JPH0527707U - Optical fiber terminal - Google Patents

Abstract

(57) [Summary] [Purpose] In an LD module, the solder creep phenomenon is small even when exposed to severe thermal stress. As a result,
An LD module with a small fluctuation in optical output at the fiber end is obtained. [Structure] PbAu was used for fixing and hermetically sealing a metal sleeve or a ceramic sleeve of an optical fiber.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to an optical fiber terminal of a laser diode module used in an optical fiber communication system.

[0002]

[Prior Art]

 FIG. 4 is a cross-sectional view showing an optical fiber terminal of a conventional laser diode module. In the figure, 1 is an optical fiber wire having a gold-plated tip, 2 is an optical fiber jacket, and 3 is an optical fiber protection. A pipe, 4 is PbSn solder, 5 is a polymer adhesive, 6 is a metal sleeve, and 6a is a flange attached to the metal sleeve. FIG. 5 is a sectional view of an example of a DIP type laser diode module in which the optical fiber terminal shown in FIG. 4 is actually used. In the figure, 7 is a package, 8 is a cover, 9 is a thermo module for controlling the temperature of a laser diode (hereinafter simply referred to as LD), 10 is a heat sink of the LD, 11 is LD, and 12 is a monitoring photodiode (hereinafter simply referred to as PD). ), 13 is a stem, 14 is a mount holding and fixing the stem 13, 15 is a thermistor for temperature detection, 16 is a holding member for mounting the thermistor 15 and fixing the mount 14, 17 is A rod lens (square refractive index distribution type lens) for condensing light from the LD 11, a lens holder 18 for holding and fixing the rod lens 17, and a sleeve 19 for holding and fixing the metal sleeve 6. The holder 20 is an airtight solder. The internal wiring is omitted.

Next, the operation will be described. First, the LD 11, the rod lens 17, and the optical fiber element wire 1, which are basic optical components, are used to perform optical axis adjustment / fixation in advance outside the package 7, and then the optical axis is incorporated into the package 7. The assembly method will be briefly described below. The stem 13 to which the LD 11 and the PD 12 are die-bonded and the mount 14 around the stem 13 are fixed by welding or the like via the heat sink 10. Next, the rod lens 17 is mounted in the lens holder 18, the LD 11 and the rod lens 17 are axially aligned, and the mount 14 and the lens holder 18 are welded. Next, in order to hold the metal sleeve 6 on which the optical fiber strand 1 is mounted, the metal sleeve 6 is put into the hole of the sleeve holder 19, and the LD 11 and the rod lens 17 which have been axially fixed are attached. Align the axes. The tip of the metal sleeve 6 is usually obliquely polished to prevent reflection from the optical fiber strand. After the position of the optical fiber strand 1 is determined, the metal sleeve 6 and the sleeve holder 19 are fixed by screws or the like in the optical axis direction, and the lens holder 18 and the sleeve holder 19 are fixed by welding or the like in the direction perpendicular to the optical axis. To fix. This completes the production of the internal module. Here, the holding material 16 to which the thermo module 9 and the thermistor 15 are attached is fixed in advance in the package 7 by soldering. Next, the internal module is put into the package 7, and the package 7 and the flange 6a provided on the metal sleeve 6 are soldered. Further, internal wiring is performed, and finally the cover 8 is seam welded to the package 7. In this module, the current supplied to the thermo module 9 is detected by detecting and feeding back the resistance value of the thermistor 15 fixed to the holding material 16 so that the temperature of the LD 11 is kept almost constant even if the ambient temperature changes. Adjust. Generally, an ATC (Automatic Temperature Control) circuit is externally attached to perform automatic temperature control.

[0004]

[Problems to be solved by the device]

 The LD module using the optical fiber terminal configured as described above is left at high temperature / low temperature for a long period of time, and subjected to thermal stress such as thermal cycle to fix the terminal of the optical fiber element wire 1 in the metal sleeve and for airtightness. The PbSn-based solder used as a material causes a creep phenomenon, and as a result, the relative position of the optical fiber element wire 1 with respect to the LD 11 and the rod lens 17 is changed, and there is a problem that the optical output at the fiber end fluctuates greatly.

The present invention has been made to solve the above problems. The creep phenomenon of solder is small even when exposed to a harsh heat stress, and as a result, the fiber end optical output of the LD module is reduced. The purpose is to obtain an LD module with small fluctuation.

[0006]

[Means for Solving the Problems]

 In the optical fiber terminal according to the present invention, PbAu solder is used for fixing the optical fiber and the metal sleeve and for hermetically sealing.

Further, in place of the metal sleeve, PbAu solder is used for the ceramic portion in which the inside is metallized and the tip is processed into a tapered shape.

Further, PbAu solder is used for the ceramic portion whose inside is metallized and whose tip is counterbored.

[0009]

[Action]

 Since the optical fiber terminal according to the present invention uses PbAu solder, the solder creep phenomenon is less than that of PbSn type solder, so that the movement of the optical fiber strand can be suppressed to a small amount against thermal stress.

[0010]

【Example】

 Example 1. FIG. 1 is a sectional view showing an embodiment of the present invention, in which 1 is an optical fiber element wire, 2 is an optical fiber jacket, 3 is an optical fiber protection pipe, 6 is a metal sleeve, and 21 is an optical fiber. This is a PbAu solder used for fixing the end of the fiber strand 1 and hermetically sealing it.

In the optical fiber terminal for the LD module configured as described above, since the PbAu solder 21 is used for fixing the optical fiber element wire 1 in the metal sleeve 6 and airtightly, it is compared with PbSn solder. The solder creep phenomenon is small and stable against heat stress. Therefore, for example, if the above-mentioned optical fiber terminal is used in the conventional DIP type LD module described above, a stable optical output at the fiber end is obtained even if it is subjected to severe thermal stress, and its fluctuation amount is small.

Example 2. FIG. 2 is a cross-sectional view showing another embodiment of the present invention, in which 1, 2, 3, 5, 6, 21 are the same as the previous embodiment. Reference numeral 22 denotes a ceramic having a hole which is larger than the outer diameter of the optical fiber strand by several microns and the tip of which is tapered, and 23 is a solder for fixing the metal sleeve 6 and the ceramic 22. It is a material. In this embodiment, the amount of PbAu solder 21 can be reduced by using the ceramic 22 that has been subjected to fine hole processing and the tip is processed into a taper 24a shape, and soldering by a laser processing machine becomes possible. The workability of fiber end processing can be improved. Of course, also in this case, since the PbAu solder 21 is used for fixing the optical fiber element wire 1 to the ceramic 22 and for hermetically sealing, a stable optical output at the fiber end can be obtained even under severe thermal stress, and the fluctuation amount thereof can be obtained. Is small.

Example 3. FIG. 3 is a sectional view showing another embodiment of the present invention, which is the same as FIG. 2 except that a counterbore 24b is processed at the tip of the ceramic 22.

By the way, in the above description, the case where the present invention is applied to the DIP type laser diode module is described, but it can be diverted to other packages such as a butterfly type laser diode module.

[0015]

[Effect of the device]

 As described above, the present invention uses the PbAu solder for fixing the optical fiber wire in the metal or ceramic sleeve and hermetically sealing it in the optical fiber terminal for the LD module so that the LD can be used even under severe thermal stress. Since the fluctuation of the coupling efficiency of the optical fibers is small, it is possible to provide an LD module with high reliability.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a sectional view showing a third embodiment of the present invention.

FIG. 4 is a cross-sectional view of a conventional optical fiber terminal.

FIG. 5: DI incorporating a conventional optical fiber terminal
It is sectional drawing of a P-type LD module.

[Explanation of symbols]

 1 Optical Fiber Element 6 Metal Sleeve 21 PbAu Solder 22 Ceramic 24a Taper 24b Counterbore

Claims (3)

[Scope of utility model registration request] 1. An optical fiber having a gold-plated tip, a protective pipe for protecting the optical fiber, the optical fiber and a metal sleeve having the protective pipe mounted thereon,
An optical fiber terminal using solder for fixing and hermetically sealing the optical fiber and the metal sleeve, wherein PbAu solder is used as the solder. 2. An optical fiber having a gold-plated tip, a protective pipe for protecting the optical fiber, the optical fiber and a metal sleeve having the protective pipe mounted thereon,
There is a hole slightly larger than the outer diameter of the optical fiber in the center, and the outer periphery of the gold-plated ceramic is brazed to the metal sleeve at the same time that the tip of the hole is tapered. An optical fiber terminal characterized in that PbAu solder is used for the tapered portion of the optical fiber and the ceramic. 3. An optical fiber having a gold-plated tip, a protective pipe for protecting the optical fiber, the optical fiber and a metal sleeve on which the protective pipe is mounted,
There is a hole slightly larger than the outer diameter of the optical fiber in the center, and the outer periphery of the gold-plated ceramic is brazed to the metal sleeve at the same time that the tip of the hole is counterbored. An optical fiber terminal characterized in that PbAu solder is used for the counterbore portion of the optical fiber and the ceramic.