JPS5960414A - Photodetector incorporating attenuating function - Google Patents

Abstract

PURPOSE:To decrease the number of parts and parts requiring precise work and assembly and to reduce the price of titled photodetector, by incorporating an attenuating element in the photodetector in one body. CONSTITUTION:A photocoupler 2 is inserted into the photodetector 1A and coupled by a screw part 13 and a cap nut 22. Light from an optical fiber cable 24 is propagated to a photodetecting element 14 through optical fibers 26 and 43 and attenuated by an attenuation film 47 as specified. Attenuating elements 18 having attenuation films 47 different in thickness stepwise according to the necessary amounts of attenuation are prepared, and an element 18 is replaced to obtain optional attenuation, making a photodetection level adjustment. An optical fiber 43 provided to the element 18 is larger in core ratio than the fiber 26. Thus, the light is increased in diameter as it reaches the element 14 through the optical fibers 26 and 43 to prevent transmission loss at respective connection parts even when there is an axial shift between respective parts.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a light receiver (two parts) constituting a transmission device.
This relates to a light receiver that has a built-in attenuation function to attenuate the receiving section.

Conventional technology and problems In optical transmission equipment that transmits and receives optical signals via optical fibers, when the level of optical power reaching the optical receiver is too high, an optical system is used to attenuate the optical power to a level that the optical receiver can receive. An attenuator is required.

Conventionally, such an optical attenuator is configured separately from the optical receiver,
A type of attenuator having a required amount of attenuation was inserted and connected to the transmission line as needed.

FIG. 1 shows a schematic configuration of a receiving section of a conventional optical transmission device including a light receiver and an optical attenuator.

In the figure, 1 is a light receiver, 2 is an optical connector, and 6 is an attenuator. The light receiver 1 is configured so that it can be fixed to other utensils, etc., using a flange portion 11, for example, and
The optical connector 2 or the attenuator 3 is fixed inside the cylindrical socket 12 (two sockets), and is in the form of a receptacle in which these can be fixed by means of a threaded portion 16 provided on the outside of the socket 12. A photoelectric conversion unit 1 includes an internal light receiving element 14 consisting of an avalanche photodiode (AI'lJ) or a PIN-)i' diode, etc.
A lead wire 17 is connected to the photoelectric conversion section 15 for taking out electrical signals to the outside.

2 optical connectors, the socket 12 of the optical receiver 1 (= the mating rod part 21 and the threaded part 15 of the optical receiver 1 on the outside thereof)
The rod part 21 has a through-hole inside, and is in the form of a plug that fixes the °C light receiving part 1 (-) by tightening the cap nut 22.The rod part 21 has a through hole inside; An optical fiber cable 24 is inserted and fixed into the large diameter portion 25 of the through hole, and a fiber 26, which is a core wire of the optical fiber cable 24, is inserted and fixed into the small diameter portion 25 of the through hole. ) 16 fine tips (26 tips are flush with the end 27 of the rod part (2 polished).

The attenuator 6 has a rod portion filter 1 that fits the receiver Lj12 of the light receiver 1 at one end and a cap nut 62 that fits the threaded portion 15 of the light receiver 1 on the outside thereof. The light receiving part 1 (-) is fixed by tightening the light receiving part 1 (-), and has a cylindrical socket 33 for receiving the rod part 21 of the optical connector 2 at the other end and a threaded part 54 provided on the outside thereof. , insert the rod part 21 and tighten the cap nut 22.
By tightening them, an adapter is formed between the light receiver 1 and the optical coil cover 2 (there are two parts) that connect and fix the two.

The rod portion 31 has an optical attenuation portion inside, and attenuates the light received from the rod portion 21 of the optical connector by an arbitrary attenuation h1-, and transmits the light to the light receiving element 14C in the light receiver.

? FIG. 142 shows a specific configuration of the rod section 31 in the attenuator 3C. The rod portion 31 has a through hole 61- inside.
1, and the through hole 51-1 has an optical fiber 131-2.
51-3 is accommodated, and the outer end surface of each optical fiber is polished so as to be flush with the end surfaces 31-4 and 51-5 of the rod portion. The inner end 61-6 of the optical fiber 51-2 is usually cut at a right angle (two cuts and polished), but the inner end 61-7 of the optical fiber 61-5 is cut and polished at an angle and this part (two cuts). A damping film is applied.The damper is formed by depositing a vapor deposited film of metal or non-metal such as titanium (Ti) or chromium (Cr) and then performing oxidation treatment, and its thickness is selected. By doing so, the amount of attenuation for the transmitted light can be arbitrarily set.
By doing this, reflected light from this part is prevented from returning to the transmitting side and causing interference with the light emitting source.

In Fig. 1, the optical receiver 1 is normally fixed, and when there is no need to attenuate the received light, the optical connector 2 is directly connected to it, and when it is necessary to attenuate the received light, the attenuation is preset in a predetermined step. Select attenuator 3 with the amount
By inserting and connecting the light receiver 1 and the optical connector 20, the level of the receiving destination can be adjusted as desired.

However, while the conventional attenuator shown in Figure fA1 is made in the form of an adapter and can be easily installed and replaced, it requires a mutual connection fastening mechanism between the receiver and the optical connector. , the number of parts increases.

In addition, in order to maintain high efficiency and stable connection between the receiver and the optical connector while maintaining compatibility, the axes of the glass fibers to be connected must be aligned closely with each other, and the end faces of the glass fibers must be aligned closely with each other. It is necessary to maintain a constant distance between the two, which requires ultra-precise processing and assembly technology, which impedes mass production. For these reasons, conventional attenuators have inevitably become extremely expensive.

OBJECT OF THE INVENTION The present invention seeks to solve the problems of the prior art, and its purpose is to provide an attenuation function within the receiver for adjusting the level of received light (by providing two functions and integrating them). The object of the present invention is to provide a light receiver that can reduce the number of parts and precision machining, thereby significantly lowering the price.

Summary of the Invention The present invention focuses on the fact that conventional attenuators are often inserted and connected just before the light receiver, and further focuses on the fact that the light receiving element built into the receiver) has a relatively large light receiving area. The attenuation section is built into the light receiver and is integrated as a groove structure that can be easily replaced.

Embodiment of the invention FIG. 3 is a diagram showing the configuration of an embodiment of the invention.
1A shows a photoreceiver of the present invention -C. 2 indicates an optical connector, and the optical connector 2 is not different from that shown in FIG. In the light receiver 1A, the same parts as those shown in FIG. 1 are indicated by the same number m, 12A is the receiver 1-1, 12B is the small diameter part thereof, and 18 is the attenuation element. In the attenuation element 18, 41 is a cylindrical support made of metal or ceramic, 42 is a center hole provided through the support 41, 43 is an optical fiber, and 41 is an end surface of the support 41 on the side of the optical connector. , 45 is an end face of the support 41 on the light receiving element side, 46 is a small diameter portion of the support 41, and 47 is an attenuation film.

In FIG. 3, the support body 41 has an outer diameter of the socket 12/l.
The damping element 18 is made to be slightly smaller than the inner diameter of the socket 12A, for example, by 1 to 3 degrees Celsius, so that the damping element 18 can be mounted in the socket 12A with a good centering accuracy of 1 minute. [There is. Further, when the support body 41 is installed in the socket 12A, the six small ball portions 12B and the small diameter portion 46 engage with each other, so that the position in the C-axis direction (1° 1°) is regulated. The end face 44 is made to have a certain length so as to maintain a certain distance from the end face 27 of the optical connector 2 when the optical connector 2 is inserted and connected to the light receiver 1. Furthermore, an optical fiber 46 is bonded to the center hole 42. The end face of the optical fiber 43 on the optical connector side is polished so as to be flush with the end face of the support body 41.

On the other hand, the end surface 45 of the support 41 on the side of the light receiving element is polished obliquely at a certain angle so as to be flush with the end surface of the optical fiber 4.
On the end face of 6, there is a damping film 4 similar to that in the case of FIG.
7 is provided. The attenuation film 47 is provided obliquely to the axis of the optical fiber 45 to prevent reflected light from returning to the transmission side.

With this configuration, the optical fiber cable 24 was transmitted when the optical connector 2 was inserted into the receiver 1A and the temperature was fixed at ℃ by the screw part 13 and the cap nut 22.)
The light is transmitted from the optical fiber 26 to the light receiving element 14 via the optical fiber 46, and is given a predetermined attenuation by the presence of the G.15 attenuation film 47.

The attenuation element 18 is prepared by having the thickness of the attenuation film 47 changed in stages according to the required amount of attenuation.
You can give any attenuation (receiver) by replacing it and adjust the level. In addition, if the transmission path characteristic 2 attenuation function is not required, the attenuation element 18 can be made into a transmission type by omitting the attenuation film 47, and by using it interchangeably, the same 4i''/component can be achieved. It is possible to avoid attenuation.

At this time, the optical fiber 4 provided in the attenuation element 18! l is
An optical fiber having a larger C core diameter than the optical fiber 26 in the optical connector is used. In this way, by sequentially increasing the diameter from the optical fiber 26 through the bi-fiber 45 to the light receiving element 14, even if there is a misalignment between these parts, the transmission loss at each connection part can be reduced. can be prevented from occurring.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the attenuation element is built into the receiver and integrated, which reduces the number of parts and reduces the number of parts that require precision machining and assembly. Therefore, it is possible to improve mass productivity and to significantly reduce the price. Further, according to the present invention, compared to conventional photoreceptors, the i,;Q receiver parts are unnecessary, resulting in an advantage that the receiver can be made smaller in size.

[Brief explanation of drawings]

FIG. 1 shows a conventional receiving section 411? consisting of a photoreceiver, an attenuator, and an optical connector. FIG. 2 is a diagram showing the configuration of a rod portion in an attenuator, and FIG. 5 is a diagram showing the (1) V configuration of an embodiment of a light receiver incorporating the attenuation function of the present invention. 1.1A...Receiver, 2...Optical connector, 3...
Attenuator, 11... Flange part, 12, 12A... Socket, 12B... Small diameter part, 13... Screw part, 14 River light receiving element, 15... Light weight conversion part, 16...・Ring-shaped screw, 17... Lead wire, 21... Rod part, 22.
... Fukuro Natsuto, 2! I... Large diameter part, 24... Optical fiber cable no. ν, 25... Small diameter fjll, 26...
Optical fiber, 27... End face of rod part, 31... Rod part, 62... Bag sut, filter 6... Receiver 11.64
... threaded part, 41 ... support body, 42 ... center hole,
46... Optical fiber, 44, 45... Support body 41
End face of, 46...Small diameter portion, 47...Dampening membrane Patent applicant Fujitsu Ltd.' Agent Patent attorney Gobe Tamadoro (3 others) Figure 1 1 No. 2 Port 1 = 63

Claims (1)

[Claims] The end of the optical fiber 4 cable that transmits the signal is f':I,
j l When a bifurcated optical connector is connected, the built-in light receiving element receives the optical signal of the optical fiber cable.
The light receiver that converts and outputs (Nio 61t) is a holder that is removably attached to the light receiver.
An optical fiber having a large core diameter is fixed to the optical fiber in the optical fiber cable, one end surface of the fiber is polished obliquely to the optical axis, and an attenuation film is attached to the polished surface. An attenuation element formed by applying the above function is built into the receiver)C4, and the output of the optical connector)0 is received through the attenuation element.
A light receiver having a built-in attenuation 1 function characterized by transmitting to 0 elements.