CN102737713A - Two-dimensional integrated optical fiber online storage based on linear array multi-core optical fiber - Google Patents

Abstract

The invention provides a two-dimensional integrated optical fiber online storage based on a linear array multi-core optical fiber. It consists of a single-mode optical fiber (7) connected to an array of multi-core side-polished optical fibers (2), and uses optical micromachining technology to form a metal gradient grating structure (4) on the surface of multiple exposed fiber cores (3). The principle of the present invention is based on the rainbow localization effect, that is, using the dispersion effect of the gradient grating to localize the plasmon resonances of different wavelengths at different spatial positions, and the light of different wavebands will stop at different two-dimensional planes on the fiber side. The spatial location can realize online two-dimensional storage of optical signals in the visible light to infrared band. The device is small in size, simple in structure, high in integration, easy to realize all-fiber integration, and has important applications in the field of optical fiber online storage.

Description

Two-dimensional integrated optical fiber online storage based on linear array multi-core optical fiber

technical field

The invention relates to an optical fiber online storage, in particular to a two-dimensional integrated optical fiber online storage based on a linear array multi-core optical fiber, which is mainly used as a filter in optical storage and communication.

Background technique

Surface plasmon polaritons (Surface Plasmon Polaritons, SPPs) are a kind of coherent resonance formed by the interaction between an external electromagnetic field and free electrons on the metal surface, which has a huge local field enhancement effect. It can overcome the diffraction limit and generate many novel optical phenomena, such as negative refraction, ultra-high resolution imaging, transmission enhancement, etc. These complex phenomena may herald new principles, new theories, and new technologies. When the metal surface structure is changed, the properties of surface plasmons, dispersion relations, excitation modes, coupling effects, etc. will all have significant changes. Active manipulation of light propagation can be achieved through the interaction between SPPs and light fields. Photonic devices developed using surface plasmons offer clear advantages in terms of miniaturization. SPPs provide possibilities for the development of new photonic devices, broadband communication systems, surface plasmon photonic chips, tiny photonic circuits, modulators and switches, data storage, microscopes, new light sources, solar cells, and new photonic sensors. At present, subwavelength optics based on SPPs has become one of the most rapidly developing research directions in optics and photonics. Optics based on metal surface plasmons have received increasing attention.

Fiber optic surface plasmon sensors (see US Patent No. 5,647,030 and No. 5,327,225) have also been reported a lot. It has also been reported that metal gratings are used to couple and excite surface plasmons, but they are all used in single-peak wavelength modulation devices, which are transmissive or reflective devices and do not have storage functions. The rainbow trapping effect produced by the surface plasmon of the metal micro-nano grating structure on the traditional waveguide substrate has been experimentally verified in the visible light band (Applied Physics Letters, 2011, 98, 251103), and this effect will be of great significance in the next generation of optical storage . However, the current structure is difficult to interconnect with existing optical communication systems, and most of them are one-dimensional constraints, and the application of the rainbow localization effect to optical fiber devices has not been reported.

Contents of the invention

The purpose of the present invention is to provide a two-dimensional integrated optical fiber online storage based on a linear array multi-core optical fiber that can realize online two-dimensional storage of optical signals in the visible light to infrared band.

The purpose of the present invention is achieved like this:

A two-dimensional integrated optical fiber online storage based on a linear array of multi-core optical fibers is composed of a single-mode optical fiber 7 connected to an array of multi-core side-polished optical fibers 2, and a metal gradient grating structure 4 is formed on the surface of multiple exposed cores 3 by using optical micromachining technology .

The gradient metal grating structure 4 is a gradient metal grating structure with protrusions directly made on the surface of the side-polished fiber core; grooves, and deposit the metal in the microgrooves.

The gradient metal grating structure means that the period Λ of the metal grating and the grid width t of the metal grating unit 5 are fixed values, and the grid height h of the metal grating unit 5 is gradually changed.

The metal material is gold, silver, aluminum or the like.

The period Λ of the metal grating has a range of 200-700 nanometers, the height h of the metal grating unit 5 is 5-1000 nanometers, and the width t of the metal grating unit 5 is 10-300 nanometers.

The coupling between the arrayed multi-core fiber and the single-mode fiber is realized on the side where the height h of the arrayed multi-core fiber gradient metal grating is smaller and the single-mode fiber is fused and tapered.

The metal gradient grating structures on each core of the arrayed multi-core side-polished optical fiber 2 have the same gradient.

The gradients of the metal gradient grating structures on each fiber core of the arrayed multi-core side-polished optical fiber 2 are different.

The distance d between the cores of the arrayed multi-core optical fiber is relatively large to ensure no crosstalk among the cores; the size of the cores can be the same or different; the refractive index of the cores can be the same or different.

The principle of the all-fiber two-dimensional integrated optical fiber online storage based on the rainbow local effect of the present invention is different from the traditional optical storage. It is based on the rainbow local effect, that is, the plasmon resonance of different wavelengths is localized In different spatial positions, the light of different wavelength bands will stop at different two-dimensional spatial positions, and online two-dimensional storage of optical signals from visible light to infrared bands can be realized.

Compared with prior art, the advantage of the present invention is:

1. The memory is small in size, simple in structure, easy to realize all-fiber integration, interconnected with existing optical fiber technology, and has important applications in the field of optical fiber online storage;

2. The memory can realize online storage of optical signals from visible light to infrared band;

3. The memory can realize two-dimensional online storage integration.

Description of drawings

Figure 1(a) is a schematic diagram of the structure of the optical fiber two-dimensional online memory with the protrusion structure of the gradient metal grating;

Figure 1(b) is a side-throw diagram of an optical fiber two-dimensional online memory with a metal grating protrusion structure;

Figure 1(c) is a schematic diagram of the metal grating unit;

Figure 1(d) is a top view of the optical fiber two-dimensional online memory with metal grating protrusion structure;

Figure 1(e) is the cross-section of the side-throwing multi-core fiber;

Figure 1(f) is a schematic diagram of the coupling of single-mode fiber and multi-core fiber;

Figure 2(a) is the cross-section of an arrayed multi-core fiber with each core having the same size;

Figure 2(b) is the cross-section of an arrayed multi-core fiber with periodic changes in each core size;

Figure 2(c) is the cross-section of the arrayed multi-core fiber with the linear change of each core size;

Figure 3(a) is a top view of the metal gradient grating structure on each fiber core with different gradients;

Fig. 3(b) is a side throwing diagram of the metal gradient grating on the fiber core 4-1;

Fig. 3(c) is a side throwing diagram of the metal gradient grating on the fiber core 4-2;

Fig. 4 is a side-thrown view of a metal grating embedded two-dimensional online memory.

Detailed ways

The present invention is described in more detail below in conjunction with accompanying drawing example:

Example 1:

The structure of a two-dimensional integrated optical fiber online storage based on a linear array of multi-core optical fibers is shown in Figure 1. It consists of a single-mode optical fiber 7 connected to an array of 7-core optical fibers 1, where the array of 7-core optical fibers 1 is processed into a side-polished optical fiber 2, namely Half of the fiber cladding 5 and fiber core are discarded, and the multiple fiber cores 3 exposed to the outside world form a protruding metal gradient grating structure 4 on the surface using optical micromachining technology. The seven fiber cores 3 have the same refractive index and the same The size of the fiber core is 4000 nanometers, and the gradient metal gratings on the surface of the seven fiber cores are all the same. The period Λ and the grid width t of the metal grating unit 5 are fixed values, which are 340 nanometers and 110 nanometers respectively. The metal grating unit 5 has a grid height of 5-785 nm and a total of 40 periods, and the grid height gradient is 20 nm. The coupling between the arrayed multi-core fiber 1 and the single-mode fiber 7 is to make the power of each core the same as that of the single-mode fiber on the side where the height h of the gradient metal grating of the arrayed multi-core fiber is smaller. The multi-wavelength light source is injected from one end of the single-mode fiber, and the light of different wavelengths will be localized in different spatial positions. The light with shorter wavelength stops at the side where the height h of the metal grating is smaller, and the wavelengths λ ₁ and λ ₂ stop at Two-dimensional online storage is realized by different positions of the optical fiber axis.

Example 2:

The two-dimensional integrated optical fiber online storage structure based on a linear array of multi-core optical fibers is shown in Figures 1 and 4. It consists of a single-mode optical fiber 7 connected to an array of 5-core optical fibers 1, where the array of 5-core optical fibers 1 is processed into a side-polished optical fiber 2 , that is, both the fiber cladding 5 and the fiber core are half thrown away, and the multiple cores 3 exposed to the outside world are formed on the surface with an embedded metal gradient grating structure 4 using optical micromachining technology. The five cores have the same refractive index But different sizes, the core diameter is from 3000-4000 nanometers, the gradient metal gratings on the surface of the five cores are all the same, and the period Λ and the grid width t of the metal grating unit 5 are fixed values, which are 340 nanometers and 110 nanometers respectively. The metal grating unit 5 has a grid height of 5-785 nm and a total of 40 periods, and the grid height gradient is 20 nm. The coupling between the arrayed multi-core fiber 1 and the single-mode fiber 7 is to make the power of each core the same as that of the single-mode fiber on the side where the height h of the gradient metal grating of the arrayed multi-core fiber is smaller. The multi-wavelength light source is injected from one end of the single-mode fiber. Because the core size of each fiber is different, the corresponding effective refractive index will be different, and the light of different wavelengths will be localized in different two-dimensional spatial positions. The wavelengths λ ₁ and λ ₂ Stop at different positions on the fiber optic surface to realize real two-dimensional online storage.

Example 3:

The two-dimensional integrated optical fiber online storage structure based on a linear array of multi-core optical fibers is shown in Figures 1 and 3. It consists of a single-mode optical fiber 7 connected to an array of 5-core optical fibers 1, where the array of 5-core optical fibers 1 is processed into a side-polished optical fiber 2 , that is, both the fiber cladding 5 and the fiber core are half thrown away, and the multiple cores 3 exposed to the outside world are formed on the surface with an embedded metal gradient grating structure 4 using optical micromachining technology. The five cores have the same refractive index With the same size, the fiber core diameter is 4000 nanometers, the period Λ of the gradient metal gratings on the surface of the five fiber cores and the grid width t of the metal grating unit 5 are fixed values, which are 340 nanometers and 110 nanometers respectively. But metal grating height gradients vary. The coupling between the arrayed multi-core optical fiber 1 and the single-mode optical fiber 7 is to make the power of each core the same as that of the single-mode optical fiber on the side where the height h of the gradient metal grating of the arrayed multi-core optical fiber is smaller. The multi-wavelength light source is injected from one end of the single-mode fiber, and the dispersion of each core metal grating is also different due to the different height gradients of the 4-1, 4-2, 4-3, 4-4, and 4-5 gratings on the surface of each fiber core. , the light of different wavelengths will be localized in different two-dimensional space positions, and the wavelengths λ ₁ , λ ₂ , λ ₃ and λ ₄ stop at different positions of the optical fiber polishing surface, realizing real two-dimensional online storage.

Claims (7)

1. A two-dimensional integrated optical fiber online storage based on a linear array of multi-core optical fibers. A metal gradient grating structure (4) is formed on the surfaces of multiple fiber cores (3). 2. The two-dimensional integrated optical fiber online storage based on linear array multi-core optical fiber according to claim 1, characterized in that: the gradient metal grating structure (4) is a gradient metal that directly makes protrusions on the surface of the side-polished optical fiber core Grating structure; or embedded metal grating structure, that is, the microgrooves of the gradient grating structure are carved on the surface of the side-polished fiber core by photolithography technology, and then the metal is deposited in the microgrooves. 3. The two-dimensional integrated optical fiber online storage based on linear array multi-core optical fiber according to claim 2, characterized in that: the gradient metal grating structure refers to the metal grating period Λ and the grating width of the metal grating unit (5) t is a fixed value, and the grid height h of the metal grating unit (5) changes in gradients. 4. The two-dimensional integrated optical fiber online storage based on linear array multi-core optical fiber according to claim 3, characterized in that: the metal grating structure (4) has a period Λ range of 200-700 nanometers, and the grating of the metal grating unit (5) The height h is 5-1000 nanometers, and the grid width t of the metal grating unit (5) is 10-300 nanometers. 5. The two-dimensional integrated optical fiber online storage based on the linear array multi-core fiber according to claim 4, characterized in that: the coupling of the array multi-core fiber and the single-mode fiber is at the height h of the array multi-core fiber gradient metal grating. The small side is achieved with single-mode fiber by fused tapering. 6. The two-dimensional integrated optical fiber online storage based on linear array multi-core optical fiber according to claim 5, characterized in that: the metal gradient grating structure on each core of the array multi-core side-polished optical fiber (2) has the same gradient. 7. The two-dimensional integrated optical fiber online storage based on linear array multi-core optical fiber according to claim 5, characterized in that: the gradient of the metal gradient grating structure on each core of the array multi-core side-polished optical fiber (2) is different .

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