JPH0457381A - Receptacle type semiconductor laser - Google Patents

Abstract

PURPOSE:To enlarge a tolerance at the time of assembly of the title laser and to contrive the improvement of the yield of the assembly of the laser by a method wherein another multi-mode optical fiber having a large core diameter is inserted and arranged between a connector ferrule holding an optical fiber and a lens. CONSTITUTION:An optical fiber 13 having a core diameter larger than that of an optical film 10 held by an optical fiber connector ferrule 11 is inserted and arranged between a lens 7 and the ferrule 11. The length of the fiber 13 is formed into a length that when a certain waveguide mode is excited at the end of the optical fiber 13, the energy of the mode is moved to other mode and the other mode is not excited. Thereby, a tolerance at the time of assembly of the title laser can be enlarged, a sufficient assembly accuracy can be fulfilled even in welding of a present YAG laser, the manhour at the time of assembly of a receptacle can be reduced and the reproducibility of attachment and detachment of the connector ferrule can also be improved.

Description

[Detailed Description of the Invention] [Summary] Regarding a receptacle-type semiconductor laser device that optically couples an optical fiber and a semiconductor laser in optical communication using an optical fiber, the present invention relates to a receptacle-type semiconductor laser device that optically couples an optical fiber and a semiconductor laser. In a receptacle-type semiconductor laser device that has an optical coupling system that optically couples the optical output from a semiconductor laser through a lens to an optical fiber held in an optical fiber connector ferrule, the lens and optical fiber connector are An optical fiber having a core diameter larger than the core diameter of the optical fiber held by the optical fiber connector ferrule is inserted between the optical fiber connector ferrule and the optical fiber connector ferrule.

[Industrial application field]

The present invention relates to a receptacle type semiconductor laser device for optically coupling an optical fiber and a semiconductor laser in optical communication using an optical fiber.

With the spread of optical communications in recent years, there has been an increasing demand for the development of receptacle-type semiconductor laser devices that can be easily coupled to customers' optical fibers.

There is a need to develop a receptacle type semiconductor laser device with sufficient characteristics to meet the demands of t1 customers.

[Conventional technology]

FIG. 3 shows a conventional receptacle type semiconductor laser device. As shown in the figure, a housing 1 is made up of a front housing 2, a rear housing 3, and a cap nut part 4, and the front housing 2 is provided with a semiconductor laser 6 having a laser chip 5 and a lens 7. , rear housing 3
A split sleeve 8 is provided, and a dummy sleeve 9 is inserted into the split sleeve 8 from one side, and a connector ferrule 11 holding an optical fiber 10 at the center is inserted from the other side. The cap nut portion 4 prevents the connector ferrule 11 from coming off and holds the optical fiber cable 12. The front housing 2 and the rear housing 3 are arranged at an outer periphery AS such that the light output from the semiconductor laser 6 is directly focused on the end face of the optical fiber 10 through the lens 7.
Part B is assembled by welding with a YAG laser.

[Problem to be solved by the invention]

In the conventional receptacle type semiconductor laser device mentioned above,
The front housing 2 and the rear housing 3 are aligned and assembled by laser welding, but the impact from the laser shot disrupts the alignment, making it impossible to achieve sufficient assembly accuracy.
It was very difficult to align the beam point with the center of the connector ferrule 11. Therefore, there has been a problem in that not only the connector reproducibility but also basic characteristics such as tracking are not as expected.

SUMMARY OF THE INVENTION In view of the above conventional problems, an object of the present invention is to provide a receptacle type semiconductor laser device that facilitates optical coupling between an optical fiber and a semiconductor laser.

[Means to solve the problem]

In order to achieve the above object, in the receptacle-type semiconductor laser device of the present invention, the optical output from the semiconductor laser 6 is passed through the lens 7 to the optical fiber connector ferrule 11.
In a receptacle type semiconductor laser device having an optical coupling system for optically coupling to an optical fiber 10 held in a receptacle type semiconductor laser device,
It is characterized in that an optical fiber 13 having a core diameter larger than the core diameter of the optical fiber 10 held by the optical fiber connector ferrule 11 is inserted between the lens 7 and the optical fiber connector ferrule 11. In addition, the optical fiber 13
The length is such that when a certain waveguide mode is excited at the end of the optical fiber, the energy of that mode is transferred to another mode and no other mode is excited.

[For production]

In the present invention, light having a core diameter larger than the core diameter of the optical fiber 10 held by the connector ferrule 11 and within a range where practical coupling efficiency can be obtained is provided between the lens 7 and the connector ferrule 11. By inserting the fiber 13 and guiding the output light from the lens 7 through the optical fiber 13, the tolerance during assembly can be expanded, and current YAG laser welding is sufficient. Able to achieve assembly accuracy. Therefore, the number of man-hours required for assembling the receptacle can be reduced, and the reproducibility of attaching and detaching the connector ferrule is also improved.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention.

As shown in the figure, this embodiment includes a front housing 2 provided with a semiconductor laser 6 and a lens 7, a split sleeve 8, and a connector ferrule 11 inserted from one side thereof.
a rear housing 2 having a fiber optic cable 12;
It is the same as the conventional example explained in FIG. This is because the multimode optical fiber 13 as described above is inserted and arranged. Note that 14 is a ferrule that holds the multimode optical fiber 13.

This multimode optical fiber 13 has a core diameter that is larger than the core diameter of the optical fiber 10 held by the connector ferrule 11 and within a range that provides a practical coupling efficiency for the optical fiber 10, and its length The length is such that when a certain waveguide mode is excited at the end, the energy of that mode is transferred to another mode and no other mode is excited.

Figure 2 is a diagram showing the coupling efficiency with a single mode optical fiber, the number of waveguide modes, and the tolerance when the core diameter of the multimode optical fiber is changed. Curve A is the coupling efficiency, and curve B is the mode. The numbers and curve C indicate the tolerance, respectively.

The practical range of coupling efficiency is 5% or more (in reality, it is not impossible to achieve a coupling efficiency of 5% or less, but as the number of waveguide modes increases, there are more opportunities for energy transition between modes, and the transmission characteristics deteriorate. In addition, with low coupling efficiency, a high laser chip output is required to obtain the required optical output, leading to deterioration of reliability), and the number of waveguide modes is the same as that of a general multimode fiber. The core diameter is the second
10-65J from the diagram! It will be about I11. Furthermore, as the core diameter increases, the tolerance also increases.

Further, the length of the optical fiber 13 is preferably 3 mm or more.

Alternatively, L≦IOA is preferable, where A (pitch) is the synchronization of the undulations that occur at the same position on a plane perpendicular to the length direction of the incident light. Note that the length shown in Figure 3 is the length that allows the single mode fiber to be firmly connected to the connector with the split sleeve, and 10A (10 mm) is a length that is sufficient to stabilize the electric field distribution within the fiber.

A is approximately 1 mm, which is a value that can be used in common with light having wavelengths in the 1.3 μ band to 1.55 band.

In this embodiment configured in this way, the light focused by the lens 7 is made to enter the multimode optical fiber 13 having a large core diameter, so that the tolerance during assembly can be expanded, and the receptacle assembly The number of man-hours can be reduced. Note that the optical fiber 13 used in the above embodiments may be a graded index optical fiber or a step index optical fiber.

〔Effect of the invention〕

As explained above, according to the present invention, by inserting and arranging another multimode optical fiber with a large core diameter between the connector ferrule holding the optical fiber and the lens, the tolerance during assembly is expanded. Assembly yield is improved. Additionally, basic characteristics such as connector ferrule attachment/detachment reproducibility and tracking are improved, and test yields are also improved.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an embodiment of the present invention; Fig. 2 is a diagram showing the coupling efficiency with a single mode optical fiber, the number of waveguide modes, and tolerance when the core diameter of the multimode optical fiber is changed; FIG. 3 is a diagram showing a conventional receptacle type semiconductor laser device. In the figure, 1 is a housing, 2 is a front housing, 3 is a rear housing, 4 is a cap nut, 5 is a laser chip, 6 is a semiconductor laser, 7 is a lens, 8 is a split sleeve, 10 is an optical fiber, and 11 is a connector 12 is an optical fiber cable cable 13 is a multimode optical fiber 14 is a ferrule. Figure 1 shows an embodiment of the present invention. Housing 8 Split sleeve 72 - Front part / Housing 10 - Optical fiber / Niro - Rear housing 11 - Connector ferrule 491 bag, bottom part 12. Optical fiber cable 51. Laser f7 15...Multi-mode optical fiber halo half 4
Body 1z-f 14... Ferrule 7 - Diagram showing the number of lenses and tolerance Figure 2 (μm)

Claims (1)

[Claims] 1. A receptacle having an optical coupling system for optically coupling optical output from a semiconductor laser (6) through a lens (7) to an optical fiber (10) held in an optical fiber connector ferrule (11). In a type semiconductor laser device, the lens (7) and the optical fiber connector ferrule (11)
A receptacle-type semiconductor laser device characterized in that an optical fiber (13) having a core diameter larger than the core diameter of the optical fiber (10) held by the optical fiber connector ferrule (11) is inserted between the optical fiber connector ferrule (11) and the optical fiber connector ferrule (11). 2. The length of the optical fiber (13) is such that when a certain guided mode is excited at the end of the optical fiber, the energy of that mode is transferred to another mode and no other mode is excited. A receptacle type semiconductor laser device according to claim 1.