KR20060118851A - Fiber laser at visible wavelength - Google Patents

Abstract

A fiber laser at visible wavelength is provided to generate optimum blue and green laser beam as a semiconductor laser excitation light source at the same time, by using an Ytterbium-doped fiber and a Thorium-doped fiber. In a laser beam generation apparatus using a semiconductor laser(10) generating a laser beam for pumping and a lens(20) collecting the pumping light generated from the semiconductor laser, an Ytterbium-doped fiber(40) makes laser oscillation by stimulated emission by an input light and emits a light by up-conversion of the laser beam of the semiconductor laser. And a second optical fiber(80) receives the light outputted from the Ytterbium-doped fiber and not-absorbed semiconductor laser beam, and emits a light by up-conversion of the incident infrared laser beam.

Description

Fiber laser at visible wavelength

1 is a block diagram of a ytterbium and thorium-doped fiber laser according to an embodiment of the present invention,

2 is a block diagram of a ytterbium and thorium-doped fiber laser according to another embodiment of the present invention,

3 is a block diagram of a ytterbium and thorium-doped fiber laser according to another embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

10: semiconductor laser 20: lens

30: first FBG 40: ytterbium-doped optical fiber

50: second FBG 60: third FBG

70: 4th FBG 80: 2nd optical fiber

90: fifth FBG 100: sixth FBG

110: mirror

The present invention relates to laser light. More specifically, when a 970 nm wavelength light is input into an ytterbium-doped optical fiber in a semiconductor laser by placing a reflecting means between the output terminal of the semiconductor laser and the pumped ytterbium-doped optical fiber, the 1120 nm band of the ytterbium-doped optical fiber The semiconductor laser light oscillating into the light and not absorbed by the ytterbium-doped optical fiber is simultaneously incident to the thorium-doped optical fiber, which is the second optical fiber. The present invention relates to an optical fiber laser that generates blue and green lasers by oscillation.

Color display devices often use three separate light sources to generate three primary colors (R, G, B) of light. The intensity of the three primary colors is changed and mixed to produce various different colors of the color image.

Of the three primary colors, red is currently available commercially as a semiconductor laser light source, but green and blue semiconductor lasers are technically impossible or at the R & D stage. As an alternative method, a solid state laser or a fiber laser using a semiconductor laser as an excitation light source is currently being researched and developed.

The present invention has been made to solve the problems of the prior art as described above, and an object of the present invention is to use an ytterbium and thorium-doped optical fiber to achieve optimal visible light, that is, blue and green laser light as one semiconductor laser excitation light source. It is to provide an optical fiber laser that occurs at the same time.

In order to achieve the above object, the technical means is a laser light generating device using a semiconductor laser for generating a pumping laser light and a lens for collecting and outputting the pumping light generated from the semiconductor laser, the laser is induced and emitted to the input light An ytterbium-doped optical fiber which oscillates but emits light of a predetermined wavelength by up-converting the laser light of the semiconductor laser; And a thorium-doped optical fiber, which is a second optical fiber that emits light of a predetermined wavelength by upwardly converting the incident laser light into the light output from the ytterbium-doped optical fiber and not absorbing the semiconductor laser light.

According to the present invention, optimum blue and green laser light can be output by using ytterbium and thorium-doped optical fibers.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic view of a ytterbium and thorium-doped fiber laser according to the present invention, including a semiconductor laser 10, a lens 20, a first FBG 30, an ytterbium-doped optical fiber 40, a second FBG 50, The third FBG 60, the fourth FBG 70, the second optical fiber 80, the fifth FBG 90, and the sixth FBG 100 are included.

In an embodiment of the present invention, an optical pumping laser is used, and the optical pumping laser is a laser in which electrons are excited to a higher energy state by absorbing light from an auxiliary light source, and pumping light having a wavelength of 970 nm for inverting an ytterbium-doped optical fiber. Is generated and input into the ytterbium-doped optical fiber.

When the light output from the semiconductor laser is emitted, the thick convex lens (ie, the condenser lens 20) collects the emitted light, forms an optical image, and outputs the optical image to the ytterbium-doped optical fiber, which is the first optical fiber.

The ytterbium-doped fiber 40 is induced and emitted to the semiconductor laser light input through the lens to cause laser oscillation. That is, when light having a high power energy of 970 nm wavelength is injected into the core structure of the ytterbium-doped optical fiber which is a rare earth as a gain medium by a pumping semiconductor laser, the pumping light excites ytterbium, which is the rare earth ion added to the ytterbium-doped optical fiber. The spontaneous emission light generated at this time is input into the ytterbium-doped optical fiber. The input signal light is amplified through stimulated emission, and laser oscillation is repeated by repeating the same process.

In addition, ytterbium has an excitation light source wavelength of 970 nm, which is close to an oscillation wavelength of 1120 nm. Thus, more than 90% of the excitation light energy can be used for laser oscillation, and heat generation can be performed efficiently, resulting in efficient oscillation.

The first FBG 30 reflects 1120 nm light oscillated from the ytterbium-doped optical fiber, and passes 970 nm light, which is the excitation light of the semiconductor laser, to be output to the ytterbium-doped optical fiber.

That is, the laser light incident from the semiconductor laser passes through the first FBG 30 and is input to the ytterbium-doped optical fiber 40, and the ytterbium-doped optical fiber 40 converts the laser light of the semiconductor laser upward and converts the light having a wavelength of 1120 nm. Emits. The first FBG 30 passes the laser light of the semiconductor laser 10 but reflects light having a wavelength of 1120 nm.

Since the second FBG 50 has a characteristic of reflecting light having a wavelength of 1120 nm, a resonator is formed by the first FBG 30 and the second FBG 50, and light having a wavelength of 1120 nm is amplified by induction emission. Laser oscillation occurs. The laser beam passing through the second FBG 50 is incident on the second optical fiber 80.

In this case, since the reflectance of the 1120 nm wavelength of the second FBG 50 is lower than the reflectance of the first FBG to emit laser light, the first FBG uses a high reflection, and the second FBG uses a low reflection. ).

Since the first FBG uses high reflection and the second FBG uses low reflection, most of the light having a wavelength of 1120 nm oscillating in the ytterbium-doped optical fiber is incident on the thorium-doped optical fiber. It is also incident on a 970 nm thorium-doped optical fiber, which is semiconductor laser light that is not partially absorbed by ytterbium.

The laser light output to the ytterbium-doped optical fiber 40 and the non-absorbing semiconductor laser light pass through the third and fourth FBGs 60 and 70 and are incident on the second optical fiber 80. The second optical fiber 80 up-converts the incident infrared laser light and emits light having wavelengths of 480 nm and 546 nm. The third and fourth FBGs 60 and 70 pass infrared laser light but reflect light of 480 nm and 546 nm wavelengths.

The second optical fiber 80 is a thorium-doped fiber, which is radioactive, and upwardly converts infrared laser light of 970 nm and 1120 nm in the ytterbium-doped optical fiber 40 to emit light having a wavelength of 546 nm and 480 nm, respectively.

Since the fifth and sixth FBGs 90 and 100 reflect light of wavelengths of 480 nm and 546 nm, the third and fourth FBGs 60 and 70 and the fifth and sixth FBGs 90 and 100 are resonators. In this way, light of the wavelengths of 480 nm and 546 nm is amplified by induced emission so that laser oscillation occurs.

In addition, since the reflectances of the 480 nm and 546 nm wavelengths of the fifth and sixth FBGs are lower than those of the third and fourth FBGs, only the blue and green laser light are emitted, the third and fourth FBGs use a high reflector, The sixth FBG uses a low reflector.

Here, the blue laser is output due to the 480 nm wavelength and the green laser is output due to the 546 nm wavelength.

The second optical fiber, which is a thorium-doped optical fiber, may be manufactured and used as a silica fiber, a ZBLAN fiber, and a chalcogenide fiber.

Silica optical fiber is the most widely used optical fiber, and it does not deform well even at high temperature (about 1000 ??) and has a characteristic of not breaking even by sudden temperature change because of small coefficient of thermal expansion. It is also transparent to light from the visible region to the infrared region.

ZBLAN fiber is a heavy metal due to the chemical combination of zirconium, barium, lanthanum, aluminum and sodium, and its transmission loss in the wavelength range of 200 nm to 8000 nm, especially 2550 nm. This is very small.

Chalcogenide (chalcogenide) glass-added optical fiber is a generic term for emulsions, selenides, and telluriums, and S, Se, Te, and the like are glass formations.

2 is a block diagram of a ytterbium and thorium-doped fiber laser according to another embodiment of the present invention, which is composed of a semiconductor laser 10, a lens 20, an ytterbium-doped fiber 40, and a second optical fiber 80. When the light of 970nm wavelength is emitted from the semiconductor laser, the convex lens collects the emitted light and emits it into the ytterbium-doped optical fiber 40. When light is incident on the ytterbium-doped optical fiber, the ytterbium-doped optical fiber converts the laser light of the semiconductor laser upwards to 970nm. And emit light at a wavelength of 1120 nm.

Afterwards, the light of the 970 nm and 1120 nm wavelengths is converted into the thorium-doped optical fiber, which is a second optical fiber connected to the first optical fiber, and when the light emitted from the ytterbium-doped optical fiber 40 is incident, the incident laser light is upward-converted. Emit a 480 nm blue laser and a 546 nm green laser.

3 is a schematic view of a ytterbium and thorium-doped fiber laser according to another embodiment of the present invention, including a semiconductor laser 10, a lens 20, a first FBG 30, an ytterbium-doped fiber 40, and a second The FBG 50, the 3rd FBG 60, the 4th FBG 70, the 2nd optical fiber 80, the 5th FBG90, the 6th FBG100, and the mirror 110 are comprised. The overall structure is similar to that of FIG. 1, and both ends of the optical fiber are used by using a mirror having high transmittance in the infrared region and high reflectance in the visible region to compensate for the blue and green laser light coming from one end of the optical fiber of FIG. Independently outputs blue and green laser light.

To realize this, the reflectance of the light of the 480 nm wavelength of the fifth FBG is lower than that of the fourth FBG, and the reflectance of the light of the 546 nm wavelength of the sixth FBG is higher than that of the third FBG, so that the blue laser light is emitted from the thorium-doped fiber end and the green laser light is emitted. Is a structure that is reflected through the mirror and output. If the FBG reflectivity is reversed, it is possible to fabricate a structure in which the blue laser light is reflected through the mirror and the green laser light is emitted from the end of the thorium-doped fiber.

In addition, since the reflectance of the light reflected by the fifth FBG is lower than that of the fourth FBG and the reflectance of the light reflected by the sixth FBG is higher than that of the third FBG to emit laser light, the fourth and sixth FBGs use high reflectors, and the third and fifth FBGs. Uses a low reflector.

The present invention is not limited to the above-described embodiments, and various changes can be made by those skilled in the art without departing from the gist of the present invention as claimed in the following claims.

As described in detail above, the present invention can output optimal blue and green laser light by using ytterbium and thorium-doped optical fibers.

In addition, by using silica, ZBLAN or Chalcogenide-based optical fiber, it is possible to output optimal blue and green laser light.

Claims (7)

In the laser light generating device using a semiconductor laser for generating a pumping laser light and a lens to collect and output the pumping light generated from the semiconductor laser, An ytterbium-doped optical fiber which is induced and emitted to the input light to generate a laser oscillation, and emits light having a predetermined wavelength by up-converting the laser light of the semiconductor laser; And And a second optical fiber in which the light output from the ytterbium-doped optical fiber and the non-absorbing semiconductor laser light are incident, and up-convert the incident infrared laser light to emit light of a predetermined wavelength. laser. The method of claim 1, A first FBG passing through laser light of the semiconductor laser and reflecting light of a predetermined wavelength emitted from the ytterbium-doped optical fiber; A second FBG which forms a resonator with the first FBG, and a laser oscillation occurs by amplifying light having a predetermined wavelength emitted from the ytterbium-doped optical fiber by induction emission; Third and fourth FBGs configured to pass the light output from the ytterbium-doped optical fiber and to enter the second optical fiber, and to pass infrared laser light and reflect light of a predetermined wavelength emitted from the second optical fiber; And And a fifth and sixth FBG, in which a resonator is formed with the third and fourth FBGs, and light having a predetermined wavelength emitted from the second optical fiber is amplified by the induced emission to cause laser oscillation. laser. The method of claim 2, And a mirror disposed between the laser semiconductor and the lens to emit a green laser through the mirror, and to emit a blue laser through the output of the second optical fiber. The method of claim 1, wherein the second optical fiber Visible optical fiber laser, characterized in that the optical fiber of any one of silica, ZBLAN or Chalcogenide series. According to claim 1, wherein the ytterbium-doped optical fiber A visible light fiber laser, characterized in that for converting the laser light up to emit light in the wavelength of 950nm to 970nm and 1050nm to 1150nm. The method of claim 1, wherein the second optical fiber Visible optical fiber laser, characterized in that for converting the infrared laser light to the upper conversion to emit light in the wavelength of 430nm to 480nm and 510nm to 550nm. The method of claim 1, wherein the second optical fiber Visible optical fiber laser, characterized in that the optical fiber of the dual cladding structure as well as the optical fiber of the common core / cladding structure.

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