TW201843484A - A plano-convex lens, fiber array module and optical receiving module - Google Patents

Abstract

The present disclosure relates to a plano-convex lens 20 having a flat surface 21A and a lens surface 23, and the lens surface 23 comprises a first convex surface A1 and a second convex surface A2 having a spherical shape arranged on a flat base surface 21B. The diameter D1 of the first virtual circle formed on the base surface 21B by the first convex surface A1 and the diameter D2 of the second virtual circle formed on the base surface 21B by the second convex surface A2 are larger than the center-to-center distance dp between the first virtual circle and the second virtual circle.

Description

Plano-convex lens, fiber matrix module and light receiving module

The present invention relates to a plano-convex lens having two convex surfaces, a fiber matrix module having the same, and a light receiving module.

A light receiving module for optical communication has been proposed (for example, refer to Patent Documents 1 and 2). In the light receiving modules of Patent Documents 1 and 2, the light beams emitted from the first optical fiber are collimated by a lens matrix, and a part of the light beams collimated by the lens matrix is partially reflected by the filter to the lens matrix, and returned to the lens matrix. The second fiber. On the other hand, in order to monitor the light in the transmission path, a portion of the light beam that is branched by the filter is received by the light receiving element provided in the subsequent stage.

In Patent Document 1 disclosed in Patent Document 2, the interval between the first optical fiber and the second optical fiber is 500 μm, and the interval between the lens matrices is also 500 μm. However, the miniaturization of the module for optical communication has progressed, and it is required to arrange the optical fibers at intervals of 500 μm such as 250 μm or 127 μm. [Prior Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open Publication No. 2009-093131. Patent Document 2: Japanese Patent Laid-Open No. 2005-043762

[The problem that the invention wants to solve]

Spherical lenses are ideal for use in lens matrices because of their ease of design and fabrication. However, in the reflective lens-fiber coupling system as in Patent Documents 1 and 2, if the interval between the optical fibers is to be narrowed, the coupling efficiency of the light beam reflected by the filter to the second optical fiber is lowered. . On the other hand, it is also conceivable to reduce the lens diameter by increasing the refractive index of the lens matrix, but the lens material having a higher refractive index is not practical.

It is an object of the present invention to prevent reflection of a light-receiving lens material without using a lens material having a relatively high refractive index even when the interval between the first optical fiber and the second optical fiber is narrow in a reflective lens-fiber coupling system. The beam is efficiently coupled to the second fiber. [Technical means to solve the problem]

The plano-convex lens of the present invention includes a flat surface and a lens surface, and the lens surface includes a first convex surface and a second convex surface having a spherical shape disposed on a flat base surface, and is formed on the base by the first convex surface The diameter of the first imaginary circle on the surface and the diameter of the second imaginary circle formed on the basal plane by the second convex surface are larger than the distance between the center of the first imaginary circle and the second imaginary circle.

In the plano-convex lens of the present invention, a saddle portion in which a shape change between the first convex surface and the second convex surface is further reduced may be further provided between the first convex surface and the second convex surface.

In the plano-convex lens of the present invention, the first convex surface and the second convex surface may include a first straight line passing through a vertex of the first convex surface and a center of the first virtual circle, and a vertex passing through the second convex surface And the second straight line at the center of the second imaginary circle, the light emitted from the first position and the second position in the specific plane of the two straight lines is parallel light, and the parallel light incident from the first convex surface is disposed When the reflecting surface of the flat surface is reflected, the second convex surface condenses the parallel light to the second position.

In the plano-convex lens of the present invention, the first convex surface and the second convex surface may include a first straight line passing through a vertex of the first convex surface and a center of the first virtual circle, and a vertex passing through the second convex surface And the second straight line at the center of the second imaginary circle; the light that enters the flat surface at the first position and the second position in the specific plane of the two straight lines is parallel light, and is from the first position and the The second position is emitted from a predetermined distance of a predetermined distance from the first straight line and the second straight line, and the parallel light emitted from the first convex surface is reflected at the point The second convex surface condenses the parallel light to the second position.

In the plano-convex lens of the present invention, the reflecting surface may be provided with a filter portion that partially transmits the parallel light incident from the first convex surface and partially reflects the parallel light to the second convex surface.

The optical fiber matrix module of the present invention includes: a first lens matrix having a plurality of plano-convex lenses of the present invention, wherein a plurality of the first convex surfaces and the second convex surface are arranged on the common base surface; and an optical fiber matrix Each of the plano-convex lenses has two optical fibers, and an end surface of each of the optical fibers is disposed at the first position or the second position of each of the plano-convex lenses.

The optical fiber matrix module of the present invention includes: the optical fiber matrix module of the present invention; the optical component having a plurality of through holes through which the parallel light transmitted from the reflective surface is transmitted, wherein each of the parallel light transmitted from the reflective surface is incident on One end of the through hole is different, and parallel light passing through the through hole is emitted from the other end of each through hole; and the second lens matrix condenses each light emitted from the other end of the plurality of through holes To the point specified for each of the through holes.

The light receiving module of the present invention includes: the optical fiber matrix module of the present invention; and a light receiving element matrix that receives the light collected by the second lens matrix. [Effects of the Invention]

According to the present invention, in a reflective lens-fiber coupling system, a lens material having a relatively high refractive index can be omitted, and light which is returned to the optical fiber after being partially branched and used for monitoring can be efficiently coupled to the optical fiber. .

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Furthermore, the present invention is not limited to the embodiments described below. The embodiments are merely illustrative, and the present invention can be implemented in various modifications and improvements based on the knowledge of the manufacturer. In the present specification and the drawings, constituent elements having the same reference numerals indicate the same elements.

(First Embodiment) A perspective view of an optical system of this embodiment is shown in Fig. 1 . The optical system of the present invention includes a bimodal plano-convex lens 20, two optical fibers 11A and 11B, and a filter portion 4. The end face P1 of the optical fiber 11A is disposed at the first position and functions as the first optical fiber. The end face P2 of the optical fiber 11B is disposed at the second position and functions as the second optical fiber. The surface on the side of the plano-convex lens 20 of the filter portion 4 functions as a reflecting surface.

First, the plano-convex lens 20 will be described. The plano-convex lens 20 of the present invention has a lens surface 23 on a base surface 21B of a flat substrate 21 which is formed of a rectangular lens material having a side parallel to the xyz orthogonal coordinate axis in the drawing. The lens surface 23 has a spherical surface A1 that functions as a first convex surface, a convex surface A2 that functions as a spherical surface of the second convex surface, and a saddle portion A3.

The convex surface A1 is a portion of the spherical surface of the peak P6 with the first straight line R1 parallel to the z-axis as the center of rotation and the intersection with the straight line R1. The convex surface A2 has a second straight line R2 parallel to the z-axis as a center of rotation, and a point of intersection with the straight line R2 as a part of the spherical surface of the peak P8. The convex surface A2 is a portion of the spherical surface of the shape obtained by moving the convex surface A1 in parallel in the x direction by the amount of the peak interval dp.

An example of an imaginary circle formed on the base surface 21B by the convex surfaces A1 and A2 is shown in FIG. On the base surface 21B, a first imaginary circle having a diameter D1 centering on a point C1 on the straight line R1 is formed by the convex surface A1. Regarding the convex surface A2, a second imaginary circle having a diameter C2 with a point C2 on the straight line R2 as a center point is also formed on the base surface 21B. The first straight line R1 passes through the apex P6 of the convex surface A1 and the center point C1 of the first imaginary circle, and the second straight line R2 passes through the apex P8 of the convex surface A2 and the center point C2 of the second imaginary circle.

The lens diameters of the two convex surfaces A1, A2 forming the lens functions are set to be larger than the peak interval dp. In other words, the peak interval dp is smaller than the diameters D1 and D2, and the first imaginary circle and the second imaginary circle are arranged to overlap each other. In the embodiment, the diameters D1 and D2 are equal, but the present invention is not limited thereto, and the diameters D1 and D2 may be different.

1, the saddle has a width of w _s and A3 overlap portion disposed on the first virtual circle of the second imaginary circle. Similarly to the contour line indicated by a broken line in FIG. 1, the saddle portion A3 is formed so as to protrude from the base surface 21B and smoothly connect the two convex portions A1 and A2. In general, the lens surface 23 including the convex surfaces A1, A2 and the saddle portion A3 is a lens central axis Ac passing through a straight line passing through the midpoints of the two peaks P6 and P8 and parallel to the z-axis. Hereinafter, a straight line passing through the two peaks P6 and P8 parallel to the x-axis is referred to as a peak line Bc.

The optical fiber 11A having an optical axis parallel to the z-axis is disposed in such a manner that its optical axis intersects the peak line Bc at a specific distance from the straight line R1 which is the center of the convex surface A1. The outgoing light from the optical fiber 11A is incident outward with respect to the peak P6 of the convex surface A1. The portion of the incident light whose intensity is a specific amount is reflected by the following structure, and is collected and incident on the optical fiber 11B which is symmetrically arranged with respect to the lens central axis Ac with the optical fiber 11A.

A lens of this form can be produced by a glass mold method using a mold. Fig. 3 shows a contour map obtained by observing the mold from the z-axis direction in the mold making step. First, as shown in Fig. 3, a concave surface corresponding to the convex surfaces A1, A2 is formed on the mold surface. In the concave shape forming step, the overlapping portions are mutually deeper concave surfaces, and ridge lines are formed at the boundary. If such a ridge line exists inside the mold, there is a possibility that the mass transfer in the molding operation may be hindered. Therefore, as shown in FIG. 4, the boundary is removed so as not to affect the projection portion Pd of the xy plane from the outgoing light intensity distribution pattern of the optical fiber, and the shape change in the boundary is relaxed. Thereby, the shape of the saddle A3 as shown in FIG. 1 is obtained.

Next, in order to explain the optical system of the present embodiment in a more easily understandable manner, FIG. 5 which is a cross-sectional view obtained by cutting the plane Pc including the straight lines R1 and R2 will be described. In the present embodiment, the optical fibers 11A and 11B are disposed on the lens surface 23 side, and the filter portion 4 is disposed on the flat surface 21A side. The end face P1 of the optical fiber 11A and the end face P2 of the optical fiber 11B are disposed at the first position and the second position, respectively. The longitudinal directions of the optical fibers 11A and 11B are arranged in parallel with the lens central axis A _{C of the} plano-convex lens 20 in the plane P _C . The plane P _C is a plane formed by the optical fibers 11A and 11B. Hereinafter, this embodiment will be referred to as Type I.

The plano-convex lens 20 of the present embodiment has two convex surfaces on the lens surface 23 having convex surfaces A1 and A2. The convex surface A1 is a curved curved surface which is parallel to the lens central axis Ac and includes a straight line R1 included in the plane Pc formed by the optical fibers 11A and 11B as a center of rotation, and the convex surface A2 is also parallel to the lens central axis Ac and included in the optical fiber. The straight line R2 of the plane Pc formed by 11A and 11B serves as a rotating curved surface of the center of rotation, and the straight lines R1, R2 are shifted symmetrically with respect to the central axis Ac of the lens toward the inner side by a specific distance.

In such a configuration, light emitted from the end surface P1 of the optical fiber 11A enters the plano-convex lens 20 from the convex surface A1. The convex surface A1 sets the light emitted from the end surface P1 of the optical fiber 11A as parallel light. The light that becomes parallel light by the convex surface A1 passes through the plano-convex lens 20, and a part thereof is reflected toward the convex surface A2 by the filter portion 4 disposed on the flat surface 21A. The convex surface A2 condenses the parallel light reflected by the filter portion 4 to the end surface P2 of the optical fiber 11B. Thereby, the parallel light reflected by the filter portion 4 is incident on the optical fiber 11B.

The plano-convex lens 20 of the present embodiment condenses the parallel light reflected by the filter portion 4 to the end surface P2 of the optical fiber 11B. Therefore, the plano-convex lens 20 of the present embodiment can efficiently couple light of a portion of the monitor light (hereinafter referred to as a tap) to the optical fiber 11B.

(Second Embodiment) Fig. 6 shows an example of the configuration of an optical fiber matrix module of the present embodiment. This is equivalent to the case where the plano-convex lens 20 of the type I is matrixed. The optical fiber matrix module of the present embodiment includes an optical fiber matrix 1 in which optical fibers 11A-1 to 11A-4 and 11B-1 to 11B-4 are alternately arranged, and a lens matrix 2 in which the plural of the first embodiment is arranged Lens surfaces 23-1 to 23-4. The lens matrix 2 functions as a first lens matrix.

The lens matrix 2 is provided with a spacer 22 at both ends of the plurality of lens faces 23-1 to 23-4. The spacer 22 may be formed in advance by forming a concave portion corresponding to the spacer at the same time as forming a concave portion corresponding to the lens, and may be formed by molding at the same time as the formation of the lens, or may be a plate sandwiching a specific thickness. The form.

The optical fiber matrix 1 and the lens matrix 2 are arranged in parallel on the plane P _C in the four fiber optic optical systems of the first embodiment. Specifically, the lens matrix 2 includes a plurality of lens faces 23-1 to 23-4 of the first embodiment. Each of the bimodal plano-convex lenses 20 included in the lens matrix 2 includes the fiberoptic lens optical system of the first embodiment as a basic unit. The lens central axes A _{C of the} respective lens faces 23 are arranged side by side in the plane P _C . The optical fiber matrix 1 has two optical fibers 11A and 11B with respect to each of the bimodal lens faces 23-1 to 23-4. The end surface PL11 of the optical fiber matrix 1 in which the end faces of the optical fibers 11A-1 to 11A-4 and the respective end faces of the 11B-1 to 11B-4 are disposed is arranged in parallel with the peak line Bc.

Referring to Figure 7, an optical system in Figures 5 and 6 will be described. The following directions are described in the same manner as the orthogonal xyz coordinate axes in the figure. On the left side of the figure, an optical fiber matrix 1 in which optical fibers 11A and 11B are arranged in parallel with the z-axis and at intervals d _f in the x-axis direction is disposed in the xz plane. The optical fiber matrix 1 is formed by a plane parallel to the x-axis and forming a specific angle with respect to the y-axis as an end surface, for example, by a casing such as TEMPAX glass.

The lens surface 23 having the lens central axis A _C parallel to the z-axis is a common plane perpendicular to the z-axis, and is spaced twice as far as the optical fiber matrix 1 by 2d _f in the x-axis direction, and adjacent thereto The lens faces 23 are matrixed by spacing adjacent intervals d _n . The convex surface A1 is formed by a rotating curved surface centered on a straight line R1 formed by a plane Pc formed by a matrix of optical fibers and parallel to the z-axis, and forms a lens action. Further, the optical axis of the optical fiber 11A is shifted toward the inner side (the lens central axis Ac side) by a specific distance. The convex surface A2 is formed in a shape symmetrical with respect to the convex axis A1 with respect to the lens central axis Ac and the saddle portion A3 across the width w _s . The interval d _p between the straight line R1 of the convex surfaces A1 and A2 and the straight line R2 (hereinafter referred to as the peak interval d _p ) is set to be smaller than the distance d _f .

The end surface PL11 of the optical fiber matrix 1 and the lens surface 23 of the lens matrix 2 are disposed via an air layer 3 having a thickness equal to the convex side focal length fv. The distance between the lens surface 23 and the flat surface 21A, that is, the thickness t _{l of the} lens is set to be a specific value thicker than the concave side focus distance f _c .

The relative position of the fiber matrix 1 and the lens matrix 2 is in the x-axis direction, and the center line of the lens center axis A _C and the adjacent fibers of the fiber matrix 1 are aligned with each other (in the figure, the center line of the fiber 11A and the fiber 11B) In the y direction, the plane formed by the matrix of the lens central axis A _C is set in the same manner as the plane formed by the center line of the optical fiber matrix 1, and the z-direction is the end face PL11 of the optical fiber matrix 1 with respect to the z direction. The distance between the peaks P6 and P8 of the lens matrix 2 and the convex focus distance f _v of the convex lens 20 are also set in the same manner.

The surface of the flat surface 21A of the lens matrix 2 may be provided with a filter portion 4 having a function of reflecting/transmitting light of a specific wavelength at a desired ratio.

In such a configuration, the path of the light emitted from the end face P1 of the optical fiber 11A is examined by the light approximation. Since the end face P1 of the optical fiber 11A is located on the convex side focal plane PL23V, and as described above, the straight line R1 in the lens surface 23 is offset in the x direction with respect to the fiber center line, the end face P1 of the optical fiber 11A is used as the point light source. The light which is emitted here and incident on the convex surface A1 of the lens matrix 2 is refracted toward the lens central axis A _C side, and becomes parallel rays which form a specific angle f with the lens central axis A _C and advances in the lens. The light that is emitted from the end of the optical fiber 11A parallel to the central axis A _{C of the} lens, that is, the z-axis, is the central light that is incident on the plano-convex lens 20 and passes through the concave side focus.

If the thickness t _l of the lens is set to be thicker than the concave side focal length f _c and the flat surface 21A is located at a specific value at a point where the center ray intersects the lens central axis A _c , the filter portion is provided on the flat surface 21A. 4. The portion of the specific intensity of the parallel light passes through the filter portion 4 and advances at an angle ψ with respect to the lens central axis A _C , but the remaining intensity portion is reflected by the filter portion 4 relative to the lens center The axis A _C reaches the convex surface A2 in the symmetrical x-direction position. The reflected light reaching the convex surface A2 passes through the parallel light after the concave side focus, and proceeds along a path symmetrical with respect to the lens central axis A _C from the optical path emerging from the optical fiber 11A and incident on the bimodal plano-convex lens 20, and finally condensed. The end face P2 of the optical fiber 11B is located at a position symmetrical with respect to the optical axis 11A with respect to the lens central axis A _C .

Here, it is assumed that when the thickness t _{l of the} lens is thinner than the above-described specific value, the reflected light obtained by the filter portion 4 reaches the surface of the convex axis A2 on the lens center axis A _C side, where the parallel light is not focused. And diffused on the end face P2 of the optical fiber 11B. On the other hand, when the thickness t _{l of the} lens is thicker than the above specific value, the reflected light obtained by the filter portion 4 reaches the surface on the outer side of the convex surface A2, and the parallel light is over-focused, and is on the end face of the optical fiber 11B. P2 spreads. In either case, the optical axis of the reflected light passing through the filter portion 4 is deviated from the end face P2 of the optical fiber 11B. Thus, specific values must be set such that the thickness of the lens is thicker than the concave side of the t _l focal length f _c, and the flat surface 21A is located in the central ray and the lens center axis A _c of the point of intersection.

Further, the light transmitted through the filter portion 4 is emitted at an angle 若 if the refractive index of the adjacent medium is the same as the refractive index n _{v of the} air layer 3. Further, although not shown, when the refractive index of the adjacent medium is the same as the refractive index of the lens matrix 2, it is emitted at an angle f .

Next, the above description is formulated using a formula. In Fig. 7, the light beam which is emitted from the optical fiber 11A having the end face P1 and which is incident on the convex surface A1 of the lens surface 23 through the air layer 3 is a parallel light which forms an angle f with the lens central axis A _C from the convex side focal plane PL23V. For the light rays incident on the peak P6 of the convex surface A1 among the light rays, since the plane of the lens surface of the incident point is perpendicular to the central axis A _{C of the} lens, the angle of incidence angle ψ as the center of the peak of the light ray, as the angle of the exit angle Between f and the refractive indices n _v and n _c , Snell's law represented by the following formula holds. (Number 1) n _v sinψ=n _c sin (1) Here, n _v and n _c are the refractive index of air and the refractive index of the lens, respectively.

Further, since the optical fiber matrix 1 is matrixed by the interval d _f and the lens matrix 2 is twice as large as the interval 2d _f , the focal length f _v to the convex side focal plane PL23V and the concave focal plane PL23C are obtained. The focal length f _{c is} based on the fiber spacing d _f , the peak interval d _p between the convex surface A1 and the convex surface A2 , the angle ψ as the incident angle to the peak P6 , and the angle f from the peak P6 to the exit angle in the lens matrix 2 . The value is determined by the following formulas (2) and (3). (number 2) f _v ={(d _f -d _p )cotψ}/2(2) (number 3) f _c ={(d _f -d _p )cot }/2(3)

Further, regarding the thickness t _l of the lens, the following equation also holds. (Number 4) t _l =d _f cot /2(4)

Further, the peak curvature radius R _p can be given by the following formula. (Number 5) R _p =(n _c -n _v )f _v /n _v (5)

Each of the convex surface A1 and the convex surface A2 constituting the bimodal peak may satisfy the above equations (1) to (5), but the curved surface that satisfies the relationship and has an axis parallel to the lens central axis A _{C as} the axis of symmetry is the most It can be preferably approximated by simply using R _p obtained according to formula (5) as the spherical surface of the radius. When the fiber spacing d _f , the lens peak interval d _p , the lens refractive index n _c , the air refractive index n _v , and the angle f of the reflection angle of the filter portion 4 are given, according to the formula (2) and the formula (2) 3) The convex and concave focal lengths f _v and f _{c of the} plano-convex lens 20 are determined, that is, the thickness t _{l of the} lens is determined according to the distance between the optical fibers 11A and 11B and the plano-convex lens 20 and the equation (4). Moreover, the peak curvature radius which is the shape standard of the mold used in the molding step of the lens manufacturing step is also known from the formula (5).

Next, the conditions for establishing such an optical system will be described. In order to achieve low loss coupling between the optical fibers 11A and 11B, it is necessary to suppress the vignetting of the lens surface 23 as much as possible. The outgoing light from the optical fiber 11A is diffused according to the NA (Numerical Aperture) of the optical fiber, but the diffusion is preferably expressed as a Gaussian beam with the fiber end as the beam waist position. The power distribution of the Gaussian beam emerging from the end face P1 of the optical fiber 11A and reaching the convex surface A1 is 99.75% of the total power in the range from the center of the beam to 1.73 times the beam radius ω. Therefore, if the range up to this point is the beam diameter BD of the light beam reaching the convex surface A1, it can be given by the following formula.

[Number 6] Here, ω ₀ and λ are the mode radius of the optical fiber 11A and the wavelength of the light, respectively.

Next, according to the configuration of the lens, the conditions required for the beam diameter of the lens surface 23 are examined in accordance with FIG. When the peak interval _dp between the convex surface A1 and the convex surface A2 is gradually increased, as shown in FIG. 8(a), the overlapping of the convex surface A1 and the convex surface A2 is eliminated and the two separated convex surfaces are obtained. That is, the saddle portion A3 and the base surface 21B are disposed on the same plane. It is referred to as a two-piece state and is considered by its comparison with the bimodal state.

First, consider the two-piece state in accordance with Fig. 8(a). In the two-piece state, in order to achieve fiber-optic coupling without vignetting and low loss, the distance between the center line of the fiber parallel to the z-axis and the outer edge of the lens on the side of the center line must be made in the x-axis direction D _E One-half of the beam diameter BD larger than the surface of the lens, so according to (number 7) BD/2 < D _E = d _p / 2-w _s / 2 - (d _{f -} d _p ) / 2 = (2d _{p -} d _f - w _s) / 2 and _{BD <2d p -d f -w s} (7) must be established. It is a two-piece condition. Here, (2d _p -d _f -w _s ) is hereinafter referred to as a two-piece conditional index. If the beam diameter BD of the lens surface is made larger than the two-plate condition index contrary to the condition of the formula (7), in order to constitute an optical system without vignetting, a bimodal configuration must be employed.

On the other hand, in the bimodal system shown in Fig. 8(b), the condition without vignetting is the distance D between the center line of the fiber and the outer edge of the lens of the x-axis direction in Fig. 8(b). Either _C and D _E are larger than one half of the beam diameter BD, so (number 8) BD < d _f -max(d _n , w _s ) (8) must be established. This condition is a condition including the broader conditional expression (7) as described below.

Here, it is explained in advance that there may or may not be a bimodal shape. In the two examples in Fig. 8, the beam region of the lens surface spans and the two sides of the peaks P6 and P8, as shown in Fig. 9(a), it is also considered that the beam region is only distributed on the outer sides of the peaks P6 and P8. . In this case, the beam diameter BD of the lens surface is sufficiently small to satisfy the conditions of the equations (7) and (8), and the following equation is satisfied. (Number 9) BD<d _f -d _p (9)

In this case, the lens shape need not be a double peak, and may be a ladder shape as shown in the contour diagram of FIG. 9(b) or FIG. 10, and the mold processing of the ladder shape is also easy and durable. Sex is also higher.

Then there is another condition. This is a manufacturing condition of a mold which is represented by the following formula regarding the peak curvature radius R _p . (Number _{10) R p = (n c} -n v) f v / n v ≧ 150 μm (10)

The reason is as follows. The plano-convex lens 20 which is the object of the present invention can be produced by a molding method. In the method, the raw material glass is pressed in a concave hole formed in the mold to transfer the concave shape into a convex shape of the glass, and the radius of curvature of the lens surface 23 depends on the ability of the machine tool for manufacturing the mold. The radius of curvature of the produced hole is set to 150 μm or more. That is, it means that the depth of the smaller radius of curvature below it cannot be formed.

Next, the above description is shown in the graphs shown in Figs. 11 and 12, and the conditions of the optical system capable of constituting the type I will be described. First, the values used in the calculation will be described. The numerical values are described below. Fiber spacing d _f : The fiber period interval often used in the fiber matrix 1 is 250 μm corresponding to a common 250 μm pitch ribbon fiber, and 127 μm obtained by setting the upper and lower nests and matrixing them. The binary value is also studied here. Wavelength λ: Set to 1.55 μm which is a representative value of the optical communication band. • Modal radius ω ₀ : Set to 5.2 μm which is a representative value of the single-mode fiber at a wavelength of 1.55 μm. Lens refractive index n _c : The refractive index of the optical glass used for the lens is distributed from 1.4 of the bismuth glass on the low refractive index side to 2.0 of the vermiculite glass on the high refractive index side. Therefore, here, the lens refractive index n _c is considered to be 1.4 to 2.0. Air refractive index n _v : Since the outside of the lens is usually air, it is set to 1.0. · Saddle width w _s and adjacent interval d _n : When a lens is produced by a glass molding method, a lens-shaped hole is engraved into the mold, but the adjacent holes must be between 10 and 20 μm. Flat part. The reason is that, assuming that the width is narrower than about 10 to 20 μm, a convex portion having a narrow width at the front end is formed between the adjacent holes, and the high temperature and high pressure in the molding step (1 MPa, 450) Above °C) will be deformed and the durability of the mold will be impaired. Therefore, here, the saddle width w _s and the adjacent interval d _n are both set to 17 μm. ·angle In the filter portion 4, a dielectric multilayer film in which a low refractive index transparent material and a high refractive index transparent material are alternately laminated with an optical thickness of λ/4 is used. The structure is obliquely incident on the multilayer film, but the polarization dependence of the tapped light transmitted there becomes a problem. In Fig. 13, a calculation example in the case where SiO ₂ (refractive index 1.44) is used as the low refractive index material and Ta ₂ O ₅ (refractive index 2.12) is used as the high refractive index material is shown. According to this calculation example, in order to set the polarization dependence of the transmitted tap light to 0.05 dB or less, it is preferable to use the angle of the reflection angle as the filter portion 4. Set to 4 degrees or less. Therefore, here, the influence of the change in the refractive index or the film thickness in the actual production is also considered, and the angle of the reflection angle as the filter portion 4 is taken. Set to 2 degrees.

Fig. 11 is a graph showing the relationship between the lens refractive index n _c and the peak curvature radius R _p for each peak interval d _p for the case where the fiber spacing d _f is 250 μm in the configuration of the type I. According to the formulas (1) to (5), since the light refracting ability increases with the increase in the refractive index n _c of the lens with respect to the peak interval d _p , the peak curvature radius R _p becomes large. Regarding the peak interval d _p , since the light becomes close to the center of the peak as it becomes larger, the radius of curvature R _p becomes smaller in order to maintain the same refractive power.

In the graph, the conditions obtained by applying the conditions of the formulas (7) to (8) and (10) are three broken lines in the graph. The dotted line L _{2C is} derived from the two-piece condition of the formula (7), and the lower line can form a region of (n _{c -} R _p ) of the two-piece optical system without vignetting. The uppermost dotted line L _2K is derived from the bimodal condition of the formula (8), and the lower line can form a region of (n _{c -} R _p ) of the optical system of the bimodal form without vignetting. The lowermost dotted line L _PC parallel to the horizontal axis of the graph is derived from the mold processing conditions of the formula (10), and becomes a region (n _{c -} R _p ) which can be formed above the straight line.

According to these contents, the two-piece form can be realized only in the region surrounded by the broken line L _2C and the broken line L _PC . On the other hand, the bimodal form is wider surrounded by the broken line L _2K and the broken line L _PC . It can be realized in the region, and the design freedom is more than 2 times. In particular, under the bimodal condition, the optical system configuration under the condition that the radius of curvature _{Rp is} larger can be realized, which means that the ease of mold processing is low.

Fig. 12 is a graph showing the relationship between the lens refractive index n _c and the peak curvature radius R _p for each peak interval d _p for the case where the fiber spacing d _f is 127 μm in the configuration of the type I. According to the formulas (1) to (5), as in the case of FIG. 11, the light refracting ability increases as the refractive index of the lens increases with respect to each peak interval, and thus the peak curvature radius increases. Regarding the peak interval d _p , since the light becomes close to the center of the peak as it becomes larger, the radius of curvature R _p becomes smaller in order to maintain the same refractive power.

In the graph, the three lines of the graphs of the equations (7) to (8) and (10) are applied in the same manner as in Fig. 11 . As is apparent, the region surrounded by the broken line L _2K and the broken line L _PC capable of realizing the bimodal form is more overwhelming than the area surrounded by the broken line L _2C and the broken line L _PC in a two-piece form. . Compared with the case where the fiber spacing d _p is 250 μm as shown in FIG. 11, the region (n _{c -} R _p ) which can be realized as the interval d _{f is} narrowed is narrowed, and a bimodal form can be realized. The region surrounded by the broken line L _2K and the broken line L _PC cannot be configured if the refractive index n _c of the lens is 1.44 or less. However, if the refractive index of BK7, which is a representative of the highly reliable borosilicate glass, is 1.501, the width of the peak interval _dp is 91.7 to 95.6 μm, but the optical system can be realized. The form can cope with miniaturization.

On the other hand, as for the two-piece condition, it can be realized only in a very limited region where n _c is 1.81 or more and the peak interval d _p is also 105 to 107 μm. This high refractive index region is a region where there is a problem of occurrence of tarnishing in terms of reliability, and it has to be said that the practical application is low. If the fiber spacing d _f is 127 μm, it can be considered that the two-piece form cannot be applied. .

(Third Embodiment) An optical system of this embodiment is shown in Fig. 14 . In the first embodiment, the light emitted from the optical fiber 11A and the incident light beam incident on the optical fiber 11B overlap the surface of the plano-convex lens and the inside thereof. This corresponds to a narrower fiber spacing d _f in FIG. 7 and thus serves as an angle of reflection angle of the filter portion 4. Smaller situation. In this case, the convex surface A1 and the convex surface A2 also of course overlap, and become a single-peak lens convex surface. Such a configuration is intended to reduce the wavelength dependence or polarization dependence of the transmitted light in the filter portion 4, and to make the reflection angle It is more effective when it is smaller.

In the present embodiment, the convex surface A1 and the convex surface A2 are formed on one portion of the spherical surface shared by the first imaginary circle and the second imaginary circle on the base surface 21B, and the lens surface 23 does not have the saddle portion A3. The distance between the center of the first imaginary circle and the second imaginary circle is zero. As described above, the present invention may also include a case where the distance between the center of the first imaginary circle and the second imaginary circle is zero.

Fig. 15 shows an example of the configuration of the optical fiber matrix module of the present embodiment. In the present embodiment, unlike the second embodiment, the optical fiber matrix 1 has an irregular pitch. This is because, in order to make the angle as the reflection angle f decreases, the optical fiber is narrower than the interval D _f of the lens 2, the lens array spacing of one-half of d _l. In this case, the conditions required for the beam diameter BD of the optical fibers 11A-1 to 4, 11B-1 to 4 on the surface of the lens are replaced by the need for the beam to reach the adjacent lens on the surface of the lens in FIG. Equation (7) becomes (number 31) BD < d _{l -} d _f (31).

(Fourth Embodiment) An optical system of this embodiment is shown in Fig. 17 . In the present embodiment, the optical fibers 11A and 11B are disposed on the flat surface 21A side of the bimodal plano-convex lens 20, and the filter portion 4 is disposed on the lens surface 23 side with the air layer 3 having a specific thickness interposed therebetween. The end face P1 of the optical fiber 11A is disposed at the first position and functions as the first optical fiber. The end face P2 of the optical fiber 11B is disposed at the second position and functions as the second optical fiber. The longitudinal directions of the optical fibers 11A and 11B are arranged in parallel with the lens central axis A _C in the plane P _C . Hereinafter, this embodiment will be referred to as Type II.

The plano-convex lens 20 of the present embodiment has a convex surface A1 that functions as a first convex surface, a convex surface A2 that functions as a second convex surface, and a saddle portion A3. The convex surface A1 is a spherical surface having a straight line R1 parallel to the lens central axis Ac and including the plane Pc as a center of rotation, and the convex surface A2 is also a spherical surface having a straight line R2 parallel to the lens central axis Ac and including the plane Pc as a center of rotation. The straight lines R1 and R2 are shifted toward the inner side by a specific distance symmetrically with respect to the lens central axis Ac.

In such a configuration, the light emitted from the end surface P1 of the optical fiber 11A enters the plano-convex lens 20 from the flat surface 21A. The light incident on the plano-convex lens 20 is transmitted through the lens 20 and is emitted from the convex surface A1 into the air layer 3. At this time, the convex surface A1 sets the light emitted into the air layer 3 as parallel light.

The light that becomes parallel light by the convex surface A1 passes through the air layer 3, and a part of the light permeable layer 41 provided at the filter portion 4 is reflected toward the convex surface A2. Part of the permeable membrane 41 functions as a reflecting surface. The parallel light reflected by the filter portion 4 is incident on the plano-convex lens 20 from the convex surface A2. The convex surface A2 condenses the parallel light reflected by the filter portion 4 to the end surface P2 of the optical fiber 11B. Thereby, the parallel light reflected by the filter portion 4 is incident on the optical fiber 11B.

In the plano-convex lens 20 of the present embodiment, since the convex surface A2 condenses the parallel light reflected by the filter portion 4 to the end surface P2 of the optical fiber 11B, the light after the monitor optical tap can be efficiently coupled to the optical fiber 11B.

(Fifth Embodiment) A configuration example of the optical fiber matrix module of the present embodiment is shown in Fig. 18 . This is equivalent to the case of matrixing the type II plano-convex lens 20. The optical fiber matrix module includes: an optical fiber matrix 1 in which optical fibers 11A-1 to 11A-4 and 11B-1 to 11B-4 are alternately arranged; and a lens matrix 2 in which a plurality of lens faces 23 of the fourth embodiment are arranged -1 to 23-4. Similarly to the second embodiment, the lens matrix 2 functions as a first lens matrix and is provided with a spacer 22 .

The optical fiber matrix 1 and the lens matrix 2 are arranged in parallel on the specific plane P _C of the four fiber lens optical systems of the fourth embodiment. Specifically, the lens matrix 2 includes a plurality of lens faces 23-1 to 23-4 of the fourth embodiment. Each of the bimodal plano-convex lenses 20 included in the lens matrix 2 includes the fiberoptic lens optical system of the fourth embodiment as a basic unit. The lens central axes A _{C of the} respective lens faces 23 are arranged side by side in the plane P _C . The optical fiber matrix 1 has two optical fibers 11A and 11B with respect to the respective lens faces 23-1 to 23-4. The end face PL11 of the optical fiber matrix 1 in which the end faces of the optical fibers 11A-1 to 11A-4 and the respective end faces of the 11B-1 to 11B-4 are disposed is arranged in parallel with the peak line Bc.

Referring to Fig. 19, an optical system in Figs. 17 and 18 will be described. The following directions are described in the same manner as the orthogonal xyz coordinate axes in the figure. At the left end of the figure, an optical fiber matrix 1 in which optical fibers are arranged in parallel with the z-axis and at intervals d _f in the x-axis direction is disposed in the xz plane. The optical fiber matrix 1 is formed by a plane parallel to the x-axis and forming a specific angle with respect to the y-axis as an end surface, for example, by a casing such as TEMPAX glass.

In addition, in FIG. 19, unlike the optical systems of the first embodiment to the third embodiment, the flat surface 21A side of the bimodal lens matrix 2 is directly attached to the end surface PL11 of the optical fiber matrix 1, and the optical fiber matrix 1 is twice as large. The lens surface 23 side of the period faces the opposite side. The lens surface 23 has a lens central axis A _C parallel to the z-axis, with a plane perpendicular to the z-axis as a common plane, spaced twice in the x-axis direction by an interval 2d _{f of the} fiber matrix 1 and spaced apart from the adjacent lens The adjacent intervals d _n are matrixed.

The lens surface 23 has a convex surface A1 and a convex surface A2. The convex surface A1 is formed by a rotating curved surface including a line Pc formed by the optical fiber matrix 1 and a straight line R1 parallel to the z-axis, and forms a lens. Further, the optical axis of the optical fiber 11A is shifted toward the inner side (the lens central axis Ac side) by a specific distance. The convex surface A2 is formed in a shape that is symmetrical with respect to the convex surface A1 via the saddle portion A3 of the width w _s with respect to the lens central axis Ac. The peak interval d _p as the interval between the straight line R1 and the straight line R2 is set to be a distance smaller than the fiber interval d _f by a specific length.

On the lens surface 23 side of the lens matrix 2, a filter portion 4 having a partially permeable film 41 perpendicular to the z-axis is disposed via the air layer 3. The distance between the lens surface 23 and the partial transmission film 41, that is, the thickness t _{r of the} air layer is set to be a specific value thicker than the convex side focus distance f _v .

The relative position of the fiber matrix 1 and the lens matrix 2 is in the x-axis direction, and the center line of the lens center axis A _C and the adjacent fibers of the fiber matrix 1 are aligned with each other (in the figure, the center line of the fiber 11A and the fiber 11B) the mode is set, the y-direction, the plane formed by the plane A _C of the lens center axis of the matrix formed by the centerline of the fiber matrix 1 is set in a consistent way, and about the z direction to the fiber matrix of an end face of the peak PL11 The distance between P6 and P8 and the concave focal length f _{c of the} convex lens 20 are set to be the same. On the right side of Fig. 19, a portion of the air layer 3 separated by a specific interval, perpendicular to the z-axis parallel to the central axis A _{C of the} lens, is provided with a function of reflecting/transmitting light of a specific wavelength at a desired ratio. Film 41. In the first embodiment to the third embodiment, the partial transmission film 41 is directly applied to the flat surface 21A side of the lens matrix 2, but in the present embodiment, the glass substrate 42 is additionally loaded on the same refractive index as the lens matrix 2. By.

In such a configuration, the path of the light emitted from the end face of the optical fiber 11A is investigated by the approximation of the light. The end face of the optical fiber 11A is located on the concave side focal plane PL23C, and as described above, the straight line R1 which is the center line of the convex surface A1 in the lens surface 23 is shifted in the x direction with respect to the fiber center line. Therefore, the light which is emitted from the end surface of the optical fiber 11A as a point light source and transmitted through the lens matrix 2 and incident on the convex surface A1 is refracted toward the lens central axis A _C side, and forms a parallel ray of a specific angle f with the lens central axis A _{C .} Advancing in the air layer 3. The light emitted from the optical fiber 11A parallel to the central axis A _{C of the} lens, that is, the z-axis, that is, the center light of the emitted light is emitted from the convex surface A1, is reflected by the filter portion 4, and passes through the convex surface A2.

Since the thickness t _r of the air layer is set to be thicker than the convex side focal length f _v , and the partial transmission film 41 is located at a point where the center light intersects with the lens central axis A _c , a portion of the intensity of the parallel light transmits through the partial transmission film 41 . with respect to the lens center axis A _C at an angle ψ of straight forward, but the remaining part of the intensity transmitted through the partial reflecting film 41, with respect to the lens center axis A _C reaches the symmetric convex surface A2 x-direction position. The reflected light reaching the convex surface A2 passes through the parallel light of the convex side focus, and proceeds along a path symmetrical with respect to the lens central axis A _{C from} the optical path emerging from the optical fiber 11A and incident on the convex surface A1, and finally condensed to be located relative to the lens. The end face P2 of the optical fiber 11B at a position where the central axis A _C is symmetrical with the optical fiber 11A.

Here, assuming that the thickness t _{r of the} air layer is thinner than a specific value, the reflected light obtained by the filter portion 4 reaches the surface of the convex axis A2 on the lens center axis A _C side, where the parallel light is not focused. And diffused on the end face P2 of the optical fiber 11B. On the other hand, the thickness of the air layer 3 is thicker than the case where t _r of the specific value, obtained by the reflected light reaches the filter portion 4 of the convex outer surface A2, the parallel beam is excessively focused, and 11B of the optical fiber The end face P2 is diffused. In either case, the optical axis of the reflected light obtained by the filter portion 4 is deviated from the end face P2 of the optical fiber 11B. Therefore, it is necessary to make the thickness t _{r of the} air layer thicker than the convex side focal length f _v , and the partial transmission film 41 is located at a point where the center ray intersects the lens central axis A _c .

Further, as for the light transmitted through the partial transmission film 41, if the refractive index of the glass substrate 42 to which the partial transmission film 41 is properly adhered is the same as the refractive index n _{c of the} lens matrix 2, it is not shown, but is not shown. Exit. Further, when the glass substrate 42 to which the partial permeable film 41 is properly adhered is a parallel substrate, when it is finally emitted to the air layer 3, it is emitted at an angle f .

Next, the above description is formulated using a formula. In Fig. 19, the light beam which is emitted from the optical fiber 11A having the end surface of the concave side focal plane PL23C and incident on the convex surface A1 of the lens surface 23 through the lens matrix 2 is a parallel light which forms an angle f with the lens central axis A _C . For the light rays incident on the peak P6 of the convex surface A1 (the intersection of the straight line R1 and the convex surface A1 as the center line) in the light rays, since the plane of the lens surface of the incident point is perpendicular to the central axis A _{C of the} lens, it is used as the light. The angle ψ of the incident angle of the peak center, the angle f between the exit angle and the refractive indices n _v and n _c are expressed by the following equation, and the Snell's law is established. (Number 11) n _c sinψ=n _v sin (11)

Further, since the optical fiber matrix 1 is matrixed by the interval d _f and the lens matrix 2 is twice as large as the interval 2d _f , the focal length f _v to the convex side focal plane PL23V and the concave focal plane PL23C are obtained. The focal length f _{c is} based on the fiber spacing d _f , the peak interval d _p between the convex surface A1 and the convex surface A2 , the angle ψ as the incident angle of the lens center, and the angle f as the exit angle, by the following formula (12), Determined by equation (13). (number 12) f _c ={(d _f -d _p )cotψ}/2(12) (number 13) f _v =((d _f -d _p )cot )/2(13)

Further, regarding the thickness t _{r of the} air layer, the following formula is also true. (Number 14) t _r =d _f cot /2(14)

Further, the radius of curvature R _{p of the} peak can be given by the following formula. (Number 15) R _p =(n _c -n _v )f _c /n _c (15)

Each of the convex surface A1 and the convex surface A2 constituting the bimodal peak may satisfy the above equations (11) to (14), but the curved surface that satisfies the relationship and has an axis parallel to the central axis A _C of the lens as the axis of symmetry is the most It can be preferably approximated by simply using R _p obtained according to equation (15) as the spherical surface of the radius. If given fiber spacing d _f, peak interval d _p of the lens, the lens refractive index n _c, refractive index of air n _v, and the reflection angle as in the filter portion 4 of the angle F, then according to equation (12) and ( 13) The concave and convex portions of the lens surface 23 are determined by the two focal distances f _c and f _v , and the thickness t _{r of the} air layer is determined according to the formula (14). Further, in the lens manufacturing step, the peak curvature radius of the shape standard of the mold used in the molding step is also known from the formula (15).

Next, the conditions for establishing such an optical system will be described. In order to achieve low loss coupling between the optical fibers 11A and 11B, it is necessary to suppress the vignetting of the lens surface 23 as much as possible. The exiting light from the optical fiber 11A is diffused according to the NA of the optical fiber, but the diffusion can preferably be expressed as the transmission of the Gaussian beam at the fiber end as the beam waist position. The power distribution of the Gaussian beam emerging from the fiber end and reaching the lens face 23 is 99.75% of the total power in the range from the center of the beam to 1.73 times the beam radius ω. Therefore, if the range up to this point is the beam diameter BD of the light beam reaching the lens surface 23, it can be given by the following formula. [Number 16] Here, ω ₀ and λ are the mode radius of the optical fiber 11A and the wavelength of the light, respectively.

Next, the conditions required for the beam diameter BD of the lens surface in Type II are established, but the same discussion as for Type I is established, and the conditions of Equations (7) and (8) are all the same. However, the condition required for the peak curvature radius R _p is replaced by (number 17) R _p = (n _{c -} n _v ) f _c / n _c ≧ 150 μm (17).

According to the above, regarding the configuration of the type II, the peak interval d _p , the beam diameter BD, the peak curvature radius R _p (according to the equation (15), and the two-sheet condition index are plotted in the same manner as the type I. The figure is obtained in Fig. 20 and Fig. 21. The value used in the calculation is the same as type I.

Fig. 20 is a graph showing the relationship between the lens refractive index n _c and the peak curvature radius R _p for each peak interval d _p for the case where the fiber spacing d _f is 250 μm in the configuration of the type II. According to the formulas (11) to (13) and (16) to (17), the light refraction ability increases with the increase in the refractive index n _c of the lens with respect to each peak interval d _p , and thus the peak curvature The radius R _p becomes larger. Regarding the peak interval, since the light becomes close to the center of the peak as it becomes larger, the peak curvature radius _Rp becomes smaller in order to maintain the same refractive power.

The conditions obtained by applying the conditions of the equations (7) to (8) and (17) to the graph are the three broken lines in the graph. Derived two dotted line L _2C condition based formula according to formula (7) of the person, than the straight line can be configured based on the lower region of the optical system of the two-piece form no vignetting of the (n _c -R _p) of. The uppermost dotted line L _2K is derived from the bimodal condition of the formula (8), and the lower line can form a region of (n _{c -} R _p ) of the optical system of the bimodal form without vignetting. The lowermost dotted line L _PC parallel to the horizontal axis of the graph is derived from the mold processing conditions of the equation (17), and becomes a region (n _{c -} R _p ) which can be formed above the straight line.

Comparing the double peak with the two-piece form, it can be seen that the two-piece form can be realized only in the region surrounded by the broken line L _2C and the broken line L _PC , whereas the double-peak form can be represented by the broken line L _2K and the dotted line. It is realized in a wide area surrounded by L _PC , and the design freedom is about 2 times wider. In particular, under the bimodal condition, the optical system configuration under the condition that the radius of curvature _{Rp is} larger can be realized, which means that the ease of mold processing is low.

Fig. 21 is a graph showing the relationship between the lens refractive index n _c and the peak curvature radius R _p for each peak interval d _p for the case where the fiber spacing d _f is 127 μm narrower than that of Fig. 20 in the configuration of the type II. According to the equations (11) to (13) and (16) to (17), as in the case of FIG. 20, the light refracting ability is increased along with the increase in the refractive index of the lens with respect to each peak interval. The peak curvature radius R _p becomes large. Regarding the peak interval d _p , since the light becomes close to the center of the peak as it becomes larger, the peak curvature radius R _p becomes smaller in order to maintain the same refractive power.

In the graph, the conditions of the equations (7) to (8) and (17) are applied in the same manner as in Fig. 20, and the three broken lines in the graph are shown. As is apparent like, and the two-piece form can be realized by a dashed line L of the area surrounded by the broken line L _2C and _{the PC} can be achieved compared bimodal morphology of predominantly wide area surrounded by a dashed line L of the line L and _{the PC 2K} . Compared with the case where the fiber period is 250 μm apart, the region of (n _c -R _p ) which can be realized as the fiber interval d _{f is} narrowed is narrowed, and the bimodal form can be realized by the bimodal condition and The triangular region surrounded by the broken line of the mold processing condition cannot be configured if the lens refractive index n _c is 1.44 or less. However, if the refractive index of BK7, which is a representative glass material of the highly reliable borosilicate glass, is 1.501, the width of the peak interval _dp is as narrow as 103.5 to 106.1 μm, but the optical system configuration can be realized. The peak shape can cope with miniaturization.

On the other hand, if it is a two-piece condition, it can be realized only in a limited area where n _c is 1.64 or more and the peak interval is also 111 to 116 μm. The high refractive index region also includes an area where there is a problem of loss of the like in terms of reliability, and it has to be said that the practical application is rather low, and it can be considered that the two-piece form can only be extremely limited at d _f 127 μm. Application.

As described above, when the two-piece type and the bimodal structure are compared, it can be considered as follows. When considering the lens refractive index n _c and the peak curvature radius R _p as two main parameters, the bimodal structure n _c -R _p region is about 2 to 3 times larger than the two-piece configuration, and is designed. The degree of freedom is higher. The bimodal structure can also cope with a narrower fiber spacing d _f and is suitable for miniaturization. The bimodal structure system peak radius of curvature R _p can be selected to a large value, and the lens diameter can be increased, so that the coupling efficiency between fibers can be maintained high. The bimodal structure is a hole having a large radius of curvature when the mold is produced, and thus it is easy to manufacture.

(Sixth embodiment) An optical system of this embodiment is shown in Fig. 22 . In the fourth embodiment, the light emitted from the optical fiber 11A and the incident light beam incident on the optical fiber 11B overlap the surface of the plano-convex lens and the outside. It is equivalent to the narrower fiber spacing d _f in Figure 19, so the reflection angle Smaller situation. In this case, the convex surface A1 and the convex surface A2 also of course overlap, and become a single-peak lens convex surface. Such a configuration is intended to reduce the wavelength dependence or polarization dependence of the transmitted light in the partial transmission film 41, and to make the reflection angle It is more effective when it is smaller.

In the present embodiment, the convex surface A1 and the convex surface A2 are formed on one portion of the spherical surface shared by the first imaginary circle and the second imaginary circle on the base surface 21B, and the lens surface 23 does not have the saddle portion A3. The distance between the center of the first imaginary circle and the second imaginary circle is zero. As described above, the present invention may also include a case where the distance between the center of the first imaginary circle and the second imaginary circle is zero.

Fig. 23 shows an example of the configuration of the optical fiber matrix module of the present embodiment. In the present embodiment, unlike the fifth embodiment, the optical fiber matrix 1 has an irregular pitch. This is because, in order to make the angle as the reflection angle f decreases, the optical fiber is narrower than the interval D _f of the lens 2, the lens array spacing of one-half of d _l. In this case, the conditions required for the beam diameter BD of the optical fibers 11A-1 to 4, 11B-1 to 4 on the surface of the lens are changed as shown in Fig. 24 in the case where the beam on the surface of the lens does not reach the adjacent lens. 3 Formula (31) described in the embodiment.

(Seventh Embodiment) An example of an optical fiber matrix module of this embodiment is shown in Fig. 25. The optical fiber matrix module shown in FIG. 25 is provided with the optical fiber matrix module, the light shielding plate 7, and the lens matrix 9 shown in FIG. The light shielding plate 7 functions as a light component, and the lens matrix 9 functions as a second lens matrix.

The visor 7 has a plurality of through holes 71. Each of the parallel light transmitted from the filter portion 4 is incident on one end of a different through hole 71. Then, the parallel light passing through the through hole 71 is emitted from the other end of each of the through holes 71. The lens matrix 9 condenses the respective lights emitted from the other end of the plurality of through holes 71 to a predetermined point for each of the through holes 71. The light receiving surface of the light receiving element 81 is disposed at this point.

An example of the light receiving module of the present embodiment is shown in Fig. 26 . The light receiving module shown in FIG. 26 includes the optical fiber matrix module shown in FIG. 25 and the light receiving element matrix 8. Each of the light receiving elements 81 included in the light receiving element matrix 8 receives the light collected by the lens matrix 9. The light receiving module shown in Fig. 26 can be used as a four-matrix optical tap monitor module.

The application area of this embodiment is, for example, an optical communication system having a wavelength of 1.55 μm. The module includes an optical fiber matrix 1, a lens matrix 2, a filter portion 4, a light shielding plate 7, a lens matrix 9, and a light receiving element matrix 8 from the left side of the drawing. The parameters represented by the fiber spacing d _f are values conforming to the type I described so far.

First, the operation and function of the module will be described. 95% of the light incident from the optical fiber 11A to the lens matrix 2 is reflected as an angle f of the reflection angle of the filter portion 4 and incident on the optical fiber 11B, and 5% of the incident light intensity is tapped and returned to the main line. . The taper light of 5% intensity is formed as an air layer in the latter stage, and is emitted as an angle of the exit angle, but in the subsequent stage of the filter portion 4, in order to prevent crosstalk caused by the mixing of the tapped light transmitted in the space. The light shielding plate 7 that is vacated through the through hole 71 is provided. The light shielding plate 7 has a size corresponding to the lens matrix 2, and a through hole 71 having the beam diameter is formed by fitting a light path to the center of the light shielding plate. In the subsequent stage of the visor 7, a lens matrix 9 identical to the lens matrix 2 is provided opposite to the lens matrix 2. The lens matrix 9 converges the diffused tap beam in the space of the through hole 71 to the light receiving surface of the light receiving element 81.

Hereinafter, each of the above constituent elements will be described. Fiber Matrix 1: Fiber Matrix 1 uses an 8-mode wavelength 1.3/1.55 μm single-mode ribbon fiber as the fiber member. The optical fiber matrix 1 was placed on a 60-degree V-groove plate by TEMPAX glass, covered with an upper cover, fixed by a UV (Ultraviolet) adhesive, and subjected to end surface polishing to form a fiber matrix 1 for connection. The fiber spacing d _f is the same as the ribbon fiber used. The optical axis of the optical fiber is in the z direction, and the connection end surface of the other element is parallel to the x-axis, and is set to be inclined at 8 degrees with respect to the y-axis direction in order to reduce the return light generated by the end surface reflection. The 8-degree inclined end surface was subjected to an Anti Reflection Coat with a wavelength of 1.55 μm.

Lens matrix 2: contains borosilicate glass, and lens faces 23 are formed at specific matrix intervals. At both end portions of the lens matrix 2 in the x direction, a spacer 22 integrally formed at the time of lens molding is provided. The spacer 22 is a trapezoidal convex portion whose surface is fitted with an 8-degree inclined end surface of the optical fiber matrix 1 and is similarly inclined at 8 degrees. The height of the spacer 22 is preferably set, for example, such that the position of the lens central axis Ac becomes a specific convex side focus distance f _v .

The lens array 2 of the flat surface 21A, is adhered to the angle f is set to 2 degrees filter section 4. The ratio of reflection/transmission is preferably 95%/5%, and as the material thereof, for example, a SiO ₂ -Ta ₂ O ₅ multilayer film obtained by an ion beam assisted vapor deposition method can be exemplified.

Light shield 7: The light shield 7 includes a square infrared absorbing glass. In the central portion thereof, a through hole 71 which is parallel to the xz plane and forms an angle ψ between the z-axis direction and the incident direction of the lens center is formed in conjunction with the optical path of the tap light. The matrix spacing in the x direction is the same as that of the lens matrix 2. The light beam of the tap light is transmitted without being in contact with the wall of the through hole 71 of the light shielding plate 7, but the diffuse reflection component caused by the structural irregularity generated by the reflection of the reflection in the lens matrix 2 or the filter portion 4 in the front stage It is blocked by the light shielding plate 7 to prevent it from reaching the light receiving element matrix 8 to form a crosstalk.

Lens Matrix 9: Here, the lens matrix 9 is the same as the lens matrix 2. Moreover, only any single peak of the double peak is used. In general, since the light-receiving surface of the light-receiving element 81 is away from the package surface, the focus distance adjustment resin 91 is inserted between the lens matrix 9 and the light-receiving element matrix 8 to be focused longer than the lens matrix 2, and concentrated in the light-receiving element matrix 8. The light receiving surface of the light receiving element 81 is in the light receiving surface. The lens matrix 9 is opposite to the orientation of the lens matrix 2 in order to fill the space between the lens matrix 9 and the light receiving element matrix 8 by the focal length adjusting resin 91. The lens matrix 9 preferably has an anti-reflection coating applied only to the flat surface 21A side.

Light-receiving element matrix 8: The light-receiving element 81 is, for example, a four-matrix InGaAs photodiode matrix. The diode matrix is preferably sealed. As can be seen from the side view, the light-receiving element matrix 8 is connected to the lens matrix 9 by being inclined by 8 degrees with respect to the z-axis direction, that is, the optical axis.

As shown in the side view, since the connection interface is entirely inclined from the fiber matrix 1 to the light-receiving element matrix 8, it is a structure for preventing reflection of return light.

Assembly step: The step has 3 steps. The first step is the connection of the fiber matrix 1 to the lens matrix 2. This is carried out by using a fiber-optic waveguide connecting device to input the modulating light from the optical fibers 11A-1 and 11A-4 which are the both ends of the optical fiber matrix 1 and monitor the light from the optical fibers 11B-1 and 11B-4. The two-axis alignment fixed conventional fiber waveguide is connected by the same steps. The connection portion is between the spacer 22 and the optical fiber matrix 1. In the second step, the light shielding plate 7, the lens matrix 9, and the light receiving element matrix 8 are connected. The connection is made by sequentially placing the light-receiving element matrix 8, the lens matrix 9, and the light-shielding plate 7 under the microscope, so that the light-receiving surface of the light-receiving element 81 can be seen from the through-hole of the light-shielding plate 7, by visual alignment ( The alignment is performed and the adhesive is fixed. In the third step, the lens unit 2 with the optical fiber matrix 1 and the light-receiving element matrix 8 and the light-shielding plate 7 with the lens matrix 9 are attached, and the alignment light is incident on the optical fiber 11A-1 and the optical fiber 11A-4, and the light-receiving element is monitored. The output of the matrix 8 is fixed on one side.

Characteristics: The characteristics of the 4 ch tap monitor module produced at 1.55 μm are insertion loss of 0.4 to 0.5 dB, reflection attenuation of 46 dB or more, and light sensitivity of 50 to 60 mA/W. Adjacent crosstalk is also above 45 dB.

(Eighth Embodiment) An example of the optical fiber matrix module of the present embodiment is shown in Fig. 27 . The optical fiber matrix module shown in FIG. 27 is provided with the optical fiber matrix module, the light shielding plate 7, and the lens matrix 9 shown in FIG. The light shielding plate 7 functions as a light component, and the lens matrix 9 functions as a second lens matrix.

The visor 7 has a plurality of through holes 71. Each of the parallel light transmitted from the filter portion 4 is incident on one end of a different through hole 71. Then, the parallel light passing through the through hole 71 is emitted from the other end of each of the through holes 71. The lens matrix 9 condenses the respective lights emitted from the other end of the plurality of through holes 71 to a predetermined point for each of the through holes 71. The light receiving surface of the light receiving element 81 is disposed at this point.

An example of the light receiving module of this embodiment is shown in Fig. 28. The light receiving module shown in FIG. 28 includes the optical fiber matrix module shown in FIG. 27 and the light receiving element matrix 8. Each of the light receiving elements 81 included in the light receiving element matrix 8 receives the light collected by the lens matrix 9. The light receiving module shown in Fig. 28 can be used as a four-matrix optical tap monitor module.

The application area is a 1.55 μm segment optical communication system. The module includes an optical fiber matrix 1, a lens matrix 2, a filter portion 4, a light shielding plate 7, a lens matrix 9, and a light receiving element matrix 8 from the left side of the drawing. The parameters represented by the fiber spacing d _f are based on the values of type II as described so far.

First, the operation and function of the module will be described. The light that is incident on the lens matrix 2 directly from the flat surface 21A side without passing through the air layer, and the light emitted from the lens surface 23 is 95% reflected by the filter portion 4 at the angle f and returned to the lens matrix 2 again. To the fiber 11B, and 5% of the incident light intensity is tapped and returned to the main line. The 5% intensity tap light is emitted as an air layer through the filter portion 4 in the latter stage, and is emitted at an angle f , but in the subsequent stage of the filter portion 4, in order to prevent mixing of the tapped light due to transmission in the space The crosstalk caused by the reduction is reduced, and the light shielding plate 7 which is vacated through the through hole 71 is provided. The light shielding plate 7 has a size corresponding to the lens matrix 2, and a through hole 71 having the beam diameter is formed by fitting a light path to the center of the light shielding plate. In the subsequent stage of the visor 7, a lens matrix 9 identical to the lens matrix 2 is provided in the same direction as the lens matrix 2. The lens matrix 9 condenses the diverging light beam that is transmitted in the space and diffused to the light receiving surface of the light receiving element 81.

Hereinafter, the contents of the above-described respective constituent elements that are not overlapped with the seventh embodiment will be described. The optical fiber matrix 1 is different from the seventh embodiment in that an anti-reflection coating is not applied to the surface of the inclined end surface of 8 degrees. The lens matrix 2 includes a borosilicate glass, and a lens surface 23 is formed in a positive direction of the z-axis at a specific matrix interval. A spacer 22 is provided at both end portions of the lens matrix 2 in the x direction. The spacer 22 is a flat plate having the same material as the lens obtained by adding the thickness t _r of the air layer given by the formula (12) to the lens recess amount.

The flat surface 21A of the lens matrix 2 is set in such a manner as to be parallel to the end surface PL11 of the optical fiber matrix 1 and inclined at 8 degrees with respect to the y-axis, and the distance between the inclined flat surface 21A and the lens central axis Ac of the lens surface 23 is The concave side focus distance f _c .

Part of the permeable membrane 41 and the glass substrate 42: In the present configuration, the partial permeable membrane 41 is appropriately adhered to the BK7 panel, and the BK7 panel is a transparent glass substrate 42 separated from the lens matrix 2, but has the same refractive index n _c . A partially permeable film 41 having an angle f is appropriately adhered to the glass substrate 42 which is parallel to both sides. The reflectance/transmission ratio is preferably 95%/5%, and as the material thereof, for example, an SiO ₂ -Ta ₂ O ₅ multilayer film obtained by an ion beam assisted vapor deposition method can be exemplified.

Light shield 7: The light shield 7 includes a square infrared absorbing glass. In the central portion thereof, a through hole 71 which is parallel to the xz plane and forms an angle of an angle f between the z-axis direction and the incident direction of the lens center is formed in cooperation with the light path of the tap light. The x-direction matrix pitch is the same as the lens matrix 2 of 500 μm. The light beam of the tap light is not transmitted to the wall of the through hole 71 of the light shielding plate 7, but the diffuse reflection component caused by the irregularity of the structure generated by the reflection of the lens matrix 2 or the partial transmission film 41 in the front stage is The visor 7 blocks and prevents it from reaching the light-receiving element matrix 8 to form a crosstalk.

As shown in the side view, since the connection interface is entirely inclined from the fiber matrix 1 to the light-receiving element matrix 8, it is a structure for preventing reflection of return light.

Assembly step: In the first step, in the first step, the lens matrix 2 and the partial transmission film 41 are first connected in advance. Since the partial permeable membrane 41 is a generally homogeneous flat plate, it is possible to connect only by the aligning operation of the mold, without the need for a aligning operation. Others are the same as in the seventh embodiment described above.

Characteristics: The characteristics of the 4 ch tap monitor module produced at 1.55 μm are insertion loss of 0.4 to 0.5 dB, reflection attenuation of 46 dB or more, and light sensitivity of 50 to 60 mA/W. Adjacent crosstalk is also above 45 dB.

(Ninth Embodiment) In the above embodiment, the matrix is one-dimensionally arranged, but it may be a two-dimensional matrix. In this case, the fiber matrix modules shown in FIG. 6 or FIG. 18 are arranged side by side in the y direction.

At this time, the fiber matrix becomes the biggest problem, and the fiber matrix 1 is produced according to Patent Document 2. The connection surface when viewed from the z direction is shown in Fig. 29. The optical fiber matrix 1 shown in Fig. 29 is provided with V-groove plates 13-2 to 13-5 in which V-grooves 14 of 60 degrees for the optical fiber matrix are implemented. In the V-groove plates 13-2 to 13-5, V-grooves 15-1 and 15-2 for vertical alignment are provided on both sides of the matrix of the V-grooves 14. Further, alignment grooves 15-3 and 15-4 are formed on the back surface of the V-groove plates 13-2 to 13-5 at the same position in the x direction as the front side. The alignment optical fiber 12 may be the same as the optical fibers 11A and 11B shown in the drawing.

In this case, if the opening width of the V-groove 14 is W ₁₄ and the opening width of the alignment groove 15 is W ₁₅ , it is set to (number 18) W ₁₄ = 2 (R √ 3). -d/√3)(18) (Number 19) W ₁₅ =(2R-d)/√3(19). In this manner, when the alignment optical fiber 12 is just mounted on the alignment groove 15, the waveguide optical fiber 11 is pressed by the upper plate. Here, the radius of the R-based fiber, d is the distance between the V-groove plates 13-2 to 13-5 and the upper plate.

The alignment grooves 15-1, 15-2, 15-3, and 15-4 must be aligned in the x direction on the front and back sides of the V-groove plate, but the front and back positions are aligned as long as the slicer or wafer is cut. In a groove processing device such as a dicing saw, the groove forming position may be adjusted in advance to observe the perpendicularity of the upper focus alignment axis of the lens barrel with respect to the processing surface.

Here, the optical fiber matrix 1 preferably performs only a part of the tilting process in the vicinity of the optical fiber core as shown in the side view of FIG. The reason for this is that if the entire surface of the matrix is inclined over the entire surface of the matrix, it becomes extremely difficult to form a two-dimensional matrix of all the components in the subsequent stage of the lens matrix 2. A double-head wafer cutter can be used in the process. It is provided with two cutting heads in a longitudinal arrangement, and is a device capable of continuous processing using two different blades in one step.

The 2D matrix of the lens matrices 2, 9, the light shielding plate 7, and the light receiving element matrix 8 other than the optical fiber matrix 1 is also matrixed. A side view of the produced 4×4 tap monitor module is shown in FIG. Regarding the appearance, the plan view is completely the same as that of Fig. 26, and is formed in a side view as in the y direction.

In the description so far, the plane P _C formed by the optical axis A _{C of the} lens and the optical axis of the optical fiber is made parallel for the sake of convenience. However, in the case where the end face of the optical fiber is obliquely set as shown in the description of the present invention for reflection prevention, in the type I, it is desirable to perform the winding between the optical fiber matrix 1 and the lens matrix 2 parallel to the axis of the x-axis. Skew adjustment.

(Effects of the Invention) As described above, by bipolarizing the lens surface as described in the present invention, even if the input/output structure is offset from the central axis of the lens, the two peak positions can be respectively paired. Optimized for both the input position and the output position, high-efficiency optical coupling can be achieved. Moreover, even if it is miniaturized and integrated, the lens aperture of the active surface can be largely maintained, and it is suitable for downsizing. Since it is a plano-convex structure, it is not necessary to work as a two-convex lens such as the front and back surfaces, and it is also possible to mass-produce the advantages of the matrix in the single-sided molding step. Since the flat surface 21A side of the plano-convex lens can directly connect the components of the front and rear sections, it is also possible to constitute a small-sized optical module in this respect. According to these contents, it is greatly advantageous to economical use of the apparatus for optical communication. [Industrial availability]

The present invention can be applied to the information communication industry.

1, 10‧‧‧ fiber matrix

2‧‧‧Lens Matrix

3‧‧‧ air layer

4‧‧‧Filter Department

7‧‧ ‧ visor

8‧‧‧Light-receiving element matrix

9‧‧‧Lens Matrix

11‧‧‧Fiber

11A‧‧‧Fiber

11A-1～11A-4, 11B-1～11B-4‧‧‧ fiber

11A-11, 11A-12, 11A-13, 11A-14, 11A-21, 11A-31, 11A-41, ‧‧11B-11, 11B-12, 11B-13, 11B-14, 11B-21 , 11B-31, 11B-41‧‧‧ fiber

11B‧‧‧Fiber

12-1, 12-2‧‧‧ Position alignment fiber

13-1, 13-2, 13-3, 13-4, 13-5‧‧‧V slot plate

14‧‧‧V slot

15-1, 15-2, 15-3, 15-4‧‧‧ position alignment slots

20‧‧‧ Plano-convex lens

21‧‧‧flat substrate

21A‧‧‧flat surface

21B‧‧‧Base surface

22‧‧‧ spacers

23‧‧‧ lens surface

23-1~23-4‧‧‧ lens surface

41‧‧‧Partial permeable membrane

42‧‧‧ glass substrate

71‧‧‧through holes

81‧‧‧Light-receiving components

91‧‧‧Focus distance adjustment resin

A1‧‧‧ convex

A2‧‧ ‧ convex

A3‧‧‧ saddle

AC‧‧‧ lens central axis

Bc‧‧‧ Peak Line

BD‧‧‧beam diameter

C1‧‧ points (center point)

C2‧‧ points (center point)

D1‧‧‧ diameter

D2‧‧‧ diameter

D _C ‧‧‧Distance

D _E ‧‧‧Distance

D‧‧‧distance

d _f ‧‧‧ Interval (fiber spacing)

d _l ‧‧‧Lens spacing

d _n ‧‧‧adjacent interval

d _p ‧‧‧ interval (peak interval)

f _c ‧‧‧ concave side focus distance

f _v ‧‧‧ convex side focus distance

L _2C ‧‧‧dotted line

L _2K ‧‧‧ dotted line

L _PC ‧‧‧ dotted line

n _c ‧‧‧refractive index (lens refractive index)

n _v ‧‧‧refractive index (air refractive index)

P1‧‧‧ end face

P2‧‧‧ end face

P3‧‧ points

P6‧‧‧ peak (vertex)

P8‧‧‧ peak (vertex)

P _C ‧‧‧ Plan

Pd‧‧‧projection section

PL11‧‧‧ end face

PL23C‧‧‧ concave side focal plane

PL23V‧‧‧ convex side focal plane

R1‧‧‧ Straight line (1st straight line)

R2‧‧‧ Straight line (2nd line)

t _l ‧‧‧Lens thickness

t _r ‧‧‧thickness

opening width w ₁₄ ‧‧‧

w ₁₅ ‧‧‧ opening width

w _s ‧‧‧Width

x‧‧‧Axis (direction)

Y‧‧‧Axis (direction)

z‧‧‧Axis (direction)

‧‧‧angle

Ψ‧‧‧ angle

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a plano-convex lens of the present invention. Fig. 2 shows an example of an imaginary circle formed on a base surface by a convex surface. Fig. 3 shows a first example of a mold for a plano-convex lens. Fig. 4 shows a second example of a mold for a plano-convex lens. Fig. 5 shows an example of a bimodal plano-convex lens according to the first embodiment. Fig. 6 shows an example of the configuration of an optical fiber matrix module according to the second embodiment. Fig. 7 is an explanatory view showing an optical system in the first and second embodiments. Fig. 8 is a view for explaining the difference between the two-piece form and the bimodal form of the present invention, wherein (a) shows a two-piece form and (b) shows a bimodal form. Fig. 9 is a view for explaining changes in the saddle, wherein (a) shows a form in which the saddle portion is lower than the peak, and (b) shows a form in which the saddle portion and the peak are at the same height. Fig. 10 shows a third example of a mold for a plano-convex lens. Fig. 11 is a graph for explaining the conditions of the vignetting-free optical system in the case where the period interval between the fibers is 250 μm in the first and second embodiments. Fig. 12 is a graph showing the conditions of an optical system without vignetting in the case where the period interval between fibers is 127 μm in the first and second embodiments. Fig. 13 shows an example of the angle dependency in the filter portion. Fig. 14 shows an example of a uniplanar plano-convex lens according to the third embodiment. Fig. 15 shows an example of the configuration of an optical fiber matrix module according to the third embodiment. Fig. 16 is an explanatory view showing an optical system in the third embodiment. Fig. 17 shows an example of a bimodal plano-convex lens according to the fourth embodiment. Fig. 18 is a view showing an example of the configuration of an optical fiber matrix module according to a fifth embodiment. Fig. 19 is an explanatory view showing an optical system in the fourth and fifth embodiments. Fig. 20 is a graph showing the conditions of the optical system without vignetting in the case where the period interval between the fibers is 250 μm in the fourth and fifth embodiments. Fig. 21 is a graph showing the conditions of an optical system without vignetting in the case where the period interval between fibers is 127 μm in the fourth and fifth embodiments. Fig. 22 shows an example of a uniplanar plano-convex lens according to the sixth embodiment. Fig. 23 is a view showing an example of the configuration of an optical fiber matrix module according to a sixth embodiment. Fig. 24 is an explanatory view showing an optical system in the sixth embodiment. Fig. 25 shows an example of the optical fiber matrix module of the seventh embodiment. Fig. 26 shows an example of the light receiving module of the seventh embodiment. Fig. 27 shows an example of the optical fiber matrix module of the eighth embodiment. Fig. 28 shows an example of a light receiving module of the eighth embodiment. Fig. 29 is a view showing an example of a connecting surface when the optical fiber matrix of the ninth embodiment is viewed from the z direction. Fig. 30 is a view showing an example of a configuration of the light receiving module according to the ninth embodiment when viewed from the x direction.

Claims (8)

A plano-convex lens having a flat surface and a lens surface, wherein the lens surface includes a first convex surface and a second convex surface having a spherical shape disposed on a flat base surface, and is formed on the base by the first convex surface The diameter of the first imaginary circle on the surface and the diameter of the second imaginary circle formed on the base surface by the second convex surface are larger than the distance between the center of the first imaginary circle and the second imaginary circle. The plano-convex lens of claim 1, further comprising a saddle portion for relaxing a shape change between the first convex surface and the second convex surface between the first convex surface and the second convex surface. The plano-convex lens of claim 1 or 2, wherein the first convex surface and the second convex surface respectively include a first straight line passing through a vertex of the first convex surface and a center of the first virtual circle, and a second convex surface The light emitted from the first position and the second position in the specific plane of the two straight lines of the apex and the center of the second imaginary circle is parallel light, and the parallel light incident from the first convex surface is arranged. When the reflecting surface of the flat surface is reflected, the second convex surface condenses the parallel light to the second position. The plano-convex lens of claim 1 or 2, wherein the first convex surface and the second convex surface respectively include a first straight line passing through a vertex of the first convex surface and a center of the first virtual circle, and a second convex surface The first position and the second position in the specific plane of the two straight lines of the imaginary line and the second line of the second imaginary circle are incident on the flat surface as parallel light, and are from the first position And the second distance from the second position is condensed to a point on the reflection surface perpendicular to the first straight line and the second straight line, and the parallel light emitted from the first convex surface is reflected at the point In this case, the second convex surface condenses the parallel light to the second position. The plano-convex lens according to claim 3 or 4, wherein the reflecting surface is provided with a filter portion that partially transmits the parallel light incident from the first convex surface and partially reflects the parallel light to the second convex surface. An optical fiber matrix module comprising: a first lens matrix having a plurality of plano-convex lenses according to any one of claims 1 to 5, wherein a plurality of the first convex surfaces and the second convex surface are arranged on the common base And an optical fiber matrix having two optical fibers with respect to each of the plano-convex lenses, and an end surface of each of the optical fibers is disposed at the first position or the second position of each of the plano-convex lenses. An optical fiber matrix module, comprising: the optical fiber matrix module of claim 6, wherein the optical component has a plurality of through holes through which the parallel light transmitted from the reflective surface is transmitted, and each of the parallel holes transmitted through the reflective surface Light is incident on one end of the different through hole, and parallel light passing through the through hole is emitted from the other end of each through hole; and a second lens matrix is emitted from each of the other ends of the plurality of through holes The light is condensed to a point defined for each of the through holes. A light receiving module comprising: the optical fiber matrix module of claim 7; and a light receiving element matrix that receives the light collected by the second lens matrix.