JP2005156210A - Method and device for collating optical fiber core - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the risk of erroneous collation to enhance collation performance, to reduce electric power of a light source, and to prolong a service life. <P>SOLUTION: This optical fiber core collating device 1 is provided with a light emitting means 20 for making a pulse signal get incident into an optical fiber core 10 in a transmission side, a light receiving means 30 for obtaining a pulse signal from leaked light of the optical fiber core 10 in a reception side, a pulse width measuring means 40 for measuring a pulse width of the pulse signal output from the photoreception means 30, a pulse period measuring means 50 for measuring a pulse period of the pulse signal output from the light receiving means 30, and a collating means 60 for comparing the pulse width measured by the pulse width measuring means 40 and the pulse period measured by the pulse period measuring means 50 with a prescribed pulse width and a prescribed pulse period of the incident pulse signal, and for determining the optical fiber core as collation when both the pulse widths and the pulse periods are respectively consistent each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical fiber core wire contrast method and an optical fiber core wire contrast device.

  In general, in order to compare optical fiber core wires, an optical signal incident on an optical fiber on the transmission side is compared with an optical signal obtained from leaked light on the reception side. Conventionally, for example, the following method is used as a method for comparing optical fiber core wires.

  (1) For example, as shown in FIG. 3, light (eg, modulated light having a wavelength of 1.55 μm) modulated at a low frequency (generally 270 Hz) of the oscillator 211 is appropriately converted to LD or the like on the transmission side. The light-emitting element 212 is incident on one end of the optical fiber core 210 to be contrasted.

  On the other hand, on the receiving side, leaked light from the optical fiber 210 obtained by bending the optical fiber is received by an appropriate light receiving element 213 such as a PD. The signal photoelectrically converted by the light receiving element 213 is amplified by the amplifier circuit 214, a component (generally 270 Hz) near the same frequency as the incident light is extracted by the band pass filter 215, and the component is rectified by the rectifier circuit 216. The comparator 217 compares the level of the same frequency component as the incident light (light intensity), and the contrast determination unit 218 determines the contrast.

(2) As another example, for example, as shown in Patent Document 1, the number of pulses of a signal obtained by photoelectrically converting leaked light on the receiving side is counted, and the count value and the incident light of the optical fiber are counted. A count set value set corresponding to the modulation frequency is compared, and if they match, it is determined as a cord contrast.
JP-A-8-110416

  However, such a conventional optical fiber core wire contrast method has the following problems.

  (1) In the former case, without changing the frequency (period) of the modulated light, the pulse emission time (pulse width) is shortened, the non-emission time is increased, and the ratio is 1: n (n> 1). Thus, it is expected that the power consumed by the light emitting element 212 on the transmission side is reduced to reduce the power consumption and extend the life of the light emitting element.

  However, since the same frequency component as that of the modulated light is detected by the band pass filter 215, when the pulse width of the modulated light is not 1: 1, the frequency component is greatly reduced, and the detection sensitivity is deteriorated. It is not an effective method, and eventually it is not possible to reduce power consumption and extend the lifetime of the light emitting element.

  For example, if the duty ratio of the modulated light is 1: n (n> 1), the same frequency component as that of the modulated light decreases as sin {π / (n + 1)} as n increases.

  (2) In the latter case, when an optical fiber different from the optical fiber to be compared is measured, there is a possibility that noise and signals used for communication may be counted, and there is a possibility of erroneous detection.

  Also, when measuring the optical fiber to be compared (the optical fiber on which the modulated light is incident), the pulse is counted by noise, or the count is decreased by an instantaneous increase in optical fiber loss. In some cases, it cannot be contrasted. This can cause the control performance to deteriorate.

  It is an object of the present invention to eliminate the problems of the above-mentioned conventional ones, to reduce the possibility of mis-contrast and to improve the contrast performance, and to reduce the power of the light source and extend the lifetime. It is an object of the present invention to provide an optical fiber core wire contrast method and an optical fiber core wire contrast device.

  The present invention solves the above-mentioned problems. The invention according to claim 1 is a pulse obtained from a pulse signal incident on an optical fiber core at a transmission side and a leaked light of the optical fiber core at a reception side. A method for comparing an optical fiber core wire by comparing the signal with a signal, wherein the pulse width and pulse period of a pulse signal obtained on the receiving side of the optical fiber core wire are monitored, and the pulse width and pulse cycle of the pulse signal are monitored. Is an optical fiber core contrast method in which the optical fiber core wire is determined as a control when it matches the pulse width and pulse period of the pulse signal incident on the transmission side.

  The invention according to claim 2 compares the optical fiber core wire by comparing the pulse signal incident on the optical fiber core wire on the transmitting side with the pulse signal obtained from the leaked light of the optical fiber core wire on the receiving side. A pulse signal having a duty ratio of 1: n (n> 1) is incident on the optical fiber core at the transmission side, and the pulse width and pulse period of the pulse signal obtained at the reception side are monitored, In this optical fiber core wire comparison method, when the pulse width and pulse period of the pulse signal coincide with the pulse width and pulse period of the incident pulse signal having the duty ratio, the optical fiber core wire is determined as a reference.

  According to a third aspect of the present invention, there is provided an optical fiber core comprising: a light emitting unit that makes a pulse signal incident on an optical fiber core at a transmitting side; and a light receiving unit that obtains a pulse signal from leakage light of the optical fiber core at a receiving side The control device is a pulse width measuring means for measuring the pulse width of the pulse signal output from the light receiving means, a pulse period measuring means for measuring the pulse period of the pulse signal output from the light receiving means, and the pulse The pulse width measured by the width measuring means and the pulse period measured by the pulse period measuring means are compared with the predetermined pulse width and the predetermined pulse period of the incident pulse signal, and both the pulse width and the pulse period coincide with each other. An optical fiber core contrast device comprising: a contrast determination unit that determines the optical fiber core as a control.

  According to a fourth aspect of the present invention, there is provided a pulse generation circuit that generates a pulse signal having a duty ratio of 1: n (n> 1), a pulse signal of the pulse generation circuit that is converted into an optical pulse, and an optical fiber core A light emitting member that is incident on one end; a light receiving member that receives and converts leaked light from the optical fiber core at the receiving side and outputs a pulse signal; and a pulse width measuring circuit that measures a pulse width of the pulse signal of the light receiving member; Comparing the pulse width measured by the pulse width measurement circuit with a predetermined pulse width of the pulse signal having the duty ratio of the pulse generation circuit. Compare the pulse period measured by the pulse width comparison circuit and the pulse period measurement circuit with a predetermined pulse period of the pulse signal having the duty ratio of the pulse generation circuit. And the comparison result of the pulse width comparison circuit and the comparison result of the pulse period comparison circuit, when the pulse width and the pulse period coincide with each other, the optical fiber core wire is determined as a control. And an optical fiber core-line contrast device.

  The invention according to claim 5 is the invention according to claim 3 or claim 4, wherein the reference determination means or the reference determination circuit is configured such that the coincidence of the pulse width and the pulse period is continuously repeated a predetermined number of times. This is an optical fiber core comparison device that performs optical fiber core comparison judgment.

  As described above, the present invention compares the optical fiber core by comparing the pulse signal incident on the optical fiber core on the transmission side and the pulse signal obtained from the leakage light of the optical fiber core on the reception side. A pulse width and a pulse period of a pulse signal obtained on the receiving side of the optical fiber core wire, and the pulse width and the pulse period of the pulse signal are incident on the transmission side and Since the optical fiber core wire is determined as a control when it coincides with the pulse period, there is an effect that the risk of miscontrol can be reduced and the control performance can be improved.

  The present invention also provides a method for comparing optical fiber cores by comparing a pulse signal incident on an optical fiber core on the transmission side with a pulse signal obtained from leakage light from the optical fiber core on the reception side. A pulse signal having a duty ratio of 1: n (n> 1) is incident on the optical fiber core wire on the transmission side, the pulse width and pulse period of the pulse signal obtained on the reception side are monitored, and the pulse When the pulse width and the pulse period of the signal coincide with the pulse width and the pulse period of the incident pulse signal having the duty ratio, the optical fiber core wire is determined as a control, so that the power of the light source can be reduced. In addition, there is an effect that the life can be extended.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing an embodiment of an optical fiber core wire contrast device according to the present invention. The optical fiber core wire contrast device 1 has a light emitting means 20 on the transmission side of an optical fiber (optical fiber core wire) 10. And a light receiving means 30, a pulse width measuring means 40, a pulse period measuring means 50, and a reference judging means 60 are provided on the receiving side.

  The light emitting means 20 includes a light emitting element 21 and an oscillator 22. The oscillator 22 drives the light emitting element 21 with a pulse signal having a short pulse HIGH time and a low LOW time (for example, 270 Hz, duty ratio 1: n (n = 100), etc.). It is.

  As a result, the light emitting element 21 is a modulated light consisting of a light pulse having the same frequency (cycle) and duty ratio as the pulse signal of the oscillator 22 (periodic narrow pulse train shorter than the time during which the light emission is not emitted). ) Is incident on one end of the optical fiber core wire 10.

  The light receiving means 30 includes a light receiving element 31, an amplifier circuit 32 and a comparator 33. The light receiving element 31 receives leaked light obtained by bending the optical fiber 10 and photoelectrically converts it.

  The amplifier circuit 32 amplifies the output of the light receiving element 31. The voltage of the output of the amplifier circuit 32 varies depending on the line loss of the optical fiber to be compared and the intensity of the leaked light when the optical fiber is bent. Therefore, the comparator 33 causes the voltage and LOW when the pulse of the pulse signal is HIGH. The voltage at the time is made constant.

  The pulse width measuring means 40 measures the voltage of the pulse signal output from the comparator 33 at intervals sufficiently shorter than the pulse width of the pulse signal of the oscillator 22. That is, the time from when the voltage is switched to HIGH until it is switched to LOW is measured, and the time when the voltage is HIGH is defined as the pulse width.

  The pulse period measuring means 50 measures the voltage of the pulse signal output from the comparator 33 at intervals sufficiently shorter than the pulse width of the pulse signal of the oscillator 22. That is, the time from when the voltage is switched to HIGH until the voltage is switched to LOW and then switched to HIGH again is measured, and the time when the voltage is HIGH and the time when it is LOW is defined as the pulse period.

  The pulse cycle measuring means 50 also measures the time from when the voltage switches to LOW until it switches to HIGH and then switches to LOW again, and the time when the voltage is LOW and the time when it is HIGH is used as the pulse cycle. Also good.

  The measurement accuracy of the pulse width measurement and the pulse period measurement is increased as the voltage measurement interval by the pulse width measurement means 40 and the pulse period measurement means 50 is shorter than the pulse width of the pulse signal of the oscillator 22. This is preferable.

  The control judgment means 60 compares the pulse width measured by the pulse width measurement means 40 and the pulse period measured by the pulse period measurement means 50 with the pulse width and pulse period of the pulse signal of the oscillator 22, and the pulse width and pulse period are compared. When both coincide, the optical fiber core wire 10 is determined as a control.

  In addition, the contrast determination unit 60 does not perform the contrast determination by matching the pulse width and the pulse period only once in order to increase the accuracy of the contrast of the cores, but when the match is repeated continuously a predetermined number of times. It is preferable to perform a control determination.

  When the contrast determination means 60 determines the contrast of the optical fiber core wire 10, the operator can be informed that the contrast is the contrast by an appropriate confirmation means 70 such as a buzzer or a display.

  FIG. 2 is a block diagram showing another embodiment of the optical fiber core contrast device according to the present invention. The optical fiber core contrast device 101 is the same as the optical fiber core contrast device 1 shown in FIG. Since they are the same, the same parts are indicated by adding 100 to the reference numerals used in FIG.

  The optical fiber core wire contrast device 101 includes a light emitting unit 120 on the transmission side of an optical fiber (optical fiber core wire) 110, and a light receiving unit 130, a pulse width measuring unit 140, and a pulse period measuring unit 150 on the receiving side. And a control judgment means 160.

  The light emitting means 120 includes a light emitting element 121, an oscillator 122, and a pulse generation circuit 123. The oscillator 122 has an oscillation period that is sufficiently shorter than the pulse width of the pulse signal generated by the pulse generation circuit 123.

  The pulse generation circuit 123 holds the HIGH output of the oscillator 122 for a time corresponding to a predetermined pulse width, and the LOW output of the oscillator 122 corresponds to a predetermined pulse period together with the hold time of the pulse width. By holding for a time, a pulse signal having a predetermined pulse width and a predetermined pulse period (for example, 270 Hz, duty ratio 1: n (n = 100), etc.) is generated.

  As a result, the light emitting element 121 is composed of an optical pulse having the same frequency (period) and duty ratio as the pulse signal of the pulse generation circuit 123 (periodic thin pulse train shorter than the time during which the light emission is not performed). Modulated light) is incident on one end of the optical fiber core 110.

  The light receiving means 130 includes a light receiving element 131, a current / voltage conversion circuit 134, an amplifier circuit 132, and a comparator 133. The light receiving element 131 receives leaked light obtained by bending the optical fiber 110 and photoelectrically converts it.

  The current / voltage conversion circuit 134 converts the output current of the light receiving element 131 into a voltage, and the amplification circuit 132 amplifies the output voltage of the current / voltage conversion circuit 134. The comparator 133 makes the voltage when the pulse of the output pulse signal of the amplifier circuit 132 is HIGH and the voltage when it is LOW constant.

  The pulse width measuring unit 140 includes a counter 141, the pulse period measuring unit 150 includes a counter 151, and the pulse width measuring unit 140 and the pulse period measuring unit 150 include an oscillator 142/152, a rising edge detection common to both. Circuit 143/153 and a fall detection circuit 144/154.

  That is, the pulse width measuring means 140 is configured as a pulse width measuring circuit including a counter 141, an oscillator 142, a rising edge detection circuit 143, and a falling edge detection circuit 144.

  The pulse period measuring means 150 is configured as a pulse period measuring circuit including a counter 151, an oscillator 152, a rising edge detection circuit 153, and a falling edge detection circuit 154.

  The oscillator 142/152 has an oscillation period sufficiently shorter (for example, several MHz) than the pulse width of the pulse signal generated by the pulse generation circuit 123 (corresponding to a 27 kHz pulse when the pulse period is 270 Hz and the duty ratio is 1: 100). It has.

  The rising edge detection circuit 143/153 detects the rising edge at which the voltage of the pulse signal output from the comparator 133 switches from LOW to HIGH. The falling detection circuit 144/154 detects a falling edge where the voltage of the pulse signal output from the comparator 133 switches from HIGH to LOW.

  The counter 141 starts counting when the rising edge detection circuit 143 detects the rising edge, and ends counting when the falling edge detection circuit 144 detects the falling edge. Then, the pulse width measurement circuit 140 sets the count value of the counter 141 as the pulse width.

  Conversely, the counter 151 starts counting when the falling detection circuit 154 detects a falling edge, and ends counting when the rising detection circuit 153 detects a rising edge. Then, the pulse period measurement circuit 150 sets the total value obtained by adding the count value of the counter 141 to the count value of the counter 151 as the pulse period.

  The reference determination unit 160 includes a pulse width comparison circuit 161, a pulse period comparison circuit 162, and a reference determination circuit 163.

  The pulse width comparison circuit 161 compares the pulse width measured by the pulse width measurement circuit 140 with the pulse width of the pulse signal generated by the pulse generation circuit 123. The pulse period comparison circuit 162 also compares the pulse width measurement circuit 150 with the pulse period measurement circuit 150. Is compared with the pulse period of the pulse signal generated by the pulse generation circuit 123.

  Based on the comparison result of the pulse width comparison circuit 161 and the comparison result of the pulse period comparison circuit 162, the reference determination circuit 163 counts both when the pulse width and the pulse period match. When coincidence of pulse width and pulse period continues, the number of coincidence is counted up. On the other hand, if they do not match, the counted number of matches is reset.

  When the coincidence number of the pulse width and the pulse period is continuously repeated a predetermined number of times, the comparison determination circuit 163 determines the optical fiber core wire 110 as a reference.

  When the comparison determination circuit 163 determines the comparison of the optical fiber core wire 110, the operator can be notified of the comparison by an appropriate confirmation unit 170 such as a buzzer or a display.

  According to the above optical fiber core wire contrast devices 1 and 101, the leakage light and the incident light of the optical fiber core wires 10 and 110 match, and the pulse width and the pulse period match. Since it is to be determined, reliable control determination can be performed.

  In addition, when the number of coincidence of the pulse width and the pulse period is repeated continuously for a predetermined number of times, it is possible to increase the accuracy of the comparison determination and reduce the possibility of miscontrast. Therefore, the contrast performance can be improved.

  In addition, by using a pulse signal having a duty ratio of 1: n (n> 1) as a core contrast, it is possible to reduce the power consumed by the light source and extend the life of the light source.

  Furthermore, it becomes possible to use a light source such as an LD for OTDR capable of high light emission output under a narrow pulse width condition.

It is a block diagram which shows one Embodiment of the optical fiber core wire contrast apparatus by this invention. It is a block diagram which shows other embodiment of the optical fiber core wire contrast apparatus by this invention. It is a block diagram which shows an example of the conventional optical fiber core wire contrast apparatus.

Explanation of symbols

1,101 Optical fiber core contrast device 10,110 Optical fiber (optical fiber core)
20, 120 Light emitting means 21, 121 Light emitting element 22, 122 Oscillator 123 Pulse generation circuit 30, 130 Light receiving means 31, 131 Light receiving element 32, 132 Amplifier circuit 33, 133 Comparator 134 Current / voltage conversion circuit 40, 140 Pulse width measuring means (Pulse width measurement circuit)
141, 151 Counter 142, 152 Oscillators 143, 153 Rising detection circuits 144, 154 Falling detection circuits 50, 150 Pulse period measuring means (pulse period measuring circuit)
60, 160 Control determination means 161 Pulse width comparison circuit 162 Pulse period comparison circuit 163 Control determination circuits 70, 170 Confirmation means

Claims (5)

A method of comparing an optical fiber core by comparing a pulse signal incident on an optical fiber core on a transmission side and a pulse signal obtained from leakage light of the optical fiber core on a reception side,
The pulse width and pulse period of the pulse signal obtained on the receiving side of the optical fiber core wire are monitored, and the pulse width and pulse period of the pulse signal coincide with the pulse width and pulse period of the pulse signal incident on the transmitting side. And determining the optical fiber core as a control when the optical fiber core is being used. A method of comparing an optical fiber core by comparing a pulse signal incident on an optical fiber core on a transmission side and a pulse signal obtained from leakage light of the optical fiber core on a reception side,
A pulse signal having a duty ratio of 1: n (n> 1) is incident on the optical fiber core at the transmission side, the pulse width and pulse period of the pulse signal obtained at the reception side are monitored, and the pulse width of the pulse signal And an optical fiber core wire comparison method, wherein the optical fiber core wire is determined as a control when the pulse period matches the pulse width and pulse period of the incident pulse signal having the duty ratio. An optical fiber core contrast device comprising: a light emitting means for injecting a pulse signal into an optical fiber core at a transmission side; and a light receiving means for obtaining a pulse signal from leakage light of the optical fiber core at a reception side,
Pulse width measuring means for measuring the pulse width of the pulse signal output from the light receiving means;
Pulse period measuring means for measuring the pulse period of the pulse signal output from the light receiving means;
The pulse width measured by the pulse width measuring means and the pulse period measured by the pulse period measuring means are compared with a predetermined pulse width and a predetermined pulse period of the incident pulse signal. A contrast determination means for determining the optical fiber core as a control when
An optical fiber core wire contrast device comprising: A pulse generation circuit for generating a pulse signal having a duty ratio of 1: n (n>1);
A light emitting member that converts a pulse signal of the pulse generation circuit into an optical pulse and enters one end of an optical fiber;
A light receiving member that receives and converts the leaked light of the optical fiber at the receiving side and outputs a pulse signal;
A pulse width measuring circuit for measuring a pulse width of a pulse signal of the light receiving member;
A pulse period measuring circuit for measuring a pulse period of a pulse signal of the light receiving member;
A pulse width comparison circuit that compares the pulse width measured by the pulse width measurement circuit with a predetermined pulse width of a pulse signal having the duty ratio of the pulse generation circuit;
A pulse period comparison circuit that compares the pulse period measured by the pulse period measurement circuit with a predetermined pulse period of a pulse signal having the duty ratio of the pulse generation circuit;
Based on the comparison result of the pulse width comparison circuit and the comparison result of the pulse period comparison circuit, a reference determination circuit that determines the optical fiber core wire as a reference when both the pulse width and the pulse period match,
An optical fiber core wire contrast device comprising:   4. The optical fiber core wire according to claim 3, wherein the control determination unit or the control determination circuit performs a control determination of the optical fiber core when the coincidence of the pulse width and the pulse period is continuously repeated a predetermined number of times. 4. The optical fiber core wire contrast device according to 4.

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