JPH06331854A - Optical connector with connector end face monitoring device - Google Patents

Abstract

PURPOSE:To obtain an optical connector incorporating a connector end face monitoring device capable of easily detecting the positional deviation of the end face of an optical fiber so that damage can be always appropriately and precisely detected in the case of monitoring the state of the end face of the optical fiber of the optical connector so that light transmission characteristic in the optical connector is excellently kept. CONSTITUTION:Inside the optical connector 1, a laser diode 7 is arranged to be opposed through a condensing lens 6 for irradiating the end face 4 of the optical fiber 2 with a laser beam 8. A photodiode 10 for receiving the reflected light 9 of the laser beam 8 irradiating the end face 4 of the optical fiber is arranged. Furthermore, a comparison circuit 12 for detecting the positional deviation and the damage of the end face of the optical fiber by inputting an electric output signal from the photodiode 10, amplifying it and comparing it with a previously set reference value is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical connector for connecting an optical fiber, and more particularly to an optical connector connecting portion for use in a laser processing machine or a medical laser knife for transmitting high-power laser light. The present invention relates to an optical connector with a connector end face monitoring device, which can easily and highly accurately detect a loss that occurs in a connector.

[0002]

2. Description of the Related Art In general, an optical connector, which is one of the components for optical communication, increases the connection loss or transmission loss of light when the end face of the optical fiber at the connecting portion is damaged, thereby transmitting the light. There is a problem of degrading the characteristics.

From such a point of view, conventionally, in this type of optical connector, a method or apparatus for detecting damage to the end face of the optical fiber has been proposed as means for monitoring the connection loss at the end face of the optical fiber which is the connecting portion of the optical fiber. Has been done.

For example, in Japanese Utility Model Laid-Open No. 2-72952, as an optical connector end face monitoring device, an optical connector for measurement having a lens inside, a light source for irradiating the end face of the optical connector to obtain reflected light, and this reflected light It is composed of an image enlarging section for receiving a light to obtain a magnified image by a lens, and an optical directional coupler for optically connecting the light source and the image enlarging section. A monitoring device is disclosed that can visually inspect the condition. In other words, this optical connector end face monitoring device connects the optical connector for measurement to the measured optical connector, takes out the end face reflected light of the light sent from the outside through the optical fiber, and magnifies it at a position away from the measured optical connector. With this configuration, it is possible to easily monitor the dirt and damage of the end face of the optical connector in a stable state without removing the optical connector such as the optical input / output unit of the optical transmitter / receiver as in the conventional case. It is configured as follows.

Therefore, as a detection device using reflected light of light, which is adopted in this kind of monitoring device, for example, FIG.
The configuration shown in is known. However, in FIG. 3, the end face of a conventionally known optical connector, that is, the connecting end face of the optical fiber is irradiated with laser light emitted from a laser diode, and the intensity of return light reflected at the end face is detected to detect the optical fiber. 2 shows a schematic configuration of an apparatus configured to monitor the transmission characteristics of the. That is, in FIG. 3, reference numeral 21 indicates an optical connector, and a laser diode 27 is sequentially provided to an end face of an optical fiber 22 connected to the optical connector 21 via a coupling lens 23, a beam splitter 24, and a collimator lens 25. The laser light 2 emitted from the laser diode 27.
8 is applied to the end face of the optical fiber 22. In this case, the return light reflected on the end face of the optical fiber 22 is reflected by the beam splitter 24, and the reflected return light 28 is detected by the photodiode 30. In FIG. 3, reference numeral 31 is a laser diode drive circuit for driving the laser diode 27, and 32 is a comparison circuit connected to the photodiode 30. Then, the comparison circuit 32
In (1), an electric signal proportional to the intensity of the return light output from the photodiode 30 is input and compared with a preset reference value to detect the degree of damage to the end face of the optical fiber.

[0006]

However, in the above-mentioned conventional optical connector, when the optical connector is connected, the positioning of the end face of the optical fiber at the connecting portion, that is, the alignment with the central axis is performed mechanically. It is performed depending on the processing accuracy. For this reason, when there is a displacement of the end face of the optical fiber with respect to the central axis, this state cannot be detected. Therefore, in the above-mentioned conventional device for monitoring damage to the end face of the optical fiber,
Since the positional displacement of the optical fiber end face is not taken into consideration, when the intensity of the returning light is reduced due to such positional displacement, the optical fiber end face is less likely to be damaged at first glance, resulting in the loss caused. May also decrease, which may result in malfunction of the monitoring device.

Therefore, an object of the present invention is to maintain good optical transmission characteristics in an optical connector, so that it is possible to always properly and accurately detect damage when monitoring the state of the optical fiber end face of the optical connector. As described above, it is an object of the present invention to provide an optical connector having a built-in connector end face monitoring device capable of easily detecting the positional deviation of the end face of the optical fiber.

[0008]

In order to achieve the above object, an optical connector with a connector end face monitoring device of the present invention has a condensing lens for irradiating an end face of an optical fiber with a laser beam inside an optical connector. A laser diode is arranged to face each other, and a photodiode for receiving the reflected light of the laser light emitted to the end face of the optical fiber is arranged,
Furthermore, the electric signal output from the photodiode is input, and this is amplified and compared with a preset reference value,
It is characterized in that a comparison circuit is provided for detecting the positional deviation and damage of the end face of the optical fiber.

In the above-mentioned optical connector with a connector end face monitoring device, the laser diode is arranged so that the laser light is incident on the end face of the optical fiber at an optical axis at an angle of about 20 ° to 30 ° with respect to the central axis thereof. The photodiode can be arranged on an optical axis that is line-symmetrical to the central axis of the optical fiber with respect to the optical axis of the laser diode.

Further, in the above-mentioned comparison circuit, the preset reference values are respectively a reference value for detecting the suitability of damage to the optical fiber end face and a reference value for detecting the positional deviation of the optical fiber end face. Can be set.

[0011]

According to the optical connector of the present invention, inside the optical connector, the laser diode and the photodiode are arranged at proper positions with respect to the end face of the optical fiber to detect whether or not the end face of the optical fiber is properly damaged. In addition, it is possible to accurately detect an abnormal state due to the positional deviation of the optical fiber end face.

[0012]

Embodiments of the optical connector according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic sectional view showing an embodiment of an optical connector with a connector end face monitoring device according to the present invention. In FIG. 1, reference numeral 1 denotes an optical connector, to which an optical fiber 2 is detachably coupled via an optical fiber plug 3.

However, for the end face 4 of the optical fiber 2 coupled to the optical connector 1, as in the case shown in FIG. 3, the spatial laser light 28 is transmitted via the coupling lens 23 to the optical fiber 2. It is configured to be irradiated along the central axis 5. The light emitting means for the spatial laser light 28 and the means for monitoring the reflected return light will be described with reference to FIG.
The configuration shown in can be adopted as it is.

Therefore, in the embodiment shown in FIG. 1, a laser diode 7 is arranged inside the optical connector 1 of the optical fiber 2 so as to face the end face 4 of the optical fiber 2 via a condenser lens 6. In this case, the optical axis of the laser light 8 emitted from the laser diode 7 irradiates the end face 4 of the optical fiber 2 at an incident angle of about 20 ° to 30 ° with respect to the central axis 5 of the optical fiber 2. Arrange oppositely. Further, the photodiode 10 for receiving the reflected light 9 of the laser light 8 reflected on the end face 4 of the optical fiber 2 has a central axis 5 of the optical fiber 2 with respect to the laser diode 7.
It is placed on the optical axis that is line-symmetric with.

In FIG. 1, reference numeral 11 indicates a laser diode drive circuit for driving the laser diode 7, and reference numeral 12 indicates a comparison circuit connected to the photodiode 10. Then, in the comparison circuit 12, an electric signal proportional to the intensity of the reflected light 9 with respect to the laser light output from the photodiode 10 is input, and this is compared with a preset reference value (for damage). Whether or not the end face 4 of the optical fiber is damaged is detected.

In the optical connector 1 of the present invention thus constructed, when the end face 4 of the optical fiber 2 is in a normal position as shown in FIG. 1, the laser light 8 emitted from the laser diode 7 is emitted. The reflected light 9 on the end face 4 of the optical fiber is directly received by the photodiode 10. Therefore, the electric signal output from the photodiode 10 in this case has the maximum value.

Therefore, for example, as shown in FIG. 2, when the end face 4 of the optical fiber 2 is positioned obliquely and is not in a normal position, the laser light 8 emitted from the laser diode 7 is reflected at the end face 4 of the optical fiber. The light 9 is the photodiode 10
Will not be received or the received light intensity will be weak. Therefore, the electric signal output from the photodiode 10 in this case has a lower level than in the normal case shown in FIG.

Therefore, in the present invention, in the comparison circuit 12, an electric signal corresponding to the amount of the reflected light 9 received by the end face 4 of the optical fiber detected by the photodiode 10 is input and preset. When the electric signal is equal to or higher than the reference value, a signal indicating a normal state is output by comparison with the reference value, and when the electric signal is equal to or lower than the reference value, the optical fiber end face 4
It is configured to output an alarm signal indicating an abnormal state due to the displacement of the position.

The optical connector 1 of the present invention thus constructed
Is a connector end face for detecting damage to the end face 4 of the optical fiber 2 by irradiating the end face 4 of the optical fiber 2 with a laser beam having an optical axis coincident with the center axis of the end face 4 and returning light reflected by the end face 4 of the optical fiber 2. In a monitor equipped with a monitoring device, a laser diode 7 is disposed inside the optical connector 1 so as to face the end face 4 of the optical fiber 2 via a condenser lens 6 for irradiating a laser beam 8 on the end face 4. A photodiode 10 for receiving the reflected light 9 of the laser light 8 applied to the laser light is arranged, and the photodiode 1 is further arranged.
The electrical signal output from 0 is input, amplified and compared with a preset reference value (with respect to the positional deviation), and the positional deviation of the optical fiber end surface 4 is detected to detect the optical fiber end surface 4 It is possible to surely prevent a malfunction at the time of detecting damage to the end surface 4 in the case of displacement.

[0021]

As is apparent from the above-described embodiments, according to the optical connector of the present invention, the laser diode is provided inside the optical connector through the condenser lens for irradiating the end face of the optical fiber with the laser beam. A photodiode for receiving the reflected light of the laser light emitted to the end face of the optical fiber is arranged opposite to each other, and an electric signal output from the photodiode is further input, which is amplified and set in advance. By providing a comparison circuit for detecting the positional deviation and damage of the optical fiber end surface by comparing with the reference value, the abnormal state due to the positional deviation of the optical fiber end surface as well as the detection of the appropriateness of the damage on the optical fiber end surface. It is possible to reliably prevent a malfunction at the time of detecting damage to the end face when the position of the end face is displaced.

Therefore, according to the present invention, by combining and arranging the laser diode and the photodiode with respect to the end face of the optical fiber, it is possible to detect whether or not the end face of the optical fiber is properly damaged, and to detect an abnormal state due to displacement of the end face of the optical fiber. Can be performed simply and properly, and the effect of improving the performance of this type of optical connector is extremely large.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of an optical connector with a connector end face monitoring device according to the present invention.

FIG. 2 is a schematic cross-sectional view showing a state in which a positional deviation of an end face of a fiber is detected in the optical connector shown in FIG.

FIG. 3 is an explanatory diagram showing a schematic configuration of an apparatus for monitoring a fiber end surface in a conventional optical connector.

[Explanation of symbols]

 1 Optical Connector 2 Optical Fiber 3 Optical Fiber Plug 4 Central Axis 5 End Face of Optical Fiber 6 Condensing Lens 7 Laser Diode 8 Laser Light 9 Reflected Light 10 Photodiode 11 Laser Diode Drive Circuit 12 Comparison Circuit 21 Optical Connector 22 Optical Fiber 23 Coupling Lens 24 Beam splitter 25 Collimating lens 27 Laser diode 28 Laser light 29 Laser return light 30 Photodiode 31 Laser diode drive circuit 32 Comparison circuit

Claims (3)

[Claims] 1. A laser diode is arranged inside an optical connector so as to face it through a condenser lens for irradiating a laser beam on the end face of an optical fiber, and the reflected light of the laser beam irradiated on the end face of the optical fiber is received. To detect the positional displacement and damage of the optical fiber end face by further arranging a photodiode for inputting the electric signal output from the photodiode, amplifying it, and comparing it with a preset reference value. An optical connector with a connector end face monitoring device, characterized in that a comparison circuit is provided. 2. The laser diode is arranged so that the laser light is incident on the end face of the optical fiber at an optical axis at an angle of about 20 ° to 30 ° with respect to the central axis of the optical fiber, and the photodiode is the light of the laser diode. The optical connector with a connector end face monitoring device according to claim 1, wherein the optical connector is arranged on an optical axis which is line-symmetrical to the central axis of the optical fiber with respect to the axis. 3. The reference value set in advance in the comparison circuit is a reference value for detecting whether or not the optical fiber end face is properly damaged and a reference value for detecting a positional deviation of the optical fiber end face. An optical connector with a connector end face monitoring device according to claim 1 or 2.