JP2020077987A - Optical transmission/reception system - Google Patents

Abstract

To provide an optical transceiver system capable of controlling an output of a light-emitting element while reducing monitor photodiodes in an optical transmitter.SOLUTION: An optical transmission/reception system 100 comprises an optical fiber 51, a metal wire 52, an optical transmitter 10 and an optical receiver 20. The optical transmitter 10 comprises an input terminal 30, a light-emitting element 15 and a current controller 17. The optical receiver 20 comprises a light-receiving element 24, an output terminal 80 and a light-receiving level detector 25. The light-receiving level detector 25 detects an average level of a high-frequency signal converted by the light-receiving element and transmits a level signal indicating the detected average level to the optical transmitter 10 via the metal wire 52. The current controller 17 controls a bias current so that an average level of intensity of an optical signal becomes a predetermined value, on the basis of the level signal transmitted from the light-receiving level detector 25.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an optical transmission / reception system used for transmitting / receiving television signals and the like.

  In recent years, in television broadcasting, so-called 4K and 8K higher-quality broadcasting has been studied. In high-quality broadcasting of 4K and 8K, the television signal has a wide band. An optical fiber capable of broadband transmission is more suitable than a coaxial cable for broadband signal transmission. Therefore, it is conceivable to convert a television signal into an optical signal and transmit the converted optical signal through an optical fiber in accordance with high-quality broadcasting. Although a light emitting element is used for converting a television signal into an optical signal, generally, the electrical / optical exchange rate of the light emitting element is lowered due to deterioration over time.

  In the optical transmitter described in Patent Document 1, a monitor photodiode for detecting the optical output power of the light emitting element is provided in the module of the light emitting element. Then, the optical transmitter described in Patent Document 1 suppresses the fluctuation of the output power of the light emitting element by adjusting the level of the bias current supplied to the light emitting element using the detection result of the monitor photodiode. ..

International Publication No. 02/069464

The optical transmitter described in Patent Document 1 has a problem that the number of parts, the size of the optical transmitter, and the cost increase because the monitor photodiode is provided in the module of the light emitting element.
An object of the present disclosure is to provide an optical transceiver system capable of controlling the average level of an optical signal output from a light emitting element while reducing the monitor photodiode in the optical transmitter.

  The invention according to claim 1 is an optical transmission / reception system, which comprises an optical fiber, a metal wire, an optical transmitter, and an optical receiver. The optical fiber transmits an optical signal. Metal wires carry electrical signals. The optical transmitter is connected to one of the two ends of the optical fiber and the metal wire, respectively. The optical receiver is connected to the other of the two ends of the optical fiber and the metal wire, respectively. The optical transmitter includes an input terminal, a current controller, and a light emitting element. A high-frequency signal, which is an electric signal, is input to the input terminal from the outside. The current control unit generates a bias current. The light emitting element receives the supply of the bias current generated by the current control unit, and outputs an optical signal having an average level according to the bias current and an intensity adjusted according to the high frequency signal input to the input terminal to the optical fiber. Output to. The optical receiver includes a light receiving element, an output terminal, and a light receiving level detector. The light receiving element receives the optical signal transmitted through the optical fiber, and converts the received optical signal into a high frequency signal which is an electric signal corresponding to its intensity. The output terminal outputs the high frequency signal converted by the light receiving element to the outside. The light-reception level detection unit detects the average level of the high-frequency signal converted by the light-receiving element, and transmits a level signal indicating the detected average level to the optical transmitter via the metal wire. Then, the current control unit controls the generated bias current based on the level signal transmitted from the light reception level detection unit so that the average level of the intensity of the optical signal becomes a predetermined value.

  According to the invention described in claim 1, the optical receiver detects the average level of the high-frequency signal converted by the light receiving element, and transmits the level signal indicating the detected average level to the optical transmitter. Then, the optical transmitter controls the bias current supplied to the light emitting element based on the level signal transmitted from the optical receiver so that the average level of the intensity of the optical signal becomes a predetermined value. Therefore, the average intensity level of the optical signal output from the light emitting element can be controlled while removing the monitor photodiode in the optical transmitter.

  In the invention according to claim 2, the current control unit estimates the average level of the intensity of the optical signal output from the light emitting element based on the level signal in consideration of the transmission loss of the optical fiber, and the estimated average level. An output control mode may be executed in which the bias current is controlled so that the output current becomes constant.

  According to the invention described in claim 2, the average level of the intensity of the optical signal output from the light emitting element is estimated based on the level signal in consideration of the transmission loss of the optical fiber, and the estimated average level is kept constant. can do. As a result, when the life of the light emitting element has expired and the average level of the intensity of the optical signal output from the light emitting element cannot be made constant, it is possible to accurately determine when the life has expired.

  In the invention according to claim 3, the current control unit executes the light receiving control mode in which the bias current is controlled based on the level signal so that the average level detected by the light receiving level detecting unit becomes constant. Good.

  According to the invention described in claim 3, when the electrical / optical conversion efficiency of the light emitting element is lowered due to deterioration over time, the average level of the intensity of the optical signal received by the light emitting element is kept constant based on the level signal. Can be maintained at. As a result, the carrier noise ratio of the electric signal converted by the light emitting element can be maintained.

In the invention according to claim 4, the current control section may select and execute either the output control mode or the light reception control mode.
According to the invention described in claim 4, it is possible to select and execute an appropriate mode of the output control mode and the light reception control mode depending on the situation.

  According to a fifth aspect of the invention, the optical transmitter includes an output unit that outputs a warning prompting maintenance of the light emitting element when the average level estimated by the current control unit is not constant in the output control mode. May be.

  According to the fifth aspect of the present invention, when the average level estimated in the output control mode is not constant, a message that prompts maintenance of the light emitting element is output. This allows the user to recognize that the light emitting element has reached the end of its life.

  In the invention according to claim 6, the optical transmitter is provided with an output unit that outputs a warning urging maintenance of the light emitting element when the average level detected by the light reception level detection unit is not constant in the light reception control. May be.

  According to the sixth aspect of the present invention, when the average level detected in the light receiving control mode is not constant, a message that the maintenance of the light emitting element is prompted is output. This allows the user to recognize that the light emitting element has reached the end of its life.

In the invention described in claim 7, the optical transmitter may include a loss setting unit for a user to set a transmission loss of the optical fiber.
According to the invention described in claim 7, the current controller can estimate the average level of the intensity of the optical signal output from the light emitting element by using the transmission loss of the optical fiber set by the user.

  In the invention described in claim 8, the current control section may include a current circuit and a variable resistor. The current circuit may include a circuit output terminal and a circuit input terminal. The output terminal is connected to the light emitting element. The circuit input terminal is connected to the metal wire. The variable resistor is connected to the circuit input terminal.

  According to the invention described in claim 8, when the average level of the intensity of the optical signal received by the light receiving element is lowered due to aging, it is applied to the current circuit by increasing the resistance value of the variable resistor. Voltage increases, and the level current supplied to the light emitting element also increases. As a result, the average level of the intensity of the received optical signal rises, and the current flowing through the light receiving element increases. Therefore, by adjusting the resistance value and changing the bias current, the current flowing through the light receiving element can be made constant. Since the current flowing through the light receiving element is proportional to the average level of the intensity of the received optical signal, the average level can be kept constant by keeping the current flowing through the light receiving element constant.

In the invention described in claim 9, the optical fiber and the metal wire may be housed in one optical cable.
According to the invention described in claim 9, the optical fiber and the metal wire are housed in one optical cable. Therefore, as compared with the case where the optical fiber and the metal wire are individually wired, simple wiring can be realized.

  In the invention described in claim 10, the optical receiver may include an amplification section and a superposition section. The amplification unit amplifies the level signal transmitted by the light reception level detection unit. The superimposing unit superimposes the power supplied to the current control unit on the level signal amplified by the amplifying unit and transmits the level signal to the optical transmitter via the metal wire.

  According to the tenth aspect of the invention, since power is supplied from the optical receiver to the optical transmitter, it is not necessary to provide the optical transmitter with an outlet and a power supply circuit for connecting to an external power source. Moreover, since the level signal is superimposed on the power supply after the level signal is amplified, the level signal is not buried in the power supply, and the time change of the level signal can be determined.

It is a figure which shows the structure of the optical transmission / reception system which concerns on 1st Embodiment. It is a figure which shows the structure of the light emission part and electric power control part of an optical transmitter, the receiving part of an optical receiver, and a light reception level detection part. It is a figure which shows the structure of the optical transmission / reception system which concerns on 2nd Embodiment. It is a figure which shows the structure of the isolation | separation part of an optical transmitter. It is a figure which shows the structure of the optical transmission / reception system which concerns on 3rd Embodiment. It is a figure which shows the structure of the isolation | separation part of an optical receiver.

Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings.
(First embodiment)
<1-1. Composition>
First, the configuration of the optical transceiver system 100 according to the first embodiment will be described with reference to FIGS. 1 and 2.

The optical transceiver system 100 includes an optical transmitter 10, an optical receiver 20, and an optical cable 50.
The optical transmitter 10 includes an input terminal 30, a first amplification adjustment unit 11, a light emitting unit 13, a bias current control unit 17, a first power supply 60, a selection switch 40, a loss setting unit 43, and an output unit. 45, and. A high-frequency signal (hereinafter, RF signal) which is an electric signal is input to the input terminal 30 from the outside. The first amplification adjustment unit 11 amplifies the RF signal input to the input terminal 30 and adjusts the amplitude of the RF signal. The RF signal is, for example, a television signal received by an external antenna.

  The light emitting unit 13 includes a mixer 14 and a light emitting element 15. The mixer 14 includes a capacitor 14a and a coil 14b. The capacitor 14a has a first end and a second end, the first end is connected to the input portion of the RF signal, and the second end is connected to the coil 14b and the light emitting element 15. The coil 14b has a first end and a second end, the first end is connected to the bias current controller 17, and the second end is connected to the capacitor 14a and the light emitting element 15. Therefore, the mixer 14 mixes the modulation current, which is the RF signal input via the capacitor 14a, and the bias current input from the bias current control unit 17 via the coil 14b to generate a drive current, The generated drive current is supplied to the light emitting element 15.

  The light emitting element 15 is composed of a laser diode or a light emitting diode. The light emitting element 15 converts the drive current into an optical signal and outputs the optical signal to the optical fiber 51. Specifically, the light emitting element 15 outputs an optical signal having an average intensity according to the bias current and an intensity adjusted according to the RF signal (that is, the intensity changes according to the change of the RF signal), which will be described later. To the optical fiber 51 included in. The wavelength of the optical signal is predetermined depending on the material of the light emitting element 15 and the like. Hereinafter, the optical signal output from the light emitting element 15 is also referred to as a light emitting signal.

  The bias current controller 17 includes a constant current IC 18, a variable resistor 16a, and a resistor 16b. In the constant current IC 18, the circuit input terminal 18b is connected to the coil 14b, and the circuit output terminal 18a is connected to a metal wire 52 described later. The variable resistor 16a has a first end and a second end, the first end is connected to the circuit input terminal 18b, and the second end is connected to the resistor 16b. The resistor 16b has a first end and a second end, the first end is connected to the variable resistor 16a, and the second end is grounded.

  The constant current IC 18 supplies a bias current according to the potential of the connection point P to the mixer 14. The connection point P is a connection point between the first end of the variable resistor 16a and the circuit input terminal 18b. That is, the magnitude of the bias current supplied by the constant current IC 18 changes according to the resistance value of the variable resistor 16a.

  The first power supply 60 is connected to a 100V AC power supply via an outlet. The first power supply 60 generates a DC power supply having a predetermined voltage from an AC power supply of 100V, and supplies the generated DC power supply to the first amplification adjustment unit 11 and the bias current control unit 17.

  The selection switch 40 is a switch for the user to select either the output control mode or the light reception control mode. The output control mode and the light reception control mode will be described later. The loss setting unit 43 is a dial or the like for the user to set the transmission loss of the optical fiber 51 in the output control mode. The user sets a fixed transmission loss of the optical fiber 51 to be used.

  The output unit 45 outputs a message urging maintenance of the light emitting element 15 when it is determined that the life of the light emitting element 15 has expired. The output unit 45 averages the intensity of the optical signal received by the light receiving element 24 when the average level of the intensity of the optical signal output from the light emitting element 15 is not constant in the output control mode, or in the light receiving control mode. When the level is not constant, it is determined that the life of the light emitting element 15 has come to an end.

  The optical receiver 20 includes a light receiving section 23, a second amplification adjusting section 21, a light receiving level detecting section 25, a second power source 70, and an output terminal 80. The light receiving section 23 includes a light receiving element 24. The light receiving element 24 is composed of a photodiode, receives the optical signal transmitted through the optical fiber 51, and converts the received optical signal into an electric signal (specifically, current) according to its intensity. .. The converted electric signal is a high frequency signal including a direct current component and a high frequency component. The DC component is a DC current having a magnitude corresponding to the average level of the intensity of the received optical signal. The high frequency component is a current whose amplitude changes according to the change in the intensity of the received optical signal. Hereinafter, the optical signal received by the light receiving element 24 is also referred to as a light receiving signal.

The second amplification adjusting unit 21 extracts and amplifies the high frequency component (that is, the modulation current) of the electric signal converted by the light receiving element 24. The amplified modulation current corresponds to the RF signal.
The output terminal 80 outputs the RF signal amplified by the second amplification adjusting unit 21 and having its amplitude adjusted to the outside. The output RF signal is input to a television or the like.

  The light-reception level detection unit 25 includes a detection coil 26, detects the average level of the intensity of the light-reception signal, and outputs a level signal indicating the detected average level via the metal wire 52 to the bias current control unit 17. Send to. Specifically, the light reception level detection unit 25 extracts the DC component (that is, DC current) of the electric signal converted by the light receiving element 24 by the detection coil 26. The magnitude of the extracted DC current corresponds to the average level of the intensity of the received light signal, and the DC current corresponds to the level signal.

  The second power source 70 is connected to a 100V AC power source via an outlet. The second power supply 70 generates a DC power supply of a predetermined voltage from an AC power supply of 100V and supplies the generated DC power supply to the second amplification adjustment unit 21.

  The optical cable 50 includes an optical fiber 51 and a metal wire 52. The optical cable 50 is configured by covering the optical fiber 51 and the metal wire 52 with a resin covering material. The optical cable 50 connects the light emitting element 15 and the light receiving element 24, and transmits the optical signal output by the light emitting element 15 to the light receiving element 24. The metal wire 52 connects the detection coil 26 and the constant current IC 18 and transmits a level signal from the detection coil 26 to the constant current IC 18.

<1-2. Operation>
The bias current control unit 17 selects and executes either the output control mode or the light receiving control mode according to the operation of the selection switch 40 by the user.

  The output control mode considers the transmission loss of the optical fiber 51, estimates the average level of the intensity of the light emission signal based on the received level signal, and makes the estimated average level of the intensity of the light emission signal constant. This is a mode for controlling the bias current.

  The transmission loss of the optical fiber 51 is set by the user from the loss setting unit 43. When the strength of the RF signal received by the television decreases, the user determines that the transmission loss of the optical fiber 51 has increased due to deterioration over time, and resets the value to a value larger than the initially set transmission loss. Good.

  When the loss set by the user becomes large, the bias current control unit 17 increases the resistance value of the variable resistor 16a and raises the potential at the connection point P. As a result, the bias current output from the constant current IC 18 increases, the increase in loss is compensated, and the average level of the intensity of the light emission signal is maintained at a predetermined value.

  On the other hand, the light receiving control mode is a mode in which the bias current is controlled based on the level signal so that the average level of the intensity of the light receiving signal becomes constant. When the electrical / optical exchange rate of the light emitting element 15 decreases due to deterioration over time, the average level of the intensity of the received light signal decreases. The bias current control unit 17 increases the resistance value of the variable resistor 16a to increase the bias current output from the constant current IC 18 when the average level of the intensity of the received light signal decreases, thereby increasing the intensity of the received light signal. Raise the average level. As a result, the average level of the intensity of the received light signal is maintained at the predetermined value.

  However, when the light emitting element 15 reaches the end of its life, the average level of the intensity of the light emitting signal cannot be maintained at a predetermined value in the output control mode. Further, when the light emitting element 15 reaches the end of its life, the average level of the intensity of the light receiving signal cannot be maintained at a predetermined value in the light receiving control mode. Therefore, the output unit 45 operates when the average level of the intensity of the light emitting signal is not maintained at the predetermined value in the output control mode and when the average level of the intensity of the light receiving signal is not maintained at the predetermined value in the light receiving control mode. Then, a warning for urging the maintenance of the light emitting element 15 is output. Specifically, the output unit 45 may be an indicator that outputs a warning by lighting or blinking, or a buzzer that outputs a warning by outputting a sound.

<1-3. Effect>
According to the first embodiment described above, the following effects can be obtained.
(1) The optical receiver 20 detects the average level of the intensity of the optical signal received by the light receiving element 24, and transmits a level signal indicating the detected average level to the optical transmitter 10. Then, the optical transmitter 10 controls the bias current supplied to the light emitting element 15 based on the level signal transmitted from the optical receiver 20. Therefore, the output of the light emitting element 15 can be controlled while removing the monitor photodiode in the optical transmitter 10.

  (2) In the output control mode, in consideration of the transmission loss of the optical fiber 51, the average level of the intensity of the light emission signal can be estimated based on the level signal, and the estimated average level can be made constant. Consequently, when the life of the light emitting element 15 has expired and the average level of the intensity of the light emission signal cannot be made constant, it is possible to accurately determine the time when the life has expired.

  (3) In the light receiving control mode, when the electric / light conversion efficiency of the light emitting element 15 is lowered due to deterioration over time, the average level of the intensity of the light receiving signal can be kept constant based on the level signal. As a result, the carrier noise ratio of the electric signal converted by the light emitting element 15 can be maintained.

(4) The user can select an appropriate mode from the output control mode and the light reception control mode depending on the situation.
(5) When the average level of the intensity of the light emitting signal is not constant in the output control mode and when the average level of the intensity of the light receiving signal is not constant in the light receiving control mode, a message prompting maintenance of the light emitting element is output. It This allows the user to recognize that the light emitting element has reached the end of its life.

  (6) When the average level of the intensity of the received light signal is lowered due to deterioration over time, the voltage applied to the constant current IC 18 is increased by increasing the resistance value of the variable resistor 16a and is supplied to the light emitting element 15. Bias current increases. As a result, the average level of the intensity of the received light signal rises, and the current flowing through the light receiving element 24 increases. Therefore, by adjusting the resistance value of the variable resistor 16a and changing the bias current, the current flowing through the light receiving element 24 can be made constant. Since the current flowing through the light receiving element 24 is proportional to the average level of the intensity of the received light signal, it is possible to make the average level of the intensity of the received light signal constant by keeping the current flowing through the light receiving element 24 constant.

  (7) The optical fiber 51 and the metal wire 52 are housed in one optical cable 50. Therefore, as compared with the case where the optical fiber 51 and the metal wire 52 are individually wired, simple wiring can be realized.

(Second embodiment)
<2-1. Differences from the first embodiment>
The second embodiment has the same basic configuration as that of the first embodiment. Therefore, the description of the common configuration will be omitted and the different points will be mainly described. The same reference numerals as those in the first embodiment indicate the same configurations, and refer to the preceding description.

  As shown in FIG. 3, an optical transmission / reception system 100A according to the second embodiment includes an optical transmitter 10A and an optical receiver 20A. The optical transmitter 10 according to the first embodiment described above includes the first power supply 60. On the other hand, the optical transmitter 10A according to the second embodiment is different from the first embodiment in that it does not include a power supply. In the second embodiment, the optical transmitter 10A receives power supply from the optical receiver 20A. The configurations of the optical transmitter 10A and the optical receiver 20A will be described below with reference to FIGS. 3 and 4.

The optical receiver 20A includes a light receiving unit 23, a second amplification adjusting unit 21, a light receiving level detecting unit 25, a second power source 70, an amplifying unit 22, a modulating unit 27, and a superposing unit 28.
The second power supply 70 is connected to the amplification unit 22, the modulation unit 27, and the superposition unit 28 in addition to the second amplification adjustment unit 21, and supplies DC power to these units.

  The amplification unit 22 is connected to the light reception level detection unit 25 and amplifies the level signal transmitted from the light reception level detection unit 25. The modulator 27 is connected to the amplifier 22 and modulates the level signal amplified by the amplifier 22.

  The superimposing unit 28 generates a superimposing signal by superimposing the DC power source supplied from the second power source 70 on the level signal modulated by the modulating unit 27, and the generated superimposing signal is transmitted via the metal wire 52 to the optical transmitter 10A. Send to. That is, power is supplied from the optical receiver 20A to the optical transmitter 10A via the metal wire 52 along with the transmission of the average level information of the intensity of the received light signal.

  The optical transmitter 10A includes a first amplification adjustment unit 11, a light emitting unit 13, a bias current control unit 17, a demodulation unit 12, a separation unit 19, a selection switch 40, a loss setting unit 43, and an output unit 45. And

  As shown in FIG. 4, the separating unit 19 includes a capacitor 19a and a coil 19b. The capacitor 19a and the coil 19b have a first end and a second end, respectively. First ends of the capacitor 19a and the coil 19b are connected to the metal wire 52. The second end of the capacitor 19a is connected to the demodulation unit 12. The second end of the coil 19b is connected to the bias current controller 17 and the first amplification adjuster 11.

  The superposed signal transmitted via the metal wire 52 is separated into a DC power source and a modulated level signal by the separating unit 19. The modulated level signal is input to the demodulation unit 12 via the capacitor 19a. The demodulation unit 12 demodulates the level signal and outputs the demodulated level signal to the bias current control unit 17. The DC power is supplied to the bias current controller 17 and the first amplification adjuster 11 via the coil 19b.

<2-2. Effect>
According to the second embodiment described above, the following effects can be obtained in addition to the effects (1) to (7) of the first embodiment described above.

  (8) Since power is supplied from the optical receiver 20A to the optical transmitter 10A, it is not necessary to provide the optical transmitter 10A with an outlet and a power source for connecting to an external power source. Moreover, since the power supply is superimposed on the level signal after the level signal is amplified by the amplifier 22, the level signal is not buried in the power supply, and the time change of the level signal can be determined.

(Third Embodiment)
<3-1. Differences from the second embodiment>
The third embodiment has the same basic configuration as that of the second embodiment, and therefore the description of the common configuration will be omitted and differences will be mainly described. The same reference numerals as those in the second embodiment indicate the same configurations, and refer to the preceding description.

  As shown in FIG. 5, an optical transmission / reception system 100B according to the third embodiment includes an optical transmitter 10A and an optical receiver 20B. The optical receiver 20A according to the second embodiment described above includes the second power supply 70. On the other hand, the optical receiver 20B according to the third embodiment is different from the second embodiment in that it does not include a power supply. In the third embodiment, the optical receiver 20B receives power supply from the television 200 and transmits the power supplied from the television 200 to the optical transmitter 10A. Hereinafter, the configuration of the optical receiver 20B will be described with reference to FIGS. 5 and 6.

The optical receiver 20B includes a light receiving section 23, a second amplification adjusting section 21, a received light level detecting section 25, an amplifying section 22, a modulating section 27, a superposing section 28, and a separating section 29.
The separation unit 29 includes a capacitor 29a and a coil 29b. The capacitor 29a and the coil 29b have a first end and a second end, respectively. The first ends of the capacitor 29a and the coil 29b are connected to the television 200 via a connector and a coaxial cable. The second end of the capacitor 29a is connected to the second amplification adjustment unit 21. The second end of the coil 29b is connected to the second amplification adjustment unit 21, the amplification unit 22, the modulation unit 27, and the superposition unit 28.

  The RF signal amplified by the second amplification adjustment unit 21 is input to the television 200 via the capacitor 29a. In addition, the DC power output from the television 200 is supplied to the second amplification adjustment unit 21, the amplification unit 22, the modulation unit 27, and the superposition unit 28 via the coil 29b. Similar to the second embodiment, the superimposing unit 28 generates a superimposing signal by superimposing the DC power supplied from the television 200 via the coil 29b on the level signal modulated by the modulating unit 27, and the generated superimposing signal. Is transmitted to the optical transmitter 10A via the metal wire 52.

<3-2. Effect>
According to the third embodiment described above, the following effects can be obtained in addition to the effects (1) to (8) of the first embodiment described above.

  (9) Since power is supplied from the television 200 to the optical receiver 20B and the optical transmitter 10A, it is not necessary to provide the optical receiver 20B and the optical transmitter 10A with an outlet and a power source that are connected to an external power source.

(Other embodiments)
Although the embodiments for implementing the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications can be implemented.

  (A) In each of the above embodiments, the optical transmitter 10 or 10A includes the selection switch 40, but the present disclosure is not limited to this. The optical transmitters 10 and 10A may not include the selection switch 40. The bias current control unit 17 may select and execute any one of the output control mode and the light receiving control mode according to the usage status of the optical transmitters 10 and 10A. For example, the bias current control unit 17 selects the light receiving control mode in which the carrier noise ratio is kept constant until the integrated value of the usage time of the optical transmitters 10 and 10A exceeds a predetermined value, and the integrated value of the usage time is If the predetermined value is exceeded, an output control mode may be selected that allows the life time of the light emitting element 15 to be accurately determined.

  (B) In each of the above embodiments, the optical fiber 51 and the metal wire 52 are housed in the single optical cable 50, but the optical fiber 51 and the metal wire 52 do not have to be integrated. That is, the optical fiber 51 and the metal wire 52 may be individually wired.

(C) As the optical fiber 51, for example, a glass optical fiber (GoF) or a plastic optical fiber (PoF) is used.
(D) A plurality of functions of one constituent element in the above embodiment may be realized by a plurality of constituent elements, or one function of one constituent element may be realized by a plurality of constituent elements. .. Further, a plurality of functions of a plurality of constituent elements may be realized by one constituent element, or one function realized by a plurality of constituent elements may be realized by one constituent element. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above-described embodiment may be added or replaced with respect to the configuration of the other above-described embodiment. Note that all aspects included in the technical idea specified only by the wording recited in the claims are embodiments of the present disclosure.

  10 ... Optical transmitter, 10A ... Optical transmitter, 11 ... 1st amplification adjustment part, 12 ... Demodulation part, 13 ... Light emission part, 14 ... Mixer, 14a ... Condenser, 14b ... Coil, 15 ... Light emitting element, 16a ... Variable resistor, 16b ... Resistor, 17 ... Bias current control section, 18 ... Constant current IC, 18a ... Circuit output terminal, 18b ... Circuit input terminal, 19 ... Separation section, 19a ... Capacitor, 19b ... Coil, 20 ... Optical Receiver, 20A ... Optical receiver, 20B ... Optical receiver, 21 ... Second amplification adjusting section, 22 ... Amplifying section, 23 ... Light receiving section, 24 ... Light receiving element, 25 ... Light receiving level detecting section, 26 ... Detection coil, 27 ... Modulation section, 28 ... Superposition section, 29 ... Separation section, 29a ... Capacitor, 29b ... Coil, 30 ... Input terminal, 40 ... Selection switch, 43 ... Loss setting section, 45 ... Output section, 50 ... Optical cable, 51 ... Optical fiber, 2 ... metal wire, 60 ... first power supply, 70 ... second power supply, 80 ... output terminal, 100 ... optical transmitting and receiving system, 100A ... optical transmitting and receiving system, 100B ... optical transmitting and receiving system, 200 ... TV, P ... connection point.

Claims (10)

An optical fiber for transmitting an optical signal,
A metal wire for transmitting electrical signals,
An optical transmitter connected to one of two ends of each of the optical fiber and the metal wire;
An optical receiver connected to the other end of the two ends of each of the optical fiber and the metal wire,
The optical transmitter is
An input terminal to which a high frequency signal that is an electric signal is input from the outside,
A current control unit that generates a bias current,
The optical signal is supplied with the bias current generated by the current control unit, and the optical signal having the average level according to the bias current and the intensity adjusted according to the high frequency signal input to the input terminal is output. A light emitting element for outputting to a fiber,
The optical receiver is
A light-receiving element that receives the optical signal transmitted through the optical fiber, and converts the received optical signal into a high-frequency signal that is an electrical signal corresponding to its intensity,
An output terminal for outputting the high frequency signal converted by the light receiving element to the outside,
A light-reception level detector that detects an average level of the high-frequency signal converted by the light-receiving element, and transmits a level signal indicating the detected average level to the optical transmitter via the metal wire,
The current control unit controls the bias current to be generated based on the level signal transmitted from the light receiving level detection unit so that the average level of the intensity of the optical signal becomes a predetermined value,
Optical transceiver system. The current control unit estimates the average level of the intensity of the optical signal output from the light emitting element based on the level signal in consideration of the transmission loss of the optical fiber, and the estimated average level is constant. To control the bias current, to execute an output control mode,
The optical transceiver system according to claim 1. The current control unit controls the bias current based on the level signal so that the average level detected by the light reception level detection unit is constant, and executes a light reception control mode.
The optical transmission / reception system according to claim 1. The current control unit considers the transmission loss of the optical fiber, estimates the average level of the intensity of the optical signal output from the light emitting element based on the level signal, and the estimated average level is constant. Output control mode for controlling the bias current so as to become, and select and execute any one of the light receiving control mode,
The optical transmission / reception system according to claim 3. The optical transmitter is
In the output control mode, an output unit that outputs a warning urging maintenance of the light emitting element when the average level estimated by the current control unit is not constant,
The optical transmission / reception system according to claim 2. The optical transmitter is
In the light receiving control mode, an output unit is provided that outputs a warning urging maintenance of the light emitting element when the average level detected by the light receiving level detecting unit is not constant.
The optical transmission / reception system according to claim 3. The optical transmitter is
A user is provided with a loss setting unit for setting the transmission loss of the optical fiber,
The optical transmission / reception system according to claim 1. The current control unit includes a current circuit and a variable resistor,
The current circuit includes a circuit output terminal connected to the light emitting element, and a circuit input terminal connected to the metal wire,
The variable resistor is connected to the circuit input terminal,
The optical transmission / reception system according to claim 1. The optical fiber and the metal wire are housed in one optical cable,
The optical transmission / reception system according to any one of claims 1 to 8. The optical receiver is
An amplification unit for amplifying the level signal transmitted by the light reception level detection unit,
A power supply to the current control unit, superposed on the level signal amplified by the amplification unit, and a superposition unit for transmitting to the optical transmitter via the metal wire,
The optical transmission / reception system according to claim 1.

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