Disclosure of Invention
Problems to be solved by the invention
An optical cable for transmitting an image is sometimes laid between devices that transmit and receive an image so as to pass through a narrow space such as a pipe, a wall, or a floor. However, the tip plugs of fiber optic cables are sometimes difficult to pass through or do not pass through narrow spaces. The size reduction of the tip plug of such a conventional optical cable for video transmission is required, but the size reduction is limited.
Further, the following are some cases of conventional optical cables for image transmission: the length of the cable actually laid between the devices is too long relative to the length of cable required for the connection between the devices and the remainder of the cable can become obtrusive.
The invention provides an optical cable laying construction method and an optical cable laying construction assembly, which can easily lead an optical cable to pass through a narrow space during laying of the optical cable and is suitable for restraining surplus of the laid optical cable.
Means for solving the problems
The present invention (1) includes an optical cable laying construction method using an optical cable laying construction kit, the optical cable laying construction kit including: an optical cable comprising a refractive index profile type plastic optical fiber and a cable jacket; a first plug having a first connection section to which the plastic optical fiber can be connected and an electrical connector that can be connected to an external device, the first plug being configured to convert an electrical signal into an optical signal; and a second plug including a second connection portion to which the plastic optical fiber can be connected and an electrical connector that can be connected to an external device, the second plug having a structure that converts an optical signal into an electrical signal, the optical cable installation method being for connecting the external devices to each other through an optical cable using an optical cable installation module, the optical cable installation method including: a laying step of laying the optical cable; a first removing process of removing a cable jacket at one end of the optical cable such that the plastic optical fiber extends outside the cable jacket; a first connecting step of connecting the plastic optical fiber extending outside the cable sheath at the one end portion to the first connecting portion of the first plug; a second removing process of removing the cable jacket at the other end portion of the optical cable such that the plastic optical fiber extends outside the cable jacket; and a second connecting step of connecting the plastic optical fiber extending outside the cable sheath at the other end portion to the second connecting portion of the second plug.
According to such a construction method for laying an optical cable, in the laying step, the optical cable can be laid between external devices before plugs are attached to both end portions of the optical cable. Optical cables without plugs at the top are easy to pass through narrow spaces such as inside pipes, in walls and under floors.
Further, according to the method, after the optical cable is laid between the external devices and before the plugs are attached to both end portions of the optical cable, the optical cable can be cut as necessary to adjust the length of the optical cable. Such a method is suitable for suppressing the surplus of the optical cable after laying.
As described above, according to the present method, the optical cable is made easy to pass through a narrow space in laying the optical cable, and it is suitable for suppressing the surplus of the optical cable after laying.
The present invention (2) includes the optical cable laying construction method according to (1), further including a step of cutting the optical cable before the first removal step and/or the second removal step.
With this configuration, the surplus of the optical cable after the laying can be suppressed.
The present invention (3) includes the optical cable laying construction method according to (1) or (2), wherein in the first connection step, the plastic optical fiber extending outside the cable sheath at the one end portion is connected to the first connection portion of the first plug via an optical connector.
Such a structure is suitable for obtaining high connection reliability between the plastic optical fiber and the first plug.
The present invention (4) includes the optical cable installation method according to any one of (1) to (3), wherein in the second connection step, the plastic optical fiber extending to the outside of the cable sheath at the other end portion is connected to the second connection portion of the second plug via an optical connector.
Such a structure is suitable for obtaining high connection reliability between the plastic optical fiber and the second plug.
The present invention (5) includes an optical cable laying construction module, including: an optical cable including a plastic optical fiber of a refractive index profile; a first plug having a first connection section to which the plastic optical fiber can be connected and an electrical connector that can be connected to an external device, the first plug being configured to convert an electrical signal into an optical signal; and a second plug including a second connection portion to which the plastic optical fiber can be connected and an electrical connector that can be connected to an external device, the second plug being configured to convert an optical signal into an electrical signal.
Such an optical cable installation module can be used in the optical cable installation method according to the present invention (1). Therefore, according to the optical cable laying construction kit, the same technical effects as those of the optical cable laying construction method can be obtained in the optical cable laying construction using the optical cable laying construction kit.
The present invention (6) includes the optical cable installation construction kit according to (5), wherein the plastic optical fiber includes a core, a cladding around the core, and an outer cladding around the cladding, the core and the cladding have an elastic modulus of 0.5GPa to 20GPa, and the outer cladding has an elastic modulus of 0.5GPa to 10 GPa.
Such a configuration is suitable for obtaining a good cut end face ensuring flatness for optical connection in an optical fiber when the optical fiber is cut by, for example, a cutter at an optical fiber laying site.
The present invention (7) includes the optical cable installation construction assembly according to (5) or (6), further comprising an optical connector for connecting the plastic optical fiber of the optical cable and the first connection portion of the first plug.
Such a structure is suitable for obtaining high connection reliability between the plastic optical fiber and the first plug.
The present invention (8) includes the optical cable installation construction assembly according to any one of (5) to (7), further comprising an optical connector for connecting the plastic optical fiber of the optical cable and the second connection portion of the second plug.
Such a structure is suitable for obtaining high connection reliability between the plastic optical fiber and the second plug.
The present invention (9) includes the optical cable installation construction assembly according to any one of (5) to (8), wherein the optical cable further includes an electric wire, the first plug further includes a third connection portion to which the electric wire can be connected, and the second plug further includes a fourth connection portion to which the electric wire can be connected.
The optical cable laying construction kit may also have such a hybrid structure that both plastic optical fibers and electric wires are used in signal transmission and reception.
Detailed Description
Fig. 1 is a schematic configuration diagram of an optical cable installation construction kit X according to an embodiment of the present invention. The optical cable installation work module X includes an optical cable C1, a plug P1, and a plug P2.
The optical cable C1 is a cable for video transmission such as HDMI transmission. The optical fiber cable C1 has a hybrid structure in which both optical fibers and electric wires are used for transmission and reception of signals. As shown in fig. 2, the optical cable C1 includes anoptical cord 10, anelectrical cord 20, and acable jacket 30. The length of the optical cable C1 is, for example, 2m to 200 m.
As shown in fig. 2, theoptical cord 10 includes a plurality ofoptical fibers 11 and acovering 12. The number ofoptical fibers 11 in theoptical cord 10 is, for example, 4.
Theoptical fiber 11 is a refractive index distribution type plastic optical fiber, and has acore 11a, acladding 11b positioned around thecore 11a, and anouter cladding 11c positioned around thecladding 11b, as shown in fig. 3, so that a plurality of optical signals can pass therethrough. The diameter of theoptical fiber 11 is, for example, 100 μm to 1000 μm.
The refractive index of thecore 11a is higher than that of thecladding 11b, and the core 11a forms the optical transmission path itself. The refractive index of the core 111a has, for example, a central axis-symmetric distribution shape that decreases as approaching thecladding 11b from the center of the cross section of the core 11 a. Examples of the material of thecore 11a include flexible resin materials such as polymethyl methacrylate and polycarbonate. The refractive index of thecladding 11b is lower than that of the core 11 a. Examples of the material constituting theclad layer 11b include fluorine-containing polymers such as fluorine-containing polyimide. Theouter cover 11c is made of polycarbonate, for example.
Thecore 11a and thecladding 11b have an elastic modulus of 0.5GPa to 20GPa, and thecladding 11c has an elastic modulus of 0.5GPa to 10 GPa. These elastic moduli are values measured by the nanoindentation method. Such a configuration is suitable for obtaining a good cut end face ensuring flatness for performing optical connection in theoptical fiber 11 when the optical fiber cable C1 is cut with a cutter, for example.
The measurement of the elastic modulus by the nanoindentation method can be performed, for example, using a nanoindenter (trade name "triboinder", manufactured by Hysitron corporation). In this measurement, the measurement mode was single indentation measurement, the measurement temperature was 25 ℃, the indenter was a Berkovich (triangular pyramid) type diamond indenter, the indentation depth of the indenter into the object to be measured was 1000nm, and the indentation speed of the indenter was 100 nm/sec. The derivation of the elastic modulus by the nanoindentation method was performed in the use apparatus. In addition, after a slice of a predetermined length of an optical fiber to be measured is embedded in a resin, an exposed cross section for measurement can be prepared by exposing a cross section of the optical fiber using a microtome apparatus, and then the elastic modulus can be measured in the cross section by the nanoindentation method.
Thecladding 12 surrounds theoptical fiber 11 to protect it. Examples of the material of the covering 12 include polyvinyl chloride, ethylene vinyl acetate copolymer, and polycarbonate.
Theoptical cord 10 may include a tensile member for preventing breakage of theoptical fiber 11 due to a tensile force applied to theoptical fiber 11. The tensile strength body is configured to extend along theoptical fiber 11 between theoptical fiber 11 and thecladding 12, for example. Examples of the material constituting the tensile strength member include aramid fibers such as poly (p-phenylene terephthalamide) fibers, polyarylate fibers, poly (p-phenylene benzobisoxazole) fibers, and polyester fibers such as polyethylene terephthalate fibers.
Instead of thecover 12, theoptical cord 10 may have a resin portion in which theoptical fiber 11 is embedded and which extends together with theoptical fiber 11. Such a resin portion is made of, for example, an ultraviolet curable resin. When theoptical cord 10 has such a resin portion, the tensile member may be disposed in the resin portion so as to extend along theoptical fiber 11.
Theelectric cord 20 includes a coveringmember 22 and a plurality ofelectric wires 21. The constituent material of theelectric wire 21 is, for example, copper.
TheWire 21 has a thickness of, for example, 26 to 32 under the AWG (American Wire Gauge) standard. The number of theelectric wires 21 in theelectric cord 20 is, for example, 6.
Thecover 22 surrounds theelectric wire 21 to protect it. Examples of the material constituting the covering 22 include fluororesins such as polyvinyl chloride and tetrafluoroethylene-hexafluoropropylene copolymer.
Thecable sheath 30 covers theoptical cord 10 and theelectrical cord 20 to protect them. Examples of the material of thecable sheath 30 include polyvinyl chloride and polyethylene.
The plug P1 is a transmission-side plug to be connected to a transmission device for video transmission, and includes aconnection portion 41 to which theoptical fiber 11 can be connected, aconnection portion 42 to which theelectric wire 21 can be connected, and anelectrical connector 43 to which an external device can be connected, as shown in fig. 4. Plug P1 further includes aphotoelectric conversion unit 44 for converting an electric signal into an optical signal. That is, the plug P1 has a structure that converts an electric signal into an optical signal.
Theconnection unit 41 is configured to be able to connect theoptical fiber 11 in a form included in theoptical cord 10 or to be able to connect theoptical fiber 11 in a form exposed outside theoptical cord 10.
Theconnection portion 42 is configured to be able to connect theelectric wire 21 included in theelectric cord 20 or configured to be able to connect theelectric wire 21 exposed outside theelectric cord 20. In addition, the connectingportion 42 has the same number ofterminals 42a as theelectric wires 21 of theelectric cord 20. Theterminals 42a correspond one-to-one to theelectric wires 21, and theterminals 42a can be brought into contact with theelectric wires 21.
Theelectrical connector 43 has a plurality of terminals (not shown). In the case where the optical cable laying construction assembly X is used for HDMI transmission, the number of terminals of theelectrical connector 43 is 19. A plurality of signal paths are formed between theelectrical connector 43 and theconnection portion 41, and a plurality of signal paths are formed between theelectrical connector 43 and theconnection portion 42.
Thephotoelectric conversion portion 44 includes the same number oflight emitting elements 44a and drive circuits (not shown) as theoptical fibers 11 of theoptical cord 10. Thelight emitting element 44a is a laser diode such as a Vertical Cavity Surface Emitting Laser (VCSEL), for example. Thelight emitting elements 44a are optically connected to theoptical fibers 11 of theoptical cord 10 one-to-one. In thephotoelectric conversion portion 44, thelight emitting element 44a may be disposed such that the emitted light thereof directly reaches theconnection portion 41, for example. Alternatively, thephotoelectric conversion unit 44 further includes a lens/mirror member (not shown) for bending the optical path by, for example, 90 degrees, and thelight emitting element 44a is disposed so that the light emitted from thelight emitting element 44a reaches theconnection unit 41 via the lens/mirror member.
Plug P1 may also have a single housing. In the case where plug P1 has a single housing, various elements of plug P1 (includingconnection portion 41,connection portion 42,electrical connector 43, and photoelectric conversion portion 44) are assembled in the housing. Alternatively, plug P1 may include a first housing and a second housing, and have a structure in which the first housing and the second housing are flexibly coupled. In this case, the plug P1 has the following structure, for example.
Theconnection portions 41 and 42 are assembled in the first housing. Theelectrical connector 43 and thephotoelectric conversion portion 44 are assembled in the second housing. When theoptical cord 10 is connected to the connectingportion 41 of the first housing, theoptical cord 10 and thephotoelectric conversion portion 44 of the second housing are optically connected by a plurality of flexible light pipes. Specifically, each light guide optically connects theoptical fiber 11 of theoptical cord 10 and thelight emitting element 44a of thephotoelectric conversion portion 44 one to one. The light guide is constituted by an optical fiber, for example. Theconnection portion 42 of the first housing and theelectrical connector 43 of the second housing are electrically connected to each other by a plurality of flexible conductor lines. Specifically, each conductor wire electrically connects theelectric wire 21 of theelectric cord 20 and the terminal of theelectric connector 43 one-to-one. The conductor line is, for example, a copper line.
The plug P2 is a receiving-side plug to be connected to a receiving device for video transmission, and includes aconnection portion 51 connectable to theoptical fiber 11, aconnection portion 52 connectable to theelectric wire 21, and anelectrical connector 53 connectable to an external device, as shown in fig. 5. Plug P2 further includes aphotoelectric conversion unit 54 for converting an optical signal into an electrical signal. That is, the plug P2 has a structure that converts an optical signal into an electrical signal.
Theconnection unit 51 is configured to be able to connect theoptical fiber 11 in a form included in theoptical cord 10 or to be able to connect theoptical fiber 11 in a form exposed outside theoptical cord 10.
Theconnection portion 52 is configured to be able to connect theelectric wire 21 included in theelectric cord 20 or configured to be able to connect theelectric wire 21 exposed outside theelectric cord 20. In addition, the connectingportion 52 has the same number ofterminals 52a as theelectric wires 21 of theelectric cord 20. Theterminals 52a correspond one-to-one to theelectric wires 21, and theterminals 52a can be brought into contact with theelectric wires 21.
Theelectrical connector 53 has a plurality of terminals (not shown). In the case where the optical cable laying construction assembly X is used for HDMI transmission, the number of terminals of theelectrical connector 53 is 19. A plurality of signal paths are formed between theelectrical connector 53 and theconnection portion 51, and a plurality of signal paths are formed between theelectrical connector 53 and theconnection portion 52.
Thephotoelectric conversion unit 54 includes the same number oflight receiving elements 54a and drive circuits (not shown) as theoptical fibers 11 of theoptical cord 10. Thelight receiving elements 54a are optically connected to theoptical fibers 11 of theoptical cord 10 one-to-one. Thelight receiving element 54a is, for example, a photodiode. Examples of the photodiode include a PIN (p-intrinsic-n) type photodiode, an MSM (Metal Semiconductor Metal) photodiode, and an avalanche photodiode. In thephotoelectric conversion portion 54, thelight receiving element 54a may be arranged such that light from theconnection portion 51 is directly incident on thelight receiving element 54a, for example. Alternatively, thephotoelectric conversion unit 54 further includes a lens/mirror member (not shown) for bending the optical path by, for example, 90 degrees, and thelight receiving element 54a is arranged so that the light from theconnection unit 51 is incident on thelight receiving element 54a via the lens/mirror member.
Plug P2 may also have a single housing. In the case where plug P2 has a single housing, various elements of plug P2 (includingconnection portion 51,connection portion 52,electrical connector 53, and photoelectric conversion portion 54) are assembled in the housing. Alternatively, plug P2 may include a third housing and a fourth housing, and have a structure in which the third housing and the fourth housing are flexibly coupled. In this case, the plug P2 has the following structure, for example.
Theconnection portion 51 and theconnection portion 52 are assembled in the third housing. Theelectrical connector 53 and thephotoelectric conversion portion 54 are assembled in the fourth housing. When theoptical cord 10 is connected to the connectingportion 51 of the third housing, theoptical cord 10 and thephotoelectric conversion portion 54 of the fourth housing are optically connected by a plurality of flexible light pipes. Specifically, each light guide optically connects theoptical fiber 11 of theoptical cord 10 and thelight receiving element 54a of thephotoelectric conversion unit 54 one-to-one. The light guide is constituted by an optical fiber, for example. Theconnection portion 52 of the third housing and theelectrical connector 53 of the fourth housing are electrically connected to each other by a plurality of flexible conductor lines. Specifically, each conductor wire electrically connects theelectric wire 21 of theelectric cord 20 and the terminal of theelectric connector 53 one by one. The conductor line is, for example, a copper line.
An optical cable laying construction method according to an embodiment of the present invention is a construction method using an optical cable laying construction kit X, and includes a laying step, a first removal step, a first connection step, a second removal step, and a second connection step.
In the laying step, the optical cable C1 is laid between external devices to be connected via the optical cable C1. After the laying step and before the first removal step and/or the second removal step, which will be described later, the optical fiber cable C1 may be cut by, for example, a cutter as necessary to adjust the length of the optical fiber cable C1 (cutting step). By performing such a cutting step, the surplus of the optical fiber cable C1 after the laying can be suppressed.
In the first removal process, as shown in fig. 6A, thecable sheath 30 is removed at one end of the optical cable C1 so that theoptical fibers 11 and theelectric wires 21 extend outside thecable sheath 30. Theoptical fiber 11 is extended out of thecable sheath 30 in a state of being included in theoptical cord 10 or being exposed out of theoptical cord 10, and theelectric wire 21 is extended out of thecable sheath 30 in a state of being included in theelectric cord 20 or being exposed out of theelectric cord 20. When theoptical fiber 11 is extended out of thecable jacket 30 so as to be exposed out of theoptical cord 10, the covering 12 of theoptical cord 10 is also removed from one end of the optical cable C1 in this step. When theelectric wire 21 is extended out of thecable sheath 30 so as to be exposed out of theelectric cord 20, the coveringmember 22 of theelectric cord 20 is also removed from one end portion of the optical cable C1 in this step. The configuration in which theoptical fiber 11 and theelectric wire 21 extend outside thecable sheath 30 is conceptually shown in fig. 6A. The same applies to the subsequent process drawings.
In the first connection process, as shown in fig. 6B, theoptical fiber 11 extending outside thecable sheath 30 at one end of the optical cable C1 is connected to theconnection part 41 of the plug P1, and theelectric wire 21 extending outside thecable sheath 30 at one end of the optical cable C1 is connected to theconnection part 42 of the plug P1.
In the second removing process, as shown in fig. 7A, thecable sheath 30 is removed at the other end portion of the optical cable C1 so that theoptical fibers 11 and theelectric wires 21 extend outside thecable sheath 30. Theoptical fiber 11 is extended out of thecable sheath 30 in a state of being included in theoptical cord 10 or being exposed out of theoptical cord 10, and theelectric wire 21 is extended out of thecable sheath 30 in a state of being included in theelectric cord 20 or being exposed out of theelectric cord 20. When theoptical fiber 11 is extended out of thecable jacket 30 so as to be exposed out of theoptical cord 10, the covering 12 of theoptical cord 10 is also removed from the other end of the optical cable C1 in this step. When theelectric wire 21 is extended out of thecable sheath 30 so as to be exposed out of theelectric cord 20, the covering 22 of theelectric cord 20 is also removed from the other end of the optical cable C1 in this step.
In the second connection process, as shown in fig. 7B, theoptical fiber 11 extending outside thecable sheath 30 at the other end of the optical cable C1 is connected to theconnection part 51 of the plug P2, and theelectric wire 21 extending outside thecable sheath 30 at the other end of the optical cable C1 is connected to theconnection part 52 of the plug P2.
The first removal step or the second removal step may be performed before the deposition step. In the case where the first removal step is performed before the laying step, the first joining step may be performed before the laying step, and the second removal step and the second joining step after the second removal step are preferably performed after the laying step. In the case where the second removal step is performed before the laying step, the second joining step may be performed before the laying step, and the first removal step and the first joining step after the first removal step are preferably performed after the laying step.
According to such an optical cable laying construction method, in the laying step, the optical cable C1 can be laid between external devices before the plugs P1 and P2 are attached to both ends of the optical cable C1. The optical cable C1 without a plug at the top end can easily pass through narrow spaces such as inside pipes, in walls, and under floors.
Further, according to the method, after the optical cable C1 is laid between external devices and before the plugs P1 and P2 are attached to both ends of the optical cable C1, the optical cable C1 can be cut as necessary to adjust the length of the optical cable C1. Such a method is suitable for suppressing the surplus of the laid optical cable C1.
As described above, according to the present method, it is easy to pass the optical cable C1 through a narrow space in the laying of the optical cable C1 and it is suitable to suppress the surplus of the optical cable C1 after the laying.
As shown in fig. 8, the optical cable installation work module X may further includeoptical connectors 61 and 62 andelectrical connectors 71 and 72 in addition to the optical cable C1 and the plugs P1 and P2. Theoptical connectors 61, 62 are, for example, MT (Mechanical Transfer) connectors.
In the optical cable installation work module X, as shown in fig. 9, the plug P1 is configured as follows: theoptical connector 61 can be connected at itsconnection portion 41, and theoptical fiber 11 in the optical cable C1 and theconnection portion 41 can be optically connected via theoptical connector 61. Meanwhile, plug P1 is configured to: theelectrical connector 71 can be connected at theconnection portion 42 thereof, and theelectric wire 21 in the optical cable C1 and theconnection portion 42 can be electrically connected via theelectrical connector 71. As shown in fig. 10, plug P2 is configured to: anoptical connector 62 can be connected to theconnection portion 51 thereof, and theoptical fiber 11 in the optical cable C1 and theconnection portion 51 can be optically connected via theoptical connector 62. Meanwhile, plug P2 is configured to: theelectrical connector 72 can be connected at theconnection portion 52 thereof, and theelectric wire 21 in the optical cable C1 and theconnection portion 52 can be electrically connected via theelectrical connector 72.
In the case where such an optical cable installation work module X is used in the optical cable installation work method described above, after the first removal step (shown in fig. 9A), in the first connection step, first, as shown in fig. 9B, theoptical fiber 11 exposed to the outside of thecable sheath 30 by the first removal step is connected to theoptical connector 61, and theelectric wire 21 exposed to the outside of thecable sheath 30 by the first removal step is connected to theelectric connector 71. Next, as shown in fig. 9C, theoptical connector 61 is connected to theconnection portion 41 of the plug P1, and theelectrical connector 71 is connected to theconnection portion 42 of the plug P1. After the second removal step (shown in fig. 10A), in the second connection step, first, as shown in fig. 10B, theoptical fiber 11 exposed to the outside of thecable sheath 30 in the second removal step is connected to theoptical connector 62, and theelectric wire 21 exposed to the outside of thecable sheath 30 in the second removal step is connected to theelectrical connector 72. Next, as shown in fig. 10C, theoptical connector 62 is connected to theconnection portion 51 of the plug P2, and theelectrical connector 72 is connected to theconnection portion 52 of the plug P2.
The above-described optical connection via theoptical connectors 61, 62 is suitable for obtaining high connection reliability between theoptical fiber 11 and the plugs P1, P2. The above-described electrical connection via theelectrical connectors 71, 72 is suitable for obtaining high connection reliability between theelectric wire 21 and the plugs P1, P2.
Instead of the optical cable C1, the optical cable installation work module X may include an optical cable C2 having a cross-sectional structure shown in fig. 11. The optical cable C2 is different from the optical cable C1 in that: the optical cable C2 includes an optical cord 10 (including a plurality ofoptical fibers 11 and a covering 12) and acable sheath 30, and the number ofoptical fibers 11 in the optical cable C2 is greater than the number ofoptical fibers 11 in the optical cable C1; and cable C2 does not have anelectrical cord 20. The number ofoptical fibers 11 in the optical cable C2 is, for example, 6.
In such an optical cable installation work module X, theconnection portion 41 of the plug P1 has a structure capable of connecting theoptical fiber 11 of the optical cable C2, and the plug P1 does not have theconnection portion 42. In addition,connection portion 51 of plug P2 has a structure capable of connectingoptical fiber 11 of cable C2, and plug P2 does not haveconnection portion 52.
In the case where such an optical cable installation module X is used in the above-described optical cable installation method, it is not necessary to perform an electric cord connection operation in the first connection step and the second connection step.
Industrial applicability
The optical cable laying construction method can be applied to the construction of optical cables for image transmission such as HDMI transmission. The optical cable laying construction assembly can be used for construction of optical cables for image transmission such as HDMI transmission.
Description of the reference numerals
X: laying a construction component for the optical cable; c1, C2: an optical cable; 10: an optical cord; 11: an optical fiber; 11 a: a core; 11 b: a cladding layer; 11 c: an outer cladding; 20: an electrical cord; 21: an electric wire; 30: a cable jacket; p1, P2: a plug; 41. 42: a connecting portion; 43: an electrical connector; 44: a photoelectric conversion unit; 44 a: a light emitting element; 51. 52: a connecting portion; 53: an electrical connector; 54: a photoelectric conversion unit; 54 a: a light receiving element; 61. 62: an optical connector.