JP2020162014A - Light-emitting device and light-emitting method - Google Patents

Abstract

To provide a light-emitting device and a light-emitting method that cause an OLT side not to make an error or at least to reduce a rate of making an error.SOLUTION: A light-emitting device includes a visible light-emitting unit that emits visible light from a house side to an optical line. The visible light-emitting unit emits from the house side visible light at intensity at which an intensity value of visible light at an optical line terminal side that receives the visible light is equal to or less than an allowable input intensity value at the optical line terminal defined in relation to a wavelength of communication light from the house side.SELECTED DRAWING: Figure 5

Description

The present invention relates to a technique for emitting visible light from the home side to an optical line.

With the spread of optical fibers, the number of optical wirings to each household has increased, but it is an issue to search for the position where the failure occurs when the failure occurs somewhere along the optical wiring path.

Currently, when searching for a failure from inside the house, visible light is emitted inside the house, and on-site workers can visually check it with the wiring inside the house or an outdoor closure without using special equipment. Judgment is being made (Fig. 8). However, if visible light is transmitted from inside the house to search for a failure, the OLT (Optical Line Thermal: optical station device) in the station will recognize an error in the input signal, so it is confirmed that there is a state equivalent to disconnection on the route. Was required in advance, and the failure search was not smooth.

Japanese Unexamined Patent Publication No. 2015-83936

The present invention has been made in view of the above, and an object of the present invention is to provide a light emitting device and a light emitting method that do not cause an error on the OLT side, or at least reduce the rate of causing an error.

According to one aspect of the present invention, a visible light emitting unit that emits visible light to an optical line from the home side is provided, and the visible light emitting unit has a visible light intensity value on the side of an optical station device that receives visible light. Provided is a light emitting device, characterized in that visible light is emitted from the home side with an intensity that is equal to or less than an acceptable input intensity value in an optical station device determined in relation to the wavelength of communication light from the side. ..

In one example, the light emitting device may further include a disconnection determination unit for measuring either the loss of communication light intensity from the device in the optical station or the loss of the optical line, and the visible light emitting unit may be a visible light source. , The intensity adjusting unit for adjusting the output intensity of visible light from the visible light source may be provided, and the output intensity of visible light is increased by the intensity adjusting unit according to at least one of the above losses measured by the disconnection determination unit. It is possible to make it.

In the above example of the light emitting device, when the wavelength of visible light is shorter than the wavelength of communication light from the home side, the output of visible light emitted from the home side is set to be lower than the allowable input intensity value in the optical station device. can do.

According to one aspect of the present invention, in the stage where visible light is emitted from the home side to the optical line, the intensity value of visible light on the device side in the optical station that receives visible light is related to the wavelength of the communication light from the home side. Provided is a light emitting method characterized by comprising a step of emitting visible light from the home side with an intensity such that the intensity is equal to or less than the allowable input intensity value in the optical station device defined as described above.

According to the present invention, it can be applied regardless of the presence or absence of disconnection by using a characteristic range (intensity, etc.) of visible light that does not cause an error on the OLT side, or at least reduces the rate of causing an error. It is possible to search for failures by emitting visible light, and it is possible to smoothly repair the increasing number of optical wiring.

The conceptual diagram which shows the use example of the light emitting device which concerns on one Embodiment of this invention. The figure which shows an example of the place where the failure search can be performed using the light emitting device which concerns on one Embodiment of this invention. The figure which shows an example of the usage mode of the light emitting device at the place shown in FIG. 2 when the failure search is performed using the light emitting device which concerns on one Embodiment of this invention. FIG. 5 is a diagram showing an example different from the mode shown in FIG. 3 in the usage mode of the light emitting device when a failure search is performed using the light emitting device according to the embodiment of the present invention at the place shown in FIG. The functional block diagram which shows the functional structure of the light emitting device which concerns on one Embodiment of this invention. The functional block diagram which shows the modification of the functional structure of the light emitting device which concerns on one Embodiment of this invention. The figure which shows the experimental composition example of the experiment which can be performed in order to determine the permissible input intensity value in the device in an optical station in the failure search using the light emitting device which concerns on one Embodiment of this invention. The figure which shows an example of the place where visible light is transmitted for failure search from the inside of a house.

Hereinafter, a light emitting device and a light emitting method according to an exemplary embodiment of the present invention will be described with reference to the drawings. However, it should be noted that the light emitting device and the light emitting method according to the present invention are not limited to the specific embodiments described below, and can be appropriately changed within the scope of the present invention. For example, the configuration of the light emitting device is not limited to the example shown in FIGS. 5 and 6, and the output adjusting unit, OTDR, power meter, and the like may not be provided. Further, in the following examples, an example in which a visible light source, an output adjusting unit, an OTDR, and a power meter are provided with a control unit and an interface unit is described. However, when an operator performs control by these control units or the like, It is not necessary to use those control units and interface units. Further, in the following, "visible light" may be an electromagnetic wave having an arbitrary wavelength (or wavelength band) in the range of 360 nm to 830 nm (in vacuum) in one example, but the wavelength range of visible light. Is not limited to the range of 360 nm to 830 nm. Further, in the following, the "communication light" may be an electromagnetic wave having an arbitrary wavelength (or wavelength band) in the range of 1000 nm to 1675 nm (in vacuum) in one example, but the wavelength range of the communication light is It does not have to be limited to the range of 1000 nm to 1675 nm, and any electromagnetic wave that can be used for communication can be used as “communication light”.

FIG. 1 is a conceptual diagram showing a usage example of a light emitting device according to an embodiment of the present invention. The light emitting device 1 emits visible light to the optical cable 2 from the home side (either inside or outside the home as shown in FIG. 1), and the visible light leaking from the faulty part of the optical cable is used for on-site work. By visually observing a person (such as visually observing the optical cables 2 and 4 and / or opening the optical closure 3 and visually observing the inside), the faulty part is identified, and repairs, replacements, and other faults are dealt with. At this time, depending on the intensity (power level) of the visible light emitted from the light emitting device 1, the device 6 in the optical station may cause an error recognition of the input signal. Therefore, the intensity of the visible light is increased in order to prevent the error recognition. Be adjusted. The optical fiber transmission line from the optical station device 6 to the house via the optical cable 4 and the optical cable 2 is a pillar 5 such as a wiring pillar (only one pillar is shown in FIG. 1, but two or more pillars). It may be pulled up from the ground or pulled down toward the house as appropriate, or an optical splitter may be arranged in the optical closure and attached to a pillar, and an optical fiber transmission line may be appropriately used. May be branched.

FIG. 2 is a diagram showing an example of a place where a failure search can be performed using the light emitting device according to the embodiment of the present invention. Communication by communication light is performed between the optical network unit (OLT) 6 installed in the station-side building 17 and the optical network unit (ONU: Optical Network Unit) 7 installed in the user's house 9. In one example, the communication light from OLT 6 to ONU 7 (hereinafter, may be referred to as “downward” communication light; the direction from OLT 6 to ONU 7 may be referred to as “downward”) is in the 1490 nm band. Communication light is used, and the communication light from ONU7 to OLT6 (hereinafter, may be referred to as "upward direction" communication light; and the direction from ONU7 to OLT6 may be referred to as "upward direction"). Communication light in the 1310 nm band is used.

A termination rack (IDM: also called an Integrated Distribution Module) 18 is installed in the station side building 17, and the downward communication light from the OLT 6 is an optical splitter 20 in the termination rack 18 and an optical coupler (not shown). ) Etc. to the outside of the station side building 17. The optical filter 19 between the OLT 6 and the optical splitter 20 has a characteristic of blocking the test light from the optical pulse tester (OTDR) described later.

The downward communication light leaving the station side building 17 is transmitted through the optical cable 4, and is used as a pillar 5 (here, a wiring pillar is used. Further, the pulling pillar and the pulling pillar are not shown and the description is omitted). It is branched by the optical splitter 14 in the optical closure 3 installed in the. Of the branched communication light, the communication light passing through the optical cable 2 drawn down to the user's house 9 is transmitted into the house via the optical cabinet 13 and received by the ONU 7 through the optical cable 11 connected to the optical rosette 12. .. On the other hand, the upward communication light emitted from the ONU 7 is transmitted in the same direction as the downward communication light from the OLT 6 to the ONU 7 in the opposite direction and is received by the OLT 6. In addition, connectors are appropriately used for connection such as connection between different optical cables and connection between parts or devices and optical cables (in FIG. 2, connectors 8B, 10A, 10B, 15A, 15B, 16A, 16B). Etc.. See also connector 21B in FIG. 3, connectors 8B and 21B in FIG. 4, connectors 21A-1 to 21A-3 in FIG. 5, connector 21A in FIG. 6 and the like).

FIG. 3 is a diagram showing an example of a usage mode of the light emitting device when a failure search is performed using the light emitting device according to the embodiment of the present invention at the place shown in FIG. In the configuration of FIG. 2, the ONU 7 is connected to the optical rosette 12 via the optical cable 11, but when searching for a failure, the ONU 7 is removed and the light emitting device 1 is connected instead. However, FIG. 3 shows an example of the connection location of the light emitting device 1, and can be placed at any position in any manner as long as it can emit visible light to the optical cable or the like that is the target of failure search. The light emitting device 1 may be arranged. In the configuration of FIG. 3, visible light is emitted from the light emitting device 1, and the visible light passes through the optical cable 11, the optical cable 2, and the like and heads for the OLT 6 in the same route as the communication light in the upward direction. At this time, it is visible because the optical cables (optical cable 11, optical cable 2, optical cable 4, etc.) in the middle are damaged (the damage may correspond to the disconnection, or the damage may be lighter than the disconnection). If the light is emitted from the damaged part to the outside, the field worker can easily identify the damaged part by visually observing the damaged part.

FIG. 4 is a diagram showing an example different from the mode shown in FIG. 3 in the usage mode of the light emitting device when a failure search is performed using the light emitting device according to the embodiment of the present invention at the location shown in FIG. .. The optical cable 11 is connected to the optical splitter 22, and the optical cable 23 of the optical cables branched by the optical splitter 22 is connected to the light emitting device 1 using the connector 21B, and the optical cable of the optical cables branched by the optical splitter 22 is used. 24 is connected to the ONU 7 using the connector 8B. With this connection, it is possible to search for a failure using the light emitting device 1 without stopping the optical communication between the OLT 6 and the ONU 7.

Configuration of the light emitting device FIG. 5 is a functional block diagram showing a functional configuration of the light emitting device according to the embodiment of the present invention. The light emitting device 1 includes a visible light source 29, an output adjusting unit 30, an optical pulse tester (OTDR: Optical Time Domain Reflectometer) 31, and a power meter 32. The visible light emitted from the visible light source 29 is transmitted from the connector 21A-1 via the optical cable 25, the output adjusting unit 30, and the optical cable 26, and the test optical pulse emitted from the OTDR 31 is transmitted from the connector 21A-2 via the optical cable 27. It is sent out, and the communication light that enters from the connector 21A-3 and passes through the optical cable 28 enters the power meter 32.

The visible light source 29 is a light source device that generates visible light by a laser diode or the like, and outputs visible light having a wavelength of about 650 nm. The visible light source 29 includes a control unit (including a CPU, a memory for storing a program, etc.) and an interface unit (including an input key, a display, other data input / output units, etc.), and responds to an external input command. It emits visible light and sends it out to the optical cable 25.

The output adjusting unit 30 is a device that adjusts the intensity of light by a variable optical attenuator (VOA: Variable Optical Attenator), an optical amplifier (for example, a semiconductor optical amplifier, SOA: Semiconductor Optical Amplifier), or the like, and is emitted from a visible light source 29. The intensity of visible light is adjusted and sent to the optical cable 26. The output adjustment unit 30 includes a control unit (including a CPU, a memory for storing a program, etc.) and an interface unit (including an input key, a display, other data input / output units, etc.), and can be used for input commands from the outside. Accordingly, the intensity of visible light entering from the optical cable 25 is adjusted and sent to the optical cable 26.

The OTDR31 is an optical pulse tester that generates an optical pulse (eg, has a wavelength in the 1550 nm band or 1650 nm band) and sends it out to the optical cable 27, and scatters it at either the position of the optical cable 27 or the optical path beyond it. , The reflected light is received and measured (measurement of loss of optical line), and the presence or absence of disconnection, position, etc. that occur in the optical path by calculation of waveform data or the like are evaluated. The OTDR 31 includes a control unit (including a CPU, a memory for storing a program, etc.) and an interface unit (including an input key, a display, other data input / output units, etc.), and responds to an external input command. Inspect for disconnection using the above optical pulse. The OTDR is provided with an optical filter that blocks light having a wavelength of communication light between the OLT 6 and the ONU 7 (here, the downlink direction is the 1490 nm band and the uplink direction is the 1310 nm band). The downlink and uplink communication lights are prevented from entering the OTDR.

The power meter 32 is a device (optical power meter) that receives light and measures the intensity of the received light by a sensor or the like using a photodiode or the like, and here, receives the communication light in the downward direction from the OLT 6. The intensity (for example, the light receiving level) is measured (measurement of loss of communication light intensity). The power meter 32 includes a control unit (including a CPU, a memory for storing a program, etc.) and an interface unit (including an input key, a display, other data input / output units, etc.), and responds to an external input command. Then, the light intensity is measured.

The visible light source 29, the OTDR 31, and the power meter 32 are configured to be able to communicate with each other by wire (not shown) or wirelessly (communication circuit, etc. are not shown), and there is no disconnection in the optical path due to measurement, calculation, etc. by the OTDR 31. A disconnection determination signal (which may be a signal indicating the loss of the optical line measured by the OTDR 31) indicating the result of the evaluation is transmitted from the OTDR 31 to the visible light source 29, and the light is measured by the power meter 32 or the like. As a result of evaluating the presence or absence of disconnection in the path (in one example, the control unit of the power meter 32 calculates using the measurement result of the light receiving level, and the disconnection occurs when the light receiving level is below a predetermined threshold. A disconnection determination signal (which may be a signal indicating a loss of communication light intensity measured by the power meter 32) indicating (determined to be) is transmitted from the power meter 32 to the visible light source 29. The control unit of the visible light source 29 determines the presence or absence of disconnection from the received disconnection determination signal, and transmits a signal indicating the presence or absence of disconnection to the control unit of the output adjustment unit 30. The control unit of the output adjusting unit 30 determines how to adjust the intensity of visible light emitted from the visible light source 29 according to the presence or absence of disconnection indicated by the signal received from the visible light source 29. In one example, the control unit of the output adjusting unit 30 is visible depending on at least one of the loss of the optical line indicated by the disconnection determination signal from the OTDR 31 and the loss of the communication light intensity indicated by the disconnection determination signal from the power meter 32. Control is performed to increase the output intensity of light.

Although the connectors 21A-1, 21, 21A-2, and 21A-3 are provided separately in the configuration of FIG. 5, as shown in FIG. 6, these connectors may be substituted by one connector 21A. In the configuration of FIG. 6, an optical coupler 33 having four ports, A port, B port, C port, and D port, is provided, an optical cable 26 is connected to the A port, and an optical cable 34 is connected to the B port. Is connected, the optical cable 27 is connected to the C port, and the optical cable 28 is connected to the D port. The space between the A port and the B port has a wavelength characteristic that the visible light emitted from the visible light source 29 and transmitted from the output adjusting unit 30 is transmitted, and the space between the B port and the C port is from the OTDR 31. It has a wavelength characteristic that the light pulse (for testing) of the above is transmitted, and has a wavelength characteristic that the downlink communication light emitted from the OLT 6 is transmitted between the B port and the D port (patented). See the optical coupler 11 shown in FIG. 3 of Document 1 and the description in paragraph [0044] of Patent Document 1). When the optical coupler 33 is used in this way, the visible light emitted from the visible light source 29 is transmitted from the light emitting device 1, the optical pulse emitted from the OTDR 31 is transmitted from the light emitting device 1, and the communication light emitted from the OLT 6 is transmitted. The reception to the light emitting device 1 can be performed using the common connector 21A, and the replacement of the optical cable and the connector to the light emitting device 1 can be omitted.

Operation of the light emitting device Next, as an example of the operation of the light emitting device, a failure search using the light emitting device 1 shown in FIG. 5 will be described. Here, an example in which the light emitting device 1 is used in a state where the ONU 7 is connected to the optical cable 24 and communication between the OLT 6 and the ONU 7 is performed as shown in FIG. 4 will be described. However, as shown in FIG. 3, the ONU 7 is used. Even when the light emitting device 1 is used after being removed, the light emitting device 1 can operate in the same manner. The configuration of the light emitting device 1 to be used will be described as the configuration shown in FIG. 5, but even when the light emitting device 1 having the configuration shown in FIG. 6 is used, it is not necessary to replace the optical cable and the connector. The light emitting device 1 can operate in the same manner.

As shown in FIG. 4, the light emitting device 1 is connected to the optical cable 23. First, the connector 21A-2 or the connector 21A-3 of the light emitting device 1 of FIG. 5 is connected to the connector 21B in FIG.

Here, it is assumed that the connector 21A-2 is first connected to the connector 21B (the operator may manually perform the connector 21A-2 or the connector 21A-2 may be automatically connected by some device. The same applies to the connection.) In response to an operator's key input from the interface section of the OTDR31, the OTDR31 sends an optical pulse to the optical cable 27, and is scattered and reflected at any position of the optical cable 27 or the optical path beyond it, and the OTDR31 The optical power (or optical power level) is measured by receiving the light returned to the OTDR31 (measurement of the loss of the optical line), and the control unit of the OTDR31 calculates using the waveform data obtained by the measurement. The control unit determines the presence / absence, position, etc. of the disconnection that occurs in the optical path (the presence / absence, position, etc. of the disconnection by the OTDR 31 may be determined by the same principle as the known OTDR operation, or different from that. It may be done by any principle.) A disconnection determination signal indicating the result of the OTDR 31 evaluating (determining) the presence or absence of disconnection in the optical path (a signal indicating the disconnection position in addition to the presence or absence of disconnection may be used. In particular, in FIG. 4, the optical cable 11, Alternatively, the disconnection determination signal may indicate that there is a disconnection only when it is determined that the optical path on the OLT6 side of the optical cable 11 has a disconnection.) Is transmitted from the OTDR 31 to the visible light source 29. Will be done.

Next, the connector 21A-3 is connected to the connector 21B. In response to an operator's key input from the interface unit of the power meter 32, the power meter 32 measures (detects) the received level of communication light emitted from the OLT 6 and entering the power meter 32 through the optical cable 28. (Measurement of communication light intensity loss from optical station equipment). When the measured light receiving level is equal to or less than a predetermined threshold value (when the loss of communication light intensity from the optical station device is equal to or more than a certain magnitude), the control unit of the power meter 32 starts from the OLT6. It is determined that the optical line up to the power meter 32 has a disconnection. When the measured light receiving level exceeds a predetermined threshold value (when the loss of communication light intensity from the optical station device is less than a certain magnitude), the control unit of the power meter 32 starts from OLT6. It is determined that there is no disconnection in the optical line up to the power meter 32. In particular, if the measurement is performed by the power meter 32 after confirming that the optical splitter 22, the optical cable 23, and the optical cable 28 are not broken, the light on the OLT 6 side of the optical cable 11 or the optical cable 11 is measured by the power meter 32. It is possible to determine the presence or absence of disconnection in the route. A disconnection determination signal indicating the result of the power meter 32 evaluating (determining) the presence or absence of disconnection in the optical path is transmitted from the power meter 32 to the visible light source 29.

Next, the connector 21A-1 is connected to the connector 21B. The control unit of the visible light source 29 determines whether or not there is a disconnection in the optical path by using at least one of the disconnection determination signal received from the OTDR 31 and the disconnection determination signal received from the power meter 32. The control unit of the visible light source 29 may determine that there is a disconnection in the optical path only when both the disconnection determination signal received from the OTDR 31 and the disconnection determination signal received from the power meter 32 indicate the presence of the disconnection. However, if at least one of the disconnection determination signal received from the OTDR 31 and the disconnection determination signal received from the power meter 32 indicates the presence of a disconnection, it may be determined that there is a disconnection in the optical path, or the wire is received from the OTDR 31. Only one of the disconnection determination signal and the disconnection determination signal received from the power meter 32 may be used for the determination, and when the disconnection determination signal used indicates the existence of the disconnection, it may be determined that the optical path has a disconnection. When the control unit of the visible light source 29 uses only one of the disconnection determination signal received from the OTDR 31 and the disconnection determination signal received from the power meter 32 for determination, the disconnection determination signal that is not used for the determination is unnecessary. Therefore, the measurement itself for generating the disconnection determination signal that is not used may be omitted. Further, the control unit of the visible light source 29 can perform the subsequent operation on the assumption that the disconnection does not exist without using the disconnection determination signal at all. In this case, the OTDR 31 or the power meter 32 is not used. The light emitting device 1 may be configured.

The control unit of the visible light source 29 determines the presence or absence of disconnection as described above, and transmits a signal indicating the presence or absence of disconnection to the control unit of the output adjustment unit 30. The control unit of the output adjusting unit 30 determines how to adjust the intensity of visible light emitted from the visible light source 29 according to the presence or absence of disconnection indicated by the signal received from the visible light source 29. When the signal received from the visible light source 29 indicates that there is a disconnection, the control unit of the output adjusting unit 30 determines that there is no problem even if the intensity of the visible light emitted from the light emitting device 1 is relatively high. In one example, the intensity of visible light emitted from the visible light source 29 and sent to the output adjusting unit 30 is not adjusted at all, or the visible light is amplified by an optical amplifier from the optical cable 26 to the outside of the light emitting device 1. Send out. When the signal received from the visible light source 29 indicates that there is no disconnection, the control unit of the output adjusting unit 30 determines that the intensity of visible light emitted from the light emitting device 1 should be relatively low. In one example, the intensity of visible light emitted from the visible light source 29 and sent to the output adjusting unit 30 is attenuated by a variable light attenuator and sent out from the optical cable 26 to the outside of the light emitting device 1.

The output adjustment unit 30 is not provided with a control unit, and the operator manually switches the connection between the variable optical attenuator, the optical amplifier, etc. of the output adjustment unit 30 and the optical cables 25, 26, etc., so that the output adjustment unit 30 operates. It is also possible to control. In this case, the operator visually confirms the presence or absence of the disconnection (for example, by checking the message regarding the presence or absence of the disconnection displayed on the display unit of any of the visible light source 29, the OTDR 31, and the power meter 32), and the disconnection occurs. If there is, the optical cables 25 and 26 may be connected to the optical amplifier, or the optical cables 25 and 26 may be directly connected. If there is no disconnection, the optical cables 25 and 26 may be connected to the variable light attenuation of the output adjusting unit 30. Visible light may be attenuated to the desired intensity by connecting to a device and operating a variable optical attenuator.

Visible light emitted from the light emitting device 1 through the optical cable 26 travels toward the OLT 6 side in FIG. 4 through the optical cable 23, the optical cable 11, the optical cable 2, and the optical cable 4, but the optical lines are damaged (disconnection level). Visible light may leak from the damaged area if there is a large damage or a minor damage that is smaller than that. The operator can identify the damaged part by looking at the leaked visible light.

Method for Determining Visible Light Intensity A specific method for determining the intensity of visible light emitted from the light emitting device 1 will be described below. When the visible light emitted from the light emitting device 1 reaches the OLT 6, depending on the magnitude of the visible light intensity at the position of the OLT 6, there is a risk of causing an error in the recognition of the signal output from the ONU 7 and input to the OLT 6 by the OLT 6. is there. Therefore, from the light emitting device 1 so that the visible light reaches the OLT 6 at an intensity equal to or less than the intensity value (acceptable input intensity value in the OLT 6) that does not cause such an error or at least is unlikely to occur. It is desirable to adjust the intensity of visible light emitted.

（１）
と換算すればよい。 Determining from the specifications of the communication optical wavelength Since the permissible input intensity value in OLT6 can change depending on the extent to which error recognition by OLT6 is allowed or not at all, there are various determination methods. Is. In one example, it may be calculated from the specification value (optical input limit) of the OLT 6 to be used in the wavelength (or wavelength band) of the communication light in the upward direction from the ONU 7. It is assumed that the specification value of the optical input limit of the OLT 6 is A1 (dBm) when the communication light in the upstream direction from the ONU 7 is in the 1310 nm band (A1 is a real number and may be positive, negative, or zero). In one example, this A1 (dBm) can be used as an acceptable input intensity value in OLT6. Here, in FIG. 4, the loss of visible light intensity that occurs from the light emitting device 1 to the OLT 6 is determined in advance by a measurement experiment in which visible light is experimentally sent from the light source 1 to the OLT 6, or a cable or the like. B1 (dBm) is determined and expressed by theoretically determining from the specifications of individual parts such as connectors (B1 is a real number of zero or more), and the visible light intensity (light emitting device) emitted from the light emitting device 1. The visible light intensity can be adjusted by the output adjusting unit 30 (or the visible light source 29 without using the output adjusting unit 30) so that the visible light intensity at the time of exiting 1 is (A1 + B1) (dBm) or less. The visible light output intensity of (A1 + B1) (dBm) or less may be set in advance). However, even if B1 is intentionally set to zero and it is assumed that there is no loss of visible light intensity between the light emitting device 1 and OLT6, the input intensity value at the position of OLT6 is A1 (dBm) or less. As such, visible light may be emitted from the light emitting device 1 at an intensity of A1 (dBm) or less. Here, dBm is decibel milliwatt, which is a unit representing strength (power level). When the power P (mW) expressed in milliwatt units is expressed as the power level A (dBm),

(1)
It can be converted to.

Here, when the visible light wavelength emitted from the light emitting device 1 is shorter than the wavelength of the communication light in the upward direction from the ONU 7, attention is paid to the difference in the mode field diameter due to the wavelength, and the above A1 (dBm) is used. The intensity of visible light emitted from the light emitting device 1 may be determined using C1 (dBm) obtained by the above calculation (C1 is a real number and may be positive, negative, or zero).

（２）
と表される（左辺の２ｗがモードフィールド径）。ここで、Ｆ²（ｑ）は出射端からの光出力（遠視野像、ＦＦＰ：Ｆａｒ Ｆｉｅｌｄ Ｐａｔｔｅｒｎ）の角度分布で、ｑ＝（１／λ）・ｓｉｎθであり、θはファイバ軸からの角度であり、λは波長である。 The mode field diameter (MFD: Mode Field Diameter) is an amount defined by the Telecommunications Standardization Division (ITU-T) of the International Telecommunication Union (ITU-T: International Telecommunications Standardization Sector).

(2)
(2w on the left side is the mode field diameter). Here, F ² (q) is the angle distribution of the light output (far field image, FFP: Far Field Pattern) from the emission end, q = (1 / λ) · sin θ, and θ is the angle from the fiber axis. And λ is the wavelength.

According to the above notation of the mode field diameter, it is possible to evaluate that the mode field diameter is substantially proportional to the wavelength on the assumption that the angular distribution of the light output from the emission end is substantially constant. In this case, it can be evaluated that the mode field diameter in visible light having a wavelength of about 650 nm is approximately (650/1310) times the mode field diameter in communication light having a wavelength in the 1310 nm band, that is, about 0. It can be evaluated to be about 5.5 times.

In view of the above, it is assumed that the size of the mode field diameter of the visible light emitted from the light emitting device 1 is 0.5 times the size of the mode field diameter of the upstream communication light transmitted from the ONU 7 to the OLT 6. Furthermore, assuming that the power of visible light entering OLT6 and the power of upward communication light entering OLT6 are equal, the power density of visible light entering OLT6 (vertical to the traveling direction of visible light at the position of OLT6). The power of visible light entering the OLT 6 per unit area in the cross section is the power density of the upstream communication light entering the OLT 6 (at the position of the OLT 6 and perpendicular to the traveling direction of the upward communication light). It can be evaluated that it is approximately four times the power of the communication light in the upstream direction entering the OLT 6 per unit area in the cross section. That is, in the above assumption, even if visible light enters the OLT 6 with the same power as the communication light in the upward direction, the power density of the visible light at the position of the OLT 6 in that case is approximately the power density of the communication light in the upward direction. It can be evaluated that it is quadrupled, and it is interpreted that sending visible light to OLT6 poses a greater risk of error recognition than sending test light of the same wavelength as the communication light in the upstream direction. be able to. In view of this, it is preferable that the intensity when transmitting visible light to the OLT 6 is determined by using a value smaller than A1 (dBm), which is a specification value of the optical input limit of the OLT 6 with respect to the communication light in the upward direction. .. In one example, as described above, the power density of visible light at the position of OLT 6 is acceptable in view of the fact that it can be evaluated that the power density of visible light is approximately four times the power density of communication light in the upward direction under certain assumptions. It is conceivable to set the maximum value E1 (mW) to be one-fourth of the input limit value E2 (mW) of the power of the upstream communication light at the position of OLT6 (E1 and E2 are real numbers of zero or more). ..

（３）
となる。ここで、電力（ｍＷ）の値であるＥ１，Ｅ２を既に説明した電力レベル（ｄＢｍ）で表示すれば、Ｅ１の電力レベル表示をＣ１として、Ｅ２の電力レベル表示をＡ１とみなして、

（４）
となり、これを変形して

（５）
が得られる。 In this case, if the relationship between E1 and E2 is expressed by an equation

(3)
Will be. Here, if E1 and E2, which are the values of electric power (mW), are displayed at the electric power level (dBm) already described, the electric power level display of E1 is regarded as C1 and the electric power level display of E2 is regarded as A1.

(4)
And transform this

(5)
Is obtained.

（６）
で与えられる電力レベル調整値Ｄ１（ｄＢｍ）に応じて決定することが可能である（Ｃ１＝Ａ１＋Ｄ１としてもよいし、端数を切り上げ、切り捨て、四捨五入する等、適宜調整することにより、Ｄ１に基づきＣ１を決定してもよい。）。 In view of the above, when the communication light in the upstream direction from the ONU 7 is in the 1310 nm band and the specification value of the optical input limit of the OLT 6 given to the communication light wavelength is A1 (dBm), this using A1 above formula (5) are shown as C1 = A1-10log ₁₀ 4 C1 to be calculated as (C1 is generally about 6dBm small compared to A1.), when transmitting the visible light from the light emitting device 1 Can be used as the output intensity value from the light emitting device 1. In other words, paying attention to the fact that the wavelength-dependent concentration of visible light in the optical line is higher than the wavelength-dependent concentration of upstream communication light in the optical line, the optical input limit of OLT. The visible light output intensity value from the light emitting device 1 can be determined by using C1 in which the specification value A1 of the above is lowered according to the increase. In particular, for C1, when the wavelength of visible light is λ1 (nm) and the wavelength of upstream communication light is λ2 (nm),

(6)
It is possible to determine according to the power level adjustment value D1 (dBm) given in (C1 = A1 + D1 may be used, or C1 based on D1 by appropriately adjusting such as rounding up, rounding down, and rounding off. May be determined.).

As described above, the loss of visible light intensity that occurs from the light emitting device 1 to the OLT 6 in the system that actually searches for a failure (for example, the system having the configuration shown in FIG. 4) is previously determined from the light emitting device 1 to the visible light (mode). It is preferable to use visible light with the same wavelength as the visible light used to calculate the field diameter.) Determined by a measurement experiment in which the visible light is sent to OLT6 on a trial basis, or from the specifications of individual parts such as cables and connectors. By theoretically determining, it is determined and expressed as B1 (dBm) (B1 is a real number of zero or more), and the visible light intensity emitted from the light emitting device 1 (visible light intensity at the time of leaving the light emitting device 1). The visible light intensity can be adjusted by the output adjusting unit 30 so that is (C1 + B1) (dBm) or less (or the visible light output intensity of the visible light source 29 is adjusted in advance (C1 + B1) without using the output adjusting unit 30. (DBm) or less). However, even if B1 is intentionally set to zero and it is assumed that there is no loss of visible light intensity between the light emitting device 1 and OLT6, the input intensity value at the position of OLT6 is C1 (dBm) or less. As such, visible light may be emitted from the light emitting device 1 at an intensity of C1 (dBm) or less. Further, C1 (dBm) determined by theoretical calculation can change depending on the visible light wavelength, but in order to simplify control, the visible light intensity emitted from the light emitting device 1 is set to a certain visible light regardless of the visible light wavelength. Using C1 (dBm) determined from the theoretical calculation at the wavelength, it may be set to (C1 + B1) (dBm) or less (in this case, B1 may be intentionally set to zero).

Experimental determination The acceptable input intensity value in OLT 6 may be determined experimentally using the measurement configuration as shown in FIG. 7 in one example. Prepare the measurement system shown in FIG. 7, and in FIG. 7, "1" (number 1 in the circle), "2" (number 2 in the circle), "3" (inside the circle) While transmitting visible light from any of the numbers 3), an upward signal (B-PON-OLT or GE-PON-OLT) is transmitted from the ONU (B-ONU or GE-ONU) to the OLT (B-PON-OLT or GE-PON-OLT). Communication light having a wavelength of communication light in the upstream direction when performing a failure search) is transmitted, and the bit error rate at the receiving side OLT of the signal is measured by a network tester. Visible light power level (dBm) in front of OLT and (upward from ONU) at OLT (B-PON-OLT or GE-PON-OLT) when OLT is receiving visible light at the visible light power level. By measuring and recording the packet loss occurrence rate (related to the communication light in the direction), the correspondence between the visible light power level (dBm) before the OLT and the packet loss occurrence rate at the visible light wavelength used in the experiment is experimentally measured. Can be decided. Visible light in front of the OLT such that the packet loss occurrence rate is less than or equal to the predetermined allowable value (the packet loss occurrence rate is zero if no packet loss is allowed) based on the correspondence determined in this way. The power level (dBm) can be an "acceptable input intensity value in the OLT" (determined in relation to the wavelength of the upbound communication light from the ONU to the OLT). Let A2 (dBm) be the "acceptable input intensity value in OLT" obtained by the experiment in this way (A2 is a real number and may be positive, negative, or zero). As already described, in a system that actually searches for a failure (for example, a system having the configuration shown in FIG. 4), the light emitting device 1 reaches OLT 6 (preferably, it is the same type of OLT as the OLT used in the experiment). The loss of visible light intensity that occurs up to this point is determined by a measurement experiment in which visible light (preferably visible light having the same wavelength as the visible light used in the experiment) is experimentally sent from the light emitting device 1 to OLT6. It is determined to be B1 (dBm) by theoretically determining from the specifications of individual parts such as cables and connectors (B1 is a real number of zero or more), and is emitted from the light emitting device 1. The visible light intensity can be adjusted by the output adjusting unit 30 (or using the output adjusting unit 30) so that the visible light intensity (visible light intensity at the time of leaving the light emitting device 1) is (A2 + B1) (dBm) or less. Instead, the visible light output intensity of the visible light source 29 may be set to (A2 + B1) (dBm) or less in advance). However, even if B1 is intentionally set to zero and it is assumed that there is no loss of visible light intensity between the light emitting device 1 and OLT6, the input intensity value at the position of OLT6 is A2 (dBm) or less. As such, visible light may be emitted from the light emitting device 1 at an intensity of A2 (dBm) or less. Further, A2 (dBm) determined from the experiment can change depending on the visible light wavelength, but in order to simplify the control, the visible light intensity emitted from the light emitting device 1 is set to a certain visible light wavelength regardless of the visible light wavelength. A2 (dBm) determined from the experiment in (A2 + B1) (dBm) or less may be used (B1 may be intentionally set to zero in this case as well).

The present invention is available in all industries related to telecommunications.

1 Light emitting device 2 Optical cable 3 Optical closure 4 Optical cable 5 pillars (wiring pillars, etc.)
6 Optical station equipment (OLT)
7 Optical network unit (ONU)
8A, 8B connector 9 User's house 10A, 10B Connector 11 Optical cable 12 Optical rosette 13 Optical cabinet 14 Optical splitter 15A, 15B Connector 16A, 16B Connector 17 Station side building 18 Termination rack 19 Optical filter 20 Optical splitter 21A, 21A-1, 21A-2, 21A-3, 21B
Connector 22 Optical splitter 23 Optical cable 24 Optical cable 25-28 Optical cable 29 Visible light source 30 Output adjuster 31 Optical pulse tester (OTDR)
32 Power meter 33 Optical coupler 34 Optical cable 81 Termination device 82 Home optical wiring cord 83 Optical outlets (optical rosette) (optical outlet)
84 Cover grip type termination "SC"-"LC"
85 0.5mm SM type indoor optical fiber "R15"
86 Outdoor small cabinet 87 0.5mm SM type IF drop optical fiber "R15"
88 AO closure

Claims (4)

It is equipped with a visible light emitting unit that emits visible light from the home side to the optical line.
In the visible light emitting unit, an acceptable input in the optical station device in which the intensity value of the visible light on the optical station device side that receives the visible light is determined in relation to the wavelength of communication light from the home side. A light emitting device, characterized in that visible light is emitted from the home side with an intensity that is equal to or less than an intensity value. The light emitting device further includes a disconnection determination unit for measuring either the loss of communication light intensity from the device in the optical station or the loss of the optical line.
The visible light emitting unit includes a visible light source and an intensity adjusting unit for adjusting the output intensity of visible light from the visible light source.
The light emitting device according to claim 1, wherein the output intensity of the visible light is increased by the intensity adjusting unit according to at least one of the losses measured by the disconnection determining unit. When the wavelength of the visible light is shorter than the wavelength of the communication light from the home side, the output of the visible light emitted from the home side shall be lower than the allowable input intensity value in the optical station device. The light emitting device according to claim 1 or 2. At the stage where visible light is emitted from the home side to the optical line, the intensity value of the visible light on the device side in the optical station that receives the visible light is determined in relation to the wavelength of the communication light from the home side. A light emitting method comprising a step of emitting the visible light from the home side with an intensity so as to be equal to or less than an acceptable input intensity value in the optical station device.

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