JPS58111381A - Light-emitting device - Google Patents

Abstract

PURPOSE:To monitor the state of luminescence of a light-emitting element by using the light-emitting element having a side rope in the directional characteristics of the intensity of light radiation and detecting the light in the light- emitting device as a transmission module used for optical communication. CONSTITUTION:In the light-emitting device as the transmission module, the light-emitting element 61 is encased into a box body 63, and the light-receiving end surface of an optical fiber 65 is arranged at a central position and onto a vertical line (theta=0 deg.) on the light-emitting surface. Each light-receiving end surface of optical fibers 67, 69 is disposed at the position of theta=+ or -40 deg. from the vertical line on the light-emitting surface of the light-emitting element 61. The optical fiber 65 receives the beams of a main rope, and transmits them. Each of both optical fibers 67, 69 receives the beams of the side rope (theta=+ or -40 deg.). These optical fibers 65, 67, 69 and the light-emitting element 61 are opposed, and mounted and fixed by the box body 63.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light emitting device used, for example, on the transmitting side of optical communication, and particularly to a light emitting device that generates an optical signal. This invention relates to a light-emitting device that can be monitored in a number of ways.

Conventionally, in light-emitting devices used for optical communication, it has been difficult to monitor the light-emitting state of the light-emitting element that supplies optical signals to the optical fiber.
Met. Therefore, there is a drawback that it is impossible to determine whether or not a communication system that performs optical communication using such a conventional light emitting device is out of order.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks, it is an object of the present invention to provide a light emitting device that can monitor the state of light emission.

The present invention will be described in detail below based on the drawings.

FIG. 1 shows a light emitting element used on the transmitting side of optical communication.

Here, a half-moon-shaped condensing lens 13 is provided on the light-emitting surface of the light-emitting portion is in the light-emitting element l/. lens/j
is for sharpening the directivity characteristics of relative radiation intensity. The directional characteristics of this light emitting element l/ are shown in FIG. Here, the angle θ on the horizontal axis is an angle obtained by taking the clockwise direction as positive and the counterclockwise direction as negative from the vertical line with respect to the surface of the light emitting portion /J. Also, the vertical axis shows the relative radiant intensity (− is taken,
It does not indicate an absolute amount.

FIG. 3 shows another light emitting element, in which there is no part on the surface of the light emitting part of the light emitting element J/ that is similar to the light collection lens shown in FIG. The directional characteristics of this light emitting element 1 are shown in the diagram. The light emitting element I does not have sharp directivity, but has a relative side slope of ±4!0° centered at 0=06. In this way, # = o@, ten invasion 6, -
The light is getting stronger at the 3 points with food 0. Note that the state of the side lobe can be changed by providing a condensing lens /k and changing its shape.

Figure #g3 shows the assembled configuration of a conventional optical fiber transmission module. The light emitting element 31 is housed and fixed inside the casing IJ of the transmitting module, and the optical fiber and the light emitting surface of the light emitting element 31 are mounted facing each other via the joint n between them. The optical signal generated by the light emitting element xi is transmitted through an optical fiber K to a receiving module (not shown). It is necessary to use the light emitting element l/ of FIG. 7 having the directional characteristics shown in FIG. 2 as the light emitting element jl of the light emitting device as such a transmission species.

Figure 1 shows the state in which the device of the present invention is installed.

In the light emitting device as a transmitting module, a light emitting element 1/ is housed inside a casing U, and the light receiving end surface of VC Optical Fiber Co., Ltd. is placed at the center on the light emitting surface and on the vertical line (0=06). Further, on the light-emitting surface of the light-emitting element 1, the light-receiving end surfaces of the optical fibers 17 and 49 are placed at a position K at 0 from the vertical line. Note that here, light emitting element 4/#1. A light-emitting element as described above shall be used. The optical fiber 4S receives and transmits the light from the main rope. In addition, two optical fibers 6 and 6
t receives side rope (0=±4to') light. These optical fiber rods, 6 and 4, and the light emitting element 6/ are made to face each other, and are mounted for identification by the housing 63&C.

FIG. 7 shows an embodiment of the present invention. Here, the mounting state of the optical fiber and the light emitting element is the same as that described with reference to FIG. The casing of the light emitting device according to this embodiment? The light receiving element is fixedly attached to the light receiving end face of one optical fiber 69 and the end face opposite to the light receiving end face. placed facing the light-receiving surface of the With this configuration, the light from the side rope with θ=-0 reaches the light receiving element! guided by.

Generally, as shown in Figure 1, the light intensity of the suid lobe is smaller than that of the main rope. Therefore, the light intensity of the side rope, K used as an optical signal for optical communication, is small. However, it can be used for monitoring the light emission state.

The drive circuit of the device of the present invention is shown in No. JWA. The signal 11 to be transmitted by the transmitting module is supplied as a driving transistor isK modulation signal via a level converter @13. The light emitting element 4 connected to the collector of this transistor 1g emits light when the signal xi is logic@1", and
No light is emitted when θ''.

Of the light emitted from the light emitting device 1/, the main rope is transmitted through the optical fiber cable and used for optical communication. In addition, the light of both side lobes corresponds to both photogenic fibers 6
and 6 de respectively. The light guided by the optical track faA9 arrives for monitoring purposes. The light receiving element 73 converts the received optical signal into an electrical signal, and differentially amplifies the converted electrical signal! , f7. The polarity-inverted output signal obtained by the voltage follower formed by the amplifier "aI!?" and the resistor it is supplied to the level converter ?/, and the output signal ?3 is supplied to one input terminal of the AND gate 93. Also, the other input terminal of 9 is the signal 1 to be sent.
/supply.

Gate f3 performs @filling of both signals l/ and t3 to obtain output signal t7. In addition, 10/ is a resistor connected between the level converter t3 and the base of the transistor It30, 103 and 103 are bias resistors for the transistor is, and /1177 is a current limiting resistor for the light emitting element 6/. be.

In the above configuration, when the signal U is logic @l/IT, the light emitting element 11 emits light, and at that time, the signal 93 as the monitoring signal E becomes logic 1/''.Therefore, the present light emitting device is In the normal case, when the signal t/ to be transmitted is logic @7', the output signal 9 of the AND date device 5 becomes logic "'l".The component circuit parts such as the light emitting element 47 are normally operated. If it is not operating, the output signal DEC will be logic @0'' even if the signal 1/ is logic @7''. In this way, the light emitting state of the light emitting device can be monitored by the logic state of the output signal DEF. I can do it.

In addition, if we replace Antogame) 9j with an exclusive OR gate and define the case where the logical output of the output signal t is @l'' as an abnormal state, if there is no signal 1/ to be transmitted, that is, the logical @0'' and the signal t3 is logical @0'' can be determined to be a normal state.

The output signal 9J thus obtained can be used as a drive signal for a display to indicate an abnormal state to the user, a control signal for prohibiting device operation, etc., to prevent inconvenient device operation.

As detailed above, according to one aspect of the present invention, in a light emitting device as a transmission module used, for example, in optical communication, a light emitting element having a nightlobe in the directivity characteristic of light radiation intensity is used, and the sidelobe light thereof is detected. ), it is possible to realize a light-emitting device in which the light-emitting state of the light-emitting element can be monitored.

[Brief explanation of the drawing]

Figure 1 is a side view of a light emitting element, Figure 1 is a characteristic diagram showing its directional characteristics, Figure 3 is a side view of another light emitting element, Figure 3 is a characteristic diagram showing its directional characteristics, and Figure 3 is a characteristic diagram showing its directional characteristics. FIG. 1 is a configuration diagram illustrating how a conventional light emitting device is installed; FIG. 7 is a configuration diagram illustrating an example of the light emitting device according to the present invention; FIG. 1 is a block diagram showing a circuit for driving the device of the present invention. // , ko/ , j/ , 4c... light emitting element, /J
, JJ...°light emitting part, /j...concentrating lens, sr, company, 4ri, 49...optical fiber, ri!・
...light receiving element, 13, ? /...Level converter. Patent applicant: Canon Co., Ltd. Figure 2 Figure 3 Figure 41

Claims (1)

[Claims] In a light emitting device in which light generated by a light emitting element is transmitted through an optical fiber, a directional sidelobe of light radiation intensity in the light emitting element is detected, and the light emitting state of the light emitting element is determined based on the detected signal. A light emitting device characterized in that it is configured to monitor.