JPS61148929A - Communication device - Google Patents

Abstract

PURPOSE:To obtain a communication system with high quality without being affected with external noise between a transceiver mounted on a mobile body and an earth station by using a optical conductor line having a light modulation effect as a space coupling line. CONSTITUTION:The light from a light source 2 supplied to an input terminal of an optical fiber 1 as an optical conductor line having alight modulation effect is subject to linear polarization by a polarizer 3, keeps a linearly polarized wave front and propagates in the optical fiber 1. An analyzer 4 placed at the output end of the optical fiber 1 is placed along with the linearly polarized wave front. An output signal from a transmitter 9 on a mobile body 8 excites an electromagnet 11 via a modulator 10, the excited magnetic field is interlinked with the optical fiber 1 and the polarized wave face is rotated by applying the linearly polarized wave front in the same direction as the propagated direction. The polarizer 4 detects the polarized component corresponding to the rotating angle of the polarized wave face. The detected output is converted into an electric signal by a photodetector 5, demodulated by a demodulator 6, received by a receiver 7, then outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a communication device using a light guide line having a light modulation effect.

<Prior art> Conventionally, an antenna of a transmitting/receiving device mounted on a mobile vehicle is electromagnetically coupled to a spatially coupled line laid on the ground, such as an inductive radio line or a leaky coaxial cable, and the above-mentioned inductive radio line or leaky coaxial cable is electromagnetically coupled. So-called mobile communication, in which τ communication is performed with a ground station connected to a cable, has been widely used.

<Problems to be Solved by the Invention> However, nothing using optical fibers as a terrestrial spatial coupling line has yet been developed.

SUMMARY OF THE INVENTION In view of the above-mentioned prior art, it is an object of the present invention to provide a new communication device using a photoconductor line as a spatial coupling line. The communication device according to the present invention can be widely applied to communication between a mobile object such as a crane vehicle and a ground station, and to conventional guided radio application fields.

<Means for Solving the Problems> A communication device according to the present invention comprises a light guide line having a light modulation effect, a light source provided at the input end of the light guide line, and the light source described above that linearly polarizes light from the light source. A polarizer provided between the input end of the optical conductor line and the optical conductor line, an analyzer provided at the output end of the optical conductor line, a light receiving element for converting the output signal of the analyzer into an electrical signal, and a demodulating element for the light receiving element. a receiving side device consisting of a receiver connected via a transmitter, a transmitter, and an optical modulator connected to the transmitter via a modulator and optically modulating linearly polarized light propagating through the optical conductor line. a side device, the linearly polarized light propagating through the optical conductor line is optically modulated by the signal transmitted from the transmitting side device, and the optically modulated modulation component is detected and received by the receiving side device. It is expressed as a percentage.

<Embodiment> An embodiment of a communication device according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a communication device according to the present invention. In FIG. 1, l is an optical fiber as a light guide line having a light modulation effect, 2 is a light source, 3 is a polarizer, 4 is an analyzer, 5 is a light receiving element, 6 is a demodulator, 7 is a receiver, and 8 9 is a moving body, 9 is a transmitter, 10 is a modulator, and 11 is an electromagnet constituting an optical modulator. The optical fiber used in the communication device according to the present invention is particularly suitable for an optical fiber having a large magneto-optic effect, such as an optical fiber whose core is made of paramagnetic glass having a large Werde constant, such as FR-5 (trade name) manufactured by Hoya Glass Co., Ltd. There is.

Also, instead of optical fiber, BSO has a large magneto-optic effect.
(Bit Sit O!o crystal) or a photoconductor line in which Zn5e elements are arranged in a rod shape.

According to the communication device according to the present invention, the light from the light source 2 entering the input end of the optical fiber 1 is linearly polarized by the polarizer 3, as shown in the drawing. This linearly polarized light is transmitted through optical fiber l.
is input into the optical fiber, and propagates within the optical fiber while maintaining the linear polarization plane. Further, the analyzer 4 placed at the output end of the optical fiber 1 is placed along a polarization plane orthogonal to the linearly polarized light carried in the optical fiber 1. -1 The signal output from the transmitter 9 on the moving body 8 passes through the modulator 10 and excites the electromagnet 11,
The excitation magnetic field is coupled to the optical fiber 1 and applied in the same direction as the propagation direction of the linearly polarized light, thereby rotating the plane of polarization. If the rotation angle is θ, then θ=VH1! V: Guelde constant, H: magnetic field strength of excitation magnetic field.

l: length of action section of the excitation magnetic field on the propagation path. A deflection component is detected by an analyzer 4 provided at the output end of the optical fiber l, and converted into an electrical signal by a light receiving probe 5.
Next, the demodulator 6 demodulates the signal, and the receiver 7 outputs the signal.

Note that the signal format may be an analog signal or a digital signal, and the modulation method may be AM, FM, PCM, etc. depending on the purpose.

Although the above is a light modulation method that uses the magneto-optic effect, it is also possible to similarly modulate light using the electro-optic effect. In the case of an optical modulator that utilizes the electro-optic effect, electrodes 12a, 1 as shown in FIG. 2 are used instead of the electromagnet shown in FIG.
2b is loaded onto the modulator lO. Note that the electrodes 12a, j2b
An electric field due to a modulated signal voltage is applied to the photoconductor line with the photoconductor line in between, thereby rotating the plane of polarization of the linearly polarized light propagating in the photoconductor line. The analyzer 4 detects the optically modulated component, converts it into an electrical signal by the light receiving element 5, and outputs it as a received signal by the receiver 7.

<Effects of the Invention> According to the communication device according to the present invention, one-way communication is possible from the transmitting side device to the receiving side device via the optical conductor line. Compared to conventional guided radio lines, the signal quality is extremely superior as there is no influence from external noise. Furthermore, the line structure is simple, and the line according to the present invention is superior in that it is less affected by dirt on the line.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of a communication device according to the present invention, and FIG. 2 is a block diagram showing the structure of an electrode for excitation of an optical fiber when an electro-optic effect is utilized in a communication device according to the present invention. In the drawing, l is an optical fiber, 2 is a light source, 3 is a polarizer, 4 is an analyzer, 5 is a light receiving element, 6 is a demodulator, 7 is a receiver, 8 is a mobile object, 9 is a transmitter, and 1O is a modulator 11 is an electromagnet, and 12a and 12b are electrodes.

Claims (1)

[Claims] A light guide line having a light modulation effect, a light source provided at the input end of the light guide line, a polarizer provided between the light source and the input end of the light guide line that linearly polarizes light from the light source, and the light guide line. A receiving side device consisting of an analyzer provided at the output end of the line, a light receiving element that converts the detection output of the analyzer into an electrical signal, and a receiver connected to the light receiving element via a demodulator, and a transmitter. and a transmitting side device consisting of an optical modulator connected to the transmitter via a modulator and optically modulating the linearly polarized light propagating through the optical conductor line, and by the signal transmitted from the transmitting side device. . A communication device, wherein the linearly polarized light propagating through the optical conductor line is optically modulated, and the optically modulated modulation component is detected and received by the receiving side device.