JP2006309066A - Optical branching module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact optical branching module having a small increasing rate of insertion loss for increased wavelength multiplexing number. <P>SOLUTION: The optical branching module includes 2<SP>p</SP>×(p+1) (p: natural number) pieces of optical couplers having two inputs and two outputs and provided with a connecting means. The connecting means makes connections such that, with the 2<SP>p</SP>×(p+1) optical couplers formed into (p+1) sets of 2<SP>p</SP>pieces each, the output ports of one optical coupler set are connected to the input ports of another optical coupler set in one-to-one correspondence; that, in order to have a cascade connection of the (p+1) sets in (p+1) stages, 2<SP>p</SP>optical couplers in the q-th (q: natural number ≤p) stage and the (q+1)th stage sets are successively formed into 2<SP>p-q+1</SP>units of 2<SP>q-1</SP>pieces each and 2<SP>p-q</SP>units of 2<SP>q</SP>pieces each; and that the 2<SP>q</SP>output ports of the optical couplers in one unit of the qth stage set are connected, one by one, to any one input port of each of the 2<SP>q</SP>optical couplers of one unit in the (q+1)th stage set. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical branching module that combines and splits light of a plurality of wavelengths propagating through an optical fiber.

  When a multiple wavelength multiplexing system is configured by PDS (Passive Double Star), an optical multiplexer / demultiplexer that multiplexes / demultiplexes light of multiple wavelengths propagating through an optical fiber is used (see, for example, Patent Document 1). Here, a conventional optical multiplexer / demultiplexer used for a wavelength division multiplexing system using PDS will be described with reference to FIG.

  FIG. 25 is a schematic configuration diagram of a wavelength division multiplexing system using PDS.

  In the wavelength division multiplexing system 400, when optical communication is performed between the optical terminators 156, 157, 158, and 159 and the optical terminator 163, light of different wavelengths transmitted from the optical terminators 156, 157, 158, and 159, respectively. Are multiplexed by the optical multiplexer / demultiplexer 170. Then, the light multiplexed by the optical multiplexer / demultiplexer 170 is branched by the optical splitters 171 and 162 that are branched by an arbitrary number of branches, and is received by the optical terminator 163. 25 shows an example in which the optical splitter 171 splits the light from the optical multiplexer / demultiplexer 170 into four branches, and the optical splitter 162 splits the light from the optical splitter 171 into eight branches.

  Conventionally, as the optical multiplexer / demultiplexer 170, for example, light is multiplexed by an AWG (arrayed waveguide diffraction grating) (see, for example, Non-Patent Document 1) or a dielectric multilayer film that transmits a specific wavelength. There is one that transmits light and condenses light by condensing with a lens. In addition, there is a type in which a plurality of optical couplers are connected to multiplex / demultiplex light.

  FIG. 26 shows a schematic configuration diagram of an optical multiplexer / demultiplexer in which a plurality of optical couplers are connected.

  In the optical multiplexer / demultiplexer 179 shown in FIG. 26, one output port of the two optical couplers 180 and 182 formed on the planar lightwave circuit board 173 is connected to the input port of the optical coupler 184, respectively. A port is connected to one input port of two optical couplers 181 and 183, respectively. By connecting in this way, in the optical multiplexer / demultiplexer 179, when light λ1 to λ4 having different wavelengths are input from the four input ports, the four lights λ1 to λ4 are output from the output ports of the respective optical couplers 181 and 183. Will be output.

JP-A-2001-333047 Optical device / material technology in wavelength division multiplexing (WDM, DWDM), technical information, pp. 131-pp. 137

  However, in the optical multiplexer / demultiplexer 179 shown in FIG. 25, there is an unconnected input / output port, and the intensity of light output from the output port decreases by 1/4 each time the wavelength multiplexing number is increased by two wavelengths. Therefore, the insertion loss becomes excessive. Therefore, it is necessary to separately provide a plurality of optical amplifiers in order to compensate for excessive insertion loss of the optical multiplexer / demultiplexer. Further, when an optical multiplexer / demultiplexer using AWG is separately provided, the AWG is expensive, which is not economical. Further, when an optical multiplexer / demultiplexer using a dielectric multilayer film and a lens is separately provided, the dielectric multilayer film has wavelength dependency, and a separate optical multiplexer / demultiplexer is required for each wavelength.

  Therefore, in a wavelength division multiplexing system to which a conventional optical multiplexer / demultiplexer is applied, the scale of the system with respect to the number of wavelength division multiplexing is large and the communication cost is high.

  Accordingly, an object of the present invention is to provide an optical branching module that has a small insertion loss with respect to the number of multiplexed wavelengths, is inexpensive, and is compact.

  In the present invention, in order to achieve the above object, when cascading optical couplers, the input / output ports of the optical coupler are connected to other input / output ports without excess or deficiency.

More specifically, the optical branching module according to the present invention 2 ^p × (p + 1) (where p is the same as the respective light input from the two input ports being substantially equally branched and output from the two output ports). The number of optical couplers and the 2 ^p × (p + 1) optical couplers are 2 ^p (p + 1) sets, and the output port of one set and another set of light Q (where q is a natural number less than or equal to p) so that the (p + 1) sets are cascade-connected to (p + 1) stages by connecting the input ports of the couplers one to one. The q-th set of 2 ^p optical couplers in the (q + 1) -th set is set as 2 ^{p -1} units of 2 ^{p-q + 1} units and 2 ^q units of 2 ^p-q units, respectively. said 2 ^q output ports of the optical coupler of one of the units of (q + 1) th stage of the set 1 And connecting means for connecting one to the 2 ^q-number of any one of the input ports of the respective optical coupler unit, to have a characterized.

  In the optical branching module according to the present invention, since the optical couplers that substantially branch the respective lights input from the two input ports and output the two lights from the two output ports are connected by the above connecting means, Waves can be performed simultaneously. Therefore, the insertion loss can be reduced compared to the case where a multiplexer / demultiplexer is separately installed as in the prior art. Even if the number of wavelength multiplexing is increased, the number of optical couplers is smaller than in the prior art, so that the insertion loss can be reduced, and it can be made inexpensive and compact.

In the optical branching module, the 2 ^p × (p + 1) optical couplers are each formed by an optical waveguide on a planar lightwave circuit board.

  In the optical branching module according to the present invention, a plurality of optical couplers can be manufactured on the same substrate by forming the optical coupler by an optical waveguide on a planar lightwave circuit board, so compared to the case of manufacturing separate optical couplers, The manufacturing cost can be reduced, and the module cost of the optical branching module can be suppressed.

Also includes the above-mentioned optical branch module, wherein the (p + 1) sets of each set of 2 ^p pieces of optical couplers are formed on the same said planar lightwave circuit board.

Optical branching module according to the present invention, by forming the 2 ^p pieces of the optical coupler of each pair on the same planar lightwave circuit board, and further reduce the manufacturing cost of the optical coupler, the module cost of the optical tributary module Can be suppressed.

  In the optical branching module, at least two sets of the optical couplers among the (p + 1) sets may be formed on the same planar lightwave circuit board.

  The optical branching module according to the present invention forms a plurality of sets of optical couplers on the same substrate by forming at least two sets of (p + 1) sets of optical couplers on the same planar lightwave circuit board. As a result, the optical branch module can be made more compact and the space can be saved as the connection distance of each set becomes shorter.

  In the optical branching module, the connection unit connects the output port of the q-th set of optical couplers to the input port of the (q + 1) -th set of optical couplers corresponding to the output port. An optical fiber or an optical fiber tape in which the optical fibers are arranged is included.

  The optical branching module according to the present invention can arbitrarily select an input / output port to be connected by using an optical fiber or an optical fiber tape as a connection means. Therefore, even if any of the optical couplers fails, it can be reconnected to the spare optical coupler, so that the management cost of the optical branching module can be reduced.

  In the above optical branching module, the connecting means includes a first optical fiber tape in which two or more optical fibers are arranged and respectively connected to output ports of the q-stage set of optical couplers; A second optical fiber tape in which the same number of optical fibers as the optical fibers are arranged and connected to the input ports of the (q + 1) -stage set of optical couplers corresponding to the output ports; and the first optical fiber tape And an optical fiber sheet accommodating optical fibers branched from and connected to each of the first optical fiber tape and the second optical fiber tape.

  The optical branching module according to the present invention enables connection between optical couplers in units of optical fiber tapes by connecting optical fiber tapes via an optical fiber sheet. Further, it is possible to protect the optical fiber wiring, facilitate the handling of the optical branching module, and reduce the module size.

  Further, in the optical branching module, the connection means is formed on a planar lightwave circuit board, the output port of the q-stage set of optical couplers, and the (q + 1) -stage set of light corresponding to the output port. An optical waveguide connecting the input port of the coupler is included.

  In the optical branching module according to the present invention, since the connection means is an optical waveguide formed on a planar lightwave circuit board, the connection distance between the optical couplers can be shortened. Can be achieved.

In the optical branching module, the connection means includes 2 ^{q + m−1} (where m is a natural number equal to or less than (p−q + 1)) optical fibers arranged in the q-th set of 2 the ^m units of 2 ^{q + m-1} pieces of said either first output port of the respective optical couplers (q + 1) and the first optical fiber tape that connects in parallel the input ports of the stage set of optical coupler 2 ^{q + m−1} optical fibers are arranged to target another one output port of each of the 2 ^{q + m−1} optical couplers and an input port of the (q + 1) -th set of optical couplers. A second optical fiber tape to be connected.

  In the optical branching module according to the present invention, the connecting means is the first optical fiber tape and the second optical fiber tape, so that one of the optical fiber tapes connects the optical couplers straight, and the other optical fiber tape. The optical couplers can be connected by twisting. Therefore, connection in units of optical fiber tapes is possible without requiring single-fiber separation or rebonization from the optical fiber tape. Therefore, the handling of the optical branching module can be facilitated, the module components can be densely mounted, and the manufacturing efficiency can be increased.

The optical branching module preferably further includes an optical filter disposed at a front stage of one or more input ports of the first-stage set of optical couplers out of the 2 ^p × (p + 1) optical couplers. .

  The optical branching module according to the present invention can facilitate multiplexing of optical communication on the IP network by including the optical filter.

  The optical branching module according to the present invention has a small increase rate of insertion loss with respect to an increase in the number of wavelength multiplexing, and is inexpensive and compact.

  Hereinafter, an embodiment of the optical branching module according to the present invention will be described in detail, but the present invention is not construed as being limited to the following description.

  FIG. 1 shows a schematic configuration diagram of an optical branching module according to the present embodiment.

The optical branching module 1 according to the present embodiment includes 2 ^p × (p + 1) optical couplers 111, 122 that substantially equally divide the light input from the two input ports and output the light from the two output ports, respectively. 133 (hereinafter “optical couplers 111, 122, 133,... Are referred to as“ optical coupler 111 etc. ”) and connection means 41, 42 for connecting the input / output ports of the respective optical couplers. , 43,... (Hereinafter, “connecting means 41, 42, 43,... Are referred to as“ connecting means 41 etc. ”)”. In FIG. 1, 2 ^p × (p + 1) optical couplers indicate each surrounded by a dotted-line square in the same manner as the optical coupler 111. Similarly to the connection means 41, the connection means indicates each closed with parentheses.

  The optical coupler 111 and the like branch the respective lights input from the two input ports substantially equally and output them from the two output ports, respectively. As this optical coupler, for example, an optical fiber type, a waveguide type, or a bulk type optical coupler can be applied, but a waveguide type optical coupler formed by an optical waveguide on a planar lightwave circuit board is desirable. A plurality of optical couplers can be manufactured on the same substrate by forming the optical coupler 111 and the like by the optical waveguide on the planar lightwave circuit board, so that the manufacturing cost is reduced compared to the case of manufacturing separate optical couplers, The module cost of the optical branching module can be suppressed.

  Further, it is desirable that the optical coupler 111 or the like is a wavelength-independent optical coupler that substantially equally branches light of any wavelength input from the input port and outputs it from the output port. By making the optical coupler 111 and the like wavelength independent, light of any wavelength can be selected, so that flexible optical multiplexing / demultiplexing is possible.

The connection means 41 and the like include 2 ^p × (p + 1) optical couplers as 2 ^p (p + 1) groups, and the output port of one set and the input port of another set of optical couplers. In a one-to-one connection, (p + 1) sets are cascaded in (p + 1) stages. In FIG. 1, the optical couplers 111 and the like are arranged in a matrix, and each column is a set of ^2p pieces. That is, 2 ^p × (p + 1) optical couplers included in the optical branching module 1 are divided into (p + 1) columns as a whole. Then, by connecting the output ports of the optical couplers included in a certain column and the input ports of the optical couplers included in another column on a one-to-one basis, (p + 1) columns of the optical coupler can be (p + 1) stages. Connected in cascade. That is, the connection means 41 or the like connects two input ports of the optical couplers included in a certain set (column) to any one output port of any two optical couplers included in the other set (column). Assuming that. In this embodiment, the optical couplers of adjacent columns are connected, and the first stage group, the second stage group,... A set of eyes,...

Further, the connecting means 41 and the like are connected to the 2 ^p optical couplers of the q-th stage and the (q + 1) -th stage group in order of 2 ^q-1 units, 2 ^{p-q + 1} units, and 2 ^q units 2 ^p-q-number of the 2 ^q output ports of the optical coupler of the q-th set of one of the unit as a unit (q + 1) to 2 ^q number any one of the input ports of the set of one of the units of the stage Connect one by one.

  That is, in FIG. 1, for example, two sets of optical couplers in the second stage constitute one unit, and two optical couplers in the third stage constitute one unit by four. It becomes. The number of optical couplers included in one unit increases by a factor of two as the next stage is reached. In this embodiment, the optical couplers in the second stage are one unit with the optical couplers 211 and 212, one unit with the optical couplers 221 and 222, one unit with the optical couplers 231 and 232, and the optical couplers 241 and 242. The optical couplers 311, 312, 313, and 314 have one unit, and the optical couplers 321, 322, 323, and 324 have one unit. It was decided to constitute a unit.

  Hereinafter, in the present specification and drawings, for example, the code of the fourth optical coupler included in the second unit of the third set is indicated as an optical coupler 324. When two separate circuits are included in one optical branch module, the highest digit of the sign digit is increased, for example, the fourth unit included in the second unit of the third stage set of the second circuit. The sign of the optical coupler is denoted as optical coupler 2324.

Then, for example, for the optical couplers 221 and 222, four output ports are connected one by one to one input port of each of the four optical couplers of any one unit in the third stage set. In the present embodiment, for the optical couplers 221, 222, the four output ports of the optical couplers 221, 222 are connected to one of the input ports of the optical couplers 311, 312, 313, 314 one by one. In other words, the connection means 41 or the like, the 2 ^q number of output ports of the optical coupler of the set of first unit of q-th stage (q + 1) of the separate stage set of first unit 2 of ^q optical coupler It is assumed that each output port is connected. In this embodiment, 2 ^q units from the top of the upper row in the drawing are used, and each unit in the q-th stage is connected in order from the upper unit in the (q + 1) -th stage in units of two.

In this way, by connecting the optical coupler 111 and the like by the connection means 41 and the like, the optical branching module 1 transmits the light of wavelength λ1 input from the input port of any optical coupler in the first stage to the (p + 1) th stage. In other words, light of wavelength λ1 can be output from all output ports of the optical coupler in the last stage. In other words, by performing the demultiplexing of 2 ^p number of wavelengths of light simultaneously, it is possible to 2 ^p branches. Therefore, the insertion loss can be reduced compared to the case where a multiplexer / demultiplexer is separately installed as in the prior art. Furthermore, since the optical branching module 1 has a smaller number of optical couplers than the conventional one even when the number of wavelength multiplexing is increased, the insertion loss can be reduced, and it can be made inexpensive and compact.

  The connection means 41 and the like may include an optical fiber or an optical fiber tape in which optical fibers are arranged to connect the output port of the q-stage set of optical couplers and the input port of the (q + 1) -stage set of optical couplers. desirable. That is, the input / output port of the optical coupler is connected by an optical fiber or an optical fiber tape. Here, the optical fiber tape refers to a structure in which optical fiber strands are arranged in a planar shape and coated with a plastic resin all together. By making the connection means 41 etc. an optical fiber or an optical fiber tape, the input / output port to be connected can be arbitrarily selected. Therefore, even if any of the optical couplers fails, it can be reconnected to the spare optical coupler, so that the management cost of the optical branching module can be reduced.

  Here, FIG. 2 to FIG. 5 show schematic configuration diagrams of an optical branching module to which another form of optical coupler is applied. FIGS. 5 to 11 show schematic configuration diagrams of an optical branching module to which another form of connecting means is applied.

Optical branch module 2 shown in FIG. 2, formed in FIG. 1 (p + 1) pieces of sets of each set of ^{2 p-number} of optical couplers identical planar lightwave circuit board 51, 52, 53 on ... It is a form. Further, the optical branching module 3 shown in FIG. 3 has a configuration in which the optical branching module 1 shown in FIG. 1 is provided with two circuits as a 4-wavelength multiplexing circuit. The first set of optical couplers of each circuit was formed on the same planar lightwave circuit board 55, and the second set of optical couplers was formed on the same planar lightwave circuit board 56. As shown in FIG. 2 or FIG. 3, by forming 2 ^p optical couplers of each group on the same planar lightwave circuit board, the manufacturing cost of the optical coupler is further reduced, and the module of the optical branching module Cost can be reduced.

  The optical branching module 4 shown in FIG. 4 has a configuration in which (p + 1) sets of first-stage and second-stage optical couplers shown in FIG. 1 are formed on the same planar lightwave circuit board 57. Further, the optical branching module 5 shown in FIG. 5 has a configuration in which the optical branching module 1 shown in FIG. 1 includes two circuits as a 4-wavelength multiplexing circuit. Then, the first-stage and second-stage optical couplers of each circuit were formed on the same planar lightwave circuit board 59. As shown in FIG. 4 or FIG. 5, by forming at least two sets of (p + 1) sets of optical couplers on the same planar lightwave circuit board, a plurality of sets of optical couplers are formed on the same board. As a result, the optical branching module can be made more compact and the space can be saved.

  The optical branching module 7 shown in FIG. 6 includes a first optical fiber tape connected to the output ports of the q-th set of optical couplers and a (q + 1) -th set for the connection means 41 shown in FIG. A second optical fiber tape connected to the input port of each of the optical couplers, and between each of the first optical fiber tape and the second optical fiber tape between the first optical fiber tape and the second optical fiber tape. And an optical fiber sheet containing optical fibers branched and connected to each other. In FIG. 6, for example, the optical fiber tape 72 as the first optical fiber tape connected to the second-stage set of optical couplers 211 and 212 and the second optical fiber tape 313 and 314 connected to the third-stage row of optical couplers 313 and 314. An optical fiber tape 77 as an optical fiber tape is connected via an optical fiber sheet 71. Here, the optical fiber sheet refers to a sheet in which a plurality of optical fibers are arranged and fixed in an arbitrary wiring shape between two plastic films.

  In FIG. 6, for example, four optical fiber tapes 72 on one side of the optical fiber sheet 71 are separated into four optical fiber strands in the optical fiber sheet 71 and arranged in an arbitrary wiring shape. Further, the four optical fiber tapes 76 on one side of the optical fiber sheet 71 are separated into four optical fiber strands in the optical fiber sheet 71 and arranged in an arbitrary wiring shape. Then, two optical fiber strands are collected from each of the optical fiber tapes 72 and 76 to form a total of four optical fiber tapes 73 and 77, respectively.

  Further, fusion splicing portions 74 and 78 are provided between the optical fiber sheet 71 and the optical fiber tapes 72 and 76, respectively, and fusion between the optical fiber sheet 71 and the optical fiber tapes 73 and 77 is provided. It has arrival connection parts 75 and 79. In the fusion splicing section, the optical fiber tapes are butted together and the opposing optical fiber strands are fusion spliced. The same applies to the fusion splicing portion described below.

  In FIG. 6, the arrangement interval of the optical fiber strands of the optical fiber tape 72 and the arrangement interval of the output ports of the optical couplers 211 and 212 are different, but this interval may be substantially the same. When the input / output port pitch of the optical coupler formed on the planar lightwave circuit boards 52 and 53 is a half pitch, the optical coupler on the planar lightwave circuit board 52 side is connected to the optical fiber tapes 72 and 76 by the optical fiber block. Can be connected without separating the optical fiber core wires from the optical fiber tapes 72 and 76. The same applies to the connection between the optical fiber tape and the optical coupler described below.

  Further, the optical branching module 8 shown in FIG. 7 has a configuration including two circuits corresponding to four as the optical branching module 1 shown in FIG. The first-stage and second-stage optical couplers of the respective circuits were formed on the same planar lightwave circuit boards 70 and 80, respectively. Further, optical fiber tapes 81 and 85 and optical fiber tapes 82 and 86 connected to every other input / output port of the first-stage and second-stage optical couplers were connected via an optical fiber sheet 89. By connecting the optical fiber tapes 81 and 85 and the optical fiber tapes 82 and 86 to every other input / output port of the first-stage and second-stage optical couplers, four 4-wavelength multiplexing circuits can be made compact. Can be provided. Note that fusion splicing portions 83, 84, 87, and 88 are provided between the optical fiber sheet 89 and the optical fiber tapes 81 and 85 and the optical fiber tapes 82 and 86.

  Here, when the pitch of the input / output ports of the optical coupler formed on the planar lightwave circuit boards 70 and 80 is a half pitch, the optical coupler on the planar lightwave circuit board 70 side is replaced with the optical fiber tapes 81 and 85 by an optical fiber block. When connecting, the optical fiber core wires from the optical fiber tapes 81 and 85 are overlapped in a comb shape and alternately connected to the output port of the optical coupler. The same applies to the optical coupler on the planar lightwave circuit board 80 side. As in the embodiment shown in FIG. 7, the connection method in the case where the optical fiber tape is connected to every other input / output port of the optical coupler is the same in the embodiments described below.

  When the optical couplers are connected to each other through the optical fiber sheet as shown in FIGS. 6 and 7, the optical fiber is connected without connecting the optical fiber strands in a single-core unit even when the optical fibers cross each other. Connection between optical couplers in units of tape is possible. Further, it is possible to protect the optical fiber wiring, facilitate the handling of the optical branching module, and reduce the module size.

  Further, in the optical branching module having four 4-wavelength multiplexing circuits shown in FIG. 7 like the optical branching module 9 shown in FIG. It is good also as connecting with the optical fiber tapes 64 and 69 as the two 4 cores optical fiber tapes 65 and 66 separated into the core and rebonated every other. Further, fusion splicing portions 67 and 68 are provided between the optical fiber tape 63 and the optical fiber tapes 64 and 69, respectively.

  9 is the same as the optical branching module 1 shown in FIG. 1 except that the connection means 41 and the like are optical waveguides formed on the planar lightwave circuit boards 60, 61, 62. is there. By using the optical waveguide formed on the planar lightwave circuit board as the connection means, the connection distance between the optical couplers can be shortened, so that the mounting density of the components of the optical branching module 6 can be increased.

  Further, the optical branching module 10 shown in FIG. 10 has a configuration in which the optical branching module 1 shown in FIG. 1 includes two circuits as a 4-wavelength multiplexing circuit. FIG. 11 shows the logical connection of the optical branching module shown in FIG.

  The optical branching module 10 shown in FIG. 10 is configured so that one of the output ports of the first-stage set of optical couplers and the input port of the second-stage set of optical couplers are parallel to the connection means 41 shown in FIG. An optical fiber tape 90 as a first optical fiber tape to be connected to the second output port of the first-stage set of optical couplers and an input port of the second-stage set of optical couplers. And an optical fiber tape 91 as an optical fiber tape. The optical fiber tapes 90 and 91 have fusion splicing portions 92 and 93, respectively.

  Here, to connect the input / output ports of the optical coupler in parallel, as shown in FIG. 11, four connections 119, 120, 121, 123 for connecting the optical couplers in the first and second stages are connected. Means that they do not cross each other. Further, to connect the input / output ports of the optical coupler to the target, as shown in FIG. 11, there are four connections 129, 130, 131, 132 for connecting the optical couplers in the first and second stages. It means that they all intersect. Note that the definition of the connection between the optical couplers is based on the assumption that the connection assumption relating to the connection means 41 described with reference to FIG. Note that the definitions of “connect in parallel” and “connect to target” are the same in the embodiments described below.

  Thus, by using the optical fiber tape 90 and the optical fiber tape 91 as the connection means, one optical fiber tape 91 connects the optical couplers straight, and the other optical fiber tape 90 is connected by the twisted portion 94. By twisting, the first-stage set of optical couplers and the second-stage set of optical couplers can be connected. Therefore, connection in units of optical fiber tapes is possible without requiring single-fiber separation or rebonization from the optical fiber tape. Therefore, the handling of the optical branching module can be facilitated, the module components can be densely mounted, and the manufacturing efficiency can be increased.

  12 to 19 show other forms of the optical branching module 10 shown in FIG.

  The optical branching module 12 shown in FIG. 12 has a configuration in which the optical branching module 1 shown in FIG. 1 includes four circuits as a four-wavelength multiplexing circuit. FIG. 13 shows the logical connection of the optical branching module shown in FIG.

  In the optical branching module 12 shown in FIG. 12, with respect to the connecting means 41 shown in FIG. 1, one output port of the first-stage optical coupler and the input port of the second-stage optical coupler are parallel to each other. A second optical fiber tape 95 as a first optical fiber tape to be connected to the second output port of the first-stage set of optical couplers and a second output port of the second-stage set of optical couplers. And an optical fiber tape 96 as an optical fiber tape. The optical fiber tapes 95 and 96 have fusion splicing portions 97 and 98, respectively. In the present embodiment, by arranging the first-stage and second-stage sets of optical couplers in order for each circuit, four 4-wavelength multiplexing circuits can be provided in a compact manner.

  Thus, by using the optical fiber tape 95 and the optical fiber tape 96 as the connection means, one optical fiber tape 95 connects the optical couplers in a straight line, and the other optical fiber tape 96 is connected to the twisted portion 99. The optical couplers can be connected by twisting. Therefore, connection in units of optical fiber tapes is possible without requiring single-fiber separation or rebonization from the optical fiber tape. Therefore, the handling of the optical branching module can be facilitated, the module components can be densely mounted, and the manufacturing efficiency can be increased.

  Further, the optical branching module 14 shown in FIG. 14 has a configuration in which the optical branching module 1 shown in FIG. 1 includes eight circuits as a 4-wavelength multiplexing circuit. FIG. 15 shows the logical connection of the optical branching module shown in FIG.

  In the optical branching module 14 shown in FIG. 14, the output means of the first-stage optical coupler and the input port of the second-stage optical coupler are parallel to the connection means 41 shown in FIG. The second optical fiber tape 100 as the first optical fiber tape to be connected to the second output port of the first-stage set optical coupler and the input port of the second-stage set optical coupler. And an optical fiber tape 101 as an optical fiber tape. The optical fiber tapes 100 and 101 have fusion splicing portions 102 and 103, respectively. In the present embodiment, by arranging the first-stage and second-stage sets of optical couplers in order for each circuit, eight 4-wavelength multiplexing circuits can be provided in a compact manner.

  Thus, by using the optical fiber tape 100 and the optical fiber tape 101 as the connection means, one optical fiber tape 100 connects the optical couplers straight, and the other optical fiber tape 101 is connected by the twisted portion 104. The optical couplers can be connected by twisting. Therefore, connection in units of optical fiber tapes is possible without requiring single-fiber separation or rebonization from the optical fiber tape. Therefore, the handling of the optical branching module can be facilitated, the module components can be densely mounted, and the manufacturing efficiency can be increased.

  Also, the optical branching module 16 shown in FIG. 16 has a configuration in which the optical branching module 1 shown in FIG. 1 is provided with two circuits as 8-wavelength multiplexing circuits. FIG. 17 shows logical connections of the optical branching module shown in FIG.

  The optical branching module 16 shown in FIG. 16 has a parallel connection between one output port of the first-stage optical coupler and an input port of the second-stage optical coupler in the connection means 41 shown in FIG. A second optical fiber tape 105 as a first optical fiber tape to be connected to the second output port of the first-stage set optical coupler and an input port of the second-stage set optical coupler. And an optical fiber tape 106 as an optical fiber tape. Further, an optical fiber tape 110 as a first optical fiber tape that connects in parallel one of the output ports of the optical couplers in the second row and the input ports of the optical couplers in the third row; And optical fiber tapes 118 and 112 as second optical fiber tapes for connecting the other output port of the optical coupler of the stage set to the input port of the optical coupler of the third stage set. The optical fiber tapes 105 and 106 have fusion splicing portions 107 and 108, respectively. The optical fiber tapes 110, 118, and 112 have fusion splicing portions 113, 114, and 115, respectively. In this embodiment, by arranging the optical couplers of the first, second and third stages in order for each circuit, two 8-wavelength multiplexing circuits can be provided in a compact manner.

  Thus, by using the optical fiber tapes 105, 106, 110, 118, and 112 as the connection means, one optical fiber tape 105 connects the optical couplers straight, and the other optical fiber tape 106 is twisted. The optical couplers can be connected by being twisted by the portion 109. Also, one optical fiber tape 110 can connect the optical couplers straight, and the other optical fiber tapes 118 and 112 can connect the optical couplers by being twisted by the twisted portions 116 and 117, respectively. Therefore, connection in units of optical fiber tapes is possible without requiring single-fiber separation or rebonization from the optical fiber tape. Therefore, the handling of the optical branching module can be facilitated, the module components can be densely mounted, and the manufacturing efficiency can be increased.

  Further, the optical branching module 18 shown in FIG. 18 has a configuration in which the optical branching module 1 shown in FIG. 1 includes four circuits as an 8-wavelength multiplexing circuit. FIG. 19 shows the logical connection of the optical branching module shown in FIG.

  The optical branching module 18 shown in FIG. 18 is configured so that any one of the output ports of the first-stage optical coupler and the input port of the second-stage optical coupler are parallel to the connection means 41 shown in FIG. A second optical fiber tape 189 as a first optical fiber tape connected to the second optical fiber tape, and the other output port of the first-stage optical coupler connected to the input port of the second-stage optical coupler. And an optical fiber tape 190 as an optical fiber tape. Also, an optical fiber tape 194 as a first optical fiber tape for connecting in parallel one of the output ports of the optical couplers in the second row and the input ports of the optical couplers in the third row, Optical fiber tapes 195 and 196 as second optical fiber tapes for connecting the other output port of the optical coupler of the stage set to the input port of the optical coupler of the third stage set. The optical fiber tapes 189 and 190 have fusion splicing portions 191 and 192, respectively. The optical fiber tapes 194, 195, and 196 have fusion splicing portions 197, 198, and 199, respectively. In the present embodiment, by arranging the first-stage, second-stage and third-stage optical couplers in order for each circuit, four 8-wavelength multiplexing circuits can be provided in a compact manner.

  Thus, by using the optical fiber tapes 189, 190, 194, 195, and 196 as connection means, one optical fiber tape 189 connects the optical couplers straight, and the other optical fiber tape 190 is twisted. The optical couplers can be connected by being twisted by the portion 193. Also, for the second stage, one optical fiber tape 194 connects the optical couplers straight, and the other optical fiber tapes 195, 196 connect the optical couplers by twisting with the twisted portions 200, 201, respectively. be able to. Therefore, connection in units of optical fiber tapes is possible without requiring single-fiber separation or rebonization from the optical fiber tape. Therefore, the handling of the optical branching module can be facilitated, the module components can be densely mounted, and the manufacturing efficiency can be increased.

  FIG. 20 shows another form of the optical branching module 9 shown in FIG. The optical branching module 19 shown in FIG. 20 has a configuration in which an optical filter 202 is further provided in the front stage of the first-stage optical coupler of the optical branching module 9 shown in FIG.

  In the optical branching module 19 shown in FIG. 20, at each of the four input ports of the optical coupler 1111 and the optical coupler 1122, one IP signal wave and three video signal waves are assigned and input to each input port one by one. The signals of the respective wavelengths are equally distributed from the output ports of 1211 and the optical coupler 1212 and output. By disposing the optical filter 202 in the preceding stage of the optical coupler 1111 and the optical coupler 1122, it is possible to prevent the video signal from leaking to the port to which the IP signal is input. In other optical couplers, input and output of IP signals and video signals are similarly performed.

  Here, FIG. 21 shows a communication wavelength band of an optical signal used in the IP network.

  For video distribution over an IP network, ITU-T Recommendation G. In the wavelength arrangement conforming to 983.3, IP communication wavelengths of 1310 nm and 1490 nm are used, and the video distribution wavelengths are from 1550 nm to 1560 nm which are video bands and 1539 nm which is a digital communication band shown in FIG. 1565 nm is used. Therefore, the optical filter 202 shown in FIG. 20 has a characteristic of blocking the wavelength band of 1539 nm or more as shown in FIG.

  In the optical filter 202 shown in FIG. 20, the eight optical fiber tapes 125 are separated into single cores, and inserted into the middle of four optical fiber tapes 127 that are revolved together every other. Thus, by arranging the optical filter 202, it is possible to reduce the manufacturing cost and increase the mounting density. Further, by including the optical filter 202, it is possible to facilitate multiplexing of optical communication on the IP network.

  In the optical filter 202, the optical fiber tape 125 is separated into a single core, and a dielectric multilayer film is applied to each optical fiber core wire connected to the input port for the IP signal of the first-stage set of optical couplers. An optical filter may be used. Also, a fiber Bragg grating (FBG) in which the optical fiber tape 125 is separated into a single core and is fused and connected to each of the optical fiber cores connected to the IP signal input port of the first-stage pair of optical couplers. ).

  FIG. 22 shows another form of the optical branching module 12 shown in FIG. The optical branching module 21 shown in FIG. 22 has a configuration in which an optical filter 229 is further provided in the front stage portion of the first-stage optical coupler of the optical branching module 12 shown in FIG. The characteristics of the optical filter 229 are the same as the characteristics of the optical filter 202 shown in FIG. In the present embodiment, one input port of the four optical couplers 1112, 2111, 3111, 4111 is used as an IP signal input port, and the optical fiber tape 136 is connected to the IP signal input port. did. The optical fiber tape connected to the IP signal input port may be an optical fiber tape 138.

  The optical filter 229 is inserted in the middle of the four-fiber optical fiber tape 136. When the optical filter 229 is inserted into the front stage of the input port, it is necessary to combine the optical fibers connected to the IP signal input port into one. In the optical branching module 21 of the form shown in FIG. 22, the optical couplers on the planar lightwave circuit board 134 are arranged in order for each circuit, so that the four-fiber optical fiber tape 136 is simply attached to the optical coupler on the planar lightwave circuit board 134. By simply arranging the input ports in the form of comb teeth, the input ports for IP signals for four circuits can be combined into one optical fiber tape 136, and the manufacturing process can be simplified. Therefore, the manufacturing cost of the optical branching module can be further reduced and the module components can be mounted with high density.

  In the optical filter 229, the optical fiber tape 136 is separated into a single core, and one dielectric multilayer film is applied to each optical fiber core wire connected to the IP signal input port of the first-stage pair of optical couplers. An optical filter may be used. Alternatively, the optical fiber tape 136 may be separated into single fibers, and FBGs may be fused and connected to each of the optical fiber cores connected to the IP signal input ports of the first-stage set of optical couplers.

  FIG. 23 shows another form of the optical branching module 14 shown in FIG. The optical branching module 23 shown in FIG. 23 has a configuration in which an optical filter 147 is further provided at the front stage of the first-stage optical coupler of the optical branching module 14 shown in FIG. The characteristics of the optical filter 147 are the same as the characteristics of the optical filter 202 shown in FIG. In this embodiment, the optical fiber tape 148 is connected to the IP signal input port. The optical fiber tape connected to the IP signal input port may be the optical fiber tape 150.

  The optical filter 147 is inserted in the middle of the 8-fiber optical fiber tape 148. When the optical filter 147 is inserted into the front stage of the input port, it is necessary to combine the optical fibers connected to the IP signal input port into one. In the optical branching module 23 of the form shown in FIG. 23, since the optical couplers on the planar lightwave circuit board 145 are arranged in order for each circuit, the eight optical fiber tapes 148 are simply placed on the planar lightwave circuit board 145. The input ports for IP signals for 8 circuits can be integrated into one optical fiber tape 148 by simply arranging the input ports in a comb-tooth shape, and the manufacturing process can be simplified. Therefore, the manufacturing cost of the optical branching module can be further reduced and the module components can be mounted with high density.

  In the optical filter 147, the optical fiber tape 148 is separated into a single core, and a dielectric multilayer film is applied to each of the optical fiber core wires connected to the input port for the IP signal of the first-stage set of optical couplers. An optical filter may be used. Alternatively, the optical fiber tape 148 may be separated into single fibers, and FBGs may be fused and connected to each of the optical fiber cores connected to the IP signal input ports of the first-stage set of optical couplers.

  Next, FIG. 24 shows a schematic configuration diagram of a video distribution system multiplexed with one IP signal wave and three video signals on an IP network to which the optical branching module described in FIGS. 1 to 23 is applied.

  24 includes an optical termination device 156, 157, 158, 159, an optical branching module 160 according to this embodiment connected to the optical termination devices 156, 157, 158, 159, and an optical branching module. An eight-branch optical splitter 162 connected to one output port of 160 through an optical fiber 164; and an optical termination device 163 connected to one output port of the eight-branch optical splitter 162 through an optical fiber 165. Have.

  The optical terminal device 156 is a device arranged in the communication facility building 161 used for IP communication. ITU-T Recommendation G. 1310 nm and 1490 nm are used as the IP communication wavelengths in a wavelength arrangement conforming to 983.3. The optical terminal devices 157, 158, and 159 are devices disposed in the communication facility building 161 used for video distribution. The optical terminators 157, 158, and 159 have different communication wavelengths. The lights output from the optical terminators 157, 158, and 159 are multiplexed / demultiplexed by the optical branching module 160 according to the present embodiment, and the signal lights of all wavelengths incident on the input ports of the optical branching module 160 are substantially omitted. The light is branched equally and output from the output port of the optical branching module 160. Then, it is further demultiplexed by the 8-branch optical splitter 162 and received by the optical termination device 163 via the optical fiber 165.

  Here, the image distribution wavelength shown in FIG. 21 is 1550 nm to 1560 nm and the digital communication band 1539 nm to 1565 nm. When three video wavelengths are set as video signals within this wavelength band, each wavelength interval becomes narrow. When combining these with low loss, the conventional optical multiplexer / demultiplexer having wavelength dependency requires mounting an optical filter having narrow-band optical characteristics in the optical multiplexer / demultiplexer according to the wavelength to be used. Become. This mounting is technically difficult and expensive to manufacture. Furthermore, in the conventional optical multiplexer / demultiplexer having wavelength dependency, it is necessary to change the optical multiplexer / demultiplexer according to the wavelength to be used. On the other hand, when adding a new video wavelength, It becomes necessary to add demultiplexed air. Therefore, the cost and the number of parts increase.

  On the other hand, in the optical branching module 160 of this embodiment, it is not necessary to change the multiplexer / demultiplexer according to the wavelength band to be used by configuring the optical branching module with a wavelength-independent optical coupler. Setting is possible.

  Further, as described above, in the conventional system in which the multiplexing and demultiplexing shown in FIG. 25 are performed separately, until the video signal 3 waves are multiplexed on the IP signal 1 wave and divided into 4 waves, Since multiplexing is performed using two bulk multiplexers / demultiplexers using a lens collimator and a dielectric multilayer film, an insertion loss of 1 dB occurs, and an insertion loss of 6.6 dB is caused by the subsequent four-branch optical splitter 171. Resulting in a total insertion loss of 7.6 dB. On the other hand, in the optical branching module 160 shown in FIG. 24, multiplexing and demultiplexing can be performed simultaneously by four optical couplers as described in FIG. For this reason, it is possible to multiplex 3 video signals to 1 IP signal with an insertion loss of 6.6 dB of two optical couplers, and to demultiplex it into 4 waves, which is 1 dB compared to the conventional system. Achieve improvements. As a result, the dynamic range of the transmission apparatus can be increased, and the area where the video distribution service can be provided is expanded.

  The optical branching module of the present invention can be applied not only as a trunk network such as a relay network but also as an optical multiplexer / demultiplexer when constructing a local area network or an access network.

It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is the figure which showed the logical connection of the optical branch module shown in FIG. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is the figure which showed the logical connection of the optical branching module shown in FIG. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is the figure which showed the logical connection of the optical branching module shown in FIG. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is the figure which showed the logical connection of the optical branching module shown in FIG. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is the figure which showed the logical connection of the optical branching module shown in FIG. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is the figure which showed one example of the communication wavelength band of the optical signal used with an IP network. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. It is a schematic block diagram of the optical branching module which concerns on 1 embodiment. FIG. 24 is a schematic configuration diagram of a video distribution system in which one IP signal wave and three video signal waves are multiplexed on an IP network to which the optical branching module shown in FIGS. 1 to 23 is applied. It is a schematic block diagram of the wavelength division multiplexing system by PDS. It is a schematic block diagram of the optical multiplexer / demultiplexer which connected the some optical coupler.

Explanation of symbols

1: Optical branch module 2: Optical branch module 3: Optical branch module 4: Optical branch module 5: Optical branch module 6: Optical branch module 7: Optical branch module 9: Optical branch module 10: Optical branch module 12: Optical branch module 14: Optical branch module 16: Optical branch module 18: Optical branch module 19: Optical branch module 21: Optical branch module 23: Optical branch module 41: Connection means 42: Connection means 43: Connection means 51: Planar lightwave circuit board 52: Planar lightwave circuit board 53: Planar lightwave circuit board 54: Planar lightwave circuit board 55: Planar lightwave circuit board 56: Planar lightwave circuit board 57: Planar lightwave circuit board 58: Planar lightwave circuit board 59: Planar lightwave circuit board 60: Planar lightwave circuit board Circuit board 61: Planar lightwave circuit board 62: Planar lightwave circuit board 63: Optical fiber tape 6 : Optical fiber ribbon 65: optical fiber ribbon 66: optical fiber ribbon 67: fusion-spliced portion 68: fusion splice 69: optical fiber tape 70: a planar lightwave circuit board
71: optical fiber sheet 72: optical fiber tape 73: optical fiber tape 74: fusion splicing part 75: fusion splicing part 76: optical fiber tape 77: optical fiber tape 78: fusion splicing part 79: fusion splicing part 80 : Planar lightwave circuit board 81: Optical fiber tape 82: Optical fiber tape 83: Fusion splicing part 84: Fusion splicing part 85: Optical fiber tape 86: Optical fiber tape 87: Fusion splicing part 88: Fusion splicing part 89 : Optical fiber sheet 90: optical fiber tape 91: optical fiber tape 92: fusion splicing part 93: fusion splicing part 94: twisting part 95: optical fiber tape 96: optical fiber tape 97: fusion splicing part 98: fusion splicing Connection part 99: Twist part 100: Optical fiber tape 101: Optical fiber tape 102: Fusion splicing part 103: Fusion splicing part 104: Twist part 105: Optical fiber tape 106: optical fiber tape 107: fusion splicing part 108: fusion splicing part 109: twisting part 110: optical fiber tape 112: optical fiber tape 113: fusion splicing part 114: fusion splicing part 115: fusion splicing part 116 : Twisted portion 117: twisted portion 118: optical fiber tape 119: connection 120: connection 121: connection 123: connection 125: optical fiber tape 126: optical fiber tape 127: optical fiber tape 128: optical fiber tape 129: connection 130: connection 131: connection 132: connection 134: planar lightwave circuit board 135: planar lightwave circuit board 136: optical fiber tape 137: optical fiber tape 138: optical fiber tape 145: planar lightwave circuit board 146: planar lightwave circuit board 147: optical filter 148 : Optical fiber tape 149: Optical fiber tape 150: Fiber Tape 156: ONT 157: ONT 158: ONT 159: ONT 160: optical branch module 161: Communication installation Building 162: optical splitter 163: ONT 164: optical fiber 165: optical fiber
167: Optical fiber 168: Optical fiber 169: Optical fiber 170: Optical multiplexer / demultiplexer 171: Optical splitter 172: Optical multiplexer / demultiplexer 173: Planar lightwave circuit board
179: Optical multiplexer / demultiplexer
180: optical coupler 181: optical coupler 182: optical coupler 183: optical coupler 184: optical coupler 189: optical fiber tape 190: optical fiber tape 191: fusion splicing part 192: fusion splicing part 193: twisting part 194: optical fiber Tape 195: optical fiber tape 196: optical fiber tape 197: fusion splicing part 198: fusion splicing part 199: fusion splicing part 200: twisting part 201: twisting part 202: optical filter 229: optical filter 300: video distribution system
400: Wavelength multiplexing system
111: Optical coupler 122: Optical coupler 133: Optical coupler 144: Optical coupler 155: Optical coupler 166: Optical coupler 177: Optical coupler 188: Optical coupler 211: Optical coupler 212: Optical coupler 221: Optical coupler 222: Optical coupler 231: Optical coupler 232: Optical coupler 241: Optical coupler 242: Optical coupler 311: Optical coupler 312: Optical coupler 313: Optical coupler 314: Optical coupler 321: Optical coupler 322: Optical coupler 323: Optical coupler 324: Optical coupler 411: Optical coupler 412: Optical coupler 413: Optical coupler 414: Optical coupler 415: Optical coupler 417: Optical coupler 417: Optical coupler 418: Optical coupler 1111: Optical coupler 1122: Optical coupler 1133: Optical coupler 1144: Optical coupler 1211: Optical coupler 1212: Optical coupler 1221: Optical coupler 1222: Optical coupler 1311: Coupler 1312: Optical coupler 1313: Optical coupler 1314: Optical coupler 2111: Optical coupler 2122: Optical coupler 2133: Optical coupler 2144: Optical coupler 2211: Optical coupler 2212: Optical coupler 2221: Optical coupler 2222: Optical coupler 2311: Optical coupler 2312 : Optical coupler 2313: Optical coupler 2314: Optical coupler 3111: Optical coupler 3122: Optical coupler 3133: Optical coupler 3144: Optical coupler 3211: Optical coupler 3212: Optical coupler 3221: Optical coupler 3222: Optical coupler 3311: Optical coupler 3312: Light Coupler 3313: Optical coupler 3314: Optical coupler 4111: Optical coupler 4122: Optical coupler 4133: Optical coupler 4144: Optical coupler 4211: Optical coupler 4212: Optical coupler 4221: Optical coupler 4222: Optical coupler 4311: Optical coupler 4312: Coupler 4313: Optical coupler 4314: Optical coupler 5111: Optical coupler 5122: Optical coupler 5211: Optical coupler 5212: Optical coupler 6111: Optical coupler 6122: Optical coupler 6211: Optical coupler 6212: Optical coupler 7111: Optical coupler 7122: Optical coupler 7211 : Optical coupler 7212: Optical coupler 8111: Optical coupler 8122: Optical coupler 8211: Optical coupler 8212: Optical coupler

Claims (9)

2 ^p × (p + 1) (where p is a natural number) optical couplers that substantially equally divide the light input from the two input ports and output the light from the two output ports, respectively,
The 2 ^p × (p + 1) optical couplers are connected in groups of 2 ^p (p + 1), and the output port of one set and the input port of another set of optical couplers are connected one-to-one. Then, so that the (p + 1) sets are cascade-connected to the (p + 1) stage, q (where q is a natural number equal to or less than p) and 2 ^p pieces of the (q + 1) stage set. 2 ^q pieces of optical coupler 2 ^{p-q + 1} single unit and the q-th set of one of the unit as a 2 ^p-q-number of units of 2 ^q pieces each of the optical coupler by 2 ^q-1 pieces sequentially each Connecting one output port at a time to one input port of each of 2 ^q optical couplers of one unit of the (q + 1) -stage set;
An optical branching module comprising: 2. The optical branching module according to claim 1, wherein the 2 ^p × (p + 1) optical couplers are each formed by an optical waveguide on a planar lightwave circuit board. 3. The optical branching module according to claim 2, wherein 2 ^p optical couplers of each of the (p + 1) sets are formed on the same planar lightwave circuit board.   4. The optical branching module according to claim 3, wherein at least two sets of optical couplers among the (p + 1) sets are formed on the same planar lightwave circuit board. 5.   The connecting means is an optical fiber that connects an output port of the q-stage set of optical couplers and an input port of the (q + 1) -stage set of optical couplers corresponding to the output port, or an array of the optical fibers The optical branching module according to claim 1, further comprising an optical fiber tape.   The connecting means includes two or more optical fibers arranged and connected to the output ports of the q-th set of optical couplers, and the same number of optical fibers as the two or more optical fibers. A second optical fiber tape arranged and connected to input ports of the (q + 1) -th set of optical couplers corresponding to the output port; the first optical fiber tape; and the second optical fiber tape. And an optical fiber sheet containing optical fibers branched from and connected to each of the first optical fiber tape and the second optical fiber tape. The optical branching module according to any one of 5.   The connection means connects an output port of the q-th set of optical couplers formed on a planar lightwave circuit board and an input port of the (q + 1) -th set of optical couplers corresponding to the output port. The optical branching module according to claim 1, further comprising an optical waveguide. The connection means includes 2 ^{q + m−1} (where m is a natural number equal to or less than (p−q + 1)) and 2 ^{q + m−} of 2 ^m units in the ^{q-th set. A first} optical fiber tape that connects in parallel one of the output ports of each of the optical couplers and the input port of the (q + 1) -th set of optical couplers; and 2 ^{q + m−1} light. A second optical fiber tape that arranges fibers and connects the other one output port of each of the 2 ^{q + m−1} optical couplers to the input port of the (q + 1) -th set of optical couplers. And an optical branching module according to any one of claims 1 to 7. 9. The optical filter according to claim 1, further comprising an optical filter disposed in a front stage portion of one or more input ports of the first-stage set of optical couplers out of the 2 ^p × (p + 1) optical couplers. The optical branching module according to any one of the above.

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