JPH0293525A - Direct transmission system for light image information - Google Patents

Abstract

PURPOSE:To transmit light image information directly with high resolution under no influence of disturbance by constituting the light image direct transmission system by using one multimode optical waveguide, and connecting a neural network to a photodetecting element arranged on the reception side. CONSTITUTION:An incident light signal 6 from a light signal source 2 is entered and propagated in the multimode optical waveguide 1, and the projection light signal 7 from the multimode optical waveguide 1 is guided to the arrayed photodetecting elements 3. In the multimode optical waveguide 1, the propagation constant is different by modes and the coupling state among the modes changes owing to disturbance, so the neural network 4 is connected right behind the arrayed photodetecting elements to prevent the change in the coupling state. An electric signal 9 is, therefore processed in the neural network 4 and an output signal 10 is obtained from an output port 5. Consequently, high- resolution reception is enabled, there is no disturbance to the multimode optical waveguide, and light image information can be transmitted directly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a technology for directly transmitting optical image information using an optical waveguide, and in particular to a system for directly transmitting optical image information using a multimode optical waveguide. be.

[Prior Art] Conventional technologies for directly transmitting optical image information using optical waveguides and the problems they have will be described below.

(a) Bundle fiber transmission This is a method that bundles many optical fibers and transmits one pixel of optical image information for each optical fiber, thereby producing one complete optical image as a whole. It is a method of transmission. This requires a large number of optical fibers corresponding to all the pixels that make up the image, and it is also necessary to prepare an optical fiber bundle in which they are regularly arranged.
Image quality is degraded by the degree of coupling between optical fibers.
The problem was that the transmission distance could not be increased.

(b) Transmission in which image information is replaced with wavelength information This is a method in which a wavelength is assigned to each pixel of an image to be transmitted, and the image information is replaced with wavelength information and transmitted using a single optical waveguide. This has problems, such as the need for optical components for wavelength fractionation, the need for an irradiation light source with a wide spectral width, or the need for a light emitting element array with different emission wavelengths for each element.

(C) In a transmission multimode optical waveguide in which mode phase compensation is performed by phase conjugation, the phase constant differs for each mode. Therefore, if an attempt is made to directly transmit optical image information, the image pattern will change with distance. The transmission that performs mode phase compensation by phase conjugation is a method in which a phase conjugate element is inserted in the middle of a multimode optical waveguide, and the phase inversion effect of this element is used to cancel out the phase change before and after the element. be. In principle, this makes it possible to reproduce the same image pattern at the output end of the multimode optical waveguide as at the input end. This method requires a special optical component called a phase conjugate element, the characteristics of the multimode optical waveguides before and after the element must match, and the multimode optical waveguide is easily affected by disturbances. There were some problems.

(d) Transmission in which image information is replaced with propagation angle information. This involves assigning the propagation angle of the optical signal propagating in the multimode optical waveguide to each pixel of the image to be transmitted, and replacing the optical image information with propagation angle information. It is a method of transmission. In this method, a plurality of light receiving elements are used to independently receive optical signals for each propagation angle at the output section of a multimode optical waveguide. The propagation angle of light within the multimode optical waveguide corresponds to the propagation mode. Therefore, this method has problems in that the existence of mode conversion makes high-resolution reception difficult and that the characteristics of the multimode optical waveguide are significantly degraded due to disturbances.

[Problems to be Solved by the Invention] Therefore, an object of the present invention is to provide a transmission system using a multimode optical waveguide that has high resolution and can directly transmit optical image information without being affected by disturbances. The aim is to provide a system.

[Means for Solving the Problems] In order to achieve such an object, the present invention provides a multimode optical waveguide capable of simultaneously transmitting a plurality of modes, a photodetecting element array capable of detecting the intensity distribution of light, and the like. , a neural network, guides and propagates an optical image information signal from one end of the multimode optical waveguide to the multimode optical waveguide, and outputs light from the other end of the multimode optical waveguide. The present invention is characterized in that an image information signal is guided to a photodetection element array, an electrical signal obtained from the photodetection element array is coupled to a neural network, and an optical image information output signal is extracted from the neural network.

Here, the neural network has a plurality of input ports that receive electrical signals obtained from the photodetector array;
a plurality of processing means, including an addition processing means that weights and adds signals from the plurality of input ports, and a nonlinear processing means that performs nonlinear processing on the signals from the addition processing means;
The apparatus may be configured to include wiring means for interconnecting a plurality of processing means.

[Function] The present invention configures an optical image information direct transmission system using one multimode optical waveguide, connects a neural network to a light receiving element array arranged on the receiving side, and thereby,
Optical image information is directly transmitted using a single multimode optical waveguide. In contrast, in conventional optical image information direct transmission systems using multimode optical waveguides, the neural network is not connected to the light receiving element array placed on the receiving side.
The output signal from the photodetector array element was used as is.

[Examples] Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows one embodiment of the invention. Here, 1 is a multi-wire optical waveguide, 2 is an optical signal source, 3 is an arrayed light receiving element,
4 is a neural network, and 5 is an output port. The optical signal source 2 may have a one-dimensional distribution of light intensity, or may have a two-dimensional distribution of light intensity. In the arrayed light receiving element 3, a plurality of light receiving elements may be distributed one-dimensionally, or may be distributed two-dimensionally. Further, 6 is an incident optical signal emitted from the optical signal source 2, and 7 is an output optical signal output from the multi-wavelength optical waveguide. 8 is a plurality of connections connecting the arrayed light receiving element 3 and the neural network 4; 9 is an electrical signal obtained by the optical-to-electric conversion function of the arrayed light receiving element 3; lO is an output signal from the neural network 4; be.

Here, the neural network 4 refers to a plurality of neural networks having an addition processing section that weights and adds signals from a plurality of input ports, and a nonlinear processing section that performs nonlinear processing on the signals from the addition processing section. It means a signal processing network composed of processing elements and a plurality of connection elements that interconnect these processing elements.

In FIG. 1, an incident optical signal 6 from an optical signal source 2 enters a multimode optical waveguide 1 and propagates therein. After propagation, the output optical signal 7 output from the multimode optical waveguide 1 is guided to the arrayed light receiving element 3. Electrical signals 9 obtained by the arrayed light receiving elements 3 are guided to the neural network 4 via a plurality of connections &98. These electrical signals 9 are processed within the neural network 4, so that
An output signal lO is obtained from output port 5. Optical signal source 2
A lens may be provided between the multimode optical waveguide 1 and the multimode optical waveguide 1, and between the multimode optical waveguide 1 and the arrayed light receiving element 3, if necessary, in order to focus the light.

In the multimode optical waveguide l, the propagation constant differs for each mode, and the coupling state between the modes changes due to disturbance.

Therefore, the image information incident on the multimode optical waveguide 1 is transmitted to the multimode optical waveguide! It is difficult to ensure that it is maintained even after propagation. Further, when the image information is two-dimensional, information elements having the same propagation angle in the multimode optical waveguide l are mixed with each other, so the image information becomes substantially one-dimensional information. For this reason, it becomes difficult or impossible to obtain the same image information at the output section of the multimode optical waveguide 1 as at the input section.

In order to solve this problem, in the embodiment shown in the first figure, a neural network 4 is installed immediately after the arrayed light receiving element 3.
are connected.

FIG. 2 shows a typical configuration example of such a neural network 40, where 11 is an input port and 12 is a processing element. Reference numeral 13 denotes an addition processing section that constitutes the processing element 12, 14 a nonlinear processing section that also constitutes the processing element 12, and 15 a connection element that connects the processing elements 12. The addition processing section 13 has a function of weighting signals coming in from a plurality of connection elements 15 connected thereto and adding them. Furthermore, in the nonlinear processing section 14, the addition processing section 1
Nonlinear processing is performed on the signal coming in from 3. For example, when the input signal level is greater than a certain threshold, output signal "l" is output, and conversely, when it is smaller, output signal "0" is output. Perform processing such as

In the example shown in FIG. 2, the input port 11 and the output port 5 are separated, but neural networks with other structures have also been proposed in which, for example, they are shared.

As is well known, a neural network can freely set the relationship between input signals and output signals by appropriately setting internal parameters. Furthermore, in neural networks, it is also possible to prevent output signals from changing in response to slight changes in human input signals, as seen in functions such as associative memory and recognition.

Furthermore, as seen in the learning function, by exemplifying several combinations of input and output signals to the neural network, the internal parameters can be automatically changed to have the desired human-output relationship. You can also do it. Therefore, according to the configuration as shown in FIG. 1, it is possible to restore image information disturbed by the multimode optical waveguide l using the neural network 4.

FIG. 3 shows a first specific embodiment. Here, 16^
16B is a lens, 17 is a one-dimensional array of light emitting elements, 18 is a one-dimensional array of light receiving elements, and 19 is an electric signal for driving the one-dimensional array of light emitting elements 17. An electrical signal 9 is obtained from the one-dimensional array of light receiving elements 18 . 1
The dimensional array light emitting elements 17 are coupled to the input end of the multimode optical waveguide 1 via the lens 16A. Also,
The output end of the multimode optical waveguide 1 is coupled to a one-dimensional arrayed light receiving element 18 via a lens l'6B.

Light emitted from the element 17-1 at one end of the one-dimensional array light emitting element 17 propagates in the multimode optical waveguide 1 at a small propagation angle. One-dimensional array light emitting device 1
The light emitted from the element 17-2 at the other end of the multimode optical waveguide 1 propagates at a large propagation angle. Due to mode coupling in the multimode optical waveguide 1 and variations thereof, the propagation angle of each propagating light is disturbed. Therefore,
The plurality of electrical signals 9 obtained by the one-dimensional arrayed light receiving element 18 are different from the plurality of electrical signals 19 that drive the one-dimensional arrayed light emitting element 17. However, by processing the plurality of electrical signals 9 obtained by the one-dimensional arrayed light receiving elements 18 using the neural network 4, the influence of disturbance within the multimode optical waveguide 1 can be compensated for.

FIG. 4 shows a second specific embodiment of the invention. Here, 21 is a two-dimensional optical signal source, and 22 is an array of light receiving elements arranged two-dimensionally. An optical signal emitted from a two-dimensional optical signal source 21 is coupled to the multimode optical waveguide 1, whereby a plurality of modes are excited and propagate within the multimode optical waveguide 1.

At the output end of the multimode optical waveguide 1, its near-field image is focused on a two-dimensional array of light receiving elements 22.

The image formed on this two-dimensional array of light receiving elements 22 is different from the image of the two-dimensional optical signal source 21. One of the reasons for this is that the propagation constant of the mode propagating in the multimode optical waveguide 1 is different for each mode, so the near-field image at the input end of the multimode optical waveguide 1 and the near-field image at the output end are completely different. It's about being different. Another reason is that the image may be transformed by the lens 16 disposed at the input end of the multimode optical waveguide 1. However, also in this embodiment, since the plurality of electrical signals obtained by the two-dimensional arrayed light receiving elements 22 are processed by the neural network 4, the multimode optical waveguide 1
Image transformations occurring during propagation can be compensated for.

Although not mentioned in the above explanation, the neural network 4 may be composed of hardware consisting of an electronic circuit or an optical circuit, or may be in the form of a computer having input/output terminals and controlled by software. .

[Effects of the Invention] As explained above, according to the present invention, optical image information can be directly transmitted using one multimode optical waveguide. Therefore, unlike methods using conventional optical communication technology, there is no need to prepare an optical-to-electrical converter or an electric-to-optical converter on the input end side of the optical waveguide, and the optical image information can be directly transmitted and processed. , the configuration of the transmission system can be simplified. This is effective when, for example, a minute sensor is required to detect two-dimensional image information in a harsh environment.

Moreover, in conventional optical communication technology, unless wavelength division multiplexing technology is used, it is difficult to provide multiple transmission channels within an L-tree multi-domain optical waveguide due to the configuration of electrical and optical systems. This was difficult because it became complicated. However, according to the present invention, by associating transmission channels with modes, it is possible to provide a plurality of transmission channels within one multimode optical waveguide.

This thing is! This is effective when performing multi-channel transmission using wooden optical fibers.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
FIG. 3 is a configuration diagram showing a configuration example of the illustrated neural network; FIG. 3 is a configuration diagram showing a first specific embodiment of the present invention; FIG. 4 is a configuration diagram showing a second specific embodiment of the present invention. It is. DESCRIPTION OF SYMBOLS 1... Multimode optical waveguide, 2... Optical signal source, 3... Arrayed light receiving element, 4... Neural network, 5... Output port, 6... Incident optical signal, 7 ... Outgoing light signal, 8... Connection, 9... Electrical signal, IO... Output signal, 11... Input port, 12... Processing element, 13... Addition processing section. 14... Nonlinear processing unit, 15-... Connection element, 16A, 16 [1... Lens, 17... One-dimensional array-shaped light emitting element, 18... One-dimensional array-shaped light receiving element, 19 , 20... Electric signal, 21... Two-dimensional optical signal source, 22... Two-dimensional arrayed light receiving element.

Claims (1)

[Claims] 1) A multimode optical waveguide capable of simultaneously transmitting a plurality of modes, a photodetection element array capable of detecting the intensity distribution of light, and a neural network, Guide the optical image information signal obtained as an output from one end of the multimode optical waveguide to the multimode optical waveguide from one end of the multimode optical waveguide to the optical detection element array, An optical image information direct transmission system, characterized in that an electrical signal obtained from a detection element array is coupled to the neural network, and an optical image information output signal is extracted from the neural network. 2) The neural network includes a plurality of input ports that receive electrical signals obtained from the photodetection element array, an addition processing means that weights and adds signals from the plurality of input ports, and a plurality of input ports that receive electrical signals from the addition processing means. 2. The optical image information direct processing apparatus according to claim 1, further comprising: a plurality of processing means including a nonlinear processing means for performing nonlinear processing on a signal; and a connection means for coupling the plurality of processing means to each other. Transmission system.