JPH0244824A - Light reproduction relaying circuit - Google Patents

Abstract

PURPOSE:To improve reliability by sharing (2n+2) number of light-emitting element groups by means of an up reproduction relaying circuit and a down reproduction relaying circuit. CONSTITUTION:A first switching means 4 transmitting two inputted up and down signals from two output terminals among (2n+2) number of output terminals in correspondence with a first control signal, and a second switching means 6 outputting two optical signals inputted from corresponding terminals among (2n+2) number of input terminals in correspondence with a second control signal are provided. The title circuit is made into redundant constitution in which the light-emitting element groups 5 are shared by the up reproduction relaying part 2 and the down reproduction relaying part 3, and 2n number of standby light-emitting elements are given for two present light-emitting elements. The number of degrees of freedom for selecting the standby light- emitting elements is enlarged compared to a conventional example. Thus, reliability can be improved without increasing cost as the reproduction relaying circuit.

Description

[Detailed Description of the Invention] [Summary] With regard to optical regenerative repeating circuits used in optical communications, the purpose of this invention is to improve the reliability of optical regenerative repeating circuits without significantly increasing the cost. In a regenerative relay circuit that converts the optical signal received in the upstream regenerative relay section and the downstream regenerative relay section into an electrical signal and reproduces it, and then converts it into an optical signal using a working light emitting element each having n preliminary light emitting elements and transmits the signal. , the two input uplink and downlink signals are input (2n
+2) output terminals, the first switching means sends out from two of the output terminals, and the output of the first switching means is (2n
A light emitting element group converts two light emitting elements into optical signals by corresponding two light emitting elements among the +2) light emitting elements, and a second a second switching means that turns on in response to a control signal;
A regenerative relay circuit is provided that transmits a first control signal and a second control signal that control the operations of the first switching means and the second switching means, and connects the (2n+2) light emitting element groups to an upstream regenerative relay circuit. and a configuration in which it is shared by the downlink regeneration relay circuit.

[Industrial application field]

The present invention relates to an optical regenerative repeater circuit used in optical communication.

When performing optical communications, a regenerative repeater is installed on the line. As shown in FIG. 6, this regenerative repeater is constructed by, for example, a plurality of regenerative repeating circuits, each consisting of an upstream regenerative repeating circuit and a downstream regenerative repeating circuit (same configuration as the upstream regenerative repeating circuit), clustered together. The operation of the regenerative repeater will be explained using the operation of the uplink regenerative repeater circuit as an example. That is, after converting the input optical signal into an electrical signal in the light receiving section 11, the attenuated and degraded signal is equalized and amplified in the 2 equalization amplification section 12 to the extent that the presence or absence of the signal can be determined, and a tie is generated and identified. Since it is added to the reproduction section 13, the identification and reproduction section uses this clock to identify and reproduce the equalized and amplified signal. This reproduction signal is transmitted to a light emitting element (for example, a laser diode) 1
6, it is converted into an optical signal and sent out to a transmission line.

Here, in order to improve the reliability of the optical communication system, it is necessary to improve the reliability of the regenerative repeater circuit without significantly increasing the cost.

[Conventional technology]

Due to the remarkable progress of semiconductor technology in recent years, most of the main electric circuit parts have been converted to LSI, and sufficient reliability has been established. However, optical components (especially semiconductor lasers used as 5 light emitting elements) still do not have a sufficient track record. , has become the most dominant component in repeater reliability design. For this reason, in trunk repeaters that require high reliability, two light emitting elements are used.
When the current light-emitting element breaks down due to heavy use, reliability is ensured by switching to a backup light-emitting element.

FIG. 7 shows a block diagram of a conventional example (redundant configuration light emitting part).

In the figure, the signal discriminated and reproduced by the discrimination and reproduction section 13 is transmitted to a currently used light emitting element (for example, a semiconductor laser).

After being converted into an optical signal by the LD 16 (hereinafter abbreviated as the working LD), the signal is sent out to the transmission line via the a-b of the optical switch 18. At this time, the three spare LDs 16' are in a cold standby state.

Here, when the optical output of the working LD falls below a predetermined value, the monitoring/control section 14 in FIG. 6 drives the optical switch 18 to the connection state shown by the dotted line, and also turns on the spare LD 16''. Therefore, the optical output of the spare LD 16'' is sent to the transmission line.

That is, the LD is duplicated, and even if the working LD 16 fails, the optical switch 18 switches to the spare LD 16' to ensure reliability.

[Problem to be solved by the invention]

Here, since the regenerative relay circuit is configured independently for uplink and downlink, when the LD is configured in the redundant configuration shown in Figure 7,
Only one spare LDL is provided for one working LD. Therefore, if both the active and standby LDs in the uplink regenerative relay circuit or the downlink regenerative relay circuit fail, communication will be interrupted.

In other words, communication is interrupted even though two LDs out of the four LDs of the two regenerative relay circuits are normal. Of course, if the number of spare LDs is increased to two or three, the probability that communication will be interrupted will be reduced, but there is a problem in that the cost of the regenerative repeater will increase.

An object of the present invention is to improve the reliability of an optical regenerative repeater circuit without significantly increasing cost.

[Means to solve problems]

FIG. 1 shows a block diagram of the principle of the present invention.

In the figure, 4 is a first switching means that sends out two input upstream and downstream signals from two output terminals out of (2n+2) output terminals in response to the second control signal. The first
This is a light emitting element group in which the output of the switching means is converted into an optical signal by corresponding two light emitting elements among the (2n+2) light emitting elements.

Further, 6 is a second switching means that outputs two optical signals inputted from corresponding terminals among the (2n+2) input terminals in response to a second control signal, and 7 is a second switching means for outputting two optical signals input from corresponding terminals among the (2n+2) input terminals, and 7 is a second switching means for outputting two optical signals input from corresponding terminals among the (2n+2) input terminals. and a control means for sending out a first control signal and a second control signal for controlling the operation of the switching means and the second switching means.

[Effect]

In the present invention, the light emitting element group 5 is shared by the upstream regenerative relay section 2 and the downstream regenerative relay section 3, and 2n
The degree of freedom in selecting a preliminary light emitting element is increased compared to the conventional example by using a redundant configuration having several preliminary light emitting elements. As a result, the reliability of the regenerative relay circuit can be improved without significantly increasing the cost.

A comparison of the reliability when the redundant configuration of the conventional example and the redundant configuration of the embodiment of the present invention are adopted is described in the section of the embodiment.

〔Example〕

FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is an explanatory diagram of the operation of FIG. 2.

Here, the switch 41 is a component of the first switching means 4,
The LDs 51 to 54 are constituent parts of the light emitting element group 5, the optical switches 61 to 64 are constituent parts of the second switching means 6, and the controller 71
1 shows the constituent parts of the control means 7. Note that the same reference numerals indicate the same objects throughout the figures. Hereinafter, the operation of FIG. 2 will be explained with reference to FIG. 3 as n-1.

In addition, the controller 71 sends switching signals that should not be sent to the switch 41 and the optical switches 61 to 64 when all the LDs are normal, when one LD is out of order, and when two LDs are out of order. is stored in advance.

Therefore, when an LD fails, the corresponding switching signals are read out and these control signals are used to control the switches 41.61-64.

(1) When 1 and D are all normal (see Figure 2), the regenerated 2 from the upstream regenerative relay section 2 and the downlink regenerative relay section 3
The two signals are converted into optical signals by one of the four LDs by the operation of the switch 41, D53.
Optical switch 61.6 is connected to the uplink through 53 b-d.
It is sent to the downlink via No. 4 a to c. Here, thick lines indicate signal paths.

(2+ If LD 53 is out of order (see Figure 3 (a))) LD 51 is operating normally, so for the downlink (1
) is the same as the term. The regenerated uplink signal is converted into an optical signal by the LD 54 by the operation of the switch 41, and then transmitted through bC of the optical switch 62 operating in cross mode and b-d of optical switch 63 operating in parallel mode. Sent to the uplink.

(If 31LD 53.54 is out of order (see Figure 3 (bl)) LD51 is in normal operation, so for the downlink (1
) is the same as the term. The regenerated uplink signal is converted into an optical signal by the operation of the switch 41 at 1 and D52, and then the optical switch 61 operating in parallel mode and the optical switch 63 operating in cross mode are indicated by thick lines. The signal is transmitted to the uplink as shown.

Next, FIG. 4 is a block diagram of another embodiment of the present invention, in which the optical switches 63 and 64 in FIG. 2 are replaced with optical combiners 63 and 64 degrees, and the function for signals is the same.

Now, FIG. 5 shows a reliability comparison diagram of FIGS. 2 and 7.

First, Fa+ in Fig. 5 is a case of the redundant configuration of the LD shown in Fig. 7, that is, a 1:1 redundant configuration for both the uplink and downlink, and the condition that communication is not possible unless both the uplink and downlink are normal. This is a diagram for determining reliability.

Now, if the LD failure rate is F, then the probability that both the active and backup LDs will fail in the uplink or downlink is F2, so the probability that they will not fail is (1-F2)
becomes. If we include the condition that both the uplink and downlink are normal, the reliability R1 of al becomes R+-(1 to F2)2 . . . ■ in FIG. 5.

In the case of fbl in FIG. 5 of the embodiment, if two of the four LDs are normal, communication is possible on the uplink and downlink, so the reliability R2 is R2=(1-F)' +4CIF(1-F) 3+4. C
2F2(1-F)2-(1-F)2(1+2F+3F"
) ・ ・ ・■. Therefore, from formula 0 and formula 0.

Therefore, the reliability of the embodiment is higher than that of the conventional example.

That is, the reliability of the optical regenerative repeater circuit can be improved without significantly increasing the cost.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a block diagram of an embodiment of the invention, Fig. 3 is an explanatory diagram of the operation of Fig. 2, and Fig. 4 is a block diagram of another embodiment of the invention. , FIG. 5 is a diagram for explaining the reliability comparison between FIG. 2 and FIG. 7, FIG. 6 is a block diagram of a regenerative relay circuit, and FIG. 7 is a block diagram of a conventional example. In the figure, 2 is an upstream regenerative relay section, 3 is a downstream regenerative relay section, 4 is a first switching means, 5 is a light emitting element group, 6 is a second switching means, and 7 is a control means. [Effects of the Invention] As described above in detail, the present invention has the effect that the reliability of the optical regenerative repeater circuit can be improved without significantly increasing the cost.

Claims (1)

[Claims] After converting the received optical signal into an electrical signal and reproducing it in the uplink regenerative repeater section (2) and the downlink regenerative repeater section (3), which have the same configuration, n each (n is a positive integer) In a regenerative repeater circuit that converts into an optical signal and transmits it using a working light emitting element having a preliminary light emitting element, two input up and down signals are sent to one of the (2n+2) output terminals corresponding to the first control signal. A first switching means (4) transmits output from two output terminals of the first switching means (4), and the output of the first switching means is transmitted to the corresponding two of the (2n+2) light emitting elements.
a light emitting element group (5) that converts into optical signals with (2n+2) light emitting elements, and outputs two optical signals input from corresponding terminals among the (2n+2) input terminals in response to a second control signal. a second switching means (6), a first control signal for controlling the operation of the first switching means and the second switching means;
A control means (7) for transmitting a control signal of relay circuit.