JP2009053608A - Optical transmission module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical transmission module that can materialize output/stop of a signal light through attaching/detaching of an optical connector even by using a general purpose optical connector, that can prevent malfunction due to electrostatic discharge, and that can detect the attaching/detaching frequency of the optical connector. <P>SOLUTION: The optical transmission module is mounted with a receptacle 13 in which an optical connector 12 attached to an optical fiber is inserted and with a signal control circuit part 21 which contains an optical device 31 for transmitting/receiving optical signals with the optical fiber. The receptacle 13 is provided with a pair of electrode pads 17a, 17b that are short-circuited by a conduction piece 15 attached to the optical connector 12, wherein the pair of electrode pads are connected to a connector circuit part 20 that is made an open circuit or a closed circuit by the attaching/detaching of the optical connector. Then, the signal control circuit part 21 is equipped with control means (29, 30) that control operation of the optical device 31 by the open circuit or the closed circuit of the connector circuit part 20, and is electrically insulated from the connector circuit part 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical transmission module that transmits and receives optical signals to and from an external device via an optical connector attached to an end of an optical fiber.

  In an optical transmission module (optical transmission module, optical reception module, optical transmission / reception module) used in a high-speed and large-capacity optical communication system, a laser beam from a high-power laser diode (LD) is generally used as a light source for the signal light. in use. The optical transmission module includes a receptacle that detachably accommodates an optical connector for connection to an optical fiber that is an optical transmission path. In an optical communication system using this optical transmission module, an optical fiber cable connection operation or the like may be performed in an operation state in which the communication device is powered on. In this case, in a state where the optical connector is not connected to the receptacle, the laser light as the signal light source is emitted from the receptacle to the outside. Depending on the arrangement of the optical transmission module and the posture of the operator, the laser light may be emitted from the human skin. There is a risk of damage from exposure to eyes and eyes.

For this reason, there is a method of closing the receptacle with a lid when the optical connector is not inserted into the receptacle. However, if the lid is not completely closed due to foreign matter being caught in the lid, the laser beam is not May leak.
Therefore, a pair of terminals are provided on the receptacle side, and a conductive connecting piece provided on the optical connector side short-circuits the terminals to electrically detect whether the optical connector is connected to the receptacle, A system that stops the output of laser light from an optical transmission module when a connector is removed has been proposed (for example, Patent Document 1).

  FIG. 3 is a diagram for explaining the outline of the optical transmission module disclosed in Patent Document 1. In FIG. 3A, reference numeral 1 denotes a receptacle having a pair of sliding contact terminals 4a and 4b, which are connected to terminals 2 and 3, respectively. One terminal 2 is grounded, and the other terminal 3 is connected to one end of the pull-up resistor 5 and the input side of the inverter 6. The other end of the pull-up resistor 5 is connected to a positive power source (not shown) so that a predetermined potential is applied to the terminal 3. The output side of the inverter 6 is connected to the light output means 7 of the light transmission module.

  FIG. 3B shows an outline of the receptacle 1, and the pair of sliding contact terminals 4a and 4b are arranged in a receptacle housing 1a having a slit 1b for guiding insertion of an optical plug 8 (optical connector). It is installed. FIG. 3C shows an outline of the optical plug 8. The optical plug 8 is attached to the end of the optical fiber cable 10, and is attached to the outer surface of the plug housing 8 a having a projection 8 b that guides the insertion into the receptacle 1 and performs positioning. A character-shaped sliding contact terminal 9 is embedded.

  When the optical plug 8 is inserted into the receptacle 1 with the above-described configuration, the sliding contact terminal 9 is simultaneously slidably contacted with the pair of sliding contact terminals 4a and 4b, and the two are electrically short-circuited. As a result, the terminal 3 is dropped to the ground potential via the sliding contact terminal 9 and the terminal 2 and is forced to the L (low) level. As a result, the output of the inverter 6 changes to the H (high) level, the optical output means of the optical module 7 is driven, and the optical signal can be set in the output state.

  On the other hand, it is assumed that the operator performs an operation of extracting (removing) the optical plug 8 from the receptacle 1 in the output state of the optical signal. When the optical plug 8 is pulled out from the receptacle 1 to some extent, the sliding contact terminals 9 are separated from the pair of sliding contact terminals 4a and 4b, thereby disconnecting the electrical connection between the sliding contact terminals 4a and 4b. At this time, since the terminal 3 is not grounded, it is raised to a predetermined potential by the power source connected to the pull-up resistor 5. As a result, the input side of the inverter 6 becomes H level, the output of the inverter 6 changes to L level, the drive of the optical output means of the optical module 7 is stopped, and the output of the optical signal can be stopped. .

As a result, even when the operator pulls out the optical plug 8 from the receptacle 1 without stopping the light output, the light output is stopped at that time, so that the operator's body or eyes may be exposed to the laser light. It is said that it can be avoided.
JP 2000-180663 A

  Since the technology disclosed in the above-mentioned document 1 has a configuration in which the sliding contact terminal is embedded in the optical connector in advance, it cannot cope with an existing communication device using a general-purpose optical connector. For this reason, it is necessary for the user to introduce a new system including a change of an existing apparatus, which is not easy to install and is expensive.

  Also, when a person with static electricity touches the optical connector when removing (or inserting) the optical connector from the receptacle of the optical transmission module, the static electricity charged on the human body passes through the optical connector to the metal of the optical transmission module. Discharged to parts and circuit conductors. This phenomenon is called electrostatic discharge (ESD) and causes a malfunction in the signal control circuit including the optical element of the optical transmission module. Further, a latch-type LC connector is usually used as the optical connector, but there is also a problem that the latch part is easily damaged when the number of attachments / detachments is exceeded.

  The present invention has been made in view of the above-described circumstances, and can output and stop signal light by attaching and detaching an optical connector even if a general-purpose optical connector is used, and malfunction due to electrostatic discharge can be realized. An object of the present invention is to provide an optical transmission module that can prevent and detect the number of times an optical connector is attached and detached.

  An optical transmission module according to the present invention is an optical transmission in which a receptacle to which an optical connector attached to an optical fiber is inserted and a signal control circuit unit including an optical element that transmits and receives an optical signal between the optical fiber is mounted. It is a module. The receptacle has a pair of electrode pads that are short-circuited by a conductive piece attached to the optical connector, and the pair of electrode pads are connected to a connector circuit portion that is opened or closed by attaching or detaching the optical connector. The signal control circuit unit includes control means for controlling the operation of the optical element when the connector circuit unit is opened or closed, and is electrically insulated from the connector circuit unit.

  The conductive piece attached to the optical connector can be retrofitted to the optical connector. An optical transmission module according to the present invention includes a light emitting element that emits light when the connector circuit portion is closed, and a signal control circuit portion that includes a light receiving element that receives and conducts light emitted from the light emitting element. The elements are electrically isolated and optically coupled by a photocoupler. In the optical transmission module, an overvoltage protection element may be connected to the connector circuit unit, and the control unit may further include a counting circuit that detects the number of times the optical connector is attached / detached.

  According to the present invention, even for a user who uses a general-purpose optical connector, it is possible to easily output / stop signal light in accordance with the attachment / detachment state of the optical connector. Further, ESD that occurs when the optical connector is attached / detached can be prevented, and the optical connector can be replaced before being damaged by monitoring the number of times the optical connector is attached / detached.

  Embodiments of the present invention will be described with reference to the drawings. 1A is a schematic diagram when an optical connector is inserted into an optical transmission module according to the present invention, FIG. 1B is a diagram illustrating an example of an optical connector used in the present invention, and FIG. It is a figure explaining an example which short-circuits an electrode pad with a conductive piece. In the figure, 11 is an optical transmission module, 12 is an optical connector, 13 is a receptacle, 14 is a latch part, 15 is a conductive piece, 16 is a receiving hole, 17a and 17b are electrode pads, 18 is a circuit board, and 20 is a connector circuit part. , 21 indicates a signal control circuit section.

  In the optical transmission module 11 according to the present invention, as shown in the schematic diagram of FIG. 1A, an optical connector 12 provided at the end of an optical fiber is inserted to perform optical communication with an external device. A receptacle 13, a control circuit unit 21 mounted on a circuit board 18 including an optical element that transmits and receives an optical signal, a connector circuit 20 described later, and the like are mounted. The receptacle 13 has a pair of electrode pads 17a and 17b in the accommodation hole 16 into which the optical connector 12 is inserted. For example, an LC type optical connector having a latch portion 14 is used as the optical connector 12 (also referred to as an optical plug), and the insertion state is locked by inserting the optical connector 12 into the receiving hole 16 of the receptacle 13. It is inserted so that it does not come off from 16.

  A commercially available general-purpose product can be used as the optical connector 12 attached to the end of the optical fiber cable. For the optical transmission module 11 according to the present invention, for example, a conductive piece 15 is attached to the latch portion 14. use. For example, as shown in FIG. 1 (B), the conductive piece 15 is formed of a conductive metal in a cylindrical shape, and can be retrofitted by fitting, winding, or the like using the shape of the latch portion 14 of the optical connector 12. A shape that can be attached is desirable. If there is a portion other than the latch portion 14 to which the conductive piece 15 can be attached, it may be attached to that portion.

  The pair of electrode pads 17 a and 17 b installed in the receptacle 13 are exposed from the wall surface of the receiving hole 16 and are installed at a position where they are electrically short-circuited by the conductive piece 15 of the optical connector 12. That is, the pair of electrode pads 17a and 17b are connected to a connector circuit unit 20 that is electrically insulated from a signal control circuit unit 21 to be described later, and function as switch contacts that are turned on and off by attaching and detaching the optical connector 12. Will be provided.

By using the optical connector 12 to which the conductive piece 15 is attached to the optical transmission module 11, the insertion of the optical connector is detected by the control means described later, and signal light such as laser light is activated. The removal of the optical connector 12 can be detected, and a protection function for stopping the output of signal light such as laser light can be provided.
The optical connector 12 is attached to an existing communication device. However, even if a new optical connector is not used, an optical connector 12 having the above function can be obtained by simply attaching the conductive piece 15 as described above to the optical connector 12. It is possible to correspond to the transmission module 11.

  2A and 2B are diagrams illustrating the internal configuration of the optical transmission module 11 according to the present invention. In the figure, 22 is a voltage switching regulator, 23 is a pull-up resistor, 24 is a photocoupler, 25 is a light-emitting element, 26 is a light-receiving element, 27 is an overvoltage protection element (varistor), 28 is a pull-up resistor, 29 is a control circuit, Reference numeral 30 denotes an LD operating circuit, 31 denotes a signal light source (optical element such as an LD), 32 denotes an attachment / detachment counting circuit, 33 denotes a control management unit, and 34 denotes a DC filter.

  In FIG. 2A, as shown on the right side of the optical connector 12 and the receptacle 13, the conductive piece 15 closes or opens between the electrode pads 17a and 17b of the receptacle 13 by attaching and detaching the optical connector 12. To do. The electrode pads 17a and 17b are connected to the connector circuit unit 20, and one electrode pad 17a is connected to the power supply side via the pull-up resistor 23 and given a predetermined potential. The other electrode pad 17 b is grounded via the light emitting element 25 of the photocoupler 24.

  Here, in the illustrated state in which the electrode pads 17a and 17b are open, no voltage is applied to the light emitting element 25, and thus no light is emitted in a non-operating state (off). However, when the electrode pads 17a and 17b are closed by the insertion of the optical connector 12, a current flows through the connector circuit 20, and the light emitting element 25 is activated (ON) to emit light. The light emitted from the light emitting element 25 is received by the light receiving element 26 of the photocoupler 24, and the light receiving element 26 is electrically connected (ON) to detect that the optical connector 12 is inserted. From this state, when the optical connector 12 is removed and the electrode pads 17a and 17b are opened, no current flows through the light emitting element 25, and the light emission is stopped due to the non-operating state (off). The light receiving element 26 is electrically non-conductive (off) due to the absence of light to be received, and detects that the optical connector 12 has been taken out.

The power supply voltage applied to the pull-up resistor 23 uses the power supply in the optical transmission module, but is preferably generated using the voltage switching regulator 22 in order to separate it from the power supply of the signal system circuit. Further, since this switching regulator also functions as a narrow-band low-pass filter, it also serves as a protection circuit for the power supply on the signal side. Further, the DC filter 34 may be connected so that external ESD and external noise do not enter the signal system via the power line.
Further, by connecting an overvoltage protection element 27 such as a varistor or a Zener diode to the pull-up resistor 23, it is possible to protect the connector circuit 20 from being applied with an overvoltage exceeding a predetermined value.

  As described above, the connector circuit unit 20 is optically coupled to the signal system of the signal control circuit unit 21 described later by the photocoupler 24 but is electrically separated, and is connected to the connector circuit unit 20 side. The grounding part FG and the signal grounding part SG are also electrically separated from each other. As a result, even if the static electricity through the operator is applied to the module housing through the optical connector 12 and the receptacle 13 in the attaching / detaching operation of the optical connector 12 or the like, it passes through the connector circuit portion 20 electrically separated from the signal system. The grounding part FG can be discharged. Therefore, it is possible to prevent the signal control circuit unit 21 from being adversely affected by static electricity and to prevent the signal system from malfunctioning.

The signal control circuit unit 21 of the optical transmission module is a control circuit that electrically detects the attachment / detachment of the optical connector and controls the operation of the LD operation circuit 30 by, for example, turning on / off the light receiving element 26 by attaching / detaching the optical connector 12. 29, control means including an LD operation circuit 30 for operating or stopping the optical element 31 such as a laser diode (LD).
Further, the signal control circuit unit 21 can include an attachment / detachment counting circuit 32 that detects a change in the input signal of the control circuit 29 that occurs when the optical connector 12 is attached / detached and counts the number of attachments / detachments. In addition, the signal control circuit unit 21 includes a control management unit 33 that manages overall control in the signal control circuit unit 21.

  In the above-described signal control circuit unit 21, when the optical connector 12 is inserted into the receptacle 13, the electrode pads 17a and 17b are closed, the connector circuit 20 is closed, and a current flows. As a result, the light emitting element 25 is activated and emits light. Light emitted from the light emitting element 25 is received by the light receiving element 26 of the photocoupler 24, and the light receiving element 26 becomes electrically conductive. When the light receiving element 26 becomes conductive, the input voltage of the control circuit 29 applied via the pull-up resistor 28 becomes the ground potential (LOW), and it can be detected that the optical connector 12 is inserted. it can. When the insertion of the optical connector 12 is detected, the LD operation circuit 30 is activated, the optical element 31 of the signal light source is turned on, and the signal light is transmitted to the outside through the optical connector 12 and the optical fiber. Is done.

  On the other hand, when the optical connector 12 is removed from the state in which the optical connector 12 is inserted and the electrode pads 17a and 17b are opened, the connector circuit 20 is opened and no current flows. As a result, the light emitting element 25 is in an inoperative state, light emission is stopped, the light receiving element 26 of the photocoupler 24 is not received, and the light receiving element 26 is electrically non-conductive. When the light receiving element 26 becomes non-conductive, the input voltage of the control circuit 29 applied via the pull-up resistor 28 becomes a high potential (HIGH), and the optical connector 12 is removed (detached). Can be detected. When the attachment / detachment of the optical connector 12 is detected, the LD operation circuit 30 is stopped, the output of the optical element 31 of the signal light source is stopped (turned off), and the signal light from the receptacle 13 is not transmitted.

  Further, the LC-type optical connector 12 described with reference to FIG. 1 is liable to break the latch portion when the number of attachments / detachments exceeds a predetermined number. When the latch portion is damaged, the latch function is lowered and it is easy to drop off. Therefore, by counting the number of times the optical connector is attached / detached by the attachment / detachment counting circuit 32, it is possible to prevent the unintentional dropout of the optical connector by grasping and replacing the deterioration of the latch portion in advance. desirable. Note that the above-described attachment / detachment count state of the optical connector can be transmitted to a higher-order monitoring system, and the number of attachments / detachments of the optical connectors of a plurality of optical transmission modules used in the optical communication system can be monitored collectively.

It is a figure explaining the insertion of the optical transmission module and optical connector by this invention. It is a figure explaining the internal structure of the optical transmission module by this invention. It is a figure explaining a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Optical transmission module, 12 ... Optical connector, 13 ... Receptacle, 14 ... Latch part, 15 ... Conductive piece, 16 ... Housing hole, 17a, 17b ... Electrode pad, 18 ... Circuit board, 20 ... Connector circuit part, 21 ... Signal control circuit unit, 22 ... voltage switching regulator, 23 ... pull-up resistor, 24 ... photocoupler, 25 ... light emitting element, 26 ... light receiving element, 27 ... overvoltage protection element (varistor), 28 ... pull-up resistor, 29 ... control Reference numeral 30: LD operation circuit 31: Signal light source (optical element) 32: Detachment counting circuit 33: Control management unit 34: DC filter

Claims (5)

An optical transmission module in which a receptacle to which an optical connector attached to an optical fiber is inserted, and a signal control circuit unit including an optical element that transmits and receives an optical signal between the optical fiber,
The receptacle has a pair of electrode pads that are short-circuited by a conductive piece attached to the optical connector, and the pair of electrode pads are connected to a connector circuit portion that is opened or closed by attaching or detaching the optical connector;
The signal control circuit section includes control means for controlling the operation of the optical element when the connector circuit section is open or closed, and is electrically insulated from the connector circuit section. .   The optical transmission module according to claim 1, wherein the conductive piece is configured to be retrofitted to the optical connector.   A light-emitting element that emits light when the connector circuit section is closed; and a light-receiving element that receives and conducts light emitted from the light-emitting element in the signal control circuit section. The light-emitting element and the light-receiving element are electrically connected by a photocoupler. The optical transmission module according to claim 1, wherein the optical transmission module is insulated and optically coupled to each other.   The optical transmission module according to claim 1, wherein an overvoltage protection element is connected to the connector circuit unit.   The optical transmission module according to claim 1, wherein the control unit includes a counting circuit that detects the number of times the optical connector is attached and detached.

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