JPH10256639A - Light receiving module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a carrier for slanting a light emitting element toward the optical axis direction unnecessary, and reduce the number of components and manhour, by fixing a light receiving element from the upper surface of a case, and making a specified inclination in an incidence part of a transparent body in such a manner that an incident light enters the light receiving surface. SOLUTION: A light receiving element 1 is fixed to a carrier 12 and arranged on the surface of a case 6 parallel to the same axis direction as the center axis of an optical fiber 4 and a lens 3'. A specified inclination θ is set on a light incidence surface 10. A light supplied form one end of the optical fiber 4 is condensed in a lens 3 and enters the light incidence surface 10. The refractive index of a transparent body 5 and the angle θ of the light incidence surface 10 are so set that an angle θ1 becomes larger than O. Thereby an incident light is made to enter the light receiving surface 11 at an angle of θ1, when the light receiving element 1 is fixed to the case 6 surface parallel to the same axis direction as the center axis of the optical fiber 4 and the lens 3, so that a signal can be outputted via the carrier 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for coupling and assembling optical receiving modules.

[0002]

2. Description of the Related Art FIG. 4 is a view showing a conventional light receiving module, wherein 1 is a light receiving element, 2 is a first carrier for fixing the light receiving element 1, 3 is a lens for condensing light, and 4 is the light receiving element. 1
5 is a transparent body that hermetically seals the light receiving element 1, 6 is a case, 7 is a second carrier that fixes the first carrier and has a wiring pattern up to the case, and 8 is the above. Fiber holder for fixing optical fiber, 9
Denotes a bonding wire, 10 denotes a light incident surface of the transparent body 5, and 11 denotes a light receiving surface of the light receiving element 1.

In FIG. 1, light supplied from one end of an optical fiber 4 is condensed by a lens 3 and is incident on a light receiving surface 11 of a light receiving element 1 via a transparent body 5 and a light incident surface 10. The incident light signal is converted into an electric signal by the light receiving element 1,
The signal is output via the bonding wire 9, the first carrier 2, and the second carrier 7.

[0004]

In FIG. 4, the central axis of the optical fiber 4, the central axis of the lens 3, and the light receiving element 1 are arranged on the same axis, and the light supplied from one end of the optical fiber 4 is The light is perpendicularly incident on the light receiving surface 11 of the light receiving element 1 via the lens 3. When the central axis of the optical fiber 4, the central axis of the lens 3, and the light receiving element 1 are arranged on the same axis, the light receiving surface 11 of the light receiving element 1 is generally 90 degrees or 88 degrees with respect to the incident axis of light. To a range of 98 degrees.
In this case, after the light receiving element 1 is fixed to the first carrier 2, the light receiving surface 11 of the light receiving element 1 is set at 90 degrees or 88 to 98 degrees in the axial direction of the light supplied from one end of the optical fiber 4. It is necessary to fix to the second carrier 7 so that it tilts,
It is difficult to work from the upper surface of the case 6 at one time, and it is necessary to divide the assembling process.

[0005]

According to a first aspect of the present invention, there is provided an optical receiving module in which a light receiving element is fixed from an upper surface of a case, a light receiving surface of the light receiving element is arranged upward, a center axis of an optical fiber and a center of a lens. Even if fixed to a case surface parallel to the same axis direction as the axis, so that incident light is incident on the light receiving surface, a predetermined inclination is provided in a light incident portion of a transparent body that hermetically seals the light receiving element, By configuring the direction of the light condensed by the lens so as to be inclined to the light receiving surface, it is possible to work at once from the upper surface of the case.

In the optical receiving module according to the second aspect of the present invention, the lens to be used is a cemented lens combining hemispherical lenses having different refractive indices, and the light-receiving surface of the light-receiving element is changed by changing the traveling angle of light in the lens. The angle of the light incident on the light-receiving surface is made closer to the direction perpendicular to the light-receiving surface, the coupling tolerance to the light-receiving surface is relaxed, and the optical axis adjustment work can be easily performed.

Further, the optical receiving module according to the third aspect of the present invention uses an optical fiber having a predetermined inclination at one end of the optical fiber on the light receiving element side, thereby providing an angle to the light supplied from the optical fiber in advance. The angle of light incident on the light receiving surface of the light receiving element is made closer to the direction perpendicular to the light receiving surface, the optical axis tolerance to the light receiving surface is relaxed, and the optical axis adjustment operation can be easily performed.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a view showing a first embodiment of the present invention, in which 1 is a light receiving element, 3 is a lens for condensing light, 4 is an optical fiber for supplying light to the light receiving element 1, and 5 is a light receiving element 1. 6 is a case, 12 is a carrier having a wiring pattern for fixing the light receiving element 1 and connecting to the case 6, 8 is a fiber holder for fixing an optical fiber, 9 is a bonding wire, and 10 is a bonding wire. The light incident surface of the transparent body 5 and the light receiving surface 11 of the light receiving element 1 are fixed on the carrier 12 and are on the surface of the case 6 parallel to the central axis of the optical fiber 4 and the same axis as the lens 3. Are located.

In FIG. 1, a light incident surface 10 has a predetermined inclination θ with respect to the center axis of the optical fiber 4 and the center axis of the lens 3.
Is provided. In such a configuration, the optical fiber 4
Supplied from one end of the lens 3 is condensed by the lens 3 and is incident on the light input surface 10.

Here, the relationship between the refractive index of the transparent body 5 is n0, the refractive index of air is n1, the predetermined inclination provided on the transparent body 5 is θ, and the angle θ1 of the light incident on the light receiving surface 11 is shown. Is calculated by Equation 1.

[0011]

(Equation 1)

From the formula 1, by setting the refractive index of the transparent body 5 and the angle θ of the light incident surface 10 so that the angle θ1 is larger than zero, the light receiving element 1 is connected to the center axis of the optical fiber 4 and the lens 3. Even if it is fixed to the surface of the case 6 parallel to the same axial direction,
Since the incident light is incident on the light receiving surface 11 at an angle of θ1, a signal can be output via the carrier 12.

Further, since light is incident on the light receiving surface 11 at an angle of θ1, the light reflected on the light receiving surface 11 is reflected at an angle of θ1, and the reflected light is coupled to the optical fiber 4 via the lens 3. Without this, noise due to multiple reflection of light can also be reduced.

Embodiment 2 FIG. FIG. 2 is a view showing Embodiment 2 of the present invention, in which 13 is a cemented lens for condensing light,
Reference numeral 14 denotes a hemispherical lens having a refractive index n2 constituting the cemented lens 13, and 15 denotes a refractive index n3 constituting the lens cemented lens 13.
The light receiving element 1 has a carrier 12
And the center axis of the optical fiber 4 and the lens 13
Are arranged on the surface of the case 6 which is parallel to the same axial direction as the central axis of the case 6.

In the figure, a predetermined inclination θ is provided on the light incident surface 10 with respect to the central axis of the optical fiber 4 and the central axis of the lens 13, and a predetermined inclination θ 2 is provided on the bonding surface of the cemented lens 13. . In such a configuration, light supplied from one end of the optical fiber 4 is condensed by the cemented lens 13 and
Light is incident on the light incident surface 10.

Here, since the cemented surface of the cemented lens 13 has an angle of θ2 with respect to the central axis of the optical fiber 4,
The angle θ3 of the light incident on the light incident surface 10 is represented by Expression 2.

[0017]

(Equation 2)

Therefore, the angle θ4 of the light incident on the light receiving surface 11 is equal to the angle θ3 and the angle θ1 obtained in the first embodiment.
And the angle θ3 are added, the angle θ4 of the light incident on the light-receiving surface 11 approaches the light-receiving surface 11 in the vertical direction by this increment, so that the coupling tolerance to the light-receiving surface 11 is increased. Since the optical axis adjustment work can be easily performed with ease, the assemblability is improved.

Embodiment 3 FIG. 3 is a diagram showing a third embodiment of the present invention, in which an optical fiber 4 shown in the second embodiment is used.
FIG. 3 is a diagram in which a predetermined inclination θf is provided at one end on the light receiving element 1 side.

In the figure, a predetermined inclination θ is provided on the light incident surface 10 of the transparent body 5 with respect to the center axis of the optical fiber 4 and the center axis of the lens 13. In such a configuration, light supplied from one end of the optical fiber 4 on the light receiving element 1 side is condensed by the cemented lens 13 and is incident on the light incident surface 10 of the transparent body 5.

Here, since one end of the optical fiber 4 on the light receiving element side is provided with an inclination θf, the refractive index of the optical fiber 4 is set to n4, and the angle θ6 of the light supplied from the optical fiber 4 and the cemented lens Angle θ7 of light emitted from 13
And the angle θ3 when the optical fiber 4 obtained in the second embodiment does not have the inclination θf is obtained by Expression 3.

[0022]

(Equation 3)

Accordingly, the angle θ6 of the light incident on the light receiving surface 11 is the angle θ1 obtained in the first embodiment, the angle θ3 obtained in the second embodiment, and the angle of the light supplied from the optical fiber 4. The angle θ6 of the light incident on the light receiving surface 11 is represented by a function of θ5, and the angle θ6 of the light incident on the light receiving surface 11 is closer to the light receiving surface 11 in the direction perpendicular to the light receiving surface 11 than in the second embodiment. And the optical axis adjustment work can be easily performed, so that the assemblability is improved.

[0024]

According to the first aspect of the present invention, the light incident surface of the transparent body for hermetically sealing the light receiving element is provided with a predetermined inclination, so that the traveling direction of the incident light is bent by this angle, Even if the light receiving element is fixed to a plane parallel to the central axis of the optical fiber and the lens, light can enter, and the light receiving element can be fixed from the top of the carrier or case. No need for a carrier,
Since the work can be performed from the upper surface of the carrier, the number of parts and the number of man-hours can be reduced.

Further, since the light incident on the light receiving element is provided with a predetermined inclination, the reflected light returning from the light receiving surface of the light receiving element is not coupled to the optical fiber, and there is an effect that noise due to multiple reflection is reduced.

According to the second aspect of the present invention, since two types of hemispherical lenses having different refractive indices are used as the lenses to be used, the joining surface angle of the hemispherical lenses and the different refractive indices of the hemispherical lenses are used. Since the traveling direction of light in the lens is further inclined, and the angle of light input to the light receiving surface of the light receiving element approaches the direction perpendicular to the light receiving surface as compared with the first embodiment, the coupling tolerance to the light receiving surface is further increased. As a result, the ease of assembly is improved and the number of man-hours is reduced.

According to the third aspect of the present invention, since a predetermined inclination is provided at one end on the light receiving element side of the optical fiber for supplying light, a predetermined angle is added to the light supplied from the optical fiber. As compared with the second embodiment, the angle of light incident on the light receiving surface of the light receiving element becomes closer to the vertical direction, the coupling tolerance to the light receiving surface is loosened, the assemblability is improved, and the number of steps is reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing Embodiment 1 of an optical receiving module according to the present invention.

FIG. 2 is a diagram showing an optical receiving module according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a third embodiment of the optical receiving module according to the present invention;

FIG. 4 is a diagram showing a conventional optical receiving module.

[Explanation of symbols]

Reference Signs List 1 light receiving element, 2 first carrier, 3 lens, 4
Optical fiber, 5 transparent body, 6 case, 7 second carrier, 8 fiber holder, 9 bonding wire,
10 light incident surface, 11 light receiving surface, 12 carrier, 13
A cemented lens, a hemispherical lens having a refractive index of n2,
15 A hemispherical lens having a refractive index n3.

Claims (3)

[Claims] 1. A light receiving element, a carrier for fixing the light receiving element, a case for fixing the carrier, a transparent body for hermetically sealing the light receiving element, and an optical fiber for supplying light to the light receiving element from one end thereof And, in an optical receiving module including a lens disposed on the same axis as the optical fiber between one end of the optical fiber and the light receiving element, a light receiving surface of the light receiving element is a central axis of the optical fiber. A light receiving module fixed to one surface of the case so as to be parallel and having a predetermined inclination on a light incident surface of the transparent body with respect to a surface perpendicular to a central axis direction of the optical fiber; . 2. A first hemispherical lens having a refractive index n2 and a second hemispherical lens having a refractive index n3 are joined as a lens for condensing light supplied from one end of an optical fiber to a light receiving element. The optical receiving module according to claim 1, wherein a cemented lens is used. 3. The optical receiving module according to claim 1, wherein a predetermined inclination is provided at one end of the optical fiber for supplying light to the light receiving element on the light receiving element side.