WO2009099281A4

WO2009099281A4 - Optical fiber connecting device and optical fiber quality measuring system using same

Info

Publication number: WO2009099281A4
Application number: PCT/KR2009/000422
Authority: WO
Inventors: 육태경; 박래혁; 박지상; 손순일; 신형수
Original assignee: 엘에스전선 주식회사
Priority date: 2008-02-05
Filing date: 2009-01-29
Publication date: 2010-01-28
Also published as: KR20090085885A; WO2009099281A3; KR100956485B1; WO2009099281A2

Abstract

The present invention relates to an optical fiber connecting device and an optical fiber quality measuring system using same. The optical fiber quality measuring system of the present invention includes a measuring unit for measuring optical fiber quality including PMD (Polarization Mode Dispersion) or optical loss of optical fiber; a connecting optical fiber including a first optical fiber connected to a transmitter end of the measuring unit and a second optical fiber connected to a receiver end of the measuring unit; an objective optical fiber connected to the first optical fiber and the second optical fiber such that optical quality of the objective optical fiber can be measured by the measuring unit; and a connector for physically and optically connecting the connecting optical fiber and the objective optical fiber. The connector includes a vacuum pump for generating vacuum pressure; and a contact retention unit for supporting the connecting optical fiber and the objective optical fiber which are uncoated and connected to each other, and retaining the contact state by sucking the connecting optical fiber and the objective optical fiber through the use of the vacuum pressure generated from the vacuum pump. The vacuum connection system of the present invention has a connection setting time shorter than that of a mechanical connection system and is suitable for use in the mass-produced optical fiber industry.

Description

Optical fiber connection apparatus and optical fiber quality measurement system using the apparatus

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for connecting an optical fiber, and more particularly, to an apparatus for connecting an optical fiber to be measured connected to a measuring instrument and a measurement optical fiber to be measured, and an optical fiber quality measuring system using the apparatus.

Recently, as the speed of optical communication and the increase of the distance have been advanced, standard specifications for optical loss and Polarization Mode Dispersion (PMD) among the quality characteristics of the optical fiber have been strengthened. Optical loss refers to a phenomenon in which an optical signal transmitted to an optical fiber is weakened inside, and the optical loss acts as a factor limiting a transmission distance of the optical signal. In addition, polarization mode dispersion refers to a phenomenon in which a speed difference occurs between each polarization mode transmitted to the inside of the optical fiber due to anisotropy of refractive index (asymmetry) of the optical fiber cross-section (i.e., core layer) generated in manufacturing the optical fiber. The transmission bandwidth of the optical fiber in which the polarization mode dispersion is generated becomes narrow and the transmission distance becomes short.

In order to prevent the shipment of the optical fiber in which the optical loss or the polarization mode dispersion occurs, in the optical fiber manufacturing site, the quality of the optical fiber is measured before the optical fiber is shipped to find out the optical fiber not meeting the predetermined standard value. That is, the final optical fiber is measured optical loss and polarization mode dispersion through a measuring device, and the optical fiber which does not meet the predetermined reference value is discarded.

In order to measure the final optical fiber quality, the ends of the optical fibers to be measured, which are respectively connected to the transmitter and the receiver of the PMD measuring instrument or optical loss measuring instrument, are connected to both ends of the finally manufactured optical fiber (that is, the measuring optical fiber). When the optical signal is transmitted from the measuring equipment, the optical signal is sequentially received via the transmitting unit, the transmitting optical fiber, the measuring optical fiber, and the receiving optical fiber, and finally received by the receiving unit of the measuring equipment. The measuring instrument then analyzes the received optical signal to determine whether the optical loss or polarization mode dispersion of the measured optical fiber meets a reference value.

However, in the process of connecting the measurement optical fiber and the measurement optical fiber, connection loss such as miss alignment, angular tilt, and end separation may appear, The optical loss and the measurement value of the polarization mode dispersion are distorted. Accordingly, the process of connecting the final optical fiber to the measured optical fiber functions as an important parameter in the process of measuring the quality of the final optical fiber.

A method of connecting the measured optical fiber to the measured optical fiber is a fusion splice method or a mechanical connection method. However, since the fusion splicing system permanently connects the measured optical fiber with the measured optical fiber, the splicing connection method is not suitable as a method of connecting the optical fiber to be shipped. In the mechanical connection method, since the measured optical fiber and the measurement optical fiber are connected to each other using a connector or the like, the connection loss is different according to the skill of the operator. In addition, the mechanical connection method is not suitable for the workplace where the optical fiber to be measured and the measurement optical fiber are connected to each other for a long time, thereby mass-producing the optical fiber.

The present invention has been proposed in order to solve the problems described above, and provides an optical fiber connection apparatus having a fast connection setting time and a low deviation of connection loss without permanent fusion of a measured optical fiber and a measurement optical fiber, and an optical fiber quality measurement system using the apparatus It has its purpose.

Other objects and advantages of the present invention will become apparent from the following description, and it will be understood by those skilled in the art that the present invention is not limited thereto. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

According to a first aspect of the present invention, there is provided a measuring apparatus for measuring optical quality characteristics such as PMD and optical loss of an optical fiber. A connection optical fiber comprising a first optical fiber connected to a transmitting end of the measuring device and a second optical fiber connected to a receiving end of the measuring device; A measurement optical fiber connected to the first and second optical fibers to measure optical quality characteristics by the measurement device; And a connecting device for physically connecting and connecting the connecting optical fiber and the measuring optical fiber optically, the connecting device comprising: a vacuum pump for generating a vacuum pressure; And a contact holding means for holding the connecting optical fiber and the measuring optical fiber in contact with each other in a state in which the cover is removed, while maintaining the contact state by sucking the connecting optical fiber and the measuring optical fiber by using the vacuum pressure generated in the vacuum pump .

Further, the optical fiber quality measurement system further includes a vacuum pipe for transmitting the vacuum pressure of the vacuum pump to the contact holding means.

And the contact holding means includes a V-shaped groove for supporting the connecting optical fiber and the measuring optical fiber; A slot formed in a bottom surface of the V-shaped groove; And an exhaust passage communicating the vacuum pipe and the slot. Preferably, the width of the slot is smaller than the diameter of the connecting optical fiber and the measuring optical fiber.

Meanwhile, when measuring the polarization mode dispersion of the measurement optical fiber, the vacuum pressure of the vacuum pump is preferably maintained at 0.15 bar to 0.40 bar, and when measuring the optical loss of the measurement optical fiber, , And is preferably maintained at 0.20 bar to 0.35 bar.

The contact holding means further includes a pressure sensor for measuring the pressure of the exhaust passage and a display device for externally displaying the pressure value measured by the pressure sensor.

According to a second aspect of the present invention, there is provided an optical fiber connection apparatus including a vacuum pump for generating a vacuum pressure; And contact holding means for holding the two optical fibers to be physically contacted for optical connection while maintaining the contact state by sucking and fixing the two optical fibers on their supporting surfaces by using the vacuum pressure of the vacuum pump .

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description of the invention given above, serve to further the understanding of the technical idea of the invention, And should not be construed as limiting.

1 is a diagram showing a configuration of a system for measuring optical fiber quality according to an embodiment of the present invention.

2 is a sectional view of a jig according to an embodiment of the present invention.

3 is a perspective view of a jig according to an embodiment of the present invention.

Description of the Related Art

110: Vacuum pump 111: Control switch

112: vacuum pipe 120: jig

121: pressure sensor 122: vacuum pressure display unit

123: engaging portion 124: exhaust passage

125: inlet 130: measuring optical fiber

140: Measuring device 141: Transmitter

142: Receiver 143, 144: Measured optical fiber

The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, in which: There will be. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1, a system for measuring optical fiber quality according to an embodiment of the present invention includes a vacuum pump 110 for generating a vacuum pressure, a measurement

optical fiber

143 and 144, A jig 120 for maintaining a connection state while supporting a polarization beam splitter 130 and a polarization mode dispersion (PMD) or a measurement device 140 for measuring optical loss.

The vacuum pump 110 includes a control switch 111 for controlling vacuum pressure, and is connected to a detachable vacuum pipe 112.

The jig 120 is connected to the detachable vacuum pipe 112 and is connected to the measured

optical fibers

143 and 144 and the measurement optical fiber 130 connected to each other in a state in which the cover is removed from the V- . It is preferable that index matching oil is injected to the connection portion of the

optical fibers

143 and 144 and the measurement optical fiber 130 to minimize the connection loss of the

optical fibers

143, 144 and 130.

Further, an exhaust passage is formed from the lower end of the V-groove of the jig 120 to a position connected to the vacuum pipe 112, thereby forming an air passage between the vacuum pipe 112 and the lower end of the V- . Accordingly, when the vacuum pump 110 generates vacuum pressure and sucks air, the measured

optical fibers

143 and 144 and the measurement optical fiber 130 supported in the V-shaped groove are sucked and the connection state is fixed.

The measurement apparatus 140 is a PMD measurement apparatus or an optical loss measurement apparatus, including a transmission unit 141 through which optical signals are transmitted and a reception unit 142 through which optical signals are received. The measurement

optical fibers

143 and 144 are connected to the transmission unit 141 and the reception unit 142 and the measurement device 140 transmits the optical signal to the measured optical fiber 143 connected to the transmission unit 141. The optical signal is finally received by the receiving unit 142 via the measuring optical fiber 130 and the measured optical fiber 144 connected to the receiving unit 142 in sequence. Accordingly, the measurement apparatus 110 measures the optical loss or the polarization mode dispersion based on the received optical signal.

2, the jig 120 according to an embodiment of the present invention includes a pressure sensor 121 and a vacuum pressure display portion 122 and includes a coupling portion 123, an exhaust passage 124, (125) is formed.

The pressure sensor 121 is connected to the vacuum pressure display unit 122 and measures the vacuum pressure generated in the exhaust passage 124.

The vacuum pressure display unit 122 displays the vacuum pressure measured by the pressure sensor 121.

The coupling part 123 inserts the vacuum pipe 112 and transmits the vacuum pressure generated by the vacuum pump 110 to the exhaust passage 124.

The exhaust passage 124 is a passage for discharging the air between the engaging portion 123 and the suction port 125. When vacuum pressure is generated in the vacuum pump 110, air around the suction port 125 is sucked.

The inlet 125 is located on the bottom surface of the V-shaped groove in which the measured

optical fibers

143 and 144 and the measurement optical fiber 130 are aligned and extends along the longitudinal direction of the V-shaped groove. The suction port 125 sucks the measurement optical fiber 130 and the measured

optical fibers

143 and 144 to maintain the connection state of the

optical fibers

130, 143 and 144 when vacuum pressure is generated in the vacuum pump 110.

Meanwhile, the measurement optical fiber 130 and the

optical fibers

143 and 144 located on the bottom surface of the V-shaped groove may be sucked into the exhaust passage 124 due to the generation of vacuum pressure. Therefore, the size of the suction port 125 is preferably narrower than the diameter of the core wires of the

optical fibers

130, 143 and 144 to prevent the phenomenon.

Referring to FIG. 3, the suction port 125 is located on the bottom surface of the V-shaped groove and extends along the longitudinal direction of the V-shaped groove. Accordingly, when the vacuum pump 110 generates vacuum pressure while the measurement optical fiber 130 and the measured

optical fibers

143 and 144 are connected and placed on the suction port 125, the two

optical fibers

130, 143, 144 are fixed in the connection state by the suction force of the suction port 125. Accordingly, it is possible to prevent the connection state of the two

optical fibers

130, 143 and 144 from being deformed due to external environment such as jiggling of the jig 120 and wobbles 130, 143 and 144 of the optical fiber.

Further, the vacuum pressure display section 122 displays the vacuum pressure of the exhaust passage 124 measured by the pressure sensor 121 as a numerical value.

Through the above-described embodiments, the operator can easily connect the measured

optical fibers

143 and 144 and the measurement optical fiber 130. The operator can easily release the connection state of the measured

optical fibers

143 and 144 and the measurement optical fiber 130 by removing the vacuum pressure of the jig 120 through the control switch 111 of the vacuum pump 110 have.

Table 1 is a table showing polarization mode dispersion (PMD) values measured while varying the vacuum pressure in an optical fiber connected by a vacuum connection method according to the present invention.

Table 1

No	Vacuum pressure (bar)	Measurement PMD [ps / km ^1/2 ]
Experiment 1	0.05	Not measurable
Experiment 2	0.10	Not measurable
Experiment 3	0.15	0.059
Experiment 4	0.20	0.055
Experiment 5	0.25	0.050
Experiment 6	0.30	0.060
Experiment 7	0.35	0.072
Experiment 8	0.40	0.102
Experiment 9	0.45	0.157
Experiment 10	0.50	0.210

That is, when the two optical fibers are connected, when the measured

optical fibers

143 and 144 and the measurement optical fiber 130 are connected to each other using a conventional fusion splicing method known to have the lowest connection loss, the PMD value is 0.058 ps / km ^{1 / 2} (measurement error ± 0.05 ps). Therefore, when the vacuum connection method according to the invention as it is set to the pressure is less than 0.15 bar and 0.40 bar in the binary jig (120), with the PMD ^{^{0.050ps / km 1/2 ~ 0.102ps}} / km 1/2 It can be confirmed that it is optimized.

Table 2 is a table showing optical loss values measured while varying the vacuum pressure in an optical fiber connected by the vacuum connection method according to the present invention.

Table 2

No	Vacuum pressure (bar)	Optical loss measurement [dB / km @ 1550nm]
Experiment 1	0.05	0.301
Experiment 2	0.10	0.290
Experiment 3	0.15	0.300
Experiment 4	0.20	0.180
Experiment 5	0.25	0.182
Experiment 6	0.30	0.182
Experiment 7	0.35	0.183
Experiment 8	0.40	0.186
Experiment 9	0.45	0.189
Experiment 10	0.50	0.200

When the measured optical fibers 143 and 444 are connected to the measurement optical fiber 130 by a conventional fusion splicing method known to exhibit the least connection loss when connecting two optical fibers, the optical loss value is 0.182 dB / km Error ± 0.002). Accordingly, in the case of the vacuum connection method according to the present invention, when the vacuum pressure generated in the jig 120 is set to 0.20 bar or more and 0.35 or less, the optical loss value is optimized to 0.180 db / km to 0.183 db / km .

Tables 3 and 4 are tables showing the standard deviation of the PMD values and the standard deviation of the optical loss values measured by the same operator repeatedly connecting the same optical fiber to the mechanical connection system and the vacuum connection system according to the present invention.

Table 3

division	Vacuum connection method	Mechanical connection method
Average	0.055	0.059
Standard Deviation	0.003	0.015
Connection setup time	5 seconds	20 seconds

Table 4

division	Vacuum connection method	Mechanical connection method
Average	0.181	0.182
Standard Deviation	0.002	0.040
Connection setup time	5 seconds	20 seconds

As can be seen from Tables 3 and 4, when the same operator repeatedly connected and disconnected the same optical fiber by the vacuum connection method according to the present invention to measure the quality (i.e., PMD or optical loss) of the optical fiber, Vacuum connection method has lower standard deviation of PMD and optical loss than mechanical connection method. In addition, the vacuum connection method has an average connection setting time of 5 seconds, which is faster than the mechanical connection method. In the vacuum connection method according to the present invention, PMD and optical loss of the measurement optical fiber 130 are measured to be lower than the mechanical connection method. That is, the vacuum connection method according to the present invention can reduce the connection loss more than the mechanical connection method.

Table 5 is a table showing PMD values and optical loss values measured by a plurality of operators connecting the same optical fiber by a mechanical connection method and a vacuum connection method according to the present invention. It can be seen from Table 5 that the vacuum connection method according to the present invention has lower standard deviation between PMD and optical loss than the mechanical connection method. That is, the mechanical connection method is severely varied according to the skill of the operator, whereas the vacuum connection method according to the present invention is less influenced by the skill of the operator.

Table 5

division	PMD [ps / km ^1/2 ]		Optical loss [db / km]
division	Mechanical connection method	Vacuum connection method	Mechanical connection method	Vacuum connection method
Worker 1	0.075	0.059	0.182	0.182
Worker 2	0.089	0.061	0.183	0.183
Worker 3	0.065	0.061	0.185	0.183
Worker 4	0.088	0.061	0.189	0.183

As described above, the vacuum connection method according to the present invention is useful for a workplace where a connection setting time is shorter than a mechanical connection method, thereby mass-producing optical fibers. Particularly, the vacuum connection method according to the present invention can be usefully used in an optical fiber inspection field in which the quality state of an optical fiber must be measured by temporarily connecting the optical fiber without permanently connecting the optical fiber.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. The present invention is not limited to the drawings.

The vacuum connection method according to the present invention is useful for a workplace where a connection setting time is shorter than a conventional mechanical connection method, thereby mass-producing optical fibers.

In particular, the present invention can minimize variations in optical loss and polarization mode dispersion (PMD) depending on the skill of the operator.

In addition, the vacuum connection method according to the present invention can be usefully used in an optical fiber inspection field for measuring the quality of a buried or installed optical fiber.

Claims

A measuring device for measuring optical quality characteristics such as PMD and optical loss of optical fiber; A connection optical fiber comprising a first optical fiber connected to a transmitting end of the measuring device and a second optical fiber connected to a receiving end of the measuring device; A measurement optical fiber connected to the first and second optical fibers to measure optical quality characteristics by the measurement device; And a connection device for physically connecting the connection optical fiber and the measurement optical fiber and optically connecting the connection optical fiber, the optical fiber quality measurement system comprising:

The connection device comprising:

A vacuum pump for generating vacuum pressure;

And a contact holding means for holding the connecting optical fiber and the measuring optical fiber in contact with each other in a state in which the cover is removed, while maintaining the contact state by sucking the connecting optical fiber and the measuring optical fiber by using the vacuum pressure generated in the vacuum pump The optical fiber quality measurement system.
The method according to claim 1,

Further comprising a vacuum pipe for transmitting the vacuum pressure of the vacuum pump to the contact holding means.
3. The method of claim 2,

Wherein the contact-

A V-shaped groove for supporting the connection optical fiber and the measurement optical fiber;

A slot formed in a bottom surface of the V-shaped groove;

And an exhaust passage communicating the vacuum pipe and the slot.
The method of claim 3,

And the width of the slot is smaller than the diameter of the connecting optical fiber and the measuring optical fiber.
5. The method according to any one of claims 1 to 4,

Wherein a vacuum pressure of the vacuum pump is maintained at 0.15 bar to 0.40 bar when the polarization mode dispersion of the measurement optical fiber is measured.
5. The method according to any one of claims 1 to 4,

Wherein the vacuum pressure of the vacuum pump is maintained at 0.20 bar to 0.35 bar when measuring the optical loss of the measurement optical fiber.
5. The method of claim 4,

Wherein the contact-

A pressure sensor for measuring the pressure of the exhaust passage,

Further comprising a display device for externally displaying a pressure value measured by the pressure sensor.
A vacuum pump for generating vacuum pressure; And

And a contact holding means for holding two optical fibers, which are physically contacted to each other for optical connection, while maintaining the contact state by sucking and fixing the two optical fibers on their supporting surfaces using the vacuum pressure of the vacuum pump Device.
9. The method of claim 8,

Further comprising a vacuum pipe for transmitting a vacuum pressure of the vacuum pump;

Wherein the contact-

A support groove formed along the longitudinal direction of the optical fiber to support the two optical fibers while being accommodated; a slot extending along the longitudinal direction of the optical fiber on a bottom surface of the support groove; And an exhaust passage for allowing the exhaust gas to pass therethrough.
9. The method of claim 8,

Wherein a width of the slot is smaller than a diameter of the two optical fibers.
11. The method of claim 10,

Wherein the contact-

A pressure sensor for measuring the pressure of the exhaust passage,

And a display device for displaying the pressure value measured by the pressure sensor on the outside.