WO2019117388A1 - Photonic wiring comprising coated nanowire and manufacturing method therefor - Google Patents

Abstract

The present invention relates to photonic wiring comprising a coated nanowire for connecting a first contact point and a second contact point. The photonic wiring comprising a coated nanowire, according to the present invention, can improve an optical signal characteristic by a reduction of optical coupling loss in a substrate and exhibit a stable optical signal characteristic without significant influence from changes in an external environment and an optical signal wavelength.

Description

Optical wiring including coated nanowires and a method for manufacturing the same

The present invention relates to an optical wiring including a coated nanowire and a manufacturing method thereof, and more particularly, to an optical wiring including a nanowire coated with a coating solution having a lower refractive index than a nanowire and a manufacturing method thereof.

High density optical integrated circuits based on the assembly of nanoscale optical components are new future technologies that can go beyond the limits of electronic integrated circuits. Over the past decade, a variety of nanoscale photonic elements have been developed for the implementation of high-density optical integrated circuits. Developing a technology that interconnects these components is a key challenge that is fundamental to the realization of nanoscale photonic integration. The most promising approach for connecting nanoscale components is to integrate a nanowire waveguide between two spaced apart components to signal the evanescent coupling.

To date, the technique of integrating nanowire optical waveguides has relied on an in-plane manual assembly of already fabricated nanowires on a plane. However, in the plane assembly, light loss occurs from the nanowire to the substrate, and manual assembly using a microprobe or the like has a problem that the process is very complicated and the nanowire is easily damaged during the process.

Conventionally, a prism lens or the like is used to change the direction of the light, and then the contacts between the optical fibers are connected to each other (Han-Soon Lee et al., Optics Express 22 (10) 11778-11787 (2014)). In this case, the light from the VCSEL must be aligned with the prism lens, and the light from the VCSEL must be aligned correctly with the optical fiber core. However, since the diameter of the core of the optical fiber is as small as about 10 μm, many defects occur due to the mechanical error occurring in alignment. In order to overcome this problem, an active alignment method is used, but this requires a lot of time and cost, and still shows a significant defect rate. Further, such a device has a limitation in reducing the size because the prism device is essentially necessary.

Korean Patent No. 10-1583736 discloses a method of optically wiring a nanowire by directly growing a nanowire to a desired position three-dimensionally. However, when the nanowire is exposed to the air in this way, the optical signal transmitted is unstable and the size of the optical signal according to the wavelength can be changed when transmitting the multi-wavelength optical signal. In addition, due to the characteristics of the three-dimensional wiring, foreign substances such as external dust may adhere or be damaged by mechanical impact.

The present invention is further developed to solve problems such as optical signal instability and stability against external environment when nanowires are manufactured in three dimensions and used in optical wiring.

It is an object of the present invention to provide a technique for coating nanowire with a material having a lower refractive index than nanowire to protect the nanowire from chemical and physical influences in the external environment and improving optical signal transmission efficiency.

The present invention relates to optical wiring comprising a coated nanowire for connecting a first contact and a second contact, wherein the nanowire comprises at least one polymer selected from the group consisting of polystyrene, methyl polymethacrylate and polycarbonate And the nanowire is coated with a material having a lower refractive index than the polymer.

Preferably, the refractive index of the material having a refractive index lower than that of the polymer is 1.33 or more.

Preferably, the material having a lower refractive index than the polymer is a high-molecular fluororesin.

Preferably, the optical wiring further includes a nano-rod formed on at least one of the first contact and the second contact, and the nanowire is connected to the nanowire in the presence of the nano-rod.

Preferably, the viscosity of the material having a lower refractive index than the polymer is in the range of 10 mPa · s to 500 mPa · s.

The present invention also relates to a method of manufacturing an optical line including a coated nanowire for connecting a first contact and a second contact, comprising the steps of: a) filling a first micropipette with a solution of a substance to form a nanowire; b) coaxially aligning the longitudinal axis of the first micropipette with an axis perpendicular to the surface of the first contact; c) forming a meniscus of the material solution to form the nanowires; d) evaporating the solvent of the material solution to form the nanowire by lifting up the first micropipette; e) contacting the first micropipette with a second contact spaced apart from the first contact to produce a nanowire; f) filling the second micropipette with the coating solution; And g) moving the second micropipette along the nanowire to discontinuously coat the coating solution.

Preferably, the coating solution has a lower refractive index than the refractive index of the nanowire.

Preferably, the refractive index of the coating solution is 1.33 or more.

Preferably, the viscosity of the coating solution is from 10 mPa · s to 500 mPa · s.

The optical wiring according to the present invention can improve optical signal characteristics due to reduction of coupling loss to the substrate.

The optical wiring according to the present invention exhibits stable optical signal characteristics without significant influence on the external environment and the change of the optical signal wavelength.

FIG. 1 (a) is a schematic view showing a part of a method for manufacturing an optical wiring according to the present invention, and FIG. 1 (b) is a schematic view showing an optical wiring manufactured according to the present invention.

2 is a graph showing optical signals according to wavelengths in the case of using coated nanowires as optical wiring according to the present invention.

Unless defined otherwise, all technical terms used in the present invention have the following definitions and are consistent with the meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In addition, preferred methods or samples are described in this specification, but similar or equivalent ones are also included in the scope of the present invention.

In the present invention, "meniscus" means a curved surface formed by the liquid surface of the tube due to the interfacial tension. Depending on the nature of the liquid, the liquid surface becomes concave or convex.

As used herein, the term "first contact" refers to a portion that emits light, for example, a light source such as an LED or an LD, or a light source such as a waveguide or an optical fiber, Means and apparatus. The term "second contact" used in the present invention means a portion for receiving light passing through an optical wiring, and may be a direct optical detecting means such as a photodetector PD, or a light source such as a waveguide or an optical fiber And means for receiving light, including transmitting light. It should be apparent to those skilled in the art that the terms first contact and second contact used in the present invention are arbitrary and may be used in the opposite sense depending on the direction of light transmission and reception.

The present invention relates to an optical wiring including a coated nanowire for connecting a first contact and a second contact requiring optical signal connection.

The nanowires of the present invention may be configured to include all organic polymers capable of forming nanowires, and preferably comprise at least one polymer selected from the group consisting of polystyrene, polymethylmethacrylate, and polycarbonate. . At 589 nm wavelength, the known polystyrene has a refractive index of 1.59, the polymethylmethacrylate has a refractive index of 1.48 and the polycarbonate has a refractive index of 1.57.

The coating solution for coating the nanowires of the present invention is a material having a lower refractive index than the organic polymer used for forming the nanowires. The refractive index of the coating solution for coating the nanowire is preferably 1.33 or more. The wavelength difference (based on 589 nm) of the coating solution coating the nanowire and the nanowire can be 0.05 to 0.5, preferably 0.1 to 0.4, and more preferably 0.25 to 0.14.

Also, the coating solution for coating the nanowire of the present invention needs to control the viscosity to uniformly coat the nanowire formed on the nanowire, and the preferable viscosity is 1 mPa · s to 1000 mPa · s to be.

Any of the coating solutions satisfying the above conditions may be used. For example, a material having a lower refractive index than the polymer and satisfying the viscosity range may be a polymer fluororesin or CYTOP of Asahi Glass Co., Ltd. The refractive index of CYTOP is 1.34 at a wavelength of 589 nm, and the viscosity can be adjusted to 10 mPa · s to 500 mPa · s.

The diameter of the nanowires produced may be less than or equal to 500 μm (zero inclusive). In addition, the coating of the nanowire may be 0.1 to 100 [mu] m thick. Excessive thickness can cause problems due to expansion / contraction.

The optical wiring may further include a nano rod formed on at least one of the first contact and the second contact. In the case where the nano rod is present, the optical wiring may include a first contact or a second contact, Can be optically wired in a connected form.

The nanorod according to the present invention may be formed on at least one of the first contact and the second contact. For example, the nanorod may be formed at the first contact, the second contact, or both the first contact and the second contact. The nanowire according to the present invention may include a nanorod formed on the second contact to reduce light loss of the nanowire because the nanowire may generate more light loss at the second contact portion due to the manufacturing method.

The nano-rods may have a cylindrical shape or a shape in which the outer peripheral surface of the nano-rods is narrowed toward the upper side or the lower side, that is, a truncated cone shape. When the nano-rods are frustum-shaped, the outer circumferential surface of the nano-rods has an angle of more than -35 degrees to less than +35 degrees with respect to the axis of the height of the nano-rods, preferably an angle of not less than -10 degrees and not more than + . Here, the "axis in the height direction of the nanorod" means an axis perpendicular to the direction in which the nanorod grows, i.e., the surface on which the nanorod is formed. In general, when the size of the contact to which light is emitted and received is larger than the size of the optical line and the adhesion with the contact point is taken into account, the shape of the nano rod is most preferably narrowed toward the upper side. Specifically, the outer circumferential surface of the nano rod has an angle of less than 35 degrees (not equal to 0) with respect to the axis of the nano rod in the height direction, and preferably an angle of not more than 10 degrees (not equal to 0).

The height of the nano-rods may be 0.5 m or more, and preferably 0.5 to 100 m. If the height is less than 0.5 μm, the light loss reduction effect obtained by the presence of the nano-rod can not be obtained. If the height exceeds 100 μm, the shape and size of the final product may be affected. However, the height of the nano-rods can be adjusted in consideration of the size of the nano-rods, the nanowires, the substrate (chips), and the distance between the contacts. The lower diameter of the nano-rods may be between 0.5 μm and 500 μm. The lower diameter of the nano-rod can be adjusted according to the size of the light-emitting contact and the amount of light emitted.

The present invention also relates to a method of manufacturing an optical line including a coated nanowire for connecting a first contact and a second contact. Specifically, the manufacturing method of the optical line may include the following steps.

a) filling a first micropipette with a substance solution to form a nanowire;

b) coaxially aligning the longitudinal axis of the first micropipette with an axis perpendicular to the surface of the first contact;

c) forming a meniscus of the material solution to form the nanowires;

d) evaporating the solvent of the material solution to form the nanowire by lifting up the first micropipette;

e) contacting the first micropipette with a second contact spaced apart from the first contact to produce a nanowire;

f) filling the second micropipette with the coating solution; And

g) applying the coating solution discontinuously by moving the second micropipette along the nanowire.

Each step will be discussed in detail below.

First, the first micropipette is filled with a substance solution to form a nanowire (step a). The material solution to form the nanowire contains all the materials capable of forming the nanowire, and includes most of the organic matter. Specifically, the material solution for forming the nanowire means a solution containing a solvent and at least one polymer selected from the group consisting of polystyrene, polymethyl methacrylate and polycarbonate. The solvent can be any material that can be easily evaporated (volatile material) and can include any material used in the art suitable for making the present invention.

Next, step (b) of aligning the longitudinal axis of the first micropipette with an axis perpendicular to the surface of the first contact. The coaxial alignment is preferably performed using two optical lenses to align the x-axis and the y-axis, respectively. When using only one optical lens, the nanowire grown using a micropipette is not aligned with the coaxial axes due to an error occurring in the other direction, so that the optical transmission loss of the connection portion increases. For coaxial alignment, it is desirable to position the optical lenses of the x-axis and the y-axis perpendicular to each other.

The micropipette used in the present invention may be manufactured by using a pipette puller to a desired diameter, or a manufactured micropipette may be purchased and used. The size of the nanowire can be adjusted according to the diameter of the end (inlet, opening) of the micropipette. The term "micropipette " as used in the present invention is a generic term for all the tools used to dispense or draw liquids and includes all the tools that can perform the same function.

Next, step (c) is performed to form a meniscus of the material solution to form the nanowires. The first micropipette filled with the material solution for forming the nanowire is spaced from the first contact so that the material solution for forming the nanowire forms a meniscus.

Next, the step (d) of evaporating the solvent of the material solution for forming the nanowire by lifting up the first micropipette. When the micropipette is lifted up while maintaining a distance to induce the meniscus of the material solution to form the nanowire, the liquid (solvent) inside rapidly evaporates and the dissolved substance solidifies to form a columnar shape. The direction in which the first micropipette is lifted is determined in consideration of the distance between the first and second spaced apart contacts, the lifting speed, etc., and a specific portion of the nanowire to be manufactured must be controlled so as not to be rapidly changed in direction, The direction of lifting should be adjusted so as to minimize the loss of light to the part.

Next, the first micropipette is brought into contact with the second contact spaced apart from the first contact to manufacture a nanowire (step e).

Next, step (f) of filling the second micropipette with the coating solution. The coating solution preferably contains a material having a lower refractive index than the refractive index of the nanowire. Further, the viscosity of the coating solution may be from 1 mPa · s to 1,000 mPa · s, and preferably from 10 mPa · s to 500 mPa · s.

Finally, the second micropipette is moved along the nanowire to discontinuously apply the coating solution (step g). Specifically, in this step, the coating solution is preferably applied to have a thickness of 0.4 to 100 μm. When the coating is applied at less than 0.4 μm, the coating may not uniformly occur. When the coating is applied at a thickness exceeding 100 μm, the reliability of the solution expansion / contraction may occur. The second micropipette is required to apply the coating solution along the top surface of the nanowire and to control the nanowire to be coated as a whole. This can be conveniently solved by being controlled through an image recognition program. It is necessary to apply the coating solution so that a portion not coated on the nanowire does not occur. If there is an uncoated portion, the transfer mode instability may occur there.

FIG. 1 is a view showing a method of manufacturing an optical wiring according to the present invention and optical wiring produced therefrom. FIG. Specifically, Fig. 1 (a) is a schematic view showing a step g of the method for manufacturing an optical wiring according to the present invention, and Fig. 1 (b) is a schematic view showing a coated optical wiring fabricated according to the present invention.

In addition, when the present invention includes a nano-rod, the nano-rod may be prepared by the following method and before the nanowire is manufactured (before the step a):

a) filling a micropipette with a nanorod material solution;

b) aligning the micropipette with the first or second contact;

c) forming a meniscus of the nanorod material solution; And

d) evaporating the solvent of the nanorod material solution by lifting the micropipette in a direction perpendicular to the surface of the contact point to manufacture the nanorod.

The method of manufacturing the nanorod is the same as the method of manufacturing the nanowire except for the special mention, and includes all the contents of Patent Application No. 2017-0142404.

Briefly, the nanorod material solution may comprise a solution comprising at least one polymer selected from the group consisting of polystyrene, polymethyl methacrylate, and polycarbonate, such as a solution of a material to form a nanowire. The micropipette is coaxially aligned so that the longitudinal axis of the micropipette is aligned with the first contact or the axis perpendicular to the surface of the second contact using optical lenses of x and y axis perpendicular to each other.

The step of lifting the micropipette in a direction perpendicular to the surface of the contact and evaporating the solvent of the nanorod material solution to manufacture the nanorod is performed by moving the micropipette in a direction in which light is emitted, .

In one embodiment, the lifting speed of the micropipette can be raised while accelerating or decelerating so that the outer circumferential surface of the nano-rod has a shape narrowing toward the upper side or the lower side. The lifting speed (drawing speed) can be adjusted in consideration of the angle with respect to the axis in the height direction of the nano-rod, the height of the nano-rod, and the like. In another embodiment, the pressure applied to the micropipette can be adjusted so that the outer circumferential surface of the nano-rod has a shape narrowing toward the upper side or the lower side. When the pressure applied to the interior of the micropipette is increased, the diameter of the nanorod increases as the discharge amount of the nanorod material solution increases. When the pressure applied to the interior of the micropipette is decreased, the discharge amount of the nanorod material solution decreases The diameter of the nanorod becomes smaller.

In the case of including a nano-rod, it is possible to further reduce the optical coupling loss occurring between the contact and the nanowire.

Hereinafter, the present invention will be described in detail with reference to examples. However, these embodiments are for illustrative purposes only, and the present invention is not limited thereto.

Experimental Example 1

1. Manufacture of nano-wires

A polymethyl methacrylate powder was dissolved in a xylene solvent at a concentration of 0.5 wt% to prepare a solution for forming nanowires. The material solution to form the nanowires was filled in a micropipette having a tip diameter of 0.5 mu m. The micropipette was brought into contact with the first contact to create a meniscus of the substance solution to form the nanowire outside the opening of the micropipette. The micropipette was lifted to remove the solvent and to grow the nanowires. The nanowires produced are about 8 μm in diameter. The micropipette was brought into contact with the upper portion of the nano-rods formed at the second contact points of the chip to complete optical wiring using nanowires. The first contact and the second contact are separated by about 500 mu m. The produced nanowire was referred to as Production Example 1.

2. Preparation of nanowires coated with water (refractive index 1.33)

In order to confirm the effect obtained when coating with a material having a low refractive index, the nanowire was coated with water having a refractive index of 1.33 so as to cover the prepared nanowire (Preparation Example 1). The results are shown in Fig. 2, in the uncoated nanowire (Production Example 1), the change in the intensity of the optical signal was great in accordance with the change of the wavelength, whereas the nanowire coated with water (Production Example 2) It can be seen that the intensity of the optical signal is constant. Thus, it can be seen that coated nanowires are more suitable for use as optical wiring.

Claims (9)

1. An optical wiring comprising a coated nanowire for connecting a first contact and a second contact,

   Wherein the nanowire comprises at least one polymer selected from the group consisting of polystyrene, polymethyl methacrylate and polycarbonate,

   Wherein the nanowire is coated with a material having a lower refractive index than the polymer.
2. The method according to claim 1,

   Wherein the refractive index of the material having a lower refractive index than the polymer is 1.33 or more.
3. The method according to claim 1,

   Wherein the material having a lower refractive index than the polymer is a polymeric fluororesin.
4. The method according to claim 1,

   Wherein the optical wiring further comprises a nanorod formed on at least one of the first contact and the second contact,

   Wherein an upper portion of the nanorod is connected to a nanowire when the nanorod is present.
5. The method according to claim 1,

   And the viscosity of a material having a lower refractive index than that of the polymer is 10 mPa · s to 500 mPa · s.
6. A method of manufacturing an optical line including a coated nanowire for connecting a first contact and a second contact,

   a) filling a first micropipette with a substance solution to form a nanowire;

   b) coaxially aligning the longitudinal axis of the first micropipette with an axis perpendicular to the surface of the first contact;

   c) forming a meniscus of the material solution to form the nanowires;

   d) evaporating the solvent of the material solution to form the nanowire by lifting up the first micropipette;

   e) contacting the first micropipette with a second contact spaced apart from the first contact to produce a nanowire;

   f) filling the second micropipette with the coating solution; And

   g) moving the second micropipette along the nanowire to discontinuously apply the coating solution. < Desc / Clms Page number 20 >
7. The method according to claim 6,

   Wherein the coating solution has a lower refractive index than the refractive index of the nanowire.
8. 8. The method of claim 7,

   Wherein the coating solution has a refractive index of at least 1.33.
9. The method according to claim 6,

   Wherein the coating solution has a viscosity of from 10 mPa · s to 500 mPa · s.

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