not easy. SW to the wavelength routing configuration for large scale, a portion of the wavelength routing has been proposed a configuration in parallel.
Fig. 4 is, to be processed in parallel in the form of a wavelength routing of the prior art showing a configuration of the SW in the wavelength routing. Fig. SW40 is a wavelength routing of the 4, the simplest of Fig. 3 compared with the configuration of the wavelength routing SW, K at a later stage of the wavelength routing unit 48-1-48-K are parallelized. The input port side, the N groups of the modulated light from the wavelength tunable KN is LD41, the distribution of the selected N (DC: Delivery and Coupling) switch, the selecting and merging, two K wavelength routing unit 48-1-48-K are supplied. Wavelength routing unit 48-1-48-K can be performed in parallel, the input port side and the wavelength of the wavelength of the variable LD41 in not increasing the number of, multi-port optical switch device can be realized. Incidentally, also referred to as a multicast switch and DC switch, a different number of input ports and output ports of the various ports available as MxN purpose.
Fig. 5 is, used in routing the wavelength of the prior art DC switch SW is a view showing an example of the configuration. DC switch 50 is, the minimum configuration of one example, the wavelength variable LD 3 from one of the 3 wave (λ1 、λ2 、λ3) and the merge respectively configured and selected, the switch 3 of the 1x3 51-1-51-3 of the optical multiplexer 3 and is composed of a 3x1 52-1-52-3. In Fig. 5, one 3 of the DC switch 50 to an input port of the wavelength λ 3 of two1 、λ2 、λ3 to, all 1 th output port 53 is output to the example set. By the DC switch 50, 3 respectively to the output port of any one wavelength can be output. Incidentally, Fig. 5 of the DC switch can be used to reverse the direction of the signal, multiplexed light (λ1 、λ2 、λ3) is distributed to only light of a wavelength of any output to the selected operation. Including in the case of such an operation, referred to as the selected distribution (DC) switch. In the direction of the optical signal shown in Fig. 5 in a reverse direction in which the method of using the DC switch, as shown in the embodiment of the present disclosure will be described later.
In Fig. 4, the variable wavelength LD 1 in the second group of one of the wavelength of 1, by the 42-1 DC switch, the wavelength of the two K routing unit 48-1-48-K in one of the 1 selected can be set so as to be connected to, KN on the output side of any of the output ports can be configured to route to a port. The inventors of the invention, can be a corresponding increase in traffic in the data center, the larger wavelength routing SW in order to achieve the configuration shown in Fig. 3 and Fig. 4 based on, a specific configuration example of the wavelength routing SW is proposed (Non-Patent Document 1).
Fig. 6 is, the inventors proposed in the prior art large-scale wavelength routing configuration of the SW in accordance with the invention. 6 Shown in Fig. SW60 is a wavelength routing, the entire structure of Fig. 4 the configuration of the switch DC of Fig. 6 including those shown in more detail, the wavelength variable LD is divided into N groups of M and the wavelength to be processed in parallel from the routing unit 63-1-63-M a. The detailed configuration, the explanation of the operation is omitted, the switch DC of 8x8, an erbium-doped fiber amplifier (EDFA: Erbium-doped fiber amplifier), using a non-cyclic AWG, 800x800 having a good transmission signal characteristic of the SW implementation of a large-scale wavelength routing as shown in Fig. 6.
Scope of claims (In Japanese)[請求項1]
最大M個(Mは2以上の自然数)の異なる波長の光を合波して、多重化光を出力するN個の合波器と、
前記N個の合波器の各々からの前記多重化光をMN個の分岐光に分岐するN個の光分岐と、
前記N個の光分岐の各々の前記分岐光の中から、前記N個の合波器の内の1つの合波器に対応する分岐光を選択するMN個のN×1光スイッチと、
前記MN個のN×1光スイッチによって選択された前記1つの合波器において合波された、最大M個の異なる波長の光から、任意の1つの波長の光を選択するMN個の可変フィルタと
を備えたことを特徴とする光スイッチ装置。
[請求項2]
最大M個(Mは2以上の自然数)の異なる波長の光を合波して、多重化光を出力するN個の合波器と、
前記N個の合波器の各々からの前記多重化光を、MN/Kが自然数となるK個の分岐光に分岐するN個の光分岐と、
前記N個の光分岐の各々の前記分岐光の中から、前記N個の合波器の内の1つの合波器に対応する分岐光を選択するK個のN×(MN/K)分配選択(DC)スイッチであって、各々が、前記N個の光分岐からの出力が接続されたN個の1×(MN/K)光分岐と、前記N個の1×(MN/K)光分岐の各々の出力ポートと接続された(MN/K)個のN×1光スイッチとから構成されたDCスイッチと、
前記N×1光スイッチの各々によって選択された前記1つの合波器において合波された、最大M個の異なる波長の光から、任意の1つの波長の光を選択するMN個の可変フィルタと
を備えたことを特徴とする光スイッチ装置。
[請求項3]
最大M個(Mは2以上の自然数)の異なる波長の光を合波して、多重化光を出力するN個の合波器と、
前記N個の合波器の各々からの前記多重化光を、MN/K≦Yとなる最少の自然数Y個の分岐光に分岐するN個の光分岐と、
前記N個の光分岐の各々の前記分岐光の中から、前記N個の合波器の内の1つの合波器に対応する分岐光を選択するY個のN×K分配選択(DC)スイッチであって、各々が、前記N個の光分岐からの出力が接続されたN個の1×K光分岐と、前記N個の1×K光分岐の各々の出力ポートと接続されたK個のN×1光スイッチとから構成されたDCスイッチと、
前記N×1光スイッチの各々によって選択された、前記1つの合波器において合波された最大M個の異なる波長の光から、任意の1つの波長の光を選択するMN個の可変フィルタと
を備えたことを特徴とする光スイッチ装置。
[請求項4]
各々が、前記最大M個の異なる波長の光の内の1つの波長の光を発生し、電気信号によって前記光を変調する手段を有し、前記1つの波長の変調光を出力する、最大M個の複数の光源をさらに備え、
前記最大M個の複数の光源および前記N個の合波器の対応する1つが、波長群発生器を構成し、
前記MN個の可変フィルタによって、任意の1つの波長の変調光が選択されること
を特徴とする請求項1乃至3いずれかに記載の光スイッチ装置。
[請求項5]
前記N個の光分岐または前記DCスイッチにおける前記光分岐の少なくともいずれかは、光分岐および波長選択スイッチを組み合わせて構成されたことを特徴とする請求項1乃至4いずれかに記載の光スイッチ装置。
[請求項6]
前記K個のN×(MN/K)DCスイッチは、M個のN×N DCスイッチであることを特徴とする請求項2に記載の光スイッチ装置。
[請求項7]
前記N個の光分岐の各々の前段または後段の少なくとも一方に1つ以上の光増幅器をさらに備えたことを特徴とする請求項1乃至6いずれかに記載の光スイッチ装置。
[請求項8]
前記合波器は、
複数のアレイ導波路回折格子(AWG)と、
前記複数のAWGからの多重化光をさらに合流する光合流器、インタリーバまたは波長選択スイッチのいずれかと
から構成されることを特徴とする請求項1乃至7いずれかに記載の光スイッチ装置。
[請求項9]
最大M(Mは2以上の自然数)個の異なる波長の光を合波して多重化光を出力するM入力L出力のN個の合波器であって、前記最大M個の異なる波長の光の各々は、L(M>Lの自然数)種類の波長からなる異なる波長グループの中から選択された1つの波長の光であり、
MN/Lは自然数であって、
前記N個の合波器の各々のL個の出力ポートの内の対応するN個の出力ポートが接続され、前記対応するN個の出力ポートから前記多重化光が入力されるL個のN入力波長分岐/選択部であって、各々が、
前記波長分岐/選択部の前記N入力にそれぞれ接続され、前記N個の合波器の各々からの前記多重化光をMN/L個の分岐光に分岐するN個の光分岐、および
前記N個の光分岐の各々の前記分岐光の中から、前記N個の合波器の内の1つの合波器に対応する分岐光を選択するMN/L個のN×1光スイッチ
を含むN入力波長分岐/選択部と、
前記MN/L個のN×1光スイッチによって選択された前記1つの合波器において合波された、異なる波長の光から、任意の1つの波長の光を選択するMN/L個の可変フィルタと
をさらに備えたことを特徴とする光スイッチ装置。
[請求項10]
各々が、前記最大M個の異なる波長の光の内の1つの波長の光を発生し、電気信号によって前記光を変調する手段を有し、前記1つの波長の変調光を出力する最大M個の複数の光源をさらに備え、
前記最大M個の複数の光源と、対応する1つの前記合波器とが波長群発生器を構成することを特徴とする請求項9に記載の光スイッチ装置。
[請求項11]
前記合波器は、
サイクリック合波器であって、前記MN/L個の可変フィルタは、前記N個の合波器の全体でM個の異なる波長から任意の1つの波長の変調光を選択するか、または、
非サイクリック合波器であって、前記MN/L個の可変フィルタは、前記N個の合波器の全体で(M+L-1)個の異なる波長から任意の1つの波長の変調光を選択する
よう構成されていることを特徴とする請求項9または10に記載の光スイッチ装置。
[請求項12]
前記波長グループの中の前記L種類の異なる波長は、連続して設定されたM個の波長の内の1つである開始波長と、前記開始波長に隣接する(L-1)個の波長から成ることを特徴とする請求項9乃至11いずれかに記載の光スイッチ装置。
[請求項13]
前記N個の合波器の各々に接続された複数の光源のMN個の変調する手段が光回線交換スイッチの入力ポートに対応し、前記可変フィルタのMN個の出力が前記光回線交換スイッチの出力ポートに対応し、波長ルーティングスイッチとして機能することを特徴とする請求項1乃至12いずれかに記載の光スイッチ装置。
  • Applicant
  • ※All designated countries except for US in the data before July 2012
  • NAGOYA UNIVERSITY
  • Inventor
  • SATO Ken-ichi
  • HASEGAWA Hiroshi
  • MORI Yojiro
  • UEDA Koh
IPC(International Patent Classification)
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