JPS587365Y2 - Laser-transparent fiber safety device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a safety device for a laser-transmitting fiber, and particularly to a safety device that automatically stops laser transmission when the transmittance of the fiber decreases due to heat loss caused by the laser. It is.

There are many problems with transmitting lasers through optical fibers.

One is that the fiber is heated.

For this purpose, the laser-transmitting fiber is provided with a cooling means, but it often overheats beyond the capacity of the cooling means, causing damage.

If the laser continues to pass through with this heat loss occurring, the heat loss will rapidly expand and become a serious problem.

An object of the present invention is to provide a safety device that immediately detects the breakage and stops the laser from entering the fiber when heat loss occurs while transmitting the laser through the fiber.

The laser-transmitting fiber safety device according to the present invention includes a shutter on the input side of the laser-transmitting fiber and a photodiode along the core near the output end, amplifies the output of the photodiode, and compares the output with a set value. , the apparatus is characterized in that operating power for the shutter is input to the shutter to open the shutter only when the output is greater than a set value.

Hereinafter, the safety device according to the present invention will be explained based on FIG. 1 of the drawings of the embodiment.

Laser transmission fiber can transmit laser light and guide light 1
It consists of a core part 2 that allows gases to pass through, a clad part 3 that allows auxiliary gases, water, etc. to pass through, and a column coating 4.

The core portion 2 and both ends of the cladding portion 30 are fixed with fixtures 7.

A cooling fluid 50 passage 6 is provided in the cladding part, and a cooling fluid 50 passage 6 is provided in the core part 2.
is now being cooled.

In addition, a shutter 9 for blocking the laser beam and the guide light 1 is provided on the input side of the fiber, and is normally in position A, which blocks the light, and is in position B, which opens the optical path while operating power is being input. be raised to.

A photodiode 10 is provided along the core portion 2 near the output end of the fiber.

The photodiode 10 receives scattered visible light transmitted through the core portion 2 and generates electric power.

The output Sl is input to the amplifier 11, and the amplified output 82G! It is input to comparator 12.

The comparator 12 outputs visible light from the normal core section 2 (this is always kept at a constant output).

) is set at a similar amplification value, which is slightly smaller than the output of the photodiode when the signal is transmitted.

The comparator 12 compares the output S2 from the amplifier 11 with the set value, and if the output S2 is larger than the set value, the power sent by closing the switch 13 is output S3 to the shutter 9, and the shutter 9 is closed. It is opened from the A position to the B position, and the laser light and the guide light 1 are transmitted to the core part 2.

When the fiber in the core section 2 undergoes heat loss, the transmittance decreases rapidly, so the output S1 of the photodiode 10, and therefore the output S2 from the amplifier 11, decreases, and the output S2 becomes smaller than the set value, causing the output to the shutter 9 to decrease. Since the output S3 is cut off, the shutter 9 returns from the B position to the A position, and the laser beam and the guide light 1 are not input to the fiber, thereby avoiding large damage to the fiber.

As mentioned above, when using the safety device of the present invention.

If there is heat loss to the fiber during laser injection, this can be detected immediately and the laser injection can be stopped, making it possible to avoid major fire damage and prevent serious accidents.

Depending on the shape of the photodiode and the mounting method, that is, by making the photodiode movable or by providing a plurality of photodiodes, it is possible to inspect the side surface of the core for flaws, investigate the transmission characteristics, etc. by injecting a visible light laser.

[Brief explanation of the drawing]

FIG. 1 shows the constituent countries of an embodiment of the safety device of the present invention. 1... Laser and guide light, 2... Core part, 3...
... Cladding part, 4 ... Column layer coating, 9 ... Shutter 10 ... Photodiode, 11 ... Amplifier, 12
...Comparator.

Claims (1)

[Scope of utility model registration request] A shutter is provided at the input end of the laser transmission fiber, a photodiode is provided along the core near the output end, the output of the photodiode is amplified, and the output is compared with a set value,
A safety device for a laser-transmitting fiber, characterized in that the operating power of the shutter is inputted to the shutter to open the shutter only when the output is larger than a set value.