JPS5928115A - Photocoupler - Google Patents

Abstract

PURPOSE:To adjust always the quantity of light to an optimum operation range, by providing a damping filter, which can be inserted and replaced through a lens, between an optical semiconductor element and an optical fiber. CONSTITUTION:When a connector plug 12 is inserted to a receptacle 11 of a photocoupler 6, the emitted light of an optical semiconductor element 7 is condensed onto the end face of the connector plug 12 by a distributed index lens 8 for photo coupling and is connected to an optical fiber 1 and is carried. A damping filter 9 for adjusting the quantity of light is arranged between the optical semiconductor element 7 and the receptacle 11 besides the distributed index lens 8, and this damping filter 9 can be inserted and replaced from the outside of the photocoupler 6. Consequently, the damping filter 9 which gives the damping quantity of a proper quantity of light in accordance with the loss of an optical transmission system is inserted to adjust the quantity of light to a proper operation range of an optical receiver.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical coupler, and more particularly to an optical coupler between an optical semiconductor element and an optical fiber used in optical fiber communication.

Generally, optical fiber communication is comprised of an optical transmitter that converts an electrical signal into an optical signal, an optical fiber that is a transmission path for the optical signal, and an optical receiver that converts the optical signal into an electrical signal. The optical receiver is designed to operate optimally under a certain amount of received light, and is usually set to operate with the smallest possible amount of light. The amount of light that reaches the optical receiver varies depending on the system, such as the length of the optical fiber used, various characteristic parameters of the optical fiber, and the type of light source. Therefore, if a large amount of light is incident on the optical receiver that exceeds the appropriate operating range, it is necessary to reduce the amount of light transmitted from the optical transmitter side or to lower the gain of the optical receiver. It was necessary to change and adjust the circuit constants of the device. For this reason, some optical receivers have a built-in automatic gain control circuit within a certain range, but it is not effective against large fluctuations in the amount of light, and it is not recommended to add such a circuit. The drawback was that it was expensive.

Now, as a conventional optical coupler for this building, the one shown in FIG. 1 is known. FIG. 1 is a schematic structural perspective view showing an optical coupler for adjusting the amount of transmitted light used in conventional optical fiber communication. In Figure 1, ' r la
l ib is an optical fiber, 2 is an optical transmitter, 3 is an optical attenuator, 4 is an optical receiver, and 5 is an optical connector. In the configuration shown in FIG. 1, the amount of light is not adjusted in the optical transmitter 2 and the optical receiver 4, but in the middle of the optical fiber 1.
The amount of light is adjusted by inserting an optical attenuator 3 having an amount of attenuation corresponding to the power within the optical fiber 1. However, in order to insert the optical attenuator 3 in the middle of the optical fiber 1, it is necessary to newly insert another optical fiber 1a or 1b.
There are several disadvantages, such as the need to prepare an optical attenuator 3 and the perspective of the space for arranging the optical attenuator 3.

The present invention has been made in order to eliminate the drawbacks of the conventional ones as described above, and includes an optical coupler for coupling an optical semiconductor element and an optical fiber. It has a configuration that includes an attenuation filter that can be inserted and replaced, and even if the amount of light fluctuates due to changes in external conditions such as the length of the optical fiber, the amount of attenuation of light is changed accordingly. The object of the present invention is to provide an optical coupler that can be constantly adjusted to an optimal operating range.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a schematic perspective view showing an optical coupler according to an embodiment of the present invention. In Fig. 2, 1 is an optical fiber, 6
7 is an optical coupler, 7 is an optical semiconductor element, 8 is a gradient index lens, 9 is an attenuation filter, 10 is a slide plate for fixing this attenuation filter 9, 11 is a receptacle, and 12 is a connector plug.

Next, the process shown in FIG. 2 will be explained. When the connector plug 12 is inserted into the receptacle 11 of the optical coupler 6 shown in FIG. The light is focused on the end face of the connector plug 12 by an optical lens (an optical lens may also be used), and the light is focused on the end face of the connector plug 12.
Combined and transported. Here, an attenuation filter 9 for adjusting the amount of light is arranged between the optical semiconductor element 7 and the receptacle 11 outside the gradient index lens 8, and this attenuation filter 9 is inserted from the outside of the optical coupler 6. , configured to be exchangeable. Therefore, by inserting an attenuation filter 9 that provides an appropriate amount of attenuation of the amount of light depending on the loss of the optical transmission system, it is possible to adjust the amount of light within the appropriate operating range of the optical receiver (not shown in FIG. 2). can.

Note that when the semiconductor laser, which is the optical semiconductor element 7, is used as a light emitting element, the optical output is adversely affected by the return light due to reflection, so the optical transmission is It is desirable to arrange the attenuation filter 9 obliquely to the path.

Furthermore, in the above embodiment, a case was explained in which a light emitting element such as a semiconductor laser or a light emitting diode is used as the optical semiconductor element 7 of the optical coupler 6, but the optical semiconductor element 7 is used as a light receiving element such as a photodiode, and an optical fiber It is also possible to appropriately adjust the amount of light that has propagated through 1 on the light receiving side, and the same effect as in the above embodiment can be achieved.

As described above, the optical coupler according to the present invention has a structure in which an attenuation filter that can be inserted and replaced via a lens is provided between the optical semiconductor element of the optical coupler and the optical fiber. Even if the amount of light fluctuates due to changes in external conditions such as the length of the optical fiber, the attenuation filter changes the amount of light attenuation accordingly, making it possible to always adjust to the optimal operating range. This has excellent effects in that it can be made inexpensive with a simple structure, and extremely accurate products can be obtained.

[Brief explanation of drawings]

Fig. 1 is a schematic structural perspective view showing an optical coupler for adjusting the amount of transmitted light used in conventional optical fiber communication;
The figure is a schematic perspective view showing an optical coupler that is an embodiment of the present invention. 1......Optical fiber, 6......
Optical coupler, 7... Optical semiconductor element, 8...
...Gradient index lens, 9...Attenuation filter, 10...Slide plate, 11...
・−・・Receptacle, 12・・・・・・・Connector plug. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Agent Makoto Kuzuno - Figure 1 Figure 2

Claims (3)

[Claims] (1) An optical coupler for coupling an optical semiconductor element and an optical fiber is provided with an attenuation filter that can be inserted and replaced via a lens between the optical semiconductor element and the optical fiber. An optical coupler characterized by: (2) The optical coupler according to claim 1, wherein the optical semiconductor element is a light emitting element such as a semiconductor laser or a light emitting diode. (3) The optical coupler according to claim 1, wherein the optical semiconductor element is a light receiving element such as a photodiode.