Optical receptacle

Abstract

This optical receptacle optically couples an optical fiber and a light receiving element and / or a light emitting element, and is composed of a receptacle body and a filter element. The receptacle body comprises an optical surface for the optical fiber, a first transmission optical surface, a second transmission optical surface, a reflection optical surface, a first transmission / reception optical surface, and a second transmission / reception optical surface. The filter element comprises an optical surface for a filter that reflects light of a wavelength in a certain range and transmits light of a wavelength in another range, and a third transmission optical surface. The optical receptacle is configured so as to pass through the optical surface for the optical fiber and the first transmission / reception optical surface, pass through a first path of light reflected on the optical surface for the filter, the optical surface for the optical fiber, and the second transmission / reception optical surface, transmit the optical surface for the filter, and form a second path of light reflected by the reflection optical surface.

Description

Optical Receptacle

[0001] The present invention relates to an optical receptacle.

[0002] Optical receptacles that optically couple an optical fiber to a light receiving element and / or a light emitting element have been developed for use with optical fibers that transmit optical signals of multiple wavelengths (for example, JP2020-160250A).

[0003] FIG. 40 is a cross-sectional view of a conventional optical receptacle used with an optical fiber that transmits optical signals of multiple wavelengths. The optical receptacle is composed of an optical receptacle body 110′ and a filter element 150′. The receptacle body 110′ includes an optical fiber optical surface 111′, a first transmitting optical surface 113′, a first transmitting / receiving optical surface 119′, and a second transmitting / receiving optical surface 121′. The filter element 150′ includes a first optical surface 151′ and a second optical surface 153′. As an example, a case will be described in which an optical signal of light having a certain range of wavelengths and light having another range of wavelengths transmitted by an optical fiber is received. The first optical surface 151′ is configured to reflect light having the certain range of wavelengths and transmit light having the other range of wavelengths. The second optical surface 153′ is configured to reflect light having the other range of wavelengths. The light in the certain wavelength range is approximately collimated by the optical fiber optical surface 111', reflected by the first optical surface 151', and focused by the first transmitting / receiving optical surface 119' onto the light-receiving surface of a light-receiving element (not shown). The light in the other wavelength range is approximately collimated by the optical fiber optical surface 111', passes through the first transmitting optical surface 113' and the first optical surface 151', is reflected by the second optical surface 153', and is focused by the second transmitting / receiving optical surface 121' onto the light-receiving surface of a light-receiving element (not shown).

[0004] FIG. 41 is a diagram showing the path of light of wavelengths in the other ranges in the optical receptacle shown in FIG.

[0005] The conventional optical receptacles described above have the following problems. The first problem is that they are difficult to manufacture. To improve the coupling efficiency of the optical receptacle, high precision is required for the dimensions and shape of the filter element 150'. In particular, the first optical surface 151' and the second optical surface 153' of the filter element 150' must be formed parallel with high precision, and high precision is also required for the distance between the above optical surfaces. The body of the filter element 150' is generally made of glass, and it is not easy to achieve the required high precision in dimensions and shape.

[0006] The second problem is that it is difficult to make the light path long.

[0007] Fig. 42 is a diagram showing a cross section of another conventional optical receptacle used for an optical fiber that transmits optical signals of multiple wavelengths. The thickness of filter element 150" of the optical receptacle shown in Fig. 42 is greater than the thickness of filter element 150' of the optical receptacle shown in Fig. 40. First optical surface 151" and second optical surface 153" of filter element 150" are formed in the same manner as first optical surface 151' and second optical surface 153' of filter element 150', respectively.

[0008] 43 is a diagram showing the path of light of wavelengths in the other ranges of the optical receptacle shown in FIG. 42. In the case of FIG. 43, the path of light is longer than in the case of FIG. 41. In particular, in the case of a multimode optical fiber with a relatively large core diameter, if the path of light is relatively long, the beam diameter of the beam passing through optical fiber optical surface 111" becomes larger than the diameter of second transmitting / receiving optical surface 121" due to divergence, as shown in FIG. 43, and the coupling efficiency of the optical receptacle decreases. In order to avoid decreasing the coupling efficiency of the optical receptacle, it is possible to converge the beam by using second optical surface 153" as a concave reflecting surface. However, as described above, the material of the body of filter element 150' is generally glass, and processing a concave reflecting surface is difficult and costly. The relationship between the path length of light and the coupling efficiency of the optical receptacle will be described in more detail later, as it is also related to the present invention.

[0009] As described above, no optical receptacle has been developed that is easy to manufacture and achieves high coupling efficiency for use with optical fibers that transmit optical signals of multiple wavelengths. Therefore, there is a need for an optical receptacle that is easy to manufacture and achieves high coupling efficiency for use with optical fibers that transmit optical signals of multiple wavelengths.

[0010] JP2020-160250A

[0011] A technical object of the present invention is to provide an optical receptacle that is used with an optical fiber that transmits optical signals of multiple wavelengths, that is easy to manufacture, and that can achieve high coupling efficiency.

[0012] An optical receptacle according to a first aspect of the present invention is an optical receptacle for optically coupling an optical fiber with a light receiving element and / or a light emitting element, and is composed of a receptacle body and a filter element. The receptacle body includes an optical fiber optical surface, a first transmitting optical surface, a second transmitting optical surface, a reflecting optical surface, a first transmitting / receiving optical surface, and a second transmitting / receiving optical surface, and the filter element includes a filter optical surface that reflects light of a certain range of wavelengths and transmits light of another range of wavelengths, and a third transmitting optical surface.

[0013] The optical receptacle is configured to form a first path of light that passes through the optical fiber optical surface and the first transmitting / receiving optical surface and is reflected by the filtering optical surface, and a second path of light that passes through the optical fiber optical surface and the second transmitting / receiving optical surface, transmits through the filtering optical surface, and is reflected by the reflecting optical surface.

[0014] When manufacturing the optical receptacle of the first aspect of the present invention, the optical fiber optical surface, the first and second transmitting optical surfaces, the reflective optical surface, and the first and second transmitting and receiving optical surfaces can be integrally molded as surfaces of the receptacle body, thereby making it possible to easily manufacture an optical receptacle in which the positional relationship between the above surfaces is determined with high precision.

[0015] In the optical receptacle of the first embodiment of the first aspect of the present invention, the optical fiber optical surface, the first transmitting / receiving optical surface, and the second transmitting / receiving optical surface are convex lens surfaces.

[0016] In the optical receptacle of the second embodiment of the first aspect of the present invention, the central axis of the optical fiber optical surface, the central axis of the first transmitting / receiving optical surface, and the central axis of the second transmitting / receiving optical surface are configured to be on the same plane.

[0017] An optical receptacle according to a third embodiment of the first aspect of the present invention is the optical receptacle according to the second embodiment, and is configured such that the central axis of the first transmitting / receiving optical surface and the central axis of the second transmitting / receiving optical surface are perpendicular to the central axis of the optical fiber optical surface on the same plane.

[0018] An optical receptacle according to a fourth embodiment of the first aspect of the present invention is the optical receptacle according to the second embodiment, wherein on the same plane, at least one of the central axis of the first transmitting / receiving optical surface and the central axis of the second transmitting / receiving optical surface forms an acute angle of 60 degrees or more and less than 90 degrees with the central axis of the optical fiber optical surface.

[0019] In the optical receptacle of this embodiment, when a transmitting / receiving optical surface, whose central axis forms an acute angle with the central axis of the optical fiber optical surface, receives light from a light-emitting element, the light that is reflected by the transmitting / receiving optical surface and returns to the light-emitting element is reduced, preventing the intensity of light emitted from the light-emitting element from becoming unstable due to the returned light and preventing a deterioration in the signal quality of optical communications.

[0020] An optical receptacle according to a fifth embodiment of the first aspect of the present invention is the optical receptacle according to the fourth embodiment, wherein the central axis of the first transmitting / receiving optical surface and the central axis of the second transmitting / receiving optical surface intersect on the same plane on the opposite side of the central axis of the optical fiber optical surface from the first and second transmitting / receiving optical surfaces.

[0021] In the optical receptacle of this embodiment, light reflected by one of the first and second transmitting and receiving optical surfaces facing the light-emitting element can be prevented from entering the light-emitting element or light-receiving element facing the other optical surface.

[0022] In the optical receptacle according to the sixth embodiment of the first aspect of the present invention, the first transmitting / receiving optical surface and the second transmitting / receiving optical surface are formed on the same plane so as to face the light receiving element or the light emitting element, respectively.

[0023] In the optical receptacle of the seventh embodiment of the first aspect of the present invention, the angle formed between the plane on which the first transmitting optical surface of the receptacle body is formed and the plane on which the second transmitting optical surface is formed is the same as the angle formed between the plane on which the filter optical surface is formed and the plane on which the third transmitting optical surface is formed, and the first transmitting optical surface and the filter optical surface and the third transmitting optical surface and the second transmitting optical surface are configured to face each other, respectively.

[0024] When manufacturing the optical receptacle of this embodiment, by combining the first transmitting optical surface and the filter optical surface, and the third transmitting optical surface and the second transmitting optical surface so that they face each other, it is possible to easily manufacture an optical receptacle in which the positional relationship between the filter optical surface of the filter element and each surface of the receptacle body is determined with high precision.

[0025] In an optical receptacle according to an eighth embodiment of the first aspect of the present invention, the reflective optical surface is configured to produce total internal reflection.

[0026] The reflective optical surface of the optical receptacle of this embodiment is configured to generate total reflection, so that an enhanced reflection film made of a dielectric multilayer film or the like is not required.

[0027] In the optical receptacle of the ninth embodiment of the first aspect of the present invention, the reflective optical surface is a concave reflective surface.

[0028] In this embodiment, the concave reflective surface is formed on a plastic receptacle body. The plastic receptacle body can be manufactured by injection molding, so the concave reflective surface can be formed with almost no increase in manufacturing effort or cost, and the coupling efficiency of the optical receptacle can be maintained even when the optical path is long.

[0029] In a tenth embodiment of the optical receptacle of the first aspect of the present invention, the first and second transmitting optical surfaces have protruding portions along at least a part of their peripheries, and the protruding portions are configured to directly contact the filtering optical surface and the third transmitting optical surface and to determine the positional relationship between the first transmitting optical surface and the filtering optical surface and the positional relationship between the second transmitting optical surface and the third transmitting optical surface.

[0030] In the optical receptacle of this embodiment, when the receptacle body and the filter element are bonded together using an adhesive or when a refractive index matching agent is applied between the surfaces of the receptacle and the filter element, the positional relationship between the first transmitting optical surface and the filter optical surface and the positional relationship between the second transmitting optical surface and the third transmitting optical surface can be easily determined, and excess adhesive can be prevented from spilling out from between the surfaces.

[0031] An optical receptacle according to an eleventh embodiment of the first aspect of the present invention includes one or more recesses between a flat surface on which the first transmissive optical surface is formed and a flat surface on which the second transmissive optical surface is formed.

[0032] In the optical receptacle of this embodiment, when the receptacle body and the filter element are joined using adhesive, excess adhesive is collected in the recess, thereby preventing excess adhesive from spilling out from between the surfaces.

[0033] An optical receptacle according to a twelfth embodiment of the first aspect of the present invention includes a protrusion between a flat surface on which the second transmissive optical surface is formed and a flat surface on which the reflective optical surface is formed.

[0034] When the receptacle body and the filter element are joined using an adhesive, the optical receptacle of this embodiment can prevent excess adhesive from spilling out from between the surfaces and adhering to the reflective optical surface, which may reduce the coupling efficiency of the optical receptacle.

[0035] An optical receptacle according to a second aspect of the present invention is an optical receptacle that optically couples an optical fiber to a light receiving element and / or a light emitting element, and is composed of a receptacle body and a filter element. The receptacle body includes M optical fiber optical surfaces, M first transmitting optical surfaces, M second transmitting optical surfaces, M reflecting optical surfaces, M first transmitting / receiving optical surfaces, and M second transmitting / receiving optical surfaces, where M represents a natural number of 2 or greater. The filter element includes M filtering optical surfaces and M third transmitting optical surfaces, each of which is formed to reflect light of a certain wavelength range and transmit light of a different wavelength range.

[0036] The optical receptacle is configured so that the sets of M types of optical surfaces correspond to M channels for M optical fibers, and in each channel, a first path of light passes through the optical fiber optical surface of the channel and the first transmitting / receiving optical surface of the channel and is reflected by the filter optical surface of the channel, and a second path of light passes through the optical fiber optical surface of the channel and the second transmitting / receiving optical surface of the channel, transmits through the filter optical surface of the channel, and is reflected by the reflecting optical surface.

[0037] In the optical receptacle of the first embodiment of the second aspect of the present invention, the M optical surfaces for optical fibers, the M first optical surfaces for transmission and reception, and the M second optical surfaces for transmission and reception are convex lens surfaces, the sets of M optical surfaces for optical fibers, the sets of M first optical surfaces for transmission and reception, and the sets of M second optical surfaces for transmission and reception are each arranged on the same plane, and the intersections of the M central axes of the M optical surfaces of each set and each of the same planes are arranged on one of three straight lines that are parallel to each other.

[0038] FIG. 1 is a diagram showing a cross section of an example of an optical receptacle of the present invention. FIG. 2 is a perspective view of the optical receptacle shown in FIG. 1. FIG. 3 is another perspective view of the optical receptacle shown in FIG. 1. FIG. 4 is a diagram showing a cross section of another example of an optical receptacle of the present invention. FIG. 5 is a perspective view of the optical receptacle shown in FIG. 4. FIG. 6 is another perspective view of the optical receptacle shown in FIG. 5. FIG. 7 is a perspective view of yet another example of an optical receptacle of the present invention. FIG. 8 is another perspective view of the optical receptacle shown in FIG. 8. FIG. 9 is a diagram showing an optical receptacle in which light of a certain range of wavelengths is used for transmission and light of another range of wavelengths is used for reception. FIG. 10 is a diagram showing the light ray paths of an optical receptacle in which light of a certain range of wavelengths is used for transmission and light of another range of wavelengths is used for reception. FIG. 11 is a diagram showing an optical receptacle in which light of a certain range of wavelengths is used for reception and light of another range of wavelengths is used for transmission. FIG. 12 is a diagram for explaining an optical receptacle including multiple channels for multiple optical fibers. 21 is a diagram showing an optical receptacle used to receive light of a certain range of wavelengths and light of another range of wavelengths; FIG. 22 is a diagram showing the ray paths of an optical receptacle used to receive light of a certain range of wavelengths and light of another range of wavelengths; FIG. 23 is a diagram showing the ray paths of an optical receptacle used to transmit light of a certain range of wavelengths and light of another range of wavelengths; FIG. 24 is a diagram showing the ray paths of an optical receptacle used to transmit light of a certain range of wavelengths and light of another range of wavelengths; FIG. 25 is a diagram showing the ray paths of an optical receptacle with a planar reflective optical surface that coincides with the central axis of the optical fiber optical surface; FIG. 26 is a diagram showing the ray paths of another optical receptacle with a planar reflective optical surface that coincides with the central axis of the light emitting surface of the light emitting element; FIG. 27 is a diagram showing a cross section of an example optical receptacle of the present invention with an increased thickness of the filter element; FIG. 28 is a perspective view of the optical receptacle shown in FIG. 20; FIG. 29 is another perspective view of the optical receptacle shown in FIG. 20; FIG. 29 is a diagram showing a cross section of an example optical receptacle with an adhesive space between the surfaces; FIG. 21 is a perspective view of the optical receptacle shown in FIG. 23; Fig. 24 is another perspective view of the optical receptacle shown in Fig. 23. Fig. 25 is a perspective view of a receptacle body of the optical receptacle shown in Fig. 23. Fig. 26 is another perspective view of the receptacle body of the optical receptacle shown in Fig. 23. Fig. 27 is a plan view of the receptacle body of the optical receptacle shown in Fig. 23.40 is a diagram illustrating a cross section of an example of an optical receptacle having a recess for excess adhesive. FIG. 41 is a perspective view of the optical receptacle shown in FIG. 29. FIG. 42 is another perspective view of the optical receptacle shown in FIG. 29. FIG. 43 is a diagram illustrating a cross section of an example of an optical receptacle having an adhesive overflow prevention wall. FIG. 44 is a perspective view of the optical receptacle shown in FIG. 32. FIG. 45 is another perspective view of the optical receptacle shown in FIG. 32. FIG. 46 is a diagram illustrating the path of light rays in an optical receptacle when path A is used for reception. FIG. 47 is a diagram illustrating the path of light rays in an optical receptacle when path B is used for reception. FIG. 48 is a diagram illustrating the path of light rays in an optical receptacle when path A is used for transmission. FIG. 49 is a diagram for explaining the divergence of a light beam incident from an optical fiber end face onto an optical fiber optical surface of an optical receptacle. FIG. 49 is a diagram illustrating a cross section of a conventional optical receptacle used with an optical fiber that transmits optical signals of multiple wavelengths. FIG. 49 is a diagram illustrating the path of light in another range of wavelengths in the optical receptacle shown in FIG. 42 is a cross-sectional view of another conventional optical receptacle used with an optical fiber that transmits optical signals of multiple wavelengths. FIG. 43 is a diagram showing the paths of light of another range of wavelengths in the optical receptacle shown in FIG.

[0039] FIG. 1 is a diagram showing a cross section of an example of an optical receptacle of the present invention.

[0040] Optical receptacle 100, which optically couples an optical fiber with a light-receiving element and / or a light-emitting element, is composed of receptacle body 110 and filter element 150. Receptacle body 110 includes optical fiber optical surface 111, first transmitting optical surface 113, second transmitting optical surface 115, reflective optical surface 117, first transmitting / receiving optical surface 119, and second transmitting / receiving optical surface 121. Filter element 150 includes filter optical surface 151 and third transmitting optical surface 153. Optical fiber optical surface 111 is disposed to face the end face of the optical fiber, and first transmitting / receiving optical surface 119 and second transmitting / receiving optical surface 121 are disposed to face the light-receiving element or the light-emitting element, respectively. Filter optical surface 151 is formed to reflect light of a certain range of wavelengths and transmit light of another range of wavelengths.

[0041] The angle formed by the plane on which the first transmitting optical surface 113 of the receptacle body 110 is formed and the plane on which the second transmitting optical surface 115 is formed is the same as the angle formed by the plane on which the filter optical surface 151 of the filter element 150 is formed and the plane on which the third transmitting optical surface 153 is formed, and the receptacle body 110 and the filter element 150 are combined so that the set of the first transmitting optical surface 113 and the filter optical surface 151 and the set of the third transmitting optical surface 153 and the second transmitting optical surface 115 face each other. As a result, a first path A for light of wavelengths in the above-mentioned certain range is formed between the optical fiber and the light receiving element or light emitting element, passing through the optical fiber optical surface 111, the first transmitting optical surface 113, the filter optical surface 151, and the first transmitting / receiving optical surface 119, and a second path B for light of wavelengths in the above-mentioned other range is formed between the optical fiber and the light receiving element or light emitting element, passing through the optical fiber optical surface 111, the first transmitting optical surface 113, the filter optical surface 151, the third transmitting optical surface 153, the second transmitting optical surface 115, the reflecting optical surface 117, and the second transmitting / receiving optical surface 121.

[0042] The filter optical surface 151 may be, for example, a dichroic filter using a dielectric multilayer film that can be realized using commercially available technology. The first transmissive optical surface 113, the second transmissive optical surface 115, and the third transmissive optical surface 153 may each include an anti-reflection dielectric multilayer film that can be realized using commercially available technology. The reflective optical surface 117 may be realized by total reflection. Reflective optical surfaces using total reflection are described later. Alternatively, the reflective optical surface 117 may be, for example, an enhanced reflection film using a dielectric multilayer film that can be realized using commercially available technology. Filters and enhanced reflection films using dielectric multilayer films are described, for example, in the Institute of Electronics, Information and Communication Engineers' "Knowledge Base," Group 9, Part 6, Chapter 2, Section 2-1-1 (https: / / www.ieice-hbkb.org / files / 09 / 09gun_06hen_02.pdf). Subwavelength structures may be used instead of dielectric multilayer films (e.g., Patent No. 3627093).

[0043] As an example, a filter element can be manufactured by forming a dielectric multilayer film on one side of a flat glass plate by vapor deposition, forming a crack in the flat glass plate with the dielectric multilayer film by laser processing, and breaking the glass plate at the crack location.

[0044] 2 and 3 are perspective views of the optical receptacle shown in Fig. 1. In Fig. 2, a protrusion for connecting the optical receptacle and the optical fiber ferrule is indicated by 135. The optical receptacle and the optical fiber ferrule are connected by fitting the protrusion 135 into a recess of the optical fiber ferrule.

[0045] In FIG. 1 and the following cross-sectional views, the protrusion 135 is shown for clarity.

[0046] The optical receptacle shown in Figures 2 and 3 has N optical fiber optical surfaces 111 and the same number of reflective optical surfaces 117. Although not shown in Figures 2 and 3, the receptacle body 110 also has N first transmitting / receiving optical surfaces 119 and N second transmitting / receiving optical surfaces 121, forming N first paths and N second paths.

[0047] A feature of the present invention relates to the construction of a single channel for a single optical fiber. As will be explained later, in an optical receptacle containing multiple channels for multiple optical fibers, the multiple channels may be of multiple different types, each of which may have a feature of the present invention.

[0048] FIG. 4 is a cross-sectional view of another example of the optical receptacle of the present invention.

[0049] 5 and 6 are perspective views of the optical receptacle shown in FIG.

[0050] The optical receptacle shown in Figures 1 to 3 has a concave reflective surface (a convex surface when viewed from the outside) as its reflective optical surface 117, whereas the optical receptacle shown in Figures 4 to 6 has a flat reflective surface as its reflective optical surface 117. The reason for making the reflective optical surface 117 concave will be explained later.

[0051] 7 and 8 are perspective views of yet another example of an optical receptacle of the present invention. In the optical receptacle of this example, some of the N reflective optical surfaces 117 are concave and the others are flat. A case where one of paths A and B is used for transmission and the other is used for reception A case where one of paths A and B is used for transmission and the other is used for reception will be described. In this specification, transmission means sending light from the light-emitting element to the optical fiber, and reception means that the light-receiving element receives light from the optical fiber.

[0052] FIG. 9 shows an optical receptacle in which light in one range of wavelengths is used for transmission and light in another range of wavelengths is used for reception.

[0053] 10 is a diagram showing the path of light rays in an optical receptacle when light of a certain range of wavelengths is used for transmission and light of another range of wavelengths is used for reception. The light of the certain range of wavelengths emitted from light-emitting surface 310 of the light-emitting element is approximately collimated by first transmitting / receiving optical surface 119, which is a convex lens surface, passes through first transmitting optical surface 113, is reflected by filter optical surface 151, passes through first transmitting optical surface 113 again, and is focused on end face 200 of the optical fiber by optical fiber optical surface 111, which is a convex lens surface. The light of the other wavelength ranges sent out from the end face 200 of the optical fiber is approximately collimated by the optical fiber optical surface 111, which is a convex lens surface, passes through the first transmitting optical surface 113, the filter optical surface 151, the third transmitting optical surface 153 and the second transmitting optical surface 115, is reflected by the reflecting optical surface 117 and is collected onto the light receiving surface 320 of the light receiving element by the second transmitting / receiving optical surface 121, which is a convex lens surface.

[0054] FIG. 11 shows an optical receptacle in which light of one range of wavelengths is used for reception and light of another range of wavelengths is used for transmission.

[0055] 12 is a diagram showing the path of light rays in an optical receptacle when light of a certain range of wavelengths is used for reception and light of another range of wavelengths is used for transmission. The light of the other range of wavelengths emitted from light-emitting surface 320 of the light-emitting element is approximately collimated by second transmitting / receiving optical surface 121, which is a convex lens surface, reflected by reflecting optical surface 117, transmitted through second transmitting optical surface 115, third transmitting optical surface 153, filter optical surface 151, and first transmitting optical surface 113, and is collected onto end face 200 of the optical fiber by optical fiber optical surface 111, which is a convex lens surface. The light of the above-mentioned certain range of wavelengths sent out from the end face 200 of the optical fiber is approximately collimated by the optical fiber optical surface 111, which is a convex lens surface, passes through the first transmitting optical surface 113, is reflected by the filter optical surface 151, passes through the first transmitting optical surface 113 again, and is focused onto the light receiving surface 310 of the light receiving element by the first transmitting / receiving optical surface 119, which is also a convex lens surface.

[0056] 10 and 12, the central axes of the optical fiber optical surface 111, the first transmitting / receiving optical surface 119, and the second transmitting / receiving optical surface 121 are configured to be on the same plane, and FIGS. 10 and 12 show cross sections that coincide with the same plane. On the same plane, the central axis of the optical fiber optical surface 111 is perpendicular to the central axis of the first transmitting / receiving optical surface 119 and the central axis of the second transmitting / receiving optical surface 121. Here, the central axis of the optical surface is the axis of rotational symmetry of the optical surface. Therefore, the central axis of the first transmitting / receiving optical surface 119 and the central axis of the second transmitting / receiving optical surface 121 are parallel to each other. Furthermore, the plane on which the first transmitting optical surface 113, the filter optical surface 151, the third transmitting optical surface 153, the second transmitting optical surface 115, and the reflecting optical surface 117 are formed is perpendicular to the same plane as above, and forms an angle of 45 degrees with the central axes of the optical fiber optical surface 111, the first transmitting / receiving optical surface 119, and the second transmitting / receiving optical surface 121, respectively.

[0057] 10 , the angle of incidence of a light ray that enters optical fiber optical surface 111 and travels along the central axis of optical fiber optical surface 111 on reflecting optical surface 117 is approximately 45 degrees. The material of receptacle body 110 is polyetherimide (PEI), which has a refractive index of 1.638 at a wavelength of 850 nanometers, so the critical angle is approximately 38 degrees. Therefore, the above light ray is totally reflected by reflecting optical surface 117.

[0058] 12, the angle of incidence of a light ray that is incident on the second transmitting / receiving optical surface 121 and travels along the central axis of the second transmitting / receiving optical surface 121 on the reflecting optical surface 117 is 45 degrees. Therefore, the light ray is totally reflected by the reflecting optical surface 117.

[0059] In the case of reception, the light beam incident on the reflecting optical surface 117 has a divergence angle of approximately 5 degrees around the central axis of the fiber optical surface 111, and in the case of transmission, it has a divergence angle of approximately 3 degrees around the central axis of the transmitting / receiving optical surface 121. In these cases as well, all light rays are incident on the reflecting optical surface 117 at angles larger than the critical angle and are totally reflected.

[0060] 13 is a diagram illustrating an optical receptacle including multiple channels for multiple optical fibers. Ch. a to Ch. Z represent multiple channels. Rx represents the first or second transmitting / receiving optical surface used for reception, and Tx represents the first or second transmitting / receiving optical surface used for transmission. The inner Rx or Tx of each channel represents the first transmitting / receiving optical surface 119, and the outer Rx or Tx represents the second transmitting / receiving optical surface 121.

[0061] The filter optical surface 151 of each channel of the optical receptacle on the left side of the upper row is formed to reflect light of wavelength W1 and transmit light of wavelength W2. The optical receptacle for each channel on the left side of the upper row is used as shown in FIG. 9 . Light of wavelength W1 is incident and transmitted via the first transmitting and receiving optical surface 119, and light of wavelength W2 is received via the second transmitting and receiving optical surface 121. The filter optical surface 151 of each channel of the optical receptacle on the right side of the upper row is formed to reflect light of wavelength W2 and transmit light of wavelength W1. The optical receptacle for each channel on the right side of the upper row is used as shown in FIG. 9 . Light of wavelength W2 is incident and transmitted via the first transmitting and receiving optical surface 119, and light of wavelength W1 is received via the second transmitting and receiving optical surface 121. As such, the structure of the filter optical surface 151 of the optical receptacle on the left side of the upper row differs from that of the optical receptacle on the right side of the upper row.

[0062] The filter optical surfaces 151 of channel a of the optical receptacles on both sides of the middle row are formed to reflect light of wavelength W1 and transmit light of wavelength W2. Channel a of the optical receptacles on both sides of the middle row are used as shown in FIG. 9 . Light of wavelength W1 is incident and transmitted via the first transmitting and receiving optical surface 119, and light of wavelength W2 is received via the second transmitting and receiving optical surface 121. Filter optical surfaces 151 of channel z of the optical receptacles on both sides of the middle row are formed to reflect light of wavelength W1 and transmit light of wavelength W2. Channel z of the optical receptacles on both sides of the middle row are used as shown in FIG. 11 . Light of wavelength W2 is incident and transmitted via the second transmitting and receiving optical surface 121, and light of wavelength W1 is received via the first transmitting and receiving optical surface 119. The configuration of the optical receptacle on the left side of the middle row is the same as the configuration of the optical receptacle on the right side of the middle row.

[0063] The filter optical surfaces 151 of channel a of the optical receptacles on both sides of the lower row are formed to reflect light of wavelength W1 and transmit light of wavelength W2. Channel a of the optical receptacles on both sides of the lower row are used as shown in FIG. 9 . Light of wavelength W1 is incident and transmitted via the first transmitting and receiving optical surface 119, and light of wavelength W2 is received via the second transmitting and receiving optical surface 121. Filter optical surfaces 151 of channel z of the optical receptacles on both sides of the lower row are formed to reflect light of wavelength W2 and transmit light of wavelength W1. Channel z of the optical receptacles on both sides of the lower row are used as shown in FIG. 9 . Light of wavelength W2 is incident and transmitted via the first transmitting and receiving optical surface 119, and light of wavelength W1 is received via the second transmitting and receiving optical surface 121. In this way, channels a and z of the optical receptacles on both sides of the lower row have different configurations. The configuration of the optical receptacle on the left side of the lower row is the same as the configuration of the optical receptacle on the right side of the lower row.

[0064] When both routes A and B are used for transmission or reception A case where both routes A and B are used for transmission or reception will be described.

[0065] FIG. 14 shows an optical receptacle that can be used to receive light of one range of wavelengths and light of another range of wavelengths.

[0066] 15 is a diagram showing the path of light rays in an optical receptacle when used to receive light of a certain range of wavelengths and light of another range of wavelengths. The light of the certain range of wavelengths sent out from end face 200 of the optical fiber is nearly collimated by optical fiber optical surface 111, which is a convex lens surface, passes through first transmitting optical surface 113, is reflected by filter optical surface 151, passes through first transmitting optical surface 113 again, and is focused onto light receiving surface 310 of the light receiving element by first transmitting / receiving optical surface 119, which is also a convex lens surface. The light of the other wavelength ranges sent out from the end face 200 of the optical fiber is approximately collimated by the optical fiber optical surface 111, which is a convex lens surface, passes through the first transmitting optical surface 113, the filter optical surface 151, the third transmitting optical surface 153 and the second transmitting optical surface 115, is reflected by the reflecting optical surface 117 and is collected onto the light receiving surface 320 of the light receiving element by the second transmitting / receiving optical surface 121, which is a convex lens surface.

[0067] FIG. 16 shows an optical receptacle that can be used to transmit light of one range of wavelengths and light of another range of wavelengths.

[0068] 17 is a diagram showing the paths of light rays in an optical receptacle when light of a certain wavelength range and light of another wavelength range are used for transmission. The light of the certain wavelength range emitted from the light-emitting surface 310 of the light-emitting element is approximately collimated by the first transmitting / receiving optical surface 119, which is a convex lens surface, passes through the first transmitting optical surface 113, is reflected by the filtering optical surface 151, passes through the first transmitting optical surface 113 again, and is focused on the end face 200 of the optical fiber by the optical fiber surface 111, which is a convex lens surface. The light of the other wavelength range emitted from the light-emitting surface 320 of the light-emitting element is approximately collimated by the second transmitting / receiving optical surface 121, which is a convex lens surface, is reflected by the reflecting optical surface 117, passes through the second transmitting optical surface 115, the third transmitting optical surface 153, the filtering optical surface 151, and the first transmitting optical surface 113, and is focused on the end face 200 of the optical fiber by the optical fiber surface 111, which is a convex lens surface.

[0069] 15 and 17 , the central axes of the optical fiber optical surface 111, the first transmitting / receiving optical surface 119, and the second transmitting / receiving optical surface 121 are configured to be on the same plane, and FIGS. 15 and 17 show cross sections that coincide with this same plane. On this same plane, the central axis of the optical fiber optical surface 111 is perpendicular to the central axes of the first transmitting / receiving optical surface 119 and the second transmitting / receiving optical surface 121. Therefore, the central axes of the first transmitting / receiving optical surface 119 and the second transmitting / receiving optical surface 121 are parallel to each other. Furthermore, the plane on which the first transmitting optical surface 113, the filter optical surface 151, the third transmitting optical surface 153, the second transmitting optical surface 115, and the reflecting optical surface 117 are formed is perpendicular to this same plane and forms a 45-degree angle with the central axes of the optical fiber optical surface 111, the first transmitting / receiving optical surface 119, and the second transmitting / receiving optical surface 121.

[0070] 15 , the angle of incidence of a light ray that enters optical fiber optical surface 111 and travels along the central axis of optical fiber optical surface 111 on reflecting optical surface 117 is approximately 45 degrees. The material of receptacle body 110 is polyetherimide (PEI), which has a refractive index of 1.638 at a wavelength of 850 nanometers, so the critical angle is approximately 38 degrees. Therefore, the above light ray is totally reflected by reflecting optical surface 117.

[0071] 17, the angle of incidence of a light ray that is incident on the second transmitting / receiving optical surface 121 and travels along the central axis of the second transmitting / receiving optical surface 121 on the reflecting optical surface 117 is 45 degrees. Therefore, the light ray is totally reflected by the reflecting optical surface 117.

[0072] In the case of reception, the light beam incident on the reflecting optical surface 117 has a divergence angle of approximately 5 degrees around the central axis of the fiber optical surface 111, and in the case of transmission, it has a divergence angle of approximately 3 degrees around the central axis of the transmitting / receiving optical surface 121. In these cases as well, all light rays are incident on the reflecting optical surface 117 at angles larger than the critical angle and are totally reflected.

[0073] 18 is a diagram showing the path of a light ray in an optical receptacle in which the reflective optical surface 117 is planar and coincides with the central axis of the optical fiber optical surface 111. As described in relation to FIGS. 15 and 17 , the central axes of the optical fiber optical surface 111, the first transmitting and receiving optical surface 119, and the second transmitting and receiving optical surface 121 are configured to be on the same plane, the central axis of the optical fiber optical surface 111 is perpendicular to the central axis of the first transmitting and receiving optical surface 119 and the central axis of the second transmitting and receiving optical surface 121, and the filter optical surface 151 and the reflective optical surface 117 form an angle of 45 degrees with the central axes of the optical fiber optical surface 111, the first transmitting and receiving optical surface 119, and the second transmitting and receiving optical surface 121, respectively. In other words, the angle formed by the normal to the filter optical surface 151 with the central axis of the optical fiber optical surface 111 and the central axis of the first transmitting / receiving optical surface 119 is 45 degrees, and the angle formed by the normal to the reflecting optical surface 117 with the central axis of the optical fiber optical surface 111 and the central axis of the second transmitting / receiving optical surface 121 is 45 degrees.

[0074] Figure 19 is a diagram showing the path of a light ray in another optical receptacle in which the reflective optical surface 117 is planar and coincides with the central axis of the light-emitting surface of the light-emitting element. In the optical receptacle shown in Figure 19, the angle between the central axis of the optical fiber optical surface and the central axis of the transmitting and receiving optical surface is changed compared to the optical receptacle shown in Figure 18. The angle between the central axis of the optical fiber optical surface 111 and the central axis of the first transmitting and receiving optical surface 119 is approximately 86 degrees when measured clockwise from the central axis of the first transmitting and receiving optical surface 119, and the angle between the central axis of the optical fiber optical surface 111 and the central axis of the second transmitting and receiving optical surface 121 is approximately 94 degrees when measured clockwise from the central axis of the second transmitting and receiving optical surface 121. In addition, the angle formed by the normal to the filter optical surface 151 with the central axis of the optical fiber optical surface 111 and the central axis of the first transmitting / receiving optical surface 119 is 43 degrees, and the angle formed by the normal to the reflecting optical surface 117 with the central axis of the optical fiber optical surface 111 and the central axis of the second transmitting / receiving optical surface 121 is 47 degrees.

[0075] When the first and second transmitting and receiving optical surfaces receive light emitted from the light-emitting elements, the optical receptacle shown in Fig. 19 can significantly reduce the amount of light emitted from each light-emitting element, reflected by each transmitting and receiving optical surface, and returned to each light-emitting element, compared to the optical receptacle shown in Fig. 18. It is generally known that when the light-emitting element is a semiconductor laser, the intensity of the light emitted from the light-emitting element becomes unstable due to the light returning to the light-emitting element as described above, degrading the signal quality of optical communications.

[0076] 19, the central axis of first transmitting and receiving optical surface 119 and the central axis 121 of the second transmitting and receiving optical surface intersect on the side opposite the central axis of optical fiber optical surface 111 from the first and second transmitting and receiving optical surfaces. Therefore, the optical receptacle shown in Fig. 19 can prevent light reflected by one of the first and second transmitting and receiving optical surfaces facing the light emitting element from being incident on the light emitting element or light receiving element facing the other optical surface.

[0077] Optical Receptacle with Increased Filter Element Thickness FIG. 20 is a diagram showing a cross section of an example of an optical receptacle of the present invention in which the thickness of the filter element is increased.

[0078] 21 and 22 are perspective views of the optical receptacle shown in FIG. 20. FIG.

[0079] Because the filter element of the optical receptacle of the present invention does not have a reflective optical surface, its thickness can be increased regardless of the path of the light beam. Generally, thin glass and plastic plates are easily broken, and thin plastic plates are even more prone to warping, making them difficult to manufacture and store. The thickness (length of the side of the square cross section) of the filter element 150 shown in Figure 1 is 0.9 millimeters, while the thickness (length of the longer side of the rectangular cross section) of the filter element 150 shown in Figure 20 is 1.3 millimeters.

[0080] Optical Receptacle with Adhesive Space Between Faces FIG. 23 is a cross-sectional view of an example optical receptacle with adhesive space between faces.

[0081] 24 and 25 are perspective views of the optical receptacle shown in FIG. 23. FIG.

[0082] 26 and 27 are perspective views of the receptacle body of the optical receptacle shown in FIG. 23. FIG.

[0083] 28 is a plan view of a receptacle body of the optical receptacle shown in FIG. 23. FIG.

[0084] The receptacle body 110 is provided with protrusions 123 on the peripheries of two sides of the plane on which the first transmitting optical surface 113 is formed and on the peripheries of three sides of the plane on which the second transmitting optical surface 115 is formed, and the protrusions 123 are configured to abut against the plane on which the filter optical surface 151 is formed and the plane on which the third transmitting optical surface 153 is formed, thereby forming spaces for adhesive to be used when bonding the plane on which the first transmitting optical surface 113 is formed and the plane on which the filter optical surface 151 is formed, and the plane on which the second transmitting optical surface 115 is formed and the plane on which the third transmitting optical surface 153 is formed. The protrusions 123 have a height of 0.02 millimeters and a width of 0.18 millimeters.

[0085] In this example, the protrusions 123 abut against the plane on which the filter optical surface 151 is formed and the plane on which the third transmitting optical surface 153 is formed, thereby making it possible to accurately determine the positional relationships between the first transmitting optical surface 113 and the filter optical surface 151 and between the second transmitting optical surface 115 and the third transmitting optical surface 153. Furthermore, the protrusions 123 can prevent the adhesive from spilling over and adhering to locations other than the bonding surfaces, particularly to the reflecting optical surface 117. If the adhesive adheres to the reflecting optical surface 117, total reflection is hindered, thereby reducing the coupling efficiency.

[0086] The adhesive is, for example, an ultraviolet curable resin such as epoxy or acrylate.

[0087] Optical Receptacle with Excess Adhesive Recess FIG. 29 is a diagram illustrating a cross section of an example of an optical receptacle with an excess adhesive recess.

[0088] 30 and 31 are perspective views of the optical receptacle shown in FIG.

[0089] The receptacle body 110 has an excess adhesive recess 125 near the boundary between the plane on which the first transmitting optical surface 113 is formed and the plane on which the second transmitting optical surface 115 is formed. The width of the excess adhesive recess 125 is approximately 0.3 millimeters, and the depth from the intersection line between the plane on which the first transmitting optical surface 113 is formed and the plane on which the second transmitting optical surface 115 is formed is 0.1 millimeters.

[0090] Excess adhesive used when joining the plane on which the first transmitting optical surface 113 is formed and the plane on which the filter optical surface 151 is formed, and the plane on which the second transmitting optical surface 115 is formed and the plane on which the third transmitting optical surface 153 is formed, flows into the excess adhesive recess 125, thereby preventing the adhesive from spilling out and adhering to the reflecting optical surface 117.

[0091] Optical Receptacle with Adhesive Extrusion Prevention Walls FIG. 32 is a diagram showing a cross section of an example of an optical receptacle with adhesive extrusion prevention walls.

[0092] 33 and 34 are perspective views of the optical receptacle shown in FIG.

[0093] Receptacle body 110 is provided with adhesive extrusion prevention wall 127 near the boundary between the plane on which second transmitting optical surface 115 is formed and the plane on which reflective optical surface 117 is formed. The cross-sectional width of adhesive extrusion prevention wall 127 is approximately 0.2 millimeters and the height is approximately 0.6 millimeters.

[0094] The adhesive overflow prevention wall 127 can prevent excess adhesive used when joining the plane on which the first transmitting optical surface 113 is formed and the plane on which the filter optical surface 151 is formed, and the plane on which the second transmitting optical surface 115 is formed and the plane on which the third transmitting optical surface 153 is formed, from overflowing and adhering to the reflecting optical surface 117.

[0095] EXAMPLES OF THE INVENTION Examples of the present invention will be described for each optical path and transmission / reception direction.

[0096] In the following example, path A uses light with a wavelength of 910 nanometers, and path B uses light with a wavelength of 850 nanometers.

[0097] The material of the receptacle body 110 is polyetherimide (PEI), which has a refractive index of 1.638 at a wavelength of 850 nanometers. The material of the filter element 150 is glass (S-TIM25 manufactured by OHARA) which has a refractive index of 1.657 at a wavelength of 850 nanometers.

[0098] A lens or a reflective concave surface can be described by the following formula: z is the coordinate in the direction of the central axis (axis of rotational symmetry) of the curved surface, x and y are the coordinates in two orthogonal directions in a plane perpendicular to the central axis, c is the curvature, R is the radius of curvature, and k is the conic constant.

[0099] In the following embodiment, the central axes of the optical fiber optical surface 111, the first transmitting / receiving optical surface 119, and the second transmitting / receiving optical surface 121 are configured to be on the same plane. On the same plane, the central axis of the optical fiber optical surface 111 is perpendicular to the central axis of the first transmitting / receiving optical surface 119 and the central axis of the second transmitting / receiving optical surface 121. The first transmitting optical surface 113, the second transmitting optical surface 115, the filter optical surface 151, and the third transmitting optical surface 153 form an angle of 45 degrees with the central axis of the optical fiber optical surface 111. The angle between the plane on which the reflecting optical surface 117 is installed and the central axis of the optical fiber optical surface 111 is 45 degrees.

[0100] The filtering optical surface 151 is a dielectric multilayer film formed on the surface of the filter element 150. The reflectance of the filtering optical surface 151 for light with a wavelength of 910 nanometers is 95 percent, and the transmittance of the filtering optical surface 151 for light with a wavelength of 850 nanometers is 95 percent.

[0101] 1) Example in which path A is used to receive light with a wavelength of 910 nanometers Figure 35 is a diagram showing the path of light rays in an optical receptacle when path A is used to receive light with a wavelength of 910 nanometers. Figure 35 and Figures 36 to 38 described below show cross sections that coincide with the same plane. In order to define the position of each surface, a coordinate system is defined that includes a z-axis that coincides with the central axis of optical fiber optical surface 111, a y-axis that is orthogonal to the z-axis on the same plane, and an x-axis that is orthogonal to the two axes described above. The origin of the coordinate system is the center of core end face 200 of the optical fiber.

[0102] Table 1 shows the position and shape of each surface in this embodiment.

[0103] In Table 1 and Tables 2 to 4 described below, vertex coordinates refer to the coordinates of a point on the central axis (axis of rotational symmetry) of a curved surface, and to the coordinates of the intersection with the optical axis in the case of a flat surface. The central axis direction refers to the direction of the normal to the central axis (axis of rotational symmetry) of the curved surface or the plane. The shape of the effective area is expressed as the shape of the effective area of ​​the optical surface projected onto a plane perpendicular to the central axis, and in the examples shown in Tables 1 to 4, the shape is a circle or an ellipse. In Tables 1 to 4, if the shape is a circle, the effective diameter is indicated by the diameter, and if the shape is an ellipse, the effective diameter is indicated by (length of axis in the x-axis direction) x (length of axis in the y-axis direction). The inter-surface material of a certain surface is the material of the medium through which light travels after passing through that surface. Adjacent means that the surface is adjacent to another surface.

[0104] 2) Example in which path B is used to receive light with a wavelength of 850 nanometers FIG. 36 is a diagram showing the path of light rays in an optical receptacle in which path B is used to receive light with a wavelength of 850 nanometers.

[0105] Table 2 shows the arrangement and shape of each surface in this embodiment.

[0106] 3) Example in which path A is used to transmit light with a wavelength of 910 nanometers FIG. 37 is a diagram showing the path of light rays in an optical receptacle in which path A is used to transmit light with a wavelength of 910 nanometers.

[0107] Table 3 shows the arrangement and shape of each surface in this embodiment.

[0108] 4) Example in which path B is used to transmit light with a wavelength of 850 nanometers FIG. 38 is a diagram showing the path of light rays in an optical receptacle in which path B is used to transmit light with a wavelength of 850 nanometers.

[0109] Table 4 shows the arrangement and shape of each surface in this embodiment.

[0110] Relationship Between the Optical Path Length and the Coupling Efficiency of the Optical Receptacle The relationship between the optical path length and the coupling efficiency of the optical receptacle will be described.

[0111] 39 is a diagram for explaining the divergence of a light beam incident on the optical fiber optical surface 111 of the optical receptacle from the optical fiber end face 200. The core diameter of the optical fiber is a, the numerical aperture is A, the focal length of the optical fiber optical surface 111 is f, the effective diameter of the optical fiber optical surface 111 is D, the refractive index of the receptacle body 110 and the filter element 150 is n, and the distance along the optical axis from the optical fiber optical surface 111 to the second transmitting / receiving optical surface 121 is d. The optical axis is the path of a light ray that follows a path that coincides with the central axis of the optical fiber optical surface 111.

[0112] 39, when the effective diameter of the second transmitting and receiving optical surface 121 is D', the condition under which the light beam falls within the effective diameter of the second transmitting and receiving optical surface 121 when d>2nf is as follows: If the light beam does not fall within the effective diameter of the second transmitting and receiving optical surface 121, the coupling efficiency of the optical receptacle decreases. The numerical aperture A of a multimode optical fiber is typically 0.2. Similarly, the core diameter a is typically 0.05 millimeters. The clear diameter D of the optical fiber's optical surface is typically 0.25 millimeters, and the focal length f is typically in the range of 0.1 to 0.7 millimeters, often in the range of 0.2 to 0.5 mm. The refractive index of the receptacle body 110 and the filter element 150 is typically in the range of 1.4 to 1.9, often in the range of 1.5 to 1.7.

[0113] Table 5 shows typical values ​​of the variables on the right hand side of equation (1). According to the values ​​in Table 1, the value of the right side of equation (1) is 1.84 millimeters. Therefore, the distance d along the optical axis from the optical fiber surface to the second transmitting / receiving optical surface needs to be, for example, smaller than 1.84 millimeters.

[0114] The above relationship also applies to the prior art shown in FIGS.

[0115] When formula (1) is not satisfied, by making reflecting optical surface 117 in the case of the present invention or second optical surface 153″ in the case of the prior art a concave reflecting surface, it is possible to fit the light beam within the effective diameter of second transmitting / receiving optical surface 121 or 121″ so as not to reduce the coupling efficiency of the optical receptacle.

[0116] Table 6 shows the relationship between the optical path length and the coupling efficiency of the optical receptacle. In both the configuration of the present invention and the conventional configuration, the coupling efficiency of the optical receptacle with a concave reflecting surface is significantly higher than the coupling efficiency of the optical receptacle with a flat reflecting surface. The coupling efficiency of the optical receptacle with a flat reflecting surface of the present invention and the optical receptacle with a concave reflecting surface of the present invention are approximately the same as the coupling efficiencies of the conventional optical receptacle with a flat reflecting surface and the conventional optical receptacle with a concave reflecting surface, respectively.

[0117] In conventional optical receptacles, the concave reflective surface is formed on a filter element. Because filter elements are generally made of glass, press molding is required to form the concave reflective surface, which requires an additional mold and increases manufacturing effort and costs. In the optical receptacle of the present invention, the concave reflective surface is formed on a plastic receptacle body. Because the plastic receptacle body can be manufactured by injection molding, the concave reflective surface can be formed with almost no increase in manufacturing effort and cost, and the coupling efficiency of the optical receptacle can be maintained even when the light path is long.

[0118] Thus, according to the present invention, an optical receptacle with approximately the same coupling efficiency as that of the prior art optical receptacle can be manufactured much more simply and at lower cost.

[0119] In general, an optical receptacle is also called an optical connector or an optical module.

Claims

1. An optical receptacle for optically coupling an optical fiber with a light receiving element and / or a light emitting element, the receptacle body comprising a filter element, the receptacle body comprising an optical fiber optical surface, a first transmitting optical surface, a second transmitting optical surface, a reflecting optical surface, a first transmitting / receiving optical surface, and a second transmitting / receiving optical surface, the filter element comprising a filter optical surface that reflects light of a certain range of wavelengths and transmits light of another range of wavelengths, and a third transmitting optical surface; a first path of light passing through the optical fiber optical surface and the first transmitting / receiving optical surface and reflected by the filtering optical surface, and a second path of light passing through the optical fiber optical surface and the second transmitting / receiving optical surface, transmitting through the filtering optical surface, and reflected by the reflecting optical surface; an angle formed between the plane on which the first transmitting optical surface of the receptacle body is formed and the plane on which the second transmitting optical surface is formed, and an angle formed between the plane on which the filtering optical surface of the filter element is formed and the plane on which the third transmitting optical surface is formed are the same, and the first transmitting optical surface and the filtering optical surface and the third transmitting optical surface and the second transmitting optical surface are configured to face each other, respectively.

2. An optical receptacle as described in claim 1, wherein the material of the filter element is glass.

3. 2. The optical receptacle according to claim 1, wherein the optical fiber optical surface, the first transmitting / receiving optical surface, and the second transmitting / receiving optical surface are convex lens surfaces.

4. 4. The optical receptacle according to claim 3, wherein the central axis of the optical fiber optical surface, the central axis of the first transmitting / receiving optical surface, and the central axis of the second transmitting / receiving optical surface are configured to be on the same plane.

5. 5. The optical receptacle according to claim 4, wherein the central axis of the first transmitting / receiving optical surface and the central axis of the second transmitting / receiving optical surface are configured to be perpendicular to the central axis of the optical fiber optical surface on the same plane.

6. 5. The optical receptacle according to claim 4, wherein on the same plane, at least one of the central axis of the first transmitting / receiving optical surface and the central axis of the second transmitting / receiving optical surface forms an acute angle of 60 degrees or more and less than 90 degrees with the central axis of the optical fiber optical surface.

7. 7. The optical receptacle according to claim 6, wherein a central axis of the first transmitting and receiving optical surface and a central axis of the second transmitting and receiving optical surface intersect on the same plane on an opposite side of the central axis of the optical fiber optical surface from the first and second transmitting and receiving optical surfaces.

8. 2. The optical receptacle according to claim 1, wherein the first transmitting / receiving optical surface and the second transmitting / receiving optical surface are formed on the same plane so as to face the light receiving element or the light emitting element, respectively.

9. The optical receptacle of claim 1 , wherein the reflective optical surface is configured to produce total internal reflection.

10. 2. The optical receptacle of claim 1, wherein the reflective optical surface is a concave reflective surface.

11. 2. The optical receptacle according to claim 1, wherein the first and second transmitting optical surfaces have protruding portions along at least a portion of their peripheries, the protruding portions being in direct contact with the filtering optical surface and the third transmitting optical surface and configured to determine a positional relationship between the first transmitting optical surface and the filtering optical surface and a positional relationship between the second transmitting optical surface and the third transmitting optical surface.

12. 2. The optical receptacle according to claim 1, further comprising one or more recesses between a plane on which the first transmissive optical surface is formed and a plane on which the second transmissive optical surface is formed.

13. The optical receptacle according to claim 1 , further comprising a protrusion between a plane on which the second transmissive optical surface is formed and a plane on which the reflective optical surface is formed.

14. An optical receptacle as defined in claim 1, wherein M represents a natural number of 2 or greater, the receptacle body comprises M optical fiber optical surfaces, M first transmitting optical surfaces, M second transmitting optical surfaces, M reflecting optical surfaces, M first transmitting / receiving optical surfaces, and M second transmitting / receiving optical surfaces, the filter element comprises M filter optical surfaces and M third transmitting optical surfaces, each of the M filter optical surfaces being formed to reflect light of a certain range of wavelengths and transmit light of another range of wavelengths, The sets of M types of optical surfaces correspond to M channels for M optical fibers, and the optical receptacle is configured to form, in each channel, a first path of light that passes through the optical fiber optical surface of the channel and the first transmitting / receiving optical surface of the channel and is reflected by the filtering optical surface of the channel, and a second path of light that passes through the optical fiber optical surface of the channel and the second transmitting / receiving optical surface of the channel, transmits through the filtering optical surface of the channel, and is reflected by the reflecting optical surface.

15. 15. The optical receptacle according to claim 14, wherein the M optical fiber optical surfaces, the M first transmitting and receiving optical surfaces, and the M second transmitting and receiving optical surfaces are convex lens surfaces, the sets of the M optical fiber optical surfaces, the sets of the M first transmitting and receiving optical surfaces, and the sets of the M second transmitting and receiving optical surfaces are each arranged on the same plane, and the intersections of the M central axes of the M optical surfaces of each set and each of the same planes are arranged on one of three straight lines that are parallel to each other.