TWI479212B - Fiber structure and its manufacturing method and the use of this fiber structure of the laser - Google Patents

Description

Optical fiber structure, manufacturing method thereof and laser oscillation cavity using the same

The present invention relates to an optical fiber, and more particularly to a cladding layer coated on the periphery of a core layer having a V-shaped groove, and the V-shaped groove is A fiber structure configured with a graphite material.

Graphene is a material that has been discovered in the past decade, and there are still few manufacturers that can stably and mass-produce this material. The graphene is currently sold in a small area of sheet material or in the form of a solution.

As shown in the U.S. Patent Publication (US 2012/0039344 A1), it discloses a configuration of a mode-locked fiber laser. The case uses graphene material as Saturable Absorber (SA), which can be regarded as a new type of clamping technology. The main technical features of the case are the type of graphene material, the preparation of the material and the fiber laser laser-mode-locking system. Among them, the graphene sheet is placed perpendicular to the axial direction of the fiber (the normal vector of graphene is in the same direction as the fiber axis), and is attached to the cross section of the inner core of the optical fiber; and the system architecture of the overall fiber laser is disclosed. In particular, fiber lasers having a ring cavity and a graphene-based saturable absorber device are disclosed. This fiber laser is designed primarily for mode-locking and Q-switching through the use of graphene-based saturable absorber devices. However, since the technique of the prior patent is to combine with the graphene through the small end face of the optical fiber, the conductivity of the core of the optical fiber is blocked, and at the same time, the transmission capability of the pulse energy is also reduced.

And, as shown in U.S. Patent Publication (US 2011/0158268 A1), which discloses the use of graphene as a saturable absorber and a processing structure on an optical fiber, graphene can be placed in the processed structure to form a mode-locking mold. Mode-locker. However, since the processing structure of the prior patent is a planar groove, the position of the fixed clamping is not clearly defined.

In addition, a graphene passive mode-locked fiber laser is disclosed in Chinese Patent Publication (CN 102208738 A). It mainly includes pump source, fiber coupler, gain fiber, output coupler, single mode fiber, graphene saturated absorber and polarization controller. Among them, the use of graphene saturated absorber can achieve high stability, high power, high energy and high efficiency of ultra-short pulse laser output and other technical features. However, this patent does not disclose the position and shape of the graphene.

Therefore, there is a need to provide a fiber structure that can solve the aforementioned problems.

SUMMARY OF THE INVENTION It is an object of the present invention to utilize a graphite material in a V-shaped trench for single point position mode locking of laser light entering the core layer.

In accordance with the above objects, the present invention provides an optical fiber structure comprising a core layer, a cladding layer, and a graphite material. The fiber layer is coated on the periphery of the core layer, the fiber layer comprising a V-shaped groove, wherein the V-shaped groove has a tip end portion adjacent to the core layer; and the graphite material is disposed in the V-shaped groove.

According to the optical fiber structure of the embodiment of the invention, the graphite material comprises graphene; wherein the graphene may be a graphene sheet (graphene sheet) or graphene solution.

According to the optical fiber structure of the embodiment of the invention, the graphite material comprises a graphite carbon tube.

According to the optical fiber structure of the embodiment of the invention, the tip end portion of the V-shaped groove further has an R angle, and the range of the R angle is <0.1 mm.

According to the optical fiber structure of the embodiment of the invention, the central direction of the opening of the V-shaped groove is perpendicular to the axial direction of the core layer.

The fiber structure in accordance with an embodiment of the invention further includes a sealing layer for sealing the graphite material within the V-groove.

The present invention further provides a method for fabricating an optical fiber structure, comprising the steps of: providing a fiber core layer and a fiber layer, wherein the fiber layer covers the periphery of the core layer; and forming a V-shaped groove in the fiber layer, wherein the V-groove The groove has a tip end portion adjacent to the core layer; the graphite material is disposed within the V-shaped groove.

According to the manufacturing method of the optical fiber structure according to the embodiment of the present invention, the V-shaped groove is processed by a diamond cutter.

The invention further provides a laser oscillation cavity, comprising: a diode pump, a gain fiber and a polarization controller; and the above fiber structure (including a core layer, a fiber layer and a V-shaped groove located in the fiber layer) Graphite material). The fiber structure is integrated with a diode pump, a gain fiber, and a polarization controller.

The embodiment of the present invention is characterized in that the V-shaped groove of the fiber layer can be used to fit the graphite material located in the V-shaped groove, and the laser light entering the core layer can be single-position clamped. Furthermore, since the V-shaped groove does not pass through the core The layer, therefore, does not block the conductivity of the core layer (ie, the pulse energy of the laser light is not reduced).

The above described objects, features, and characteristics of the present invention will become more apparent from the aspects of the invention.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of an optical fiber structure according to an embodiment of the present invention. As can be seen from FIG. 1, the optical fiber structure 1 includes a core layer 10, a cladding layer 11, and a graphite material 12.

The optical fiber layer 11 is coated on the periphery of the core layer 10. And the surface of the optical fiber layer 11 has a V-shaped groove 110 which does not pass through the core layer 10; the graphite material 12 is located in the V-shaped groove 110. It is worth mentioning that the V-shaped groove 110 should contain a groove similar to a V-shaped structure.

In the method for fabricating an optical fiber structure according to an embodiment of the present invention, the method comprises the steps of: providing a core layer 10 and an optical fiber layer 11 of an optical fiber, wherein the optical fiber layer 11 covers the periphery of the core layer 10. Then, a V-shaped groove 110 is formed in the optical fiber layer 11, wherein the V-shaped groove 110 has a tip end portion 111. The tip end portion 111 is adjacent to the core layer 10. Finally, the graphite material 12 is disposed within the V-shaped trench 110 as shown in FIG. The V-shaped groove 110 can be formed using a processing or molding method. For example, in practice, the V-groove 110 can be machined with a diamond tool in combination with ultra-precision machining techniques to achieve optical grade shape accuracy and surface roughness, so that the V-groove 110 has a smooth surface, which will help The lock pattern of the graphite material 12 for laser light, that is, the graphite material 12 can be used as a fiber-optic laser mode-locker.

In particular, the graphite material 12 may comprise graphene or graphite carbon tubes. Graphene or graphitic carbon tubes can be used to absorb the energy of laser light and act as a mode-locking element in ultrafast laser mechanisms. Among them, the graphene may be a graphene sheet or a graphene solution.

When a graphene sheet is used as a Saturable Absorber (SA), the graphene sheet is disposed in the V-shaped groove 110 in an attached manner; when a graphene solution is used as a saturated absorber, this The graphene solution is disposed in the V-groove 110 in a coating manner. In this embodiment, the graphite material 12 is exemplified by a graphene sheet, but is not limited thereto.

It is worth mentioning that the periphery of the optical fiber structure 1 can be further provided with a sealing layer 13. For example, the sealing layer can be coated on the periphery of the optical fiber layer 11. The sealing material 13 can be used to seal the graphite material 12 within the V-shaped groove 110 and to protect the core layer 10 and the fiber layer 11. In addition, the tip end portion 111 of the V-shaped groove 110 may further have an R angle r (for example, a range of the R angle r is less than 0.1 mm); and preferably, the central direction A of the opening of the V-shaped groove 110 may be perpendicular to the axis The axial direction H of the layer 10.

Please refer to FIG. 2. FIG. 2 is a schematic diagram of laser light entering the optical fiber structure of FIG. 1.

As shown in FIG. 2, when the laser light L enters the core layer 10 of the optical fiber structure 1, the V-shaped trench 110 and the graphite material 12 located in the V-shaped trench 110 are used as a saturated absorber, and the laser light L can be applied. Perform mode locking at a single point. The saturated absorber can lock the light wave mode, because the saturated absorber can have With the characteristic of nonlinear absorption, the absorption coefficient decreases with the increase of light intensity, so the pulse with the strongest intensity can obtain the minimum loss, and the ultrashort pulse can be output by the interaction of the saturated absorber and the gain medium.

Wherein, since the V-shaped groove 110 can further have the tip end portion 111 (the position of the R angle r), the lock mode property at the single point position is further improved, and the pulse energy of the laser light L is increased (Ray) The pulse width of the illuminating light L is shortened so that the thermal effect of the laser light L on the workpiece is lower, which contributes to the processing or processing efficiency of the laser light L to the workpiece.

Moreover, since the V-shaped groove 110 does not pass through the core layer 10, the conductivity of the core layer 10 is not blocked (that is, the pulse energy of the laser light L is not lowered); and, the V-shaped groove 110 The graphite material 12 can be used for single-point clamping of the laser light L (with a clear clamping position) to ensure the stability and reproducibility of the clamping mode.

Please refer to FIG. 3. FIG. 3 is a schematic diagram of a laser oscillation cavity using a fiber structure according to an embodiment of the present invention.

In addition, the optical fiber structure 1 of the present embodiment can also be applied to a fiber loop, and a diode pump 21 (pump LD), a gain fiber 22, and a polarization controller 23 (Polarization Controller). Integrated into a laser oscillator cavity 2 (laser oscillator cavity). The laser oscillating cavity 2 illustrated in FIG. 3 may further include optical related components such as a WDM coupler, an output coupler 25, and an isolator 26 (Isolator). It can be seen that the optical fiber structure 1 of the present embodiment can be applied to ultra-fast lasers (for example, femtosecond fibers). Laser related technology. This ultra-fast laser technology can be used in related industries such as medical equipment, optical communication, measurement or precision processing.

In summary, the present invention is only described as a preferred embodiment or embodiment of the technical means for solving the problem, and is not intended to limit the scope of the invention. That is, the equivalent changes and modifications made in accordance with the scope of the patent application of the present invention or the scope of the invention are covered by the scope of the invention.

1‧‧‧Fiber structure

10‧‧‧Axis core layer

11‧‧‧Fiber layer

110‧‧‧V-groove

111‧‧‧ tip

12‧‧‧Graphite materials

13‧‧‧Closed layer

2‧‧‧Laser oscillation chamber

21‧‧‧ diode pump

22‧‧‧Gain Fiber

23‧‧‧Polarization controller

24‧‧‧Dividing multiplex coupler

25‧‧‧Output coupler

26‧‧‧Isolator

A‧‧‧ opening center direction

H‧‧‧Axis direction

L‧‧‧Laser light

r‧‧‧R angle

1 is a schematic view of an optical fiber structure according to an embodiment of the present invention.

2 is a schematic view showing the structure of the laser light entering the optical fiber of FIG. 1.

3 is a schematic diagram of a laser oscillating cavity using an optical fiber structure according to an embodiment of the present invention.

1‧‧‧Fiber structure

10‧‧‧Axis core layer

11‧‧‧Fiber layer

110‧‧‧V-groove

111‧‧‧ tip

12‧‧‧Graphite materials

13‧‧‧Closed layer

A‧‧‧ opening center direction

H‧‧‧Axis direction

r‧‧‧R angle

Claims (9)

An optical fiber structure comprising: a shaft core layer; a fiber layer covering a periphery of the core layer, the fiber layer comprising a V-shaped groove, the V-shaped groove having a tip end adjacent to the axis a core layer, wherein the tip end portion of the V-shaped groove has an R angle, the R angle range is less than 0.1 mm; and a graphite material disposed in the V-shaped groove, whereby the tip end of the V-shaped groove The part is used for clamping the graphite material to a single point of position. The fiber structure of claim 1, wherein the graphite material comprises a graphene. The fiber structure of claim 2, wherein the graphene is a graphene sheet or a graphene solution. The fiber structure of claim 1, wherein the graphite material comprises a graphite carbon tube. The fiber structure of claim 1, wherein a central direction of an opening of the V-shaped groove is perpendicular to an axial direction of the core layer. The optical fiber structure of claim 1, further comprising a sealing layer for sealing the graphite material in the V-shaped groove. A method for fabricating an optical fiber structure, comprising the steps of: providing a core layer and a fiber layer, wherein the fiber layer covers a periphery of the core layer; Forming a V-shaped groove in the fiber layer, wherein the V-shaped groove has a tip end portion adjacent to the core layer, wherein the tip end portion of the V-shaped groove has an R angle, The R angle range is <0.1 mm; and a graphite material is disposed in the V-shaped groove, whereby the tip end portion of the V-shaped groove is used to allow the graphite material to be clamped at a single point position to a laser light. The method of fabricating an optical fiber structure according to claim 7, wherein the V-shaped groove is machined from a diamond cutter. A laser oscillating cavity, comprising: a diode pump, a gain fiber, and a polarization controller; and the fiber structure as described in claim 1 to 6, the fiber structure and the diode pump The gain fiber and the polarization controller are integrated.