JPS61165710A - Multiterminal photodetector module - Google Patents

Abstract

PURPOSE:To reduce the number of parts to facilitate assembling them and improve the reliability and the temperature characteristic by approximating the end face of a fiber bundle, where input fibers are bundled close, to the photoelectric conversion surface of a photoelectric transducer fixing the junction part between a bundle holder and a package holding the photoelectric transducer by welding. CONSTITUTION:The end face of fiber bundle 6 is so formed that its area is smaller than the area of a photoelectric transducer 10 of a photodetector 5, and the end face of the fiber bundle 6 is approximated sufficiently to the photoelectric conversion surface of the photoelectric transducer 10 and is fixed. Thus, optical signals of individual input fibers 1 can be made incident on the photoelectric transducer 10 without loss. That is, a bundle holder 7 is inserted into the inside diameter part of a package 5a of the photodetector 5, and positions of the bundle holder 7 and the package 5a on the joint surface between them are so adjusted that optical signals of input fibers 1 constituting the fiber bundle 6 are inputted to the photoelectric transducer 10 without loss, and the junction part between them is fixed, thereby completing a multiterminal photodetector module.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a multi-terminal photodetector module that receives optical signals from a plurality of transmission lines using optical fibers and converts them into electrical signals using a photoelectric conversion element. It is.

[Conventional technology]

FIG. 5 is a perspective view showing a conventional multi-terminal light receiving element module. In the figure, 1 is the input fiber.

2 is a bundle, 3 is a mixer, and 4 is a rod lens.

5 is a light receiving element, 10 is a photoelectric conversion element mounted inside the light receiving element 5, and 11 is an adhesive.

In the conventional multi-terminal photodetector module configured as described above, one end of each of the plurality of input fibers 1 is connected to a transmission line (not shown) K. Therefore, the bundle 2 contains a plurality of optical signals. is input. This optical signal passes through the bundle 2 and reaches the interface with the mixer 3. Here, as shown in FIG. 6, the bundle 2 is composed of a fiber bundle 6 in which a plurality of fibers are bundled in a circular shape with a diameter, and a bundle holder 7. On the other hand,
As shown in FIG. 7, the mixer 3 joined to the bundle 2 is composed of a mixing fiber 8 having a core diameter D''(D'≧D) larger than the above-mentioned diameter and a mixer holder 9. Therefore, the fiber bundle By aligning and fixing the mixing fiber 6 and the mixing fiber 8 with high accuracy, the optical signals of the individual fibers constituting the fiber bundle 6 can be made to enter the core portion of the mixing fiber 8.

In this way, the optical signals incident on the core of the mixing fiber 8 are mixed while propagating through the mixing 7 eyeball 8.
It reaches the other end of mixer 3. after that.

The optical signal enters a rod lens 4 provided immediately after the mixer 3, is focused 3fE by the rod lens 4, and enters the photoelectric conversion element 10 of the light receiving element 5.

Here, the optical signal is converted into an electrical signal by this photoelectric conversion element 10.

[Problem that the invention seeks to solve]

In the conventional multi-terminal light receiving element module as described above, as shown in FIG. 5, a bundle 2 and a mixer 3, a mixer 3 and a rod lens 4. An adhesive 11 such as an epoxy resin or an ultraviolet curing resin is used to bond the rod lens 4 and the light receiving element 5 together. However, these adhesives 11 are polymeric compounds, and the temperature range in which their adhesive strength is guaranteed is narrow, from -10°C to 60°C, and they cannot be used in places where the ambient temperature is outside the above temperature range. There was a problem that it could not be used.

Further, even within the above temperature range, the adhesive 11 deteriorates when subjected to sudden temperature changes, and the bundle 2. Mixer 3. Due to the thermal expansion and contraction of the rod lens 4 and the light receiving element 5, the adhesive 11 is repeatedly subjected to tensile and compressive forces, and eventually the adhesive strength weakens, and eventually peels off, causing the light receiving element 5 to There is a problem in that the level of the optical signal that reaches it fluctuates as the temperature changes.

Furthermore, the above configuration requires the mixer 3A and the rod lens 4 in addition to the bundle 2, which means that the number of parts is large, the price is high, it takes time to assemble, and there are many joints as described above. Therefore, there was a problem that the i! tendency was poor.

This invention was made in order to solve these problems, and has a small number of parts, a low price, easy assembly, high reliability, and a multifunctional product that can improve temperature characteristics. The purpose is to obtain a terminal photodetector module.

[Failure to solve the problem]

The multi-terminal light receiving element module according to the present invention allows optical signals passing through the bundle to be processed without going through a mixer or rod lens.
In order to make the input fibers directly enter the light receiving element, the end face of a fiber bundle in which the input fibers are tightly bundled is placed close to the photoelectric conversion surface of the photoelectric conversion element, and a bundle holder and a package for holding the photoelectric conversion element are arranged. The joints are fixed by welding.

[Effect]

In the multi-terminal light-receiving element module of the present invention, since the mixing fiber and Hirod lens used in the conventional example are not used, the cost is low, assembly is easy, and reliability can be improved. Furthermore, since the number of joints is reduced compared to the conventional example, loss due to Fresnel reflection is also reduced, and loss fluctuations due to temperature fluctuations are also reduced. Furthermore, since the bond between the band holder and the package is fixed by welding, the problems of deterioration and peeling that occur when conventional adhesives are used are eliminated, and temperature characteristics are improved.

〔Example〕

FIG. 1 is a perspective view showing a multi-terminal light receiving element module which is an embodiment of the present invention, and FIG. 2 is a perspective view showing an assembled configuration of the multi-terminal light receiving element module of FIG.
．． 2.5 to 7 and 10 are completely the same components as those of the above-mentioned conventional example. In each figure, 12 is a beam welding machine (
The welds are welded by welding (not shown) and are provided at four locations as indicated by diagonal lines in FIG. 5a
is a package of the light receiving element 5.

In the multi-terminal photodetector module which is an embodiment of the present invention configured as described above, the end face of the fiber bundle 6 is manufactured to be smaller than the area of the photoelectric conversion element 10 of the photodetector 5. If it is arranged and fixed sufficiently close to the photoelectric conversion surface of the photoelectric conversion element 10, the optical signal of each input fiber 1 can be made to enter the photoelectric conversion element 10 with almost no loss. Therefore, a multi-terminal light receiving element module can be constructed without the mixer 3 and rod lens 4 that are required in the conventional example described above, and as a result, the cost can be reduced by reducing the number of parts, and the ease of assembly can be improved. Furthermore, reliability can be improved by reducing the number of joints.

Here, FIG. 2 shows the package 5a of the light-receiving element 5 and the bundle 2 necessary for bringing the light of the photoelectric conversion element 10 of the light-receiving element 5 as close as possible to the conversion surface of the end face of the fiber bundle 6. Specific examples of shapes are shown.

In a generally commercially available light receiving element 5, a photoelectric conversion element 10 is mounted on a package 5a of the light receiving element 5, and a window made of a material such as sapphire or glass is provided on the front side of the socket cage 5a. The one shown in the figure either has no window or has a window close to the photoelectric conversion element 10. Further, as shown in FIG. 2, the bundle holder 7 has a cylindrical shape in which the diameter of the tip portion is smaller than the diameter of the other portion, and the length of this portion is determined by the pan cage 5a of the light receiving element 5.
The photoelectric conversion element 10 is viewed from the shaded area in FIG.
The length up to the photoelectric conversion surface is also slightly shorter. Furthermore, the outer diameter of the tip of the bundle holder 7 is smaller than the inner diameter of the package 5a, so that the bundle holder 7t1'' is inserted into the inner diameter of the package 5a of the light receiving element 5 in the direction shown by the arrow in FIG. Therefore, after inserting the bundle holder 7 into the inner diameter of the package 5a of the light receiving element 5, the optical signal of each input fiber 1 constituting the fiber bundle 6 enters the photoelectric conversion element 10 without loss. Next, the positions of the bonding surfaces of the bundle holder 7 and the package 5a are adjusted and their bonded portions are fixed, thereby completing the multi-terminal light receiving element module.

Next, it will be described that the temperature characteristics can be improved by changing the method of fixing the joint between the package 5a and the holder 7 on the pan. This means that the package 5a of the light receiving element 5 and the bundle holder 7 are made of weldable metal, whereas the conventional example shown in FIG. 5 uses adhesive 11 to fix the joint. The joint part between the two is welded and fixed using a beam welder. - Specific examples include stainless steel tl as weldable metals.
- If a YAG laser welding machine is used as the beam welding machine, welding can be easily performed as shown in the four welded parts 12 in Fig. 1, and in this case, the above adhesive 1
The adhesive strength does not deteriorate due to temperature fluctuations as would be the case when the adhesive is fixed at No. 1, and the heat resistance performance can be greatly improved. According to the applicant's experimental confirmation,
The laser output energy of the YAG laser welding machine is approximately 5 to 6
When welded as a joint, tensile strength and shear strength of approximately 25 to 4 or more can be obtained per weld 12, and as shown in Figure 1, when welded with four welds 12, was able to obtain tensile strength and shear strength of about 100 noodles or more. This is similar to the conventional example mentioned above.

Number 1 obtained when using 1 volume of epoxy adhesive 11
This value is much larger than the tensile strength and shear strength of 0 Kf, and it was found that sufficient joint strength can be obtained by welding with such four welded parts 12. Also,
When a heat cycle test was actually conducted and the fluctuation range of the optical signal level was investigated, it was confirmed that the fluctuation width of the optical signal level was smaller when the joint was fixed by welding than when it was fixed with adhesive 11.

Incidentally, in the above embodiment, a case was explained in which stainless steel was used as the weldable metal.

The present invention is not limited to this, and other weldable metals such as steel, nickel steel, and amber may be used. In particular, when amber is used, its linear thermal expansion coefficient is almost the same as that of quartz glass, so it is possible to match the changes in the length of the fiber bundle 6 and the length of the bundle holder 7 due to temperature changes. Accordingly, the stress applied to the fiber bundle 6 can be reduced.

Therefore, it is possible to reduce the deterioration in reliability caused by repeated stress during conventional heat cycle tests.

Further, in the above embodiment, a welding method using a YAG laser welding machine was described, but the present invention is not limited to this.
Other welding methods such as an electron beam welder or an arc welder may also be used.

FIG. 3 and FIG. 4 are conceptual diagrams each showing the operation mode of a multi-terminal light receiving element module which is another embodiment of the present invention. The device shown in FIG. 3 is constructed by tilting the optical can change direction of the photoelectric conversion element 10 with respect to the central axis 13 of the fiber bundle 6. In this case, the light reflected by the light 1 conversion element 10 is Since the light does not enter the fiber bundle 6 again, return optical noise induced by the light returning to the light source such as a semiconductor laser, and re-incoming light are reflected by an optical fiber connector (not shown), etc. When the light is incident on the light turtle changing element 10, four points are improved in total.

Improvement of the characteristic deterioration of the photoelectric conversion element 10 due to the reflected light of the optical conversion signal is achieved as shown in FIG. The same effect can also be achieved by forming the photoelectric conversion surface of the photoelectric conversion surface at a similar angle. In this case, in addition to making it possible to narrow the distance between the end face of the fiber bundle 6 and the photoelectric conversion surface of the optical 1 converter element 10, even if a part of the reflected light enters the fiber of the fiber bundle 6,
Since the total internal reflection condition within the fiber is not satisfied, the light leaks out, and therefore the amount of light propagating through the fiber is reduced. As described above, the other embodiments shown in FIGS. 3 and 4 have the advantage of improving the characteristic deterioration caused by the reflected light on the photoelectric conversion surface of the photoelectric conversion element 100.

〔Effect of the invention〕

As described above, the present invention provides a multi-terminal photodetector module in which the end face of a fiber bundle in which input fibers are tightly bundled is arranged close to the photoelectric conversion surface of a photoelectric conversion element, and the bundle holder and the photoelectric conversion element are connected. Since the joint with the package to be held is fixed by welding, the structure is simple and has a small number of parts, making it inexpensive and easy to assemble, increasing reliability and improving temperature characteristics. It has excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a multi-terminal light receiving element module which is an embodiment of the present invention, FIG. 2 is a perspective view showing the assembly and purchase costs of the multi-terminal light receiving element module of FIG. The figures are a conceptual diagram showing the operation mode of a multi-terminal light-receiving element module which is another embodiment of the present invention, FIG. 5 is a perspective view showing a conventional multi-terminal light-receiving element module, and FIGS. 6 and 7 are FIG. 6 is a sectional view of a bundle and a mixer, which are components of the multi-terminal light-receiving element module of FIG. 5, respectively. In the figure, 1... input fiber, 2... bundle, 3... mixer, 4... rod lens, 5... light receiving element, 5a... package of light receiving element 5, 6...
Fiber bundle, 7...Bundle holder, 8...
Mixing fiber, 9... Mixer holder, 10...
- Photoelectric conversion element, 11... Adhesive, 12... Welding part, 13... Central axis of fiber bundle 6. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A plurality of input fibers, one end of which is coupled to a communication network using optical fibers as a signal transmission path and into which optical signals are input, a fiber bundle in which the other ends of these input fibers are tightly bundled, and this fiber A bundle holder made of a weldable metal that holds a bundle, a photoelectric conversion element having an area larger than the end face of the fiber bundle, and a package made of a weldable metal that holds this photoelectric conversion element, and the input The fiber bundle is arranged close to the photoelectric conversion element so that the optical signal from each fiber enters the photoelectric conversion element without loss, and the bond between the bundle holder and the package is fixed by welding. A multi-terminal photodetector module characterized by the following. (2) The multi-terminal light receiving element module according to claim 1, wherein the photoelectric conversion surface of the photoelectric conversion element is formed at an angle with respect to the central axis of the fiber bundle.