JPH04216224A - Optical transmission equipment - Google Patents

Abstract

PURPOSE:To easily change the output level of an optical signal without exchanging parts or the like and further to present the optical transmission equipment having high economization and reliability concerning the optical transmitter used for maintaining the optical transmission equipment or the like. CONSTITUTION:An optical signal generating means 3 is provided to generate the optical signal, and an optical fiber 10 is provided to transmit the optical signal inputted from the optical signal generating means 3. Then, an optical signal branching means 12 is composed of the optical fiber 10 and an optical fiber 11 for branching deposited to the above-mentioned optical fiber 10 so as to transmit the optical signal transmitted in the optical fiber 10 after branching it at a low distribution rate, and optical fiber cable connecting means 20 and 21 are provided at the respective optical output terminals of the optical fiber 10 and the optical fiber 11 for branching so as to connect those fibers to an optical fiber cable 30.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transmitter used for maintenance of optical transmission equipment.

With the recent development of optical communications, various optical transmission devices have become necessary for maintenance and operation of optical transmission devices.

[0003] Such an optical transmitter is connected to the transmitting end side of an optical propagation path that is subject to maintenance, but the optical signal transmitted within the optical fiber is attenuated in accordance with the transmission distance. Therefore, the optical signal level is high on the receiving side where the transmission distance is short, and the optical signal level is low on the receiving side where the transmission distance is long.

However, since the allowable reception level range on the optical receiver side has a certain limited width, it is necessary on the optical transmitter side to adjust the level of the optical signal to be sent out according to the transmission distance.

[0005] Therefore, it is generally considered that the output level from the optical transmitter is prepared to be large enough to support long-distance transmission, and when the transmission distance is short, the output level is attenuated in the optical transmitter. There is.

[0006]

[Prior Art] In a conventional optical transmitter, if necessary, the input end of an optical fiber cable is connected to the
By connecting optical attenuators in series to attenuate the level of passing light, the level of the optical signal input to the optical fiber cable is attenuated.

For example, in the case of long-distance transmission, a laser diode for generating an optical signal and an optical fiber cable are directly connected with an optical fiber, and the high-level optical signal output from the laser diode is directly transmitted. When inputting to an optical fiber cable and the transmission distance is short, connect an optical attenuator with an attenuation rate corresponding to the transmission distance between the optical fiber and the optical fiber cable, and adjust the output level to the permissible reception level of the optical receiver. I lowered it to the range and was transmitting.

[0008]

[Problems to be Solved by the Invention] As mentioned above, conventional optical transmitters have a structure that uses an optical attenuator with an attenuation rate that corresponds to the transmission distance, so various optical attenuators that correspond to the transmission distance are prepared. Must. However, since optical attenuators are relatively expensive, preparing a large number of them as maintenance parts poses a significant economic burden.

Furthermore, since it is necessary to attach and detach the optical attenuator to the optical connector each time it is used, it is time-consuming to prepare the optical attenuator, and at the same time, even slight differences in the connection between the optical attenuator and the optical connector may cause attenuation. The rate was easy to change, and the characteristics tended to be unstable.

Furthermore, since the optical attenuator has a large number of parts and is easily damaged by impact, etc., there is a high possibility of failure and low reliability.

The present invention eliminates such conventional drawbacks, and provides an optical transmitter that can easily change the output level of an optical signal without replacing parts, and is highly economical and reliable. The purpose is to provide.

0012

[Means for Solving the Problems] In order to achieve the above object, an optical transmitter according to the present invention is provided as shown in FIG.
As shown in FIG. 2, an optical signal generating means 3 for generating an optical signal, an optical fiber 10 for transmitting the optical signal inputted from the optical signal generating means 3, and light transmitted within the optical fiber 10. an optical signal branching means 12 consisting of a branching optical fiber 11 fused to the optical fiber 10 so as to branch and transmit signals with a small distribution ratio; and optical fiber cable connecting means 20, 21 provided at each optical output end of the branching optical fiber 11.

[0013] Also, the optical fiber connecting means 20, 23
, 24 may be provided, and a plurality of the optical signal branching means 12, 15, 16 may be provided so that the levels of the optical signals outputted from each of them are different from each other.

[0014]

[Operation] The optical signal generated from the optical signal generating means 3 is transmitted through the optical fiber 10 and branched by the branching optical fiber 11 of the optical signal branching means 12 at a small distribution ratio. As a result, the optical signal is branched at a large distribution ratio by the optical signal branching means 12, a high level optical signal is output from the optical output end of the optical fiber 10, and a low level optical signal is output from the optical output end of the branching optical fiber 11. An optical signal is output.

Therefore, if either of the optical fiber cable connecting means 20, 21 provided at the optical output end of the optical fiber 10 and the branching optical fiber 11 is selected and the optical fiber cable 30 is connected, the transmission distance can be adjusted according to the transmission distance. The optical fiber cable 30 can output an optical signal with a higher output level.

[0016] Also, optical fiber connecting means 20, 23, 2
At least three optical signal branching means 12 are provided, and the optical signal branching means 12 is arranged so that the level of the optical signal outputted from each of them is different from the other.
, 15, and 16, it is possible to output optical signals in three or more levels.

[0017]

[Embodiment] An embodiment will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the invention. In the figure, reference numeral 1 denotes an optical transmission unit used for maintenance of an optical transmission device, and each component is attached to a unit plate 2.

3 is a laser diode for oscillating laser light. 4 is a drive circuit for driving the laser diode 3 to perform an oscillation operation. 7 is the main body (not shown)
This is an electrical connector connected to the main body, and electrical signals from the main body are input to the drive circuit 4 via this electrical connector 7.

The drive circuit 4 outputs a drive current to the laser diode 3 in response to an electrical signal input from the main body via the electrical connector 7. The oscillation operation of the laser diode 3 is controlled by the drive current input from the drive circuit 4, and the oscillation operation of the laser diode 3 is controlled by the drive current inputted from the drive circuit 4.
Bm) is outputted from the output end of the laser diode 3.

The output end of the laser diode 3 is connected to the input end of an optical fiber 10.
A high-level optical signal is transmitted within.

A branching optical fiber 11 is fused in the middle of this optical fiber 10, and a so-called fusion type optical coupler 12 is formed there.

This fusion type optical coupler 12 connects the optical fiber 1 by heating or chemically treating the branching optical fiber 11.
It is formed by fusing to 0.

The fused optical coupler 12 thus formed
The optical signal transmitted through the optical fiber 10 can be branched to the branching optical fiber 11 side with a low distribution ratio with almost no loss, and the remaining optical signal can be transmitted as is through the optical fiber 10.

In the fusion type optical coupler 12 of this embodiment, the high-level optical signal transmitted within the optical fiber 10 is
Branching optical fiber 11 for 90% of optical fiber 10 side
It is set to be distributed at a rate of 10%.

[0026] Here, the output level of the optical signal oscillated from the laser diode 3 is set to, for example, 0 dBm, and the distribution ratio of the fusion type optical coupler 12 is set to 9:1, but the permissible reception level on the optical receiver side You can freely set these according to your needs.

The output end of such a fusion type optical coupler 12,
In other words, the output end of the optical fiber 10 and the branching optical fiber 11
First and second optical connectors 20 and 21 are attached to the output end of the optical connector.

The first and second optical connectors 20 and 21 are
Optical fiber cable 30 for transmitting optical signals over long distances
The output end face of the optical fiber 10 or the branching optical fiber 11 and the input end face of the optical fiber cable 30 can be aligned and connected.

In the apparatus of the embodiment configured as described above, high-level maintenance (
An optical signal of 0 dBm) is oscillated from the laser diode 3, transmitted through the optical fiber 10, and connected to the fusion type optical coupler 12.
is input.

The high-level optical signal that approaches the fusion type optical coupler 12 is distributed to the output side optical fiber 10 of the fusion type optical coupler 12 and the branching optical fiber 11 at a distribution ratio of 9:1. 9 to 1 for the first and second optical connectors 20 and 21
Output at a rate of .

Therefore, the optical connector 3 of the optical fiber cable 30 is connected to the first optical connector 20 of the optical transmission unit 1.
1, high-level optical signals (e.g. -0.46
dBm) is output to the optical fiber cable 30, and the optical signal transmitted from the optical transmitting unit 1 can be received within the permissible reception level range on the long-distance transmission receiving side.

On the other hand, if the optical fiber cable 30 is connected to the second optical connector 21 of the optical transmission unit 1, a low level optical signal (eg -10 dBm) is output to the optical fiber cable 30, so short distance transmission is possible. On the receiving side, the transmitted optical signal can be received within the acceptable reception level range.

FIG. 2 shows a second embodiment of the present invention, in which a second branching optical fiber 10 is fused to a first branching optical fiber 11 similar to the first embodiment described above. The third branching optical fiber 14 is further fused to the first branching optical fiber 11, and the first and second branching optical fibers 13 are fused.
and forming third fusion type optical couplers 12, 15, 16,
The distribution ratio of each of the fusion type optical couplers 12, 15, and 16 is set to 9:1.

Then, first and second optical connectors 20 and 23 are attached to each output end of the optical fiber 10 on the output side of the second fusion type optical coupler 15 and the second branching optical fiber 13, and A third optical connector 24 is attached to the output end of the third branching optical fiber 14 of the third fusion type optical coupler 16.

Therefore, in this embodiment, by selecting one of the first to third optical connectors 20, 23, 24 and connecting the optical connector 31 of the optical fiber cable 30, the transmission distance can be adjusted according to the transmission distance. , high level (e.g. -0.92dBm), medium level (e.g. -10.46dBm)
Three types of maintenance optical signals can be transmitted to the receiving side: low-level (eg, -20 dBm) and low-level (for example, -20 dBm).

In the above embodiment, an example was shown in which the present invention was applied to an optical transmitter for maintenance, but the present invention is not limited to this and can be applied to other optical transmitters. Furthermore, instead of the laser diode 3, a light emitting diode or the like may be used. Furthermore, the method of connecting each optical fiber is not limited to the method of the second embodiment, but can take various forms.

[0037]

[Effects of the Invention] According to the optical transmitter of the present invention, since the optical signal branching means is formed by fusing the branching optical fiber to the optical fiber, it is possible to easily branch the optical signal with a large distribution ratio. Since optical signals with greatly different levels are output to the plurality of optical output ends separated by this optical signal branching means, the optical fiber cable is connected to one of the optical fiber cable connection means provided at these output ends. By connecting these, it is possible to easily output an optical signal at a level corresponding to the transmission distance to the optical fiber cable without replacing any parts or the like.

Furthermore, since the optical signal branching means has a simple structure in which a branching optical fiber is fused to an optical fiber, it can be manufactured at low cost, has no failures, and has stable characteristics.
Excellent economy and reliability.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment.

FIG. 2 is a block diagram showing a second embodiment.

[Explanation of symbols]

3 Laser diode (optical signal generating means) 10 Optical fibers 11, 13, 14 Branching optical fibers 12, 15, 1
6 Fusion type optical coupler (optical signal branching means) 20, 21,
23, 24 Optical connector (optical fiber cable connection means) 30 Optical fiber cable

Claims (2)

[Claims] Claim 1: Optical signal generating means for generating an optical signal (
3), an optical fiber (10) for transmitting the optical signal input from the optical signal generating means (3), and an optical signal transmitted within the optical fiber (10) that is branched at a small distribution ratio and transmitted. an optical signal branching means (comprised of a branching optical fiber (11) fused to the optical fiber (10) so as to
12), the optical fiber (10) and the branching optical fiber (1) for connection to the optical fiber cable (30).
An optical transmitting device characterized in that it has optical fiber cable connecting means (20, 21) provided at each optical output end of (1). Claim 2: The optical fiber connection means (20, 23, 2
4), and a plurality of the optical signal branching means (12, 15, 16) are provided so that the levels of the optical signals outputted from each of them are different from each other. Optical transmitter.