JPH0257030A - Optical signal communication equipment - Google Patents

Abstract

PURPOSE:To improve transmission efficiency by measuring the length of a lead-in wire and controlling the sending timing of an optical signal sent to a normal system based on such a measuring result. CONSTITUTION:An optical taper fiber coupler is used for coupling with an optical bus 11. For example, the optical signal of a constant wavelength is sent from an optical transmitter OS to a lead-in wire 152a coupled through an optical taper fiber coupler 122 to an optical bus 112. This optical signal is folded by the optical taper fiber coupler 122, transmitted in a lead-in wire 152b and received by an optical receiver OR. Then, a transmission time from the transmission of the optical signal to the reception of the signal is counted. Accordingly, when the sending timing of the optical signal sent to a lead-in wire 151a of the normal system is controlled based on the measuring result of the lead-in wires 152a and 152b in an auxiliary system, the optical signal can be securely loaded during an idle time on an optical fiber line 111. In such a case, since the measurement of the lead-in wire is executed in the auxiliary system, the transmission efficiency can be improved.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Industrial Application Field) This invention relates to optical signal communication in which a large number of optical transceiver stations are connected to an optical bus, and each optical transceiver station communicates with optical signals. Regarding equipment.

(Prior art) A conventional optical signal communication device is equipped with an optical tap that branches and merges optical signals on an optical bus, and connects the optical tap and an optical transmitting/receiving station via a drop-in line. There is a method for optical communication between optical transmitting and receiving stations. In this system, the transmission efficiency of the communication system is determined by the length of the drop-in line from the optical tap to the optical transmitting/receiving station.

By the way, in the method using optical taps as described above, if the branching ratio of the optical tap is small and most of the light passes on the bus, the optical tap cannot erase the input optical signal, so generally A communication method based on a polling method is adopted. This polling method is a method used for optical signal transmission in which multiple optical transmitting/receiving stations share an optical bus, and it scans other transmitting/receiving stations to find available free time for transmission. This method identifies stations and communicates via an optical bus.

In the case of this polling method, the transmission efficiency depends on the scale of the network, and particularly on the maximum distance between the polling station and other stations.

In order to improve transmission efficiency, there is a method of measuring the length of the optical fiber between the polling station and other stations, and adjusting the signal sending timing of each station based on the measurement results. At this time, the optical fiber length can be measured by measuring the propagation time of the optical signal or vice versa. However, in either method, measurements must be taken at regular intervals, requiring measurement time during which communication is not possible, and a significant improvement in transmission efficiency cannot be expected.

(Problem to be solved by the invention) As mentioned above, the conventional optical (≦) communication device adopts the communication (,; system) which is based on the polling method, and uses the optical fiber length between the polling transmitter and receiver. Even if the signal transmission timing is adjusted, the length must be measured at appropriate intervals, so it is not expected to improve the transmission efficiency much.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide an optical signal communication device that can significantly improve transmission efficiency.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, an optical signal communication device according to the present invention is provided with first and second optical fiber lines, one for regular use and the other for general use. an optical bus serving as a standby system, and the first and second optical buses;
a pair of two-input, two-output optical taper fiber couplers to be installed at substantially the same location on an optical fiber line; a pair of drop-in wires each having one end connected to the pair of optical taper fiber couplers; and the pair of drop-in wires. an optical transceiver station that is connected to the other end of the optical fiber line and transmits and receives optical signals to and from the regular optical fiber line by selecting one of the drop-in lines; Send an optical signal of a certain wavelength to the drop-in line, measure the transmission time from sending out until it is returned and received by the optical taper fiber coupler, and calculate the length of the drop-in line from the wavelength and transmission time of the optical signal. A drop-in line a+++ length means for measuring the length of the drop-in line a+++, and an adjusting means for adjusting the sending timing of the optical signal to be sent to the regular system based on the length of the drop-in line obtained by this means (iif
It is composed of i.

(Function) In the optical signal communication device having the above configuration, the optical bus is composed of first and second optical fiber lines 17, one of which is used as a regular system and the other as a standby system. A pair of 2-input, 2-output optical taper fiber couplers is installed at almost the same location on the first and second optical fiber lines, and each optical taper fiber coupler has a -
The transmitting and receiving stations are coupled via a χ·1 lead-in line. This transmitting/receiving station selects one of the drop-in lines and transmits and receives optical signals to and from the regular optical fiber line. At this time, an optical signal of a certain wavelength is sent to the drop-in line connected to the backup system, and the transmission time from sending out to being returned and received by the optical taper fiber coupler is measured. Measure the length of the lead-in line from the wavelength and transmission time of the optical signal [7
Based on this measurement result, the timing of transmitting the optical signal to the regular system is adjusted.

Well, the length of the drop-in line affects the transmission efficiency of polling transmission and reception, so measure only the length of the drop-in line and adjust the transmission timing based on the measurement result. By doing so, it is possible to eliminate collisions between optical signal merging and colliding by the optical tapered fiber coupler. In addition, since a backup system is used to measure the length of the lead-in wire, there is no need to secure measurement time.

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

FIG. 1 shows its configuration, and 11 is an optical bus.

This optical bus 11 is connected to the first and second optical fiber lines II+
, 11.2, one is for regular use and the other is]
'rR system. First and second optical fiber lines 111. , 112 arbitrary locations (here, 3 locations a
A pair of two-input, two-output optical taper fiber couplers 121 and 122 are located at approximately the same positions in -C).

131, 132, 141, 142 are installed,
Each coupler 121 , 122 , 131 , 132 , 1
41 and 142 each have a pair of lead-in wires 151a,
151b, 152a, 152b, 161a.

161b, 1B2a, l02b, 1.71
The optical receiver OR and the optical transmitter O8 of the optical transmitting/receiving station 18.19.20 are coupled via the optical transmitter/receiver station 18.19.20 via the optical transmitter/receiver station 18.19.20.

The optical taper fiber couplers 121 and 122 (the same applies to other coupler parts) are connected to the main optical fiber A that forms part of the optical fiber lines 1.11' and '112, as shown in FIG. It consists of a sub-optical fiber B which is partially coupled to this main optical fiber A, and an optical transmitter O8 of the optical transmitting/receiving station 18 is coupled to the optical converging side via lead-in lines +51a and 152a, and to the optical branching side. is the lead-in line 151b
, 152b to the optical receiver OR of the optical transceiver station 18. That is, the optical signal sent out from the optical transmitting/receiving station 18 is partially branched by the optical taper fiber couplers 121 and 122, and is returned to the optical transmitting/receiving station 18 again.

On the other hand, the optical transmitting/receiving station 18 includes an optical taper fiber coupler 1.
An optical signal of a certain wavelength is sent to the drop-in line 152a which is coupled to the standby optical bus 112 via the optical fiber coupler 122, and the optical signal is returned by the optical taper fiber coupler 122 until it is received. It is equipped with a length measurement function that measures the transmission time and the length of the drop-in line based on the wavelength of the optical signal and the transmission time. Furthermore, an adjustment function is provided to adjust the sending timing of the optical signal sent to the regular system based on the length of the lead-in line obtained by this function.

That is, in the optical signal communication device having the above configuration, focusing on the fact that the length of the lead-in wire affects the transmission efficiency of polling transmission and reception, an optical tabular fiber coupler is used for coupling with the optical bus 11, and for example, Optical taper fiber coupler 1
An optical signal of a certain wavelength is sent from the optical transmitter O8 to the drop-in line 152a which is connected to the standby optical bus 112 via the optical transmitter O8. This optical signal is transmitted through the drop-in line 152a, turned back by the optical taper fiber coupler 122, transmitted through the drop-in line 152b, and received by the optical receiver OR. Therefore, the transmission time from when an optical signal is transmitted until it is received is measured.

That is, if the transmission time is measured as described above, the length 152a of the drop-in line between the backup optical fiber line 112 and the transmitting/receiving station 18 is determined based on the wavelength and transmission time of the optical signal.
152b can be determined by calculation. Here, the length of the drop-in lines 1.51a, 151b between the optical fiber line 111 of the regular system and the transmitting/receiving station 18 is approximately equal to the length of the drop-in lines 152a, 152b connected to the protection system. Therefore, the standby system lead-in lines 152a, 152
By adjusting the sending timing of the optical signal to be sent to the regular service drop-in line 151a based on the length measurement result of b, the optical signal can be reliably placed in the free time on the optical fiber line 111. This also applies to the other transmitting/receiving stations 19 and 20.

At this time, the length of the lead-in wire is measured using a preliminary system, so
There is no need to secure measurement time as in the conventional method. For this reason, transmission efficiency can be improved in a stratified manner. especially,
Since each optical transmitting/receiving station performs length measurement and transmission timing adjustment by itself, it has the advantage that it does not interfere with communication between other stations.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide an optical signal communication device that can significantly improve transmission efficiency.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an optical signal communication device according to the present invention, and FIG. 2 is a diagram showing a part of the same embodiment. 11... Optical bus, 111, 112... Optical fiber line, 121, 122, 131, 132, 14
1, 142... optical taper fiber coupler, 151a
, 151b, 152a, 1521),
161a. IBlb, 182a, I[i2b, 171
a, 171b, 172a, 172b... drop-in line, 18.19.20... optical transmitting/receiving station, OR...
- Optical receiver, O8... optical transmitter. Applicant's agent Patent attorney Takehiko Suzue] O

Claims (1)

[Claims] Equipped with first and second optical fiber lines, one for regular use,
An optical bus with the other as a standby system, a pair of 2-input and 2-output optical taper fiber couplers installed at substantially the same location on the first and second optical fiber lines, and one optical taper fiber coupler, one of which is attached to each of the pair of optical taper fiber couplers. a pair of drop-in lines whose ends are joined; and a pair of drop-in lines whose ends are coupled to the other end of the pair of drop-out lines;
An optical transceiver station that selects one drop-in line and sends and receives optical signals to and from the regular optical fiber line, and an optical signal of a fixed wavelength that is installed at this optical transceiver station and sends an optical signal of a fixed wavelength to the drop-in line that is connected to the protection line. , a drop-in line length measuring means for measuring the transmission time from sending out to being folded back and received by the optical taper fiber coupler, and measuring the length of the drop-in line from the wavelength and transmission time of the optical signal; and this means An optical signal communication device comprising: adjusting means for adjusting the sending timing of an optical signal to be sent to a regular system based on the length of the lead-in line obtained in .