JPH0244893A - Optical exchange - Google Patents

Abstract

PURPOSE:To simplify constitution by providing an optical channel with a laser diode optical gate matrix switch provided with a distributing connection function and a photo-electric conversion function. CONSTITUTION:A communication control signal sent from s subscriber is inputted to the optical channel 1-1 as it is, and is detected by the photo-electric conversion function of an optical gate element in an optical matrix, and the optical channel 1-1 is controlled by this detection information, and simultaneously, the information is distributed to plural subscribers by the distributing connection function of optical matrix switches 1-21, 1-22. Namely, the optical gate element to constitute the optical matrix switches 1-21, 1-22 comes to fulfil two duties of an photo-electric conversion operation and a distributing connection operation. Thus, an exclusive light receiving element, etc., for signal detection need not be provided, and parts become useless, and an economical exchange can be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an optical switch, and particularly relates to an optical switch that exchanges optical signals as they are in a service that distributes the same information to multiple subscribers. be.

[Conventional technology]

The optical switching system was introduced into switching equipment with the development of the optical fiber transmission system, and by incorporating it into the communication path system, high-speed and broadband switching becomes possible. The next step will be to incorporate it into control systems. Note that optical exchange is described, for example, in "Electronic Information and Communication Handbook, II 63.3.30, published by Ohmsha Co., Ltd., pp. 2] 72-2] 73.

FIG. 2 is a diagram showing the arrangement of communication control receiving devices in an optical exchange.

In optical switching equipment, two types of systems are considered for devices that receive communication control signals, ie, calling signals, dialing signals, etc. sent from subscribers, depending on their location.

One is to place it on the subscriber side of the communication path, as shown in Figure 2(a), and the other is to place it on the subscriber side of the communication path, as shown in Figure 2(a).
As shown in b), this is a method of arranging it on the trunk line side of the communication path. In addition, a pair such as a videophone], (end-
For connection type services (to-end), any of the above-mentioned arrangement methods can be used. However, in one-to-many (center-to-end) connection type services such as video distribution services (for example, CATV services), since multiple subscribers are connected to one information source, communication control signals are relayed. If received on the line side, signals from multiple subscribers overlap, making reception impossible. Therefore, in order to receive communication control signals for subscribers, a signal receiving device must necessarily be placed on the subscriber side of the communication path. In Fig. 2(a) and (b), 2-1-1-2-1.3 is the subscriber side terminal to which the subscriber terminal is connected, and 2-21 to 2-23 are the terminals for optical signals. It is an optical splitter for branching 2-41 to 2-
43 is a relay side terminal to which a relay line is connected.

FIG. 3 is a diagram showing the arrangement of communication control signal receiving devices in a conventional optical switch.

In FIG. 3, 3-3 is an optical communication path using an optical gate matrix switch, 3-7 is a control device for controlling each switch of the optical communication path 33, and 321 to 3-23 are data optical signals. An optical splitter for branching the optical signal of the control signal, 3-51 to 353 are light receiving elements for receiving the optical signal and converting it into an electric signal, and 3-6 is for receiving the control signal of the electric signal. , a receiving electrical circuit that transfers this to the control device.

In a conventional optical switch, as shown in FIG.
-3, for example, laser diode optical cable 1 hema I.
Optical communication elements such as a RX switch were used, and no optical circuit was used in other parts, for example, the control device 3-7. Therefore, the optical signals, which are control signals such as calling signals and dialing signals sent through the subscriber line, are branched by the optical splitters 3-21 to 3-23, and sent to the light receiving element 3-5.
1 to 3-53, it was necessary to convert the light into an electrical signal and then input it to the control device 3-7.

[Problem to be solved by the invention]

As described above, in conventional optical switching equipment, it was necessary to branch signals from subscribers using an optical branching device, and convert the signals into electrical signals using a light-receiving element. However, this method requires as many light-receiving elements and optical splitters as there are subscribers, which increases the amount of expensive optical components used and increases the cost I of the system.

An object of the present invention is to solve such conventional problems and provide an economical optical switching device that uses fewer optical components.

[Means to solve the problem]

In order to achieve the above object, the optical switch of the present invention performs a light-to-electrical conversion operation in an optical switch that distributes the same information to a plurality of subscriber terminals, and also allows an optical signal to pass through when a current is injected. An optical communication path using a matrix switch of a laser diode light gate that blocks optical signals if not injected, and a control device that controls opening and closing of the optical communication path and monitors the status of a plurality of subscriber terminals. , detects the communication control signal sent from the subscriber by the optical-to-electrical conversion operation of the laser diode light gate in the matrix match, and transmits this to the control device, which controls the communication control signal as described above. It is characterized by controlling the opening and closing of the optical communication path and transmitting the same information to a plurality of subscriber terminals through the optical gate opened by the optical 71-RIX switch.

[For production]

In the present invention, a communication control signal sent from a subscriber is directly input into the optical communication path, is detected by the photoelectric conversion function of the optical gate element in the optical 7 trix, and the detected information is used to connect the optical communication path. At the same time, information is distributed to multiple subscribers using the distribution connection function of the optical matrix switch.

That is, the optical gate element constituting the optical 7-trix switch performs two roles: photoelectric conversion operation and distribution connection operation. This eliminates the need to provide a dedicated light-receiving element or the like for signal detection, and eliminates the need for parts, making it possible to realize an economical exchange.

〔Example〕

The principles and embodiments of the present invention will be explained in detail below with reference to the drawings.

FIG. 4 is a diagram showing the operating principle of the present invention.

FIGS. 4(a) and 4(b) are diagrams showing the configuration of the laser diode 1, the optical device, and the elements that are the constituent elements of the optical group 1 to multi-helix switch. In Figure 4, 4-1.4
--3 is an optical waveguide, 4-2 is a laser diode optical gate, which is a laser diode coated with an antireflection film on both end faces, and 4-4 is an oscilloscope.

The switching operation principle of the optical gate to the laser diode-1 is described, for example, in the document W Switch L to the laser diode-1 (M
, Ikeda, “La5erdiode st+j
tch”E], electronics 1etters
vol, 17. pp, 899-900.1981)
is described in detail. That is, switching of the optical signal utilizes the amplification effect due to stimulated emission and the absorption effect due to stimulated absorption of the laser diode. When an appropriate current is injected into the laser diode-1 gate, the gate operates as an optical amplifier and passes the optical signal (ON state). Furthermore, when no current is injected, the gate acts as an absorber and blocks optical signals (OFF state). In the left diagram of FIG. 4(a), a current is injected into the laser diode gate 4-2, and the input light is optically amplified and output. Further, in the right diagram of FIG. 4(a), no current is injected, so the input light is absorbed, resulting in an FF state.

In addition, in FIG. 4(a), input light enters the laser diode light gate 4-2 from the left side, and output light is output from the right side, but the structural symmetry of the laser diode light gate 4-2 is Depending on the characteristics, it is of course possible to input the input light from the right side and output the output light from the left side. Thereby, when bidirectional communication is performed using one optical fiber, it is possible to simultaneously switch the light that enters the laser diode light gate from both sides.

In addition, since the laser tie switch 1 has a photovoltaic effect based on the PN junction, it is possible to detect optical signals using this (for example, see the document "Signal of Laser Diode Optical Switch"). Monitoring characteristics J (M, I keda
,Signal-monjtoring char
actorjsties for 1aser-d
jode optical swGches'.

IEEE Journal], of Lj4ht
wave Technol, ogy.

vol, LT-3, pp, 909-913.1.985
reference). In other words, when light exceeding the bandgap of the PN junction is incident, an electromotive force corresponding to the power of the incident light is generated between the PN poles, so the laser diode optical gate 1~switch can also be operated as an optical-to-electrical converter. Can be done.

In FIG. 4(b), when input light is input, an electromotive force corresponding to the power of the incident light is generated in the laser diode gates 1-4 and -2, and this is extracted and displayed by an oscilloscope 4-4.

FIG. 5 is a block diagram of an optical gate matrix switch whose basic components include a laser diode 1 to optical gate 1 switch.

The matrix for the optical game 1 generally has an NXM (M, N are positive integers) configuration, but in FIG. 5, it is shown as a 4X4 matrix switch for simplicity. In Figure 5, 5-11 to 514 are entry lines, 5-21
~5-24, and 5-31 to 5-38 are optical splitters, 5
-4] ~ 5-56 are optical gates, 5-61 ~ 5-68 and 5-71 ~ 5-74 are optical combiners, 5-81 ~ 5-84
is the outgoing line. In addition, 4×4 laser diode light source 1~
As an example of a matrix switch, for example, the document "Silica-based optical waveguide 71 - matrix switch" (A, Hi
meno el al,,”Sj,1],ca-b
ased opticalw a v e (5u
i d e m a t r i x s w j
, tclzo, proceedj, ng o
fSPTE Dj, gj, tal optica]
, computing, 752. pp.

48-55.1987).

For optical goo 1 to matrix switch, input 5-11 to 5
-14 and outgoing lines 5-81 to 5-84 are light games 1-5-41 to
5-56, and if you want to connect a certain incoming line and outgoing line, you just need to inject a current into the corresponding optical gate to turn it on.

In this way, by constructing an optical communication path using the optical gate matrix shown in FIG. 5, it is possible to easily realize a distributed connection service in which the same information is distributed to a plurality of subscribers.

In addition, in the optical case, by utilizing the optical-to-electrical conversion function of the laser diode optical gate 1-1 mentioned above, the optical signal entering from each input line is converted to the optical gate coupled to the input line. It is possible to detect each incoming line. Now, when the signal from the subscriber is input from the incoming line,
For example, consider a case where a calling signal, dialing signal, etc. are input from a subscriber line. The optical signal power input from each input line is branched into four in the 4x4 switch, and each
be guided by As a result, by monitoring changes in the terminal voltages to the corresponding optical gates 1, it is possible to detect communication control signals sent from subscribers.

In this way, the present invention provides a laser diode optical game device 1 having a distributed connection function and an optical-to-electrical conversion function.
By applying a 71-MARIX switch to an optical communication path, it becomes possible to realize distributed connection of optical signals and optical-to-electrical conversion of communication control signals using the same 71-RIX switch. As a result, it is no longer necessary to use dedicated optical components for signal reception as in the past, and an economical optical switch can be realized. In Fig. 5, the incoming line and outgoing line are distinguished for simplicity, but as mentioned above, due to the structural symmetry of the laser diode light gate, it is possible to input a signal from the outgoing line and receive a signal from the incoming line. Even if you output it, the same operation will occur. Furthermore, an optical branching device and an optical multiplexer are structurally completely the same, and their names are simply distinguished based on the direction in which the optical signal travels.

FIG. 1 is a block diagram of an optical switch showing an embodiment of the present invention.

In Figure 1, 1-1 is an optical communication path, 1-21.1-2
2 is an optical gate matrix switch, 1-3 is a switch drive/signal receiving circuit, 1-4 is a control device, 1-5
1 to 1-58 are subscriber side terminals, codes 61 to 1-64 are optical branching devices, and 1-71 to 1-74 are information center side terminals. That is, the subscriber terminal is connected to an optical exchange via an optical fiber, and the exchange is further connected to a news center via a trunk optical fiber. Subscribers connected to this information center can receive various services, such as message services,
You will receive seat reservation service, calculation service, answering machine service, etc.

``No.'' In the figure, to simplify the explanation, the number of terminals on the subscriber side is 8, the number of terminals on the information center side is 4, and the number of optical terminals is 1.
Although the number of Rx switches is two and the number of input/output terminals of the optical gate matrix and Rix switch is four each (4×4 switches), these numbers can be expanded or decreased to any number.

Hikari Goo 1 ~ Matritus Switch 1. -21.1722 uses the optical-to-electrical conversion function of the optical gate to receive communication control signals (service request signals, channel selection signals, etc.) from subscribers that enter from the subscriber side terminals +-51 to 1-58. It is converted into an electrical signal and sent to the switch drive/signal receiving circuit 1-3. The switch drive/signal receiving circuit 1-3 converts the electrical signals sent from the optical switches 1 to 1-21.1-22 into an appropriate signal format and sends them to the control device 14. Control device]-4 is a switch drive/
Based on the signal sent from the signal receiving circuit]-3, the request from the subscriber is analyzed and a control signal for controlling the optical switch is sent to the switch driving/signal receiving circuit 1-3. The switch drive/signal receiving circuit 1-3 generates a drive current based on the optical switch control signal sent from the control device 1-4, and operates the optical switch 1-matrix switch 1-21.1-.
22 and turning ON or OFF the optical game 1, a desired terminal among the information center side terminals 1-71- to 1-74 is connected or disconnected from the subscriber terminal. This allows each subscriber to selectively call up a desired information center by performing an operation exactly similar to changing television channels. Note that the optical branching devices 1-61 to 1-64 route information signals input from the information center to a plurality of optical gate matrix switches 1-64.
21. It has the function of distributing to 1-22.

Furthermore, in the case of a distributed connection service, even after a subscriber is connected to a desired information center, it is necessary to constantly monitor the subscriber line in order to change the connection destination and monitor the end of a call. In such a case, the optical gate connecting the subscriber and the information center is turned on.
in a state. Therefore, although the signal detection sensitivity of game 1~ is reduced, it is sufficient for the remaining three optical gates (in the case of 4x47 trix switches) in the FF state connected to the same subscriber terminal. By using these three detection voltages, it is possible to constantly monitor communication control signals from the subscriber even while the subscriber is connected. Furthermore, these O
It is also possible to improve the detection sensitivity by adding the detection voltages of the three optical gates 1 to 1 in the FF state.

In this embodiment, only a video distribution type connection service has been explained, but a videophone type (end-to-end) connection service that connects subscribers one to one can also be applied using laser diode light. Since it is possible to receive communication control signals by the Ge1-71 helix switches, it is possible to realize an optical switch in exactly the same way as a video distribution type connection service.

〔Effect of the invention〕

As described above, according to the present invention, the distribution and connection operation of optical signals is achieved by applying a laser diode optical gate camera i. Since the optical-to-electrical conversion operation of communication control signals and communications control signals can be performed using the same matrix switch, there is no need to use dedicated optical components for signal detection as in the past, and the same information can be transmitted to multiple subscribers. It is possible to economically realize an optical switching system that distributes information to individuals.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an optical switch showing an embodiment of the present invention, Fig. 2 is a diagram showing a method of arranging communication control signal receiving devices in the optical switch, and Fig. 3 is a diagram showing communication control signal reception in a conventional optical switch. A diagram showing the arrangement of the device, Figure 4 shows the laser diode
1 - Operation principle diagram of optical gate element, FIG. 5 shows laser diode optical gate 7 trix switch 1-1, l-3.3-3: Optical communication path, 1-21. 1-22: Optical gate matrix switch, 1--3
: Switch drive/signal receiving circuit, 1-4. , 2-6. 3-7 two control devices, 1-51~i-58.2-11~2
-13.3-11 to 3-13: Subscriber side terminal, 1-61
~>64-, 2-21-2-23.321-3-23.
5-31 to 5-38: Optical splitter, 1-7"--1-7
4. : Information center side terminal, 2-5 double signal receiving device, 2
-41~2-/1 3.3-4 1~3-43: Relay side terminal, 4-1.4-3: Optical waveguide, 4-2: Laser diode optical gate, 4-4 Nioscilloscope, 5- 61
~5-68.5-71~5-74: Optical multiplexer, 5-1
1-5-1 4. : Incoming line, 5-82 to 5-84.
: Departing line. Figure (Part 1) (a) Method of placing it on the subscriber line side Figure (Part 2) (b) Method of placing it on the trunk line side

Claims (1)

[Claims] (1) In an optical switch that distributes the same information to multiple subscriber terminals, a laser diode light that performs optical-to-electrical conversion operation and allows the optical signal to pass when current is injected, and blocks the optical signal when no current is injected. It is equipped with an optical communication path using a matrix switch of a gate, and a control device that controls the opening and closing of the optical communication path and monitors the status of a plurality of subscriber terminals. Detecting by the optical-to-electrical conversion operation of a laser diode light gate in the switch and transmitting this to the control device,
An optical switching system characterized in that the control device controls the opening and closing of the optical communication path and transmits the same information to a plurality of subscriber terminals through the opened optical gate of the optical matrix switch.