JP2616213B2 - Optical output circuit - Google Patents

Description

The present invention relates to an optical output circuit.

[Prior Art] FIG. 3 shows a conventional light output circuit of this kind. The input terminal 1 is connected to the input terminal of the light emitting element 9 via the drive circuit 3.

On the other hand, the drive circuit 3 has a terminal 2 for controlling the drive current of the light emitting element 9 described above, and the terminal 2 is provided with a variable resistor RV.
Connected to earth through.

In the light output circuit having such a configuration, in order to set the light output power, the light output of the light emitting element 9 is adjusted by the variable resistor RV and is connected to the light output meter 8 connected via the optical fiber cable 10. The light output power of the light emitting element 9 is displayed.

[Problems to be Solved by the Invention] However, when setting the optical output power in such an optical output circuit, it is necessary to adjust the above-described variable resistor RV while observing the optical output meter 11 described above. Had the disadvantage of being troublesome.

SUMMARY OF THE INVENTION The present invention has been made to eliminate the above-mentioned disadvantages of the conventional optical output circuit.
Another object of the present invention is to provide an optical output circuit capable of storing the set value.

[Means for Solving the Problem] An optical output circuit according to the present invention is an optical output circuit having a light emitting element for converting an electric signal to an optical signal, and a drive circuit for driving the light emitting element, wherein the drive circuit comprises the light emitting element A drive current control terminal for controlling the drive current of the control circuit, the control terminal being connected to a plurality of resistors, each of the plurality of resistors including a switch for inserting or disconnecting the resistor from / to a circuit; One input terminal is connected to the address input terminal of the memory, the second input terminal is connected to the control terminal of the selector and the control terminal of the counter, respectively, and the data output of the memory is connected to the first input terminal of the selector. The output terminal of the counter is connected to the second input terminal of the selector, and the output terminal of the selector is an input terminal for controlling the "on-off" of the switch. It is characterized by being connected to each.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration diagram of one embodiment of the present invention, in which 9 is a light emitting element for converting an electric signal into an optical signal, 3 is a drive circuit for driving the light emitting element 9, and An input is connected to an output of the driving circuit 3, and an input of the driving circuit 3 is connected to a signal input terminal 1.
Has a drive current control terminal 2 for controlling the drive current of the light emitting element 9, and the control terminal 2 is connected to one end of a plurality of resistors R1, R2, R3, and is connected to the plurality of resistors R1, R2, R3. The other ends are connected to the ground via switches SW1, SW2, and SW3, respectively. The first input terminal 8 is connected to the address input terminal of the memory 5, the second input terminal 7 is connected to the control terminal of the selector 4 and the control terminal of the counter 6, respectively, and the data output of the memory 5 is 4 is connected to the first input terminal A, the output terminal of the counter 6 is connected to the second input terminal B of the selector 4, and the output terminal of the selector 4 is connected to the switches SW1, SW2 and SW3. Each is connected to an input terminal for controlling “on-off”. In such a configuration, an input signal is input to the signal input terminal 1, is converted into an optical digital signal by the light emitting element 9 via the driving circuit 3 and emits light, and the optical signal is transmitted via the optical fiber cable 10 to the optical output meter 11. And the optical output power can be measured.

Now, in the initial state, since the drive current of the light emitting element for setting the required optical output power is unknown, the signal of the measurement mode is inputted from the terminal 8 and the output of the selector 4 is switched to the counter 6 side. The counter 6 is counted up in order, and the light emitting element 9 changes according to the combination of the resistors R1, R2, and R3.
The switches SW1, SW2, and SW3 are switched based on the combination table (FIG. 4) of the switches SW1, SW2, and SW3 corresponding to the drive currents, and the optical output power changed by the switches is measured by the optical power meter 11, and Optical output power P and switch SW as shown in Fig. 5
A relationship diagram of the combination of 1, SW2 and SW3 is obtained.

When a combination of the optical output power P1 to be set and the switch is determined according to FIG. 4 and input to the memory 5 from the terminal 7, the optical output power P1 is stored in the memory 5 and can be output simultaneously.

FIG. 2 is a circuit diagram showing a second embodiment of the present invention.
Parts having the same reference numerals as those in the drawings have the same functions.

In FIG. 2, a signal input terminal 1 is connected to a light emitting element 9 via a driving circuit 3, and a driving current control terminal 2 for controlling a driving current of the light emitting element 9 is integrated at one end of resistors R1, R2 and R3. And connected to the ground via switches SW1, SW2 and SW3, respectively. On the other hand, the first input terminal 7 is connected to the address input terminal of the memory 5 and the second input terminal 8
Are connected to the control terminal of the counter 6 and the control terminal of the selector 4, respectively. The data output of the memory 5 is connected to a first input terminal A of the selector 4, and the data output of the counter 6 is connected to a second input terminal B of the selector 4.
Connected to. Further, an output terminal of the selector 4 is connected to an input terminal for controlling "on-off" of the switches SW1, SW2 and SW3, respectively. The light output of the light emitting element 9 is input to the light output meter 8 via the optical fiber 10, and the output data of the light output meter 11 is connected to the input of the computer 12, and the output terminals C and D of the computer 12 are respectively connected to the input terminals. Connected to terminals 7 and 8.

In such a configuration, the input signal is applied to the signal input terminal 1
Is converted into an optical digital signal by the light emitting element 9 via the drive circuit 3 and emits light. The optical signal is input to the optical output meter 11 via the optical fiber cable 10 and the optical output power can be measured. .

Now, in the initial state, since the drive current of the light emitting element for setting the required optical output power is unknown, the computer 12 outputs a measurement mode signal from the output terminal C of the computer 12 and The output is switched to the counter 6 side, and the counter 6 is counted up in order.
Light that changes by switching the switches SW1, SW2, and SW3 based on the combination table (FIG. 4) of the switches SW1, SW2, and SW3 according to the drive current of the light emitting element 9 that changes according to the combination of 1, R2, and R3. The output power is measured by the optical power meter 11 described above, and the relationship as shown in FIG. Next, the optical output power P1 to be set is determined by the computer from the previously measured data, and an address signal in the setting mode is output from the output terminal D of the computer 12 and stored in the memory 5 described above. At this time, if the control terminal of the selector 4 is set so as to select the normal memory data output, the condition of this time can be stored in the memory 5 at the same time as outputting the set value of the optical output power of this circuit.

[Effect of the Invention] The present invention described above can be controlled by a computer.
The optical output power can be set freely, and can be set independently of the characteristics of the light emitting element and the drive circuit.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of one embodiment of the present invention, FIG. 2 is a circuit diagram of another embodiment of the present invention, FIG. 3 is a circuit diagram of a conventional optical output circuit, and FIG. Diagram showing a table of combinations,
FIG. 5 is a diagram showing the relationship between the measured value of the optical output power and the set address. Explanation of symbols: 1 is a signal input terminal, 2 is a drive current control terminal, 3 is a drive circuit, 4 is a selector, 5 is a memory, 6 is a counter, and 7 is a first
, 8 is a second input terminal, 9 is a light emitting element, 10 is an optical fiber cable, 11 is an optical output meter, 12 is a computer,
C and D are computer output terminals, R1, R2 and R3 are resistors, SW1 and SW
2, SW3 represents a switch, and RV represents a variable resistor.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H04B 10/26 10/28

Claims (1)

(57) [Claims] A light emitting element for converting an electric signal into an optical signal;
In an optical output circuit having a drive circuit for driving the light emitting element, the drive circuit has a drive current control terminal for controlling a drive current of the light emitting element, and the control terminal is connected to a plurality of resistors. Each has a switch for inserting and disconnecting the resistor from the circuit, a first input terminal is connected to an address input terminal of the memory,
A second input terminal is connected to a control terminal of the selector and a control terminal of the counter, respectively, a data output of the memory is connected to a first input terminal of the selector, and an output terminal of the counter is connected to a second terminal of the selector. Connected to the input terminal, and the output terminal of the selector is connected to the "ON-
Connected to input terminals for controlling “OFF”, inputting the converted optical output of the light emitting element to an electrical output to a computer, connecting the output of the computer to the first and second input terminals, A signal in a measurement mode is output from an output terminal of a computer, the output of the selector is switched to the counter side, the counter is sequentially counted up, the plurality of switches are switched, and the optical output power that changes thereby is measured. An optical output circuit which obtains a relationship between a combination of switches and an optical output power, outputs a desired optical output power, and simultaneously stores setting conditions at this time in the memory.