JPH07283425A - Light transmission/reception module - Google Patents

Abstract

PURPOSE:To receive light with smaller number of openings than the number of openings of an optical fiber by the optical fiber by spreading the spacing between a transmission IC including a light emission element and an optical fiber incidence end face as compared with the spacing between a reception IC and the optical fiber irradiation end face. CONSTITUTION:Second and fourth lead pins 6 of a transmission side IC1 are bent forward by the lead pitch and first and third lead pins 6 of a reception side IC3 are bent backward, thus shifting a light emission surface 4 and a light reception surface 5 of an IC forward or backward by the width of lead pitch of the lead pins 6 without changing the width and row of the lead pitch. Therefore, since a fiber end face 8 of a connector 7 in one piece for transmission and reception is mated to a same surface for both transmission and reception sides by a gap 9 for achieving the same height, the light emission surface 4 of the transmission side IC and the fiber end face 8 are spaced. By increasing the distance between the optical fiber incidence end face of the transmission IC and the optical fiber irradiation end face of the reception IC, light with a smaller number of openings than the original number of openings of optical fibers can be taken into the optical fiber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transceiver module, and more particularly to a bidirectional optical transceiver module incorporating a light emitting element and a light receiving element.

[0002]

2. Description of the Related Art As a conventional transmission / reception integrated bidirectional optical communication transmission module, for example, there is one proposed by Japanese Patent Laid-Open No. 3-58637. This module
The light-receiving surface of the light-receiving element is positioned by lowering the light-receiving surface of the light-receiving element backward by an appropriate value. As a result, the light receiving elements are not interfered with by the light for transmission emitted from the light emitting elements forming the same group, and erroneous detection and erroneous operation for optical communication can be prevented at low cost.

Further, the one proposed in Japanese Patent Application Laid-Open No. 2-222227 has a light collecting element such as a convex lens between the light emitting element and the light receiving element to efficiently transmit the light from the light emitting element to the light receiving element. However, the light amount of the light emitting element is reduced.

[0004]

The transmission band is determined by the characteristics of the optical fiber used, and in order to realize a wider transmission band with the existing optical fiber, the transmission distance should be shortened or the band must be shortened. The only option was to use wide optical fibers. An object of the present invention is not to select an optical fiber having a numerical aperture smaller than that of an existing optical fiber to widen the transmission band, but to provide a structure capable of supporting wider band transmission by other methods. is there.

[0005]

In order to achieve the above object, in the present invention, first, as a means for realizing wideband transmission, the distance between a transmitting IC including a light emitting element and an incident end face of an optical fiber is set to a receiving IC and an optical fiber. By widening the gap between the fiber emission end faces, light with a numerical aperture smaller than the original numerical aperture of the optical fiber can be taken into the fiber, thus solving the above problems. As a result, it is possible to reduce the numerical aperture of light on the incident end face of the optical fiber and consequently widen the transmission band.

[0006]

According to the above structure, the receiving IC is formed by bending the lead pin of the transmitting / receiving IC including the light emitting / receiving element.
The distance between the transmission IC and the optical fiber incident end surface is made wider than the distance between the optical fiber emitting end surface and. As a result, light is input to the optical fiber with a numerical aperture smaller than the original numerical aperture of the optical fiber. Since light is transmitted in the optical fiber according to the input numerical aperture, it is equivalent to the case where an optical fiber having a smaller numerical aperture is used, and as a result, the transmission band is improved.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. The same reference numerals indicate the same parts.

FIG. 1 is a cross-sectional view of the transmission / reception integrated bidirectional optical transmission module as viewed from above. Here is the sending IC
The light-emitting surface (4) and the light-receiving surface (5) of the receiving-side IC (3) covered by (1) and the receiving-side IC shield case (2) are facing leftward.

The lead pin (6) of the transmitter IC is shown in FIG.
As shown in (a) and (c), it is bent into a half-pitch pattern and has a zigzag arrangement as shown in FIG.

Consider the case where the transmission / reception integrated connector (7) is inserted from the left side in the structure of FIG. Here, the transmitting side IC (1) is I as shown in FIGS.
The second and fourth lead pins (6) from the left as viewed from the front of C are bent forward by the lead pitch. On the other hand, the receiving side I housed in the shield case (2)
As for C (3), as shown in FIGS.
The first and third lead pins (6) from the left as viewed from the front of C are bent backward by the lead pitch. Therefore, it is possible to shift the light emitting surface (4) and the light receiving surface (5) of the IC forward or backward by the width of the lead pitch of the lead pin (6) without changing the width or row of the lead pitch.

As a result, the transmission / reception integrated connector (7)
Fiber end face (8) of connector (7) when inserted
Due to the gap (9), the transmitting side and the receiving side have the same height on the same surface, that is, the front surface (the light receiving surface (5) of the receiving side IC in FIG. 1), so that the transmitting side IC
A gap is created between the light emitting surface (4) of the fiber and the end surface (8) of the fiber. As a result, the numerical aperture of the light that is taken into the optical fiber can be reduced, and as a result, a structure that can support wideband transmission can be obtained.

Also, when bending the lead pin (6),
By reversing the direction of the light emitting surface (4) or the light receiving surface (5) of the IC, it is possible to form the respective bending directions of the lead pins of the transmitting / receiving IC including the light emitting / receiving element using the same lead pin molding jig. .

Further, as shown in FIG. 3, the numerical aperture of the light received by the light receiving surface (5) is set at a distance between the end face (8) of the optical fiber and the IC (3) on the receiving side, and the output aperture of the actual optical fiber is calculated. Even if the number is smaller than the number, a structure capable of supporting wideband transmission can be realized only by mechanical operation as in FIG.
Further, as shown in FIG. 4, the same effect can be obtained even with a structure in which a space is provided between both the light emitting surface (4) and the light receiving surface (5) of the transmitting / receiving IC including the light emitting / receiving element and the end face (8) of the optical fiber. .

FIG. 5 shows an example of a correlation diagram between the distance between the light emitting surface and the fiber end surface and the band. From this figure, it can be seen that the numerical aperture of the light taken into the optical fiber decreases and the band increases by increasing the distance. It is understood that provision of a space of about 1 mm can be realized to obtain a band of 10 MHz.

FIG. 6 shows an example of the application of the present invention. Here, the ferrule (13) is inserted in the structure of FIG. 1, and the connector surface (8) is aligned with this surface on both the transmitting and receiving sides by the gap (9) provided on the transmitting side. However, when the connector is attached, the ferrule spring (12)
When there is a margin, the receiving-side connector surface can be slightly moved back and forth within this range of the allowable amount of the spring (12). FIG. 6 shows an example in which the receiving side connector surface is pushed inward until it comes into contact with the shield case (2) by the force of the spring (12). At this time, since the receiving side ferrule (13) is inside, the gap (9) between the transmitting side IC light emitting surface (4) and the connector side (8) is made smaller than the IC lead pitch. be able to. In this way, the distance of the gap (9) can be made smaller than the lead pitch of the IC or, conversely, made larger. Furthermore, when the ferrule (13) is a metal ferrule, the ferrule (13) itself can be grounded by directly contacting the shield case (2), and a structure with excellent noise resistance can be realized. it can.

[0016]

As described above, according to the present invention, the distance between the transmitting IC including the light emitting element and the optical fiber incident end surface is made wider than the distance between the receiving IC including the light receiving element and the optical fiber emitting end surface to the optical fiber. The numerical aperture of the light to be taken in can be made smaller than the numerical aperture of the original optical fiber, whereby a structure capable of supporting wider band transmission can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of claim 1 of the present invention.

FIG. 2 is a structural diagram showing an embodiment of the present invention.

FIG. 3 is a sectional view showing an embodiment of claim 2 of the present invention.

FIG. 4 is a sectional view showing an embodiment of claims 1 and 2 of the present invention.

FIG. 5 is a graph showing a correlation between a gap length and a band according to claim 1.

FIG. 6 is a cross-sectional view showing an application example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Transmitting side IC, 2 ... Shield case, 3 ... Receiving side IC, 4 ... Transmitting side IC light emitting surface, 5 ... Receiving side IC light receiving surface, 6 ... Lead pin, 7 ... Transmission / reception integrated connector, 8 ... Connector surface, 9 ... IC surface-connector surface gap, 10 ... Receptacle housing, 11 ... Fiber, 12 ... Spring, 13 ... Ferrule.

Claims (2)

[Claims] 1. A light emitting element, a transmitter IC in which a drive circuit for the light emitting element is housed in a package, and a receiver IC in which a light receiving element and a signal processing circuit for the light receiving element are housed in a package, and when fitted with an optical fiber. In a receptacle that optically separates a transmission IC and a reception IC, an optical transmission / reception module, characterized in that the distance between the transmission IC and the end face of the optical fiber is made larger than the distance between the reception IC and the end face of the optical fiber. 2. As a means for providing a space according to claim 1, a transmitting or receiving IC whose lead pins become lead pins of the entire module when incorporated in a module is used, and the bending direction of the lead pin is called a transmitting IC. An optical transmission / reception module having a structure in which the means can be obtained only by mutually reversing in a receiving IC.