JP3206607B2 - Optical fiber fusion splicer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber fusion splicing apparatus for discharging and fusing at least one pair of optical fibers whose end faces are abutted to each other.

[0002]

2. Description of the Related Art As the demand for communication increases, the number of cores of an optical cable is steadily increasing, and a more accurate fusion splicing technique is desired.

[0003] In the optical fiber fusion technique, the amount of heat of air discharge which determines the fusion of the fiber is an important factor for realizing low splice loss, and there is an appropriate range for each applied fiber.

Therefore, there has been proposed a device which detects a discharge current and an atmospheric pressure so that the amount of heat applied to an optical fiber becomes constant, and controls the current in accordance with the detected atmospheric pressure (Japanese Patent Laid-Open No. 63-106706). According to this device, the air pressure is detected and automatically fed back to the discharge current, so that the amount of heat generated by the discharge becomes constant.

[0005]

However, according to this device, it is not possible to adapt to various environmental changes (temperature, humidity, etc.) other than the atmospheric pressure, so that the discharge state cannot be controlled accurately. was there.

Accordingly, an object of the present invention is to provide a device capable of accurately controlling the discharge state, that is, the calorific value of air discharge.

[0007]

In order to achieve the above object, the present invention provides an optical system for observing an optical fiber, an image processing system for analyzing a fiber image of the observed optical fiber to determine a fusion amount, and A discharge electrode for fusing the end of the optical fiber;
Control means for controlling the discharge power by increasing or decreasing the discharge current, wherein the control means determines whether or not the actual melting amount of the optical fiber is within an appropriate range, and the actual melting amount is out of the appropriate range. In this case, the difference between the actual melting amount and the optimum melting amount obtained in advance corresponding to the number of optical fiber cores is obtained, and based on the difference in the melting amount, the number of optical fiber cores is determined in advance. It is characterized in that the correction amount of the discharge current is obtained from the conversion table storing the relationship between the obtained difference in the melting amount and the correction amount of the discharge current, the discharge current is corrected, and the discharge power is maintained at an appropriate value within a predetermined range. And

[0008]

According to the present invention, if the external environment such as the atmospheric pressure, the temperature, and the humidity changes, the amount of melting of the fiber changes.
The amount of fusion of the fiber has a fixed relationship with the discharge power, and the control means determines whether or not the actual amount of fusion of the fiber is within an appropriate range. Then, when the actual melting amount is out of the appropriate range, a melting amount difference between the actual melting amount and the optimum melting amount obtained in advance corresponding to the number of optical fiber cores is determined, and based on the difference in the melting amount. Then, the correction amount of the discharge current is obtained from the conversion table storing the relationship between the fusion amount difference and the correction amount of the discharge current obtained in advance corresponding to the number of optical fibers, and the discharge current is corrected. As a result, the amount of fusion of the fiber, that is, the discharge power is maintained at an appropriate value within a desired range.

[0009]

An embodiment of the present invention will be described below with reference to the accompanying drawings. In the description, the same elements will be denoted by the same reference symbols, without redundant description.

FIG. 1 is an explanatory view showing a fusion splicing apparatus according to a first embodiment of the present invention. The fusion splicing apparatus according to the present embodiment includes a microscope 1 as an optical system, a camera 2 and an image memory 3 as an image processing system, a CPU 4, a program memory 5, a data memory 6, and a discharge circuit 7 as control means. (See FIG. 3A).

The tape-shaped optical fiber 8 has a part of the coating removed, and a plurality of exposed optical fiber cores 8 a are held in a state of being aligned by a V-groove substrate 9. Since the pair of V-groove substrates 9 are arranged so that the V-grooves coincide with each other, the ends of the held pair of optical fibers 8a are in an abutted state.

An illumination light source 10 and a microscope 1 are arranged above and below the optical fiber 8a butted against each other, so that an enlarged fiber image of the optical fiber 8a is formed on the camera 2. Further, a pair of discharge electrodes 11 are arranged on both sides of the butted optical fiber 8a. Since the optical fibers 8a are arranged slightly away from the straight line connecting the discharge electrodes 11, the heat generated by the discharge can be given to the optical fibers 8a almost uniformly.

An image memory 3 is connected to the camera 2 and stores the enlarged image data of the optical fiber 8a. As the camera 2, a CCD camera having a built-in CCD 2a (see FIG. 1B) can be used, and as the image memory 3, a frame memory can be used.

A program memory 5, a data memory 6, and a discharge circuit 7 are connected to the CPU 4, and based on the melting amount of the optical fiber 8a obtained from the above-described image processing system, the melting amount is within an appropriate range. It is determined whether or not there is, and when the melting amount is out of the proper range, a control signal is sent to the discharge circuit 7 in order to increase or decrease the discharge current of the discharge electrode 11. Thereby, the discharge power of the discharge electrode 11 changes,
The melting amount of the optical fiber 8a is maintained at an appropriate value. The program memory 5 stores a program for executing this control, and the data memory 6 stores necessary data described below. Hereinafter, an example of a control method in the CPU 4 will be described.

First, the relationship between the connection loss α and the discharge current I is measured, and the range of an appropriate current for obtaining a low loss is determined. Next, information indicating the relationship between the discharge current I and the fiber melting amount M is collected. Fiber melt quantity M, using the apparatus shown in FIG. 1, after the butt optical fiber 8a captured in the camera 2 at regular intervals L _1, and making brief discharge,
Measuring the end face spacing L ₂ at that time (see Figure 2). Since these measured values are measured using the camera 2 based on the enlarged fiber image 8a ', the measured values can be obtained with high accuracy. Then, the difference between L ₂ and L _1, i.e., defined as the fiber melt volume erosion of the fiber. In the case of a multi-core fiber, a fiber serving as a reference (for example, an outer fiber) may be selected, and the fiber fusion amount may be determined based on this.

FIG. 3 is an example of a graph created based on the above information, and shows the relationship between the connection loss α and the discharge current I, and the relationship between the discharge current I and the amount of fiber fusion M. Based on this graph, a relational expression between the discharge current I and the fiber melting amount M can be obtained. When a function indicating this relation is represented by f, the relational expression can be expressed as follows.

M = f (I) (1) This relational expression (1) is stored in the data memory 6 in advance as a conversion table. Further, assuming a case where the use environment at the site changes and the amount of fiber fusion deviates from an appropriate range, the amount of fiber fusion M measured at that time is assumed.
m and the initial optimum fiber melting amount Mo, the current correction amount Δ
A relational expression for calculating I is obtained in advance. If a function indicating this relation is represented by f ⁻¹ , the relational expression can be expressed as follows.

ΔI = f ⁻¹ (Mm−Mo) (2) This relational expression (2) is also stored in the data memory 6 in advance as a conversion table. The discharge current is automatically corrected based on this correction amount.

An experiment was conducted to determine whether or not the correction was properly performed using the above-described apparatus. The experiment will be described below. In the experiment, discharge fusion in a high place environment and discharge fusion using a deteriorated electrode rod were used. As described above, even when the fiber fusion amount deviates from the appropriate range, the discharge current is appropriately corrected, and low-loss fusion can be realized.

As described above, according to the fusion splicing apparatus of this embodiment, the change with time such as deterioration of the discharge electrode rod, the atmospheric pressure, the temperature,
Even if the use environment such as humidity changes, the discharge power that affects the connection loss can be monitored, and feedback can always be made to be appropriate. Therefore, it is effective for connection work under an unstable environment where the use environment frequently changes.

Further, since the above-mentioned feedback is automatically performed, the on-site worker can connect the optical fiber with low loss without any technique for adjusting the discharge power.
High practicality.

The present invention is not limited to the above embodiment. For example, the specific structure of the optical system and image processing system, the number and type of optical fibers used, and the like vary depending on the fusion conditions, and do not limit the present invention.

[0023]

As described above, the present invention can realize a low-loss optical fiber connection without depending on the external environment.

[Brief description of the drawings]

FIG. 1 is a view showing an optical fiber fusion splicing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a fiber image before and after discharge obtained from an image processing system of a fusion device according to an embodiment of the present invention.

FIG. 3 is a diagram showing an example of a graph serving as a basis of data stored in a data memory of the fusing apparatus according to the embodiment of the present invention.

[Explanation of symbols]

1. Microscope, 2. Camera, 3. Image memory, 4. CP
U, 5: Program memory, 6: Data memory, 7
... discharge circuit, 8 ... tape type optical fiber, 9 ... V-groove substrate,
10: Light source for illumination, 11: Discharge electrode.

Claims (1)

(57) [Claims] 1. An optical fiber fusion splicing apparatus for discharging and fusing at least one pair of optical fibers whose end faces are butted together, comprising: an optical system for observing the optical fibers; and a fiber image of the observed optical fibers. An image processing system for analyzing and determining the amount of fusion, a discharge electrode for fusing the end of the optical fiber, and control means for controlling discharge power by increasing or decreasing a discharge current, wherein the control means comprises: It is determined whether or not the actual amount of fusion of the fiber is within an appropriate range.If the actual amount of fusion is out of the appropriate range, it is determined in advance in accordance with the actual amount of fusion and the number of cores of the optical fiber. Determine the melting amount difference from the obtained optimum melting amount, based on the melting amount difference, the relationship between the previously determined melting amount difference corresponding to the number of optical fibers and the correction amount of the discharge current. From the stored conversion table, the discharge current An optical fiber fusion splicing apparatus, wherein a discharge amount is corrected by obtaining a correction amount, and the discharge power is maintained at an appropriate value within a predetermined range.