JPH0651154A - Device for producing optical fiber coupler - Google Patents

Abstract

PURPOSE:To produce an accurate optical fiber coupler by measuring the characteristic of the optical fiber coupler in terms of each wavelength and each input with few errors in the midst of producing the optical fiber coupler. CONSTITUTION:Light from light sources 18 and 19 having different wavelength is selected by an optical switch 20, attenuated by a specified attenuating amount by a programmable optical attenuator 21, and made incident on an optical fiber 2. Output light from the coupler by the optical fibers 1 and 2 is received by a photodetector part 16, and a branching ratio is calculated by a control part 13, then drawing is stopped at a specified value. Connection loss and the output fluctuation of the light source are corrected by the attenuator 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber coupler manufacturing apparatus for manufacturing an optical fiber coupler used in an optical communication system or the like.

[0002]

2. Description of the Related Art Generally, in an optical fiber coupler manufacturing apparatus, an optical fiber coupler is manufactured by joining a plurality of optical fibers, heating, fusing, and stretching. In the manufactured optical fiber coupler, for example, an optical fiber coupler used as a demultiplexer, the wavelength characteristic for demultiplexing is determined by the extension amount. Therefore, during the drawing, light of a specific wavelength is made incident on the optical fiber, the emitted light is received, and the drawing operation is performed while monitoring. However, in the conventional optical fiber coupler manufacturing apparatus, the coupler is manufactured using only light of one wavelength during the drawing. Therefore, when it is necessary to inspect the characteristics of a plurality of wavelengths, the characteristics at each wavelength are measured after manufacturing. When measuring the demultiplexing characteristics, it is necessary to adjust the optical axis with high accuracy in order to suppress the connection loss between the optical fiber and the light receiving section. Also,
In order to improve the measurement accuracy of the branch loss, the demultiplexing loss, and the branch ratio (isolation), the difference in the connection loss in each light receiving unit that receives light from a plurality of optical fibers is set to, for example, 0.
It was necessary to suppress it to about 2 dB or less. Furthermore, in the case of multiple inputs, the characteristic of using an optical fiber other than one optical fiber measured during manufacturing as an input needs to be separately measured after manufacturing.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and the characteristics of the optical fiber coupler at each wavelength and each input can be reduced by a small error during the manufacture of the optical fiber coupler. It is an object of the present invention to provide an optical fiber coupler manufacturing apparatus capable of manufacturing an optical fiber coupler by measuring in.

[0004]

According to a first aspect of the present invention, there is provided an optical fiber coupler manufacturing apparatus for manufacturing an optical fiber coupler by fusion-spreading a plurality of optical fibers, wherein a plurality of different wavelengths are used. Light source, an optical switch for switching the light source, an optical attenuator capable of controlling the amount of light transmitted through the optical switch, a light receiver for receiving the light passing through the optical fiber coupler, and various parts of the device are controlled. It is characterized by having a control unit.

[0005]

According to the present invention, a plurality of light sources having different wavelengths,
Since it has an optical switch for switching the light sources, it is possible to perform stretching while switching light sources having different wavelengths even in the manufacture of a demultiplexer or the like. Further, in the multi-input optical fiber coupler, by using the second optical switch, one of the optical fibers on the input side is selected and connected so that light from the light source is incident, The optical fiber coupler can be manufactured while measuring the characteristics of the optical fiber on the input side. Furthermore, since it has an optical attenuator that can control the light intensity, it is possible to adjust the light intensity so as to cancel the variations in the light source and the light receiving part, the connection loss between the light receiving part and the optical fiber, etc. Fiber coupler measurements can be performed. The adjustment of the light amount can be automatically performed by the control unit.

[0006]

FIG. 1 is a schematic configuration diagram showing a first embodiment of an optical fiber coupler manufacturing apparatus of the present invention. 1, 2 in the figure
Is an optical fiber, 3 is a drum, 4 is a first pulse stage, 5 is a second pulse stage, 6 is a third pulse stage, 7 is a fourth pulse stage, 8 is an O ₂ cylinder, 9
Is O ₂ mass flow, 10 is LPG cylinder, 11 is LPG
Mass flow, 12 heating device, 13 control unit, 14 controller box, 15 computer, 16 light receiving unit, 17 light emitting unit, 18 first light source, 19 second light source, 20 optical switch , 21 are programmable optical attenuators. This figure shows a case of manufacturing a one-input and two-output optical fiber coupler.

The optical fibers 1 and 2 are fixed to the first and second pulse stages 4 and 5 without slack while the coating is removed at the portions to be fused and stretched and the glass portion of the optical fibers is exposed. Has been done. The exposed glass portions of the optical fiber are clamped so as to be in contact with each other, for example, at both ends of the glass portions. The end portion of the optical fiber on the side fixed to the first pulse stage 4 is a case of manufacturing an optical fiber coupler having one input in the example of FIG. 1, so that one optical fiber, for example, the drum 3 is used. The unwound optical fiber 2 is connected to the light emitting portion 17. If the optical fiber wound on the drum 3 is left unwound, it is not necessary to attach and detach the optical fiber wound on the drum 3 until the optical fiber wound on the drum 3 is used up. It is possible to reduce the connection work. On the other hand, the end of the optical fiber on the side fixed to the second pulse stage 5 is connected to the light receiving unit 16.

First and second pulse stages 4, 5
Is configured so that the optical fibers 1 and 2 are fixed and stretched, and is movable in the longitudinal direction of the optical fibers 1 and 2, and the optical fibers 1 and 2 are extended. Further, the second pulse stage 5 adjusts the fixed positions of the optical fibers 1 and 2,
It is configured to be movable in two directions perpendicular to the optical fiber axis direction. The heating means 12 is attached to the third pulse stage 6 and is configured to move along the optical fibers while heating the optical fibers 1 and 2. Further, the fourth pulse stage 7 is provided for moving up and down the third pulse stage 6. The first to fourth pulse stages 4 to 7 are controlled by the controller 13 and driven in their respective moving directions by pulse output from the controller 13. A pulse motor or the like can be used for driving.

The heating means 12 uses a burner to which O ₂ and LPG are supplied. O ₂ and LPG are supplied from the O ₂ cylinder 8 and the LPG cylinder 10 with their flow rates adjusted in the O ₂ mass flow 9 and the LPG mass flow 11, respectively. O ₂ mass flow 9, LPG mass flow 1
The flow rate adjustment in 1 is performed according to a command from the control unit 13.

The control unit 13 controls each unit of the optical fiber coupler manufacturing apparatus. In this embodiment, the control unit 13 is composed of a computer 14 and a controller box 15. Of course, only the computer 14 or a controller having only hard logic may be used. As described above, the control unit 13 controls the first to fourth pulse stages 4 to 7, the O ₂ mass flow 9, the LPG mass flow 11 and the like, and is connected to the light receiving unit 16 and the light emitting unit 17. Then, the optical switch 20 and the programmable optical attenuator 21 in the light emitting unit 17 are controlled, and the received light amount data output from the light receiving unit 16 is received to measure the characteristics of the optical fiber coupler.

The light receiving unit 16 has detectors D1 and D2, is connected to the optical fibers 1 and 2, respectively, receives the light transmitted through the optical fibers 1 and 2, and receives the data of the amount of received light as the control unit 13. Pass to.

The light emitting section 17 is connected to the control section 13,
While being controlled, it is connected to the optical fiber 2 and sends out light for characteristic measurement to the optical fiber 2. The light emitting section 17 is composed of first and second light sources 18 and 19, an optical switch 20, and a programmable optical attenuator 21. The first and second light sources 18, 19 are
Light sources that emit light of different wavelengths, for example,
It can be configured with a laser diode or the like. The wavelength of light emitted needs to be set according to the optical fiber coupler to be manufactured. For example, the wavelength of the first light source 18 is 1.
3 μm, and the wavelength of the second light source 19 is selected to be 1.55 μm. The optical switch 20 is a switch that selects either the first light source or the second light source, and inputs the light emitted from the selected light source to the programmable optical attenuator 21. The selection of the light source is performed according to an instruction from the control unit 13. With this optical switch 20, the wavelength of the light incident on the optical fiber 2 is selected.
The programmable optical attenuator 21 is the optical switch 20.
The light emitted from the light source selected by the control unit 1
It is attenuated according to the instruction from 3 and is incident on the optical fiber 2.

FIG. 2 shows a second optical fiber coupler according to the present invention.
It is a schematic block diagram which shows the light-emitting part of the Example of FIG. In the figure, the same parts as those in FIG.
Reference numeral 22 is an optical switch, and 23 is a V-groove connection portion. In this embodiment, a case of manufacturing a 2-input 2-output optical fiber coupler is shown. Further, except for this light emitting portion, it is the same as the first embodiment except that the optical fiber 1 is connected to the light emitting portion.

When manufacturing a two-input optical fiber coupler, it is necessary to make light incident on two input optical fibers. However, in order to measure the characteristics, it suffices that light can be incident on each side. Therefore, the programmable optical attenuator 21
The output light of 1 is input to the optical fiber 1 or 2 by the optical switch 22. The optical fiber 2 is
Similar to the first embodiment, it is connected to the optical switch 22 while being wound on the drum 3. The optical fiber 1 has already been cut, and the optical switch 22 is connected via the V-groove connection portion 23.
Connected with. The optical switch 22 and the optical switch 20 for switching the light source allow light of a predetermined wavelength to be incident on an arbitrary optical fiber. The attenuation amount of the programmable optical attenuator 21 is controlled according to the switching of the optical switch 22.

FIG. 3 shows a third embodiment of the optical fiber coupler of the present invention.
It is a schematic block diagram which shows the Example of. In the figure, the same parts as those in FIG. 1 and FIG. Two
Reference numerals 4 and 25 are broadband couplers. In this embodiment, a case of manufacturing a 2-input 2-output optical fiber coupler is shown. Further, in FIG. 3, a light emitting portion, an optical fiber, a light receiving portion,
Only the control unit is shown, and the other configurations are the same as those in the first embodiment, and therefore omitted.

In the third embodiment, wideband couplers 24 and 25 are inserted between the optical switch 22 inserted in the second embodiment and the optical fibers 1 and 2, respectively, and the optical fiber 1 or 2 is inserted. A part of the light incident on is branched. The branched light is received by the auxiliary detectors S1 and S2 provided in the light receiving unit 16, and the light incident on the optical fibers 1 and 2 is monitored. When the light amount of the light source fluctuates based on the monitor output, the control unit 13 controls the programmable optical attenuator 21 to ensure a uniform incident light amount.

In the first to third embodiments, the one-input, two-output or two-input, two-output optical fiber couplers have been described. However, the optical switch for the one-input n-output and m-input n-output optical fiber couplers is also used. By changing the configuration, the same configuration can be achieved.

The operation of the optical fiber coupler manufacturing apparatus of the present invention will be described with reference to FIGS. 4 to 15 based on the third embodiment. The first and second embodiments can be considered to be different from the third embodiment in that the operation of switching the input side optical fiber and the operation of detecting the amount of light incident on the optical fiber are excluded. The description of the operation of the second embodiment will be omitted. First, the wavelength of the second light source, lambda _1, is described as the lambda _2, the wavelength lambda _1, lambda _2, for example 1.3 .mu.m,
The wavelength can be 1.55 μm.

First, the amount of attenuation at each wavelength such that the voltage generated at the detectors D1 and D2 at both wavelengths λ ₁ and λ ₂ has a predetermined value is measured in advance. That is, in FIG. 4, the amount of light emitted from the broadband couplers 24 and 25 at each wavelength is received by the auxiliary detectors S1 and S2, and the attenuation amount is set so that both have a predetermined value.

Next, in FIG. 5, the optical fiber 1 is connected between the broadband coupler 24 and the detector D2. The optical fiber 1 to be connected may be wound around a drum, for example. The optical switch 20 is switched to the first light source 18, and the optical switch 22 is switched to the broadband coupler 24. In addition, the programmable optical attenuator is set to the attenuation amount according to the wavelength λ ₁ . Then, the voltage value V ₃₂ corresponding to the amount of light received by the detector D2 at the wavelength λ ₁ is recorded.

[0021] In FIG. 6, to select the wavelength lambda ₂ by switching the optical switch 20, sets a programmable optical attenuator in the attenuation amount in accordance with the wavelength lambda _2, the voltage value V ₅₂ corresponding to the received light amount of the detector D2 recording To do.

In FIG. 7, the optical fiber 1 is cut to a predetermined length, disconnected from the detector D2, and connected to the detector D1. In addition, the optical fiber 2 is connected to the broadband coupler 2
5 and detector D2. Then, the voltage value V ₅₁ at the wavelength λ ₂ is recorded.

In FIG. 8, the optical switch 20 is switched to select the first light source, the programmable optical attenuator is set to the attenuation amount according to the wavelength λ _1, and the voltage value V ₃₁ at the detector D1 is recorded.

[0024] In FIG. 9, switching the optical switch 22 to the optical fiber 2, the voltage value corresponding to the amount of light emitted to the detector D2 through the optical fiber 2 at the wavelength lambda ₁ V _'32
To record. Further, in FIG. 10, by switching the optical switch 20 selects the second light source, also sets the programmable optical attenuator in the attenuation amount in accordance with the wavelength lambda _2, the voltage value at the wavelength lambda ₂ via the optical fiber 2 to record the V _'52.

Here, the optical fibers 1 and 2 are mounted on the first and second pulse stages 4 and 5 in FIG. Figure 1
1, the optical switch 20 is switched to select the first light source, the programmable optical attenuator is set to the attenuation amount according to the wavelength λ ₁ , and the optical switch 22 is switched to the detector D1 to detect the voltage value V of the detector D1. ₃₁ is recorded again, and it is confirmed that there is not much difference from the voltage value recorded in the step shown in FIG. When there is a big difference, an error is issued.

Next, fusion and drawing are performed. In FIG. 1, the third pulse stage 6 is aligned with the position to be heated, the fourth pulse stage 7 is lowered, and the O ₂ and LP supplied from the O ₂ mass flow 9 and the LPG mass flow 11 are supplied.
The mixed gas of G is burned in the heating device 12 to heat the optical fibers 1 and 2 and to fuse them first. After fusing, the first and second pulse stages 4 and 5 are moved to pull and stretch the optical fibers 1 and 2. During this stretching,
Perform the following measurements.

First, as shown in FIG. 12, the voltage value x of the detector D1 during stretching and the voltage value y of the detector D2 during stretching are recorded. Since fusion has already been performed, the light from the light source reaches the detectors D1 and D2 during stretching. At this time, the loss due to the optical fiber coupler can be calculated by Loss = −10 log (x / V ₃₁ + y / V ₃₂ ). Further, the branching ratio can be calculated by the branching ratio = (x / V ₃₁ ) / (x / V ₃₁ + y / V ₃₂ ).

Further, as shown in FIG. 13, the optical switch 20 is switched to select the second light source, the programmable optical attenuator is set to the attenuation amount according to the wavelength λ _2, and the voltage of the detectors D1 and D2 at this time is set. Record the values x ₁ and y ₁ . The loss and the branching ratio of the optical fiber coupler at the wavelength λ ₂ are: Loss = −10 log (x ₁ / V ₅₁ + y ₁ / V ₅₂ ) Branching ratio = (x ₁ / V ₅₁ ) / (x ₁ / V ₅₁ + y ₁ / It can be calculated by V ₅₂ ).

In FIG. 14, the optical switch 22 is switched so that the light from the light source enters the optical fiber 2,
Record the voltage values x ₂ and y ₂ of the detectors D1 and D2.
Loss and branching ratio of the optical fiber coupler at this time are Loss when α ₅ = (V ₅₂ / V ′ ₅₂ ) x ₂ / V ₅₁ β ₅ = (V ₅₂ / V ′ ₅₂ ) y ₂ / V ₅₂ = −10 log (α ₅ + β ₅ ) Branching ratio = α ₅ / (α ₅ + β ₅ ) It can be calculated.

In FIG. 15, the optical switch 20 is switched to select the first light source, the programmable optical attenuator is set to the attenuation amount according to the wavelength λ ₁ , and the detector D
Record the voltage values x ₃ and y ₃ of 1 and D2. Loss and branching ratio of the optical fiber coupler at this time are Loss when α ₃ = (V ₃₂ / V ′ ₃₂ ) × ₃ / V ₃₁ β ₃ = (V ₃₂ / V ′ ₃₂ ) y ₃ / V ₃₂ = −10 log (α ₃ + β ₃ ) Branching ratio = α ₃ / (α ₃ + β ₃ )

When the optical fiber is stretched, the optical fiber is stretched to a predetermined value while comparing the preset branching ratio with the branching ratio calculated as described above. In the measurements and calculations shown in FIGS. 12 to 15, four measurements and calculations may be performed at any time during stretching, or some or one of the four measurements may be performed while stretching, and the rest may be measured. The stretching may be performed after stretching to a certain extent, and the amount of stretching can be finely adjusted.

The measurement of the attenuation amount for each light source shown in FIG. 4 is performed every time one or a plurality of optical fiber couplers are manufactured, and the attenuation amount is changed in accordance with the fluctuation of each light source. Therefore, the measurement corresponding to the light amount of the light source can always be performed.

[0033]

As is apparent from the above description, according to the present invention, the characteristics of the optical fiber coupler are measured by using light of a plurality of wavelengths during the drawing in the drawing step in the manufacturing process of the optical fiber coupler. By carrying out the drawing, an optical fiber coupler having desired characteristics can be easily manufactured. Also, in the process of manufacturing a multi-input optical fiber coupler, it is possible to manufacture a desired optical fiber coupler by extending the optical fibers on the respective input sides while measuring the characteristics. Further, there is an effect that it is possible to perform accurate measurement by eliminating influences such as variations and fluctuations in the light amount of the light source, connection loss of the optical fiber to the light receiving unit, and the like.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of an optical fiber coupler manufacturing apparatus of the present invention.

FIG. 2 is a schematic configuration diagram showing a light emitting portion of a second embodiment of the optical fiber coupler of the present invention.

FIG. 3 is a schematic configuration diagram showing a third embodiment of the optical fiber coupler of the present invention.

[Figure 4]

FIG. 15 is an explanatory diagram of the operation of the embodiment of the present invention.

[Explanation of symbols]

1, 2 optical fiber 3 drum 4 first pulse stage 5 second pulse stage 6 third pulse stage 7 fourth pulse stage 8 O ₂ cylinder 9 O ₂ mass flow 10 LPG cylinder 11 LPG mass flow 12 heating device 13 control Section 14 controller box 15 computer 16 light receiving section 17 light emitting section 18 first light source 19 second light source 20 optical switch 21 programmable optical attenuator 22 optical switch 23 V-groove connection section 24, 25 broadband coupler

Claims (1)

[Claims] 1. An optical fiber coupler manufacturing apparatus for manufacturing an optical fiber coupler by fusion-spreading a plurality of optical fibers, wherein a plurality of light sources having different wavelengths, an optical switch for switching the light sources, and an optical switch are provided. An optical fiber coupler manufacturing apparatus comprising: an optical attenuator capable of controlling the amount of transmitted light, a photoreceiver for receiving light passing through an optical fiber coupler, and a control section for controlling each section of the apparatus.