JP6821965B2 - Underwater communication device and underwater irradiation device - Google Patents

Description

The present invention relates to an underwater communication device and an underwater irradiation device that perform visible light communication underwater.

Various communication media such as sound waves and electromagnetic waves have been used in wireless communication between underwater mobiles in the sea. For example, when sound waves are used, signal attenuation is small and the transmission distance is as good as 3 km or more.

However, the transmission capacity is about 30 kbps, and the propagation speed is also limited to 1500 m / s because sound is used.

Therefore, in recent years, a wireless communication method using light has been attracting attention with the aim of achieving even higher capacity and higher speed communication. In particular, as shown in FIG. 4 (Non-Patent Document 1), visible light absorbs less light in the sea and is suitable as a communication medium. FIG. 5 shows a block diagram of a conventional underwater communication device using visible light.

The underwater moving body A includes an irradiation unit 10A that irradiates light, a light receiving unit 20A that receives light from the underwater moving body B, and a control unit 30A that controls the irradiation unit 10A and the light receiving unit 20A. The underwater moving body B includes an irradiation unit 10B that irradiates light, a light receiving unit 20B that receives light from the underwater moving body A, and a control unit 30B that controls the irradiation unit 10B and the light receiving unit 20B. The underwater mobile body A and the underwater mobile body B perform wireless communication underwater.

In this case, when a light emitting diode (LED) is used as the light source, the beam spreads and the transmission distance is limited to about several tens of meters. Therefore, underwater wireless communication using a laser has been proposed (Patent Document 1 and Patent Document 2).

JP-A-2009-278455 Japanese Unexamined Patent Publication No. 5-228456

JAMSTEC Rep.Res.Dev.Volume 19.September 2014, 11-18

However, in the underwater communication device using a laser, larvae or living organisms of large aquatic attached organisms such as barnacles are attached to the irradiated portion. That is, the optical path is blocked by an underwater shield or the like, and communication becomes impossible.

Regarding the removal of large aquatic organisms, there are chemical removal methods such as chemical injection and paint application, physical removal methods such as ultrasonic wave and ultraviolet irradiation, and mechanical removal methods using robots and water jets.

However, with the chemical removal method, environmental pollution caused by chemical substances is regarded as a problem, and damage to the irradiated part is unavoidable with ultrasonic waves. The mechanical removal method has many problems such as an increase in size of the device and difficulty in maintenance.

Further, in Patent Document 2, an excimer laser is applied to an underwater shield to kill the underwater shield. However, as shown in FIG. 4, since ultraviolet rays are hardly transmitted in the sea, the underwater shield cannot be removed.

An object of the present invention is to provide an underwater communication device and an underwater irradiation device capable of removing underwater shields such as large aquatic organisms.

The underwater communication device according to the present invention is an underwater communication device that communicates with another underwater communication device in order to solve the above problems, and is an irradiation unit that irradiates the other underwater communication device with visible light. The irradiation unit has a light receiving unit that receives visible light from the other underwater communication device, and a control unit that controls the irradiation unit and the light receiving unit. The irradiation unit has a wavelength of 400 nm as the visible light. The communication is performed based on the output from the blue semiconductor laser that emits blue light, the light detection unit that detects the light reflected by the undersea shield among the light emitted from the blue semiconductor laser, and the output from the light detection unit. The communication determination unit that determines whether or not it is possible, the power supply device that increases the power when the communication determination unit determines that the communication is impossible, and the power increased by the power supply device. It is characterized by including a laser driving unit that removes an underwater shield by the blue semiconductor laser driven by driving the blue semiconductor laser by a corresponding current.

Further, the present invention is an underwater irradiation device provided in an underwater communication device that communicates with another underwater communication device and irradiates the other underwater communication device with visible light, and the wavelength of the visible light is different. Based on the blue semiconductor laser that emits blue light in the 400 nm band, the light detection unit that detects the light reflected by the undersea shield among the light emitted from the blue semiconductor laser, and the output from the light detection unit. The communication determination unit that determines whether or not the communication is possible, the power supply device that increases the power when the communication determination unit determines that the communication is impossible, and the power supply device increase the power. It is characterized by including a laser driving unit for removing an undersea shield by the blue semiconductor laser driven by driving the blue semiconductor laser with a current corresponding to the electric power.

According to the present invention, a blue semiconductor laser having a wavelength in the 400 nm band has the smallest light attenuation, so that communication can be performed over a long distance. Further, the underwater shield is calcium carbonate or an organic substance, and when the underwater shield is irradiated with the light of a short wavelength blue semiconductor laser, the underwater shield can be killed, so that the underwater shield can be removed from the irradiated portion.

In addition, the photodetector detects the light reflected by the underwater shield, the communication determination unit determines whether communication is possible based on the output from the light detection unit, and it is determined that communication is not possible. In this case, the power supply device increases the power, and the laser drive unit drives the blue semiconductor laser with the current corresponding to the increased power, so that the output of the blue semiconductor laser increases and the underwater shield can be easily removed. Can be removed.

It is a block diagram of the structure of the underwater communication apparatus of Example 1. FIG. It is a flowchart for demonstrating operation of the underwater communication apparatus of Example 1. FIG. It is a block diagram of the structure of the underwater communication device of Example 2. It is a figure which shows the absorption rate with respect to the frequency in the sea. It is a block diagram of the structure of the conventional underwater communication device.

Hereinafter, embodiments of the underwater communication device and the underwater irradiation device of the present invention will be described in detail with reference to the drawings.

(Example 1)
FIG. 1 is a block diagram of the underwater communication device of the first embodiment. Although FIG. 1 shows the configuration of one underwater communication device, another underwater communication device (not shown) that communicates with this one underwater communication device also has the same configuration as one underwater communication device.

The underwater communication device shown in FIG. 1 includes an irradiation unit 1 that irradiates another underwater communication device with visible light, a light receiving unit 2 that receives light from the other underwater communication device, and an irradiation unit 1 and a light receiving unit 2. A control unit 3 for controlling is provided.

The irradiation unit 1 includes a semiconductor laser 11, a light detection unit 12, a laser control unit 13, a power supply device 14, a modulation device 15, and a laser drive unit 16.

The semiconductor laser 11 emits blue light having a wavelength in the 400 nm band. In seawater, light with a short wavelength such as blue is transmitted more than other wavelengths such as red light. Therefore, in Example 1, a semiconductor laser 11 having a wavelength in the 400 nm band, which has the least light attenuation in seawater, is used. The output of the semiconductor laser 11 is several watts to several tens of watts, and oscillates a continuous wave (CW).

In addition, the main components of sessile organisms such as shellfish and barnacles are calcium carbonate and organic substances, and the underwater shield can be removed by the blue semiconductor laser 11 that emits light of a short wavelength.

The photodetection unit 12 is composed of a photodiode or the like, and detects the light reflected by the underwater shield among the light emitted from the semiconductor laser 11. The laser control unit 13 constitutes a communication determination unit that determines whether or not communication with another underwater communication device is possible based on the output from the light detection unit 12.

When it is determined that communication is impossible, the laser control unit 13 outputs a signal for increasing the electric power to the electric power supply device 14. The power supply device 14 increases the electric power based on the signal from the laser control unit 13, and outputs the increased electric power to the laser drive unit 16.

The laser drive unit 16 drives the semiconductor laser 11 with a current corresponding to the increased electric power from the power supply device 14 to increase the output of the semiconductor laser 11.

The modulation device 15 modulates the information and outputs the modulated wave signal to the laser drive unit 16. The laser driving unit 16 drives the semiconductor laser 11 with a current corresponding to the modulated wave signal from the modulation device 15 and the increased power from the power supply device 14.

Next, the operation of the underwater communication device of the first embodiment configured in this way will be described in detail with reference to the flowchart shown in FIG. Here, communication between the first underwater communication device and the second underwater communication device will be described as an example.

First, in the first underwater communication device, the laser drive unit 16 drives the semiconductor laser 11 with a current corresponding to the modulated wave signal from the modulation device 15 and the electric power from the power supply device 14. Then, the semiconductor laser 11 emits blue light having a wavelength in the 400 nm band, and transmits the blue laser light to the second underwater communication device (step S11).

Further, in the first underwater communication device, the photodetector 12 detects the reflected light reflected by the underwater shield among the light emitted from the semiconductor laser 11 (step S12). The underwater shield is a large aquatic attached organism, and the large aquatic attached organism is a shellfish such as a barnacle, a purple mussel, and an oyster, and is attached to the irradiation unit 1.

Next, the laser control unit 13 determines whether or not communication with the second underwater communication device is possible based on the output from the light detection unit 12 (step S13).

When it is determined that communication is impossible (No in step S13), the laser control unit 13 outputs a signal for increasing the power to the power supply device 14. The power supply device 14 increases the electric power based on the signal from the laser control unit 13, and outputs the increased electric power to the laser drive unit 16.

Next, the laser driving unit 16 drives the semiconductor laser 11 with a current corresponding to the increased electric power from the power supply device 14 to increase the output of the semiconductor laser 11 (step S14). When the light of the blue semiconductor laser 11 having a short wavelength is irradiated to the underwater shield, the underwater shield can be killed, so that the underwater shield can be removed from the irradiation unit 1 (step S15).

Therefore, the second underwater communication device can receive the modulated wave signal from the first underwater communication device by the light receiving unit 2, and the control unit 3 of the second underwater communication device receives the modulated wave signal received by the light receiving unit 2. Can be demodulated to obtain information from the first underwater communication device.

Therefore, normal laser communication can be performed between the first underwater communication device and the second underwater communication device (step S16).

As described above, according to the underwater communication device of the first embodiment, the blue semiconductor laser having a wavelength in the 400 nm band has the smallest light attenuation, so that communication can be performed over a long distance. Further, the underwater shield is calcium carbonate or an organic substance, and when the underwater shield is irradiated with the light of a short wavelength blue semiconductor laser, the underwater shield can be killed, so that the underwater shield can be removed from the irradiation unit 1.

Further, the light detection unit 12 detects the light reflected by the underwater shield, the laser control unit 13 determines whether or not communication is possible based on the output from the light detection unit 12, and the communication is performed. When it is determined that it is impossible, the power supply device 14 increases the electric power, and the laser driving unit 16 drives the semiconductor laser 11 with a current corresponding to the increased electric power.

Therefore, since the output of the semiconductor laser 11 increases, the underwater shield can be easily removed.

(Example 2)
FIG. 3 is a block diagram of the underwater communication device of the second embodiment. In the underwater communication device of the second embodiment shown in FIG. 3, a plurality of semiconductor lasers 11a to 11e and a plurality of semiconductor lasers 11a are provided instead of the semiconductor laser 11 of the underwater communication device of the first embodiment shown in FIG. It is characterized by including an optical coupling portion 17 for coupling a plurality of laser beams emitted from the to 11e to one optical fiber 4.

In this case, the laser driving unit 16 drives the plurality of semiconductor lasers 11a to 11e by passing an electric current through the plurality of semiconductor lasers 11a to 11e.

As described above, according to the underwater communication device of the second embodiment, the plurality of laser beams emitted from the plurality of semiconductor lasers 11a to 11e are combined by the optical coupling unit 17 and guided to one optical fiber 4. Therefore, a high-power laser output can be obtained, an underwater shield can be easily removed, and laser communication can be performed over a long distance.

The underwater communication device according to the present invention is applicable to a laser communication device.

1 Irradiation unit 2 Light receiving unit 3 Control unit 4 Optical fiber 1111a to 11e Semiconductor laser 12 Light detection unit 13 Laser control unit 14 Power supply device 15 Modulation device 16 Laser drive unit 17 Optical coupling unit

Claims (5)

An underwater communication device that communicates with other underwater communication devices.
An irradiation unit that irradiates the other underwater communication device with visible light,
A light receiving unit that receives visible light from the other underwater communication device,
It has a control unit that controls the irradiation unit and the light receiving unit.
The irradiation unit includes a blue semiconductor laser that emits blue light having a wavelength in the 400 nm band as visible light.
A photodetector that detects the light reflected by the underwater shield among the light emitted from the blue semiconductor laser, and
A communication determination unit that determines whether or not the communication is possible based on the output from the optical detection unit, and
A power supply device that increases power when the communication determination unit determines that the communication is impossible.
A laser drive unit that removes an underwater shield by the blue semiconductor laser driven by driving the blue semiconductor laser with a current corresponding to the increased power in the power supply device.
An underwater communication device characterized by being provided with. The underwater communication device according to claim 1, wherein the output of the blue semiconductor laser is several watts to several tens of watts. A plurality of the blue semiconductor lasers are installed side by side.
The laser driving unit drives a plurality of the blue semiconductor lasers.
The underwater communication device according to claim 1 or 2, further comprising an optical coupling unit that couples a plurality of lights from the plurality of blue semiconductor lasers to one optical fiber. An underwater irradiation device provided in an underwater communication device that communicates with another underwater communication device and irradiates the other underwater communication device with visible light.
A blue semiconductor laser that emits blue light with a wavelength in the 400 nm band as visible light,
A photodetector that detects the light reflected by the underwater shield among the light emitted from the blue semiconductor laser, and
A communication determination unit that determines whether or not the communication is possible based on the output from the optical detection unit, and
A power supply device that increases power when the communication determination unit determines that the communication is impossible.
And Les chromatography The drive unit for removing the sea shield by the blue semiconductor laser in which the driving blue semiconductor laser is driven by a current corresponding to the increased power by the power supply device,
An underwater irradiation device characterized by comprising. A plurality of the blue semiconductor lasers are installed side by side.
The laser driving unit drives a plurality of the blue semiconductor lasers.
The underwater irradiation apparatus according to claim 4, further comprising an optical coupling portion for coupling a plurality of lights from the plurality of blue semiconductor lasers to one optical fiber.

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