JPH0453282B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical fiber fusion splicing device that uses a piezo element for positioning the optical fibers when aligning and fusion splicing the optical fibers. This is about a positioning method.

More specifically, the piezo element having hysteresis characteristics and creeping characteristics can be used as a positioning element for positioning with good reproducibility and high precision.

[Prior Art] Next, the configuration of an optical fiber fusion splicing device using piezo elements will be explained with reference to FIG. In Figure 1, 1A and 1B are optical fibers, 2A and 2B are V blocks, 3A and 3B are parallel springs, 4A and 4B are piezo elements, 5A and 5B are the ends of the optical fibers, 6A and 6
B is a coating of the optical fiber, 7A and 7B are piezo element tips, 8A is a light source, and 8B is a photovoltaic meter.

The optical fibers 1A and 1B are composed of a quartz glass portion with few impurities and a covering portion of nylon, plastic, etc. provided on the outer periphery of the quartz glass portion. The optical fibers 1A and 1B shown in FIG.
It is set to B.

The V blocks 2A, 2B are connected to piezo elements 4A, 4B via parallel springs 3A, 3B. When a voltage is applied to the piezo elements 4A, 4B, the piezo element tips 7A, 7B expand and contract in response to the voltage. Therefore, when a voltage is applied to the piezo elements 4A and 4B in FIG. 1, the V blocks 2A and 2B move in the X-axis direction.
Since it is mechanically displaced in the Y-axis direction, the optical fiber 1
The centers of A and 1B can be aligned.

That is, the V block 2A, the parallel spring 3A, the piezo element 4A, and the piezo element tip 7A constitute an X-axis displacer, and the V block 2B and the parallel spring 3B
Piezo element 4B and piezo element tip 7B are Y
Configure the shaft displacement device.

In FIG. 1, light from a light source 8A is transferred to an optical fiber 1.
A, the output light from the end 5A is input into the optical fiber 1B from the end 5B of the optical fiber 1B, and the reception level of the output light is measured by a photovoltaic meter 8B connected to the optical fiber 1B.

By adjusting the blocks 2A and 2B to maximize the light receiving level, the optical fibers 1A and 1B can efficiently transmit the light from the light source 8A. Therefore, after positioning the optical fibers 1A and 1B, the end portions 5
Fusion splice A and 5B.

Next, the hysteresis characteristics of the piezo element will be explained with reference to FIG. The horizontal axis in FIG. 2 is the voltage applied to the piezo element, and the vertical axis is the mechanical displacement. As is clear from FIG. 2, there is a difference between the displacement when the voltage is changed from small to large and the displacement when the voltage is changed from large to small, and this is the hysteresis characteristic of the piezo element.

Next, the creeping characteristics of the piezo element will be explained with reference to FIG. The creeping characteristic is a characteristic in which the piezo element further expands and contracts after a certain voltage is applied to the piezo element and the piezo element is mechanically displaced.

The horizontal axis in FIG. 3 is the elapsed time after voltage application, and the vertical axis is the mechanical displacement. Figure 3A shows the characteristics when the voltage is increased, and Figure 3B shows the characteristics when the voltage is lowered. ΔE ₁ to ΔE ₄ in FIG. 3 represent changing voltages.

As is clear from FIG. 3, the shorter the time after the applied voltage changes, the larger the displacement, and the larger the amount of change in the applied voltage, the larger the displacement. Furthermore, the direction in which the displacement occurs coincides with the direction of change in the applied voltage; when the applied voltage is increased, the displacement increases, and when the applied voltage is decreased, the displacement decreases.

[Problem to be solved by the invention] As shown in Figures 2 and 3, piezo elements have hysteresis characteristics and creeping characteristics, so when using piezo elements for positioning, these characteristics must be must be compensated.

In conventional devices, a displacement detector is attached and this displacement detector is incorporated as a closed loop for control, but the control system becomes complicated. Furthermore, since the positional accuracy and resolution are determined by the performance of the displacement detector, the high resolution characteristics of the piezo element cannot be utilized.

This invention focuses on the fact that creeping characteristics match the direction of change in applied voltage, and provides means for compensating for hysteresis characteristics and creeping characteristics.
The purpose of this paper is to realize stable and reproducible positioning of an optical fiber fusion splicer using piezo elements.

[Means for Solving the Problem] In order to achieve this object, the present invention provides a voltage
For piezo elements 4A and 4B that are mechanically displaced in the range of voltage V ₀ to V ₂ , photovoltaic meter 8B
When the measurement range of is from voltage V ₃ (voltage V ₃ > voltage V ₀ ) to voltage V ₄ (voltage V ₄ < voltage V ₂ ), voltage V ₃
, increase the voltage, find the voltage V ₁ (voltage V ₃ < voltage V ₁ < voltage V ₄ ) at which the photovoltaic meter 8B indicates the maximum, then add the voltage V ₂ , then increase the voltage V ₀ . In addition,
Next, add the voltage V ₅ (voltage V ₅ = voltage V ₁ + voltage ΔV _A ), then add the voltage V ₆ (voltage V ₆ = voltage V ₅ − voltage ΔV _B , |ΔV _B |≧|ΔV _A |) In this state, the optical fiber 1A and the optical fiber 1B are fusion spliced.

[Operation] Next, the positioning method according to the present invention will be explained with reference to FIGS. 4 to 6. FIG. 4 is an explanatory diagram when measuring the received light level with the optical power meter 8B of FIG. 1. The horizontal axis in FIG. 4 is the voltage applied to the piezo element, the vertical axis in FIG. 4A is the mechanical displacement, and the vertical axis in FIG. 4B is the output level of the photovoltaic meter 8B.

From Figure 4A, the voltage applied to the piezo element is V ₀
to V ₂ and the mechanical displacement correspondingly varies from X ₀ to X ₂ .

From Figure 4 A, the voltage applied to the piezo element is V ₃ ,
When V ₁ and V ₄ , the output levels of the optical power meter 8B become D ₃ , D ₁ and D ₄ .

Then, when the voltage applied to the piezo element is V ₁ , the output level D ₁ is maximum, and the measurement range of the photovoltaic meter 8A is the voltage range from V ₃ to V ₄ , and the mechanical displacement is
It ranges from X ₃ to X ₄ .

FIG. 5 is an explanatory diagram of the creeping characteristic compensation means. In FIG. 5, the voltage V ₅ is the sum of the voltage ΔV A and the voltage _{V 1} at which the output level of the photovoltaic meter 8B is maximum.
is added, and then lowered by voltage ΔV _B from voltage V ₅ to voltage V ₆ . At this voltage V ₆ , the optical fiber 1
Fusion splice A and 1B. The voltages ΔV _A and V _B are
It is determined experimentally using the configuration shown in FIG. 1 and set in the voltage setting device 9A.

For example, in the piezo element manufactured by OWIS, the voltage V ₀
= OV, voltage V ₂ = 490V, voltage V ₁ = 200V, voltage V ₅
= 230V, voltage V ₆ = 200V, and a displacement of 0.4 μm occurs after 10 seconds with voltage V ₁ remaining.

Next, a flowchart of the positioning direction according to the present invention will be explained with reference to FIG. In step 11, the voltage applied to the piezo element is set to _V3 in FIG. 4A. In step 12, data from the photovoltaic meter 8B when the voltage is _V3 is taken.

In steps 13 to 15, data from the photovoltaic meter 8B is taken while increasing the voltage from _V3 to _V4 . In step 16, the maximum value of the photovoltaic meter 8B
Find D ₁ and the voltage V ₁ at that time. However, this voltage V ₁ changes depending on the characteristics of the piezo element.

Steps 17 to 20 are compensation means for the piezo element 4 according to the present invention. step
17, take the voltage to V ₂ and the displacement to X ₂ . That is, it is set to the upper right point in FIG. 4A. step
18, make the voltage V ₀ and the displacement X ₀ . That is, it is set to the lower left point in FIG. 4A. step
17 and 18 are for hysteresis prevention.

In step 19, the voltage is set to _V5 in FIG. Voltage V ₅ is voltage V ₁ plus voltage ΔV _A. This results in a displacement of X ₅ . step
20, the voltage V ₆ is reduced by the voltage ΔV _B from the voltage V ₅
Make it. This results in a displacement of X ₁ . In addition,
For actual positioning, the operations shown in FIG. 6 are performed independently in each of the X-axis direction and the Y-axis direction. Further, in the configuration shown in FIG. 1, the optical fibers 1A and 1B are positioned by measuring the transmitted light on the optical fiber 1B side, but the cladding mode leakage light may be monitored.

Numerical examples according to the present invention are as follows. For example, in a piezo element that has a displacement of 0.1 μm per 1 V, creeping of about 0.5 μm occurs within a few seconds after setting the voltage. On the other hand, in the case where the compensation means according to the present invention is taken, after setting the voltage,
Creeping characteristics can be suppressed to 0.1 μm or less within seconds, and 0.2 μm or less in 30 seconds or more.

[Effects of the Invention] According to the present invention, the hysteresis characteristics and creeping characteristics of the piezo element can be compensated for, resulting in the following effects.

A. Hardware can be simplified.

B. High-resolution control of piezo elements can be utilized as is.

C. Since the conventional displacement detector is not required, the device can be made smaller and lighter.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of the optical fiber fusion splicing device, Figure 2 is a hysteresis characteristic diagram of a piezo element, Figure 3 is a creeping characteristic diagram of a piezo element, and Figure 4 is an explanation of the light reception level measurement of the photovoltaic meter 8B. 5 is an explanatory diagram of the creeping characteristic compensating means, and FIG. 6 is a flowchart of the positioning method according to the present invention. 1A, 1B...Optical fiber, 2A, 2B...V
Block, 3A, 3B...Parallel spring, 4A, 4B
... Piezo element, 5A, 5B ... End, 6A, 6
B... Covering part, 7A, 7B... Tip part, 8A...
Light source, 8B...Photovoltaic meter, 9A...Voltage setting device,
9B...Controller.

Claims (1)

[Claims] 1. The first V block, the first parallel spring, and the first piezo element constitute an X-axis displacement device, and the second V block, the second parallel spring, and the second piezo element A Y-axis displacer is constructed by placing the first optical fiber with the coating removed on the first V block, placing the second optical fiber with the coating removed on the second V block, and placing the first optical fiber with the coating removed on the first V block. The end A of the optical fiber and the end B of the second optical fiber are arranged facing each other, the first piezo element is connected to the first V block via the first parallel spring, and the second piezo element is connected to the first V block through the first parallel spring. The element is connected to a second V-block via a second parallel spring, the light from the light source is input into the first optical fiber, and the output light from end A of the first optical fiber is input into the second V-block. Insert the end B of the optical fiber into the second optical fiber, measure the received level of the emitted light with a photovoltaic meter connected to the second optical fiber, and adjust the X-axis displacement device and the Y-axis displacement device. In an optical fiber fusion splicing apparatus for adjusting the received light level to a maximum and fusion splicing end A of a first optical fiber to end _B of _a second optical fiber, With respect to the first piezo element and the second piezo element which are mechanically displaced within a range, the measurement range of the photovoltaic meter is a voltage V ₃ (voltage V ₃ > voltage
V ₀ ) to voltage V ₄ (voltage V ₄ <voltage V ₂ ), voltage V ₃ is added to increase the voltage until the voltage V ₁ (voltage V ₃ < voltage V ₁ ＜
Find the voltage V ₄ ) (the position corresponding to the voltage V ₁ is displaced due to the characteristics of the first piezo element and the second piezo element), then add the voltage V ₂ , then add the voltage V ₀ ,
Next, voltage V ₅ is added (voltage V ₅ = voltage V ₁ + voltage ΔV _A ), then voltage V ₆ (voltage V ₆ = voltage V ₅ − voltage ΔV _B , |ΔV _B |≧|ΔV _A |, voltage ΔV _A and voltage ΔV _B
is determined and set experimentally. 1.) A positioning method for an optical fiber fusion splicing device, which comprises fusion splicing a first optical fiber and a second optical fiber in a state in which the first optical fiber and the second optical fiber are added.