JPS5820042A - Information transmitting method - Google Patents

Abstract

PURPOSE:To realize transmission of information economically which is free from the electromagnetic induction, by making an optical pulse incident to each of the optical delay elements consisting of plural optical fibers of different lengths and connecting these optical delay elements to an optical fiber for transmission. CONSTITUTION:An optical pulse 5 is synchronously made incident to optical fibers 4 of different lengths, and these fibers are conneced to an optical fiber 7 forming a transmission line via a coupler 6. The receiving terminal of the fiber 7 detects the optical pulse which is transmitted in time division via a photodetector 8. For instance, the different images are made incident to the incident pulse by means of a lens array as the optical pulse to be transmitted via a transmission line. Thus the information on the different images can be received at a terminal. In such way, plural types of information can be transmitted with just an optical fiber to obtain an economical optical sensor which is free from the external electromagnetic induction and has high reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information transmission method using an optical delay element composed of a plurality of optical fibers of different lengths.

Optical fibers for communications are designed to have a small refractive index difference between the core and cladding in order to reduce transmission loss and secure as much transmission bandwidth as possible. Generally, the smaller the refractive index difference, the less the pulse spread, and therefore broadband transmission is possible. As shown in the characteristic diagram of Figure 1, this characteristic is as follows: The input optical pulse 2 with the length L of the optical 7 eyeper ''IK is added to the input optical pulse 2, and the pulse spread of the output optical pulse 3 at the terminal is 13 m, which is the arrival time t. It is expressed as a numerical formula that shows its characteristics.

Notynax=ΔnL/C Δn is the refractive index difference between the core and cladding of the optical fiber mentioned above.

L is the length of the optical fiber, and C is the speed of light in vacuum. Seven-
The maximum value of pulse broadening due to optical dispersion is proportional to the refractive index difference between the core and cladding of the optical fiber, and proportional to the length of the optical fiber. Therefore, by using the characteristic that the delay time of optical pulses differs depending on the length of the optical fiber, it is used as a delay element, and by arranging a plurality of such delay elements, various information is transmitted as input optical pulses to a remote location, and the light is received at a terminal. It is received by the device as an output optical pulse. For example, as shown in the block diagram of FIG.
The information from the seven speakers, B, C, and D is input into the optical fiber, and the delay elements AD, BD, CD, which have different optical fiber lengths,
The output pulses forming Pm, pgPc, and Pn are sent to the photoreceiver R,,R, via DD.

R, , R4 in a time-division manner. The configuration is easy and the light 7
By using AIPA, information can be transmitted without being affected by electromagnetic induction noise from the outside, but since multiple optical cables are required, the cost of laying cables increases especially when transmitting to remote locations. In view of the above points, the object of the present invention is to provide an information transmission method in which a number of optical fibers are combined into a single optical cable for multiplexing, and the amount of optical sudden change is detected in a time-division manner.

The above object is an information transmission method of arranging a plurality of optical fibers of different lengths to form an optical delay element, and optically transmitting the amount of change for each sensor inputted to the optical delay element via a sensor device. , an information transmission method in which skeleton optical fibers are coupled into a single optical fiber via 1:n coupling couplers, and at the output end of the optical fiber, the amount of change for each sensor is detected in a time-sharing manner by a light receiver. A light pulse from one optical fiber is input into each optical fiber of an optical delay element, which is made up of a plurality of optical fibers of different lengths, and the output from the optical delay element is coupled into one fiber through a coupler. This is accomplished by nine information transmission methods, in which optical pulses are detected in a time-division manner at the output end of the optical fiber.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a block diagram showing an information transmission method using an optical seven-eyeper which is an embodiment of the present invention. As shown in the figure, optical pulses 5 are synchronously injected into optical fibers 4 of different lengths, and are coupled via a coupling coupler 6 to an optical fiber 7 forming a transmission path.
The light is detected in a time-division manner by the light receiver 8 at the terminal. For example, a lens array is used for an incident pulse to make different images incident as light pulses, and the information on the different images can be received and detected at a terminal by transmitting them via a transmission path. In this way, multiple pieces of information can be transmitted with one optical 7-eyeper, making it economical.
A highly reliable optical sensor that is less susceptible to external electromagnetic induction can be obtained.

FIG. 4 is a block diagram showing a card reading device using an optical fiber, which is an applied example of FIG.

When the card 11 is inserted between the lens arrays 9 and 10 for collimating F and a light pulse (λ to F) is emitted from the light source 12, it is transmitted to the transmission line 1 via the coupling coupler 13 as shown in FIG.
4, and the information A' to n of the card 11 is transmitted by the terminal light receiver 15 to B' to nB'C' to nCI...
-Can read p/~nF'.

FIG. 5 is a block diagram showing another embodiment of the present invention.

In the figure, a single optical fiber (21) is branched into 7-eye optical fibers 22 of different lengths, information for each fiber 22 is detected by a sensor 23, and then connected to a single optical 7-eye optical fiber 24 via a coupler 2s. The time-divided information can be obtained by the optical receiver 26 at the terminal.

By providing branching, coupling, and detection circuits in this way,
Only one optical fiber can be used for remote transmission, making economical information transmission possible.

Figures 6(a) and 6(b) show a block diagram (a) and a data recording diagram (b) showing data transmission of a wind vane using an optical fiber, which is an applied example of FIG. 5. It is an optical fiber device that includes a rotary disk 28 that rotates integrally with a blade plate 27, converts it into a parallel beam by a detection lens 29 forming a lens array, and transmits the direction of the wind via a light receiving lens 30.

The optical fiber 31 is passed through the spectrometer 32' to 4g as shown in the figure.
The light beams are branched into seven eyeglasses 33 with different lengths, passed through lens arrays 29 and 30, and then coupled to a single optical fiber 35 via a coupler 34 for remote transmission. Detect. The data information corresponds to the slit 37 provided in the rotary disk 28, and since the light receiver 36 can detect a pulse code corresponding to the rotation angle, the wind direction is detected by obtaining data as shown in FIG.

By using the transmission method of the present invention, it is possible to perform remote transmission with a single half-fiber, which has the effect of making it possible to transmit excellent information without having to rely on electrical transmission, which is rumored to be economical.・

[Brief explanation of drawings]

Fig. 1 is a diagram showing the characteristics of an optical fiber, Fig. 2 is a diagram showing a conventional information transmission method, Fig. 3 is a Plutz diagram showing an embodiment of the present invention, and Fig. 4 is an application example of Fig. 3. Figure 6 is a block diagram showing another practical example of the present invention, and Figures (A) and (B) in Figure 6 are application examples of Figure 5. It is. In the figure, 1, 4, 7.14, 21, 22, 24°31.3
3.31$ is the optical fiber, 2.5cm is the input optical pulse, 3 is the output optical pulse, 3m is the pulse spread, 6.13, 25
．． 34 is a coupler, 8.15°26.36 is a receiver, 32
27 is a spectroscope, 27 is a blade plate, 2B is a rotary desk, 29 is a detection lens, 30 is a light receiving lens, and 37 is a transmitted light attenuator.

Claims (1)

[Claims] (1) In an information transmission method in which a plurality of optical fibers of different lengths are arranged to form optical delay elements with different delay times, the output of the optical delay element is is coupled to a single optical fiber via a coupling coupler, and the output (2) of the optical pulse from the single optical fiber is input to each optical fiber of an optical delay element consisting of multiple optical fibers of different lengths. and the output from the optical delay element is coupled to a single optical fiber via a coupling coupler, and the optical noculus is detected in a time-division manner at the output end of the optical fiber. Transmission method.