JPH02216109A - Semiconductor laser module - Google Patents

Abstract

PURPOSE:To realize a miniaturize module where parts are easily aligned by connecting a multimode optical fiber, which has the front end worked into a ball and has the same diameter as a single mode optical fiber, to the front end of the single mode optical fiber. CONSTITUTION:A multimode optical fiber (MMF) 8 having the same diameter as a single mode optical fiber (SMF) 9 is connected to the front end of the SMF 9, and the front end of the MMF 8 is worked into a ball whose outside diameter is larger than that of the fiber. Then, the spot size of the SMF 9 is expanded without precise adjustment. Consequently, a semiconductor laser 1 or two lenses having the diameter considerably larger than that of the SMF 9 which are conventionally used are omitted to miniaturize the module. The SMF 9 and the MMF 8 are easily aligned, and the assembling cost is reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention integrates a semiconductor laser, a lens, and a single-mode optical fiber, and efficiently couples the light emitted from the semiconductor laser to the single-mode optical fiber. The present invention relates to a semiconductor laser module, and particularly relates to a semiconductor laser module that uses one or more lenses to form a coupling system.

[Conventional technology]

In order to efficiently couple the light emitted from a semiconductor laser (hereinafter abbreviated as LD) to a single mode optical fiber (hereinafter abbreviated as SMF), one or more lenses are usually used to connect the LD.
The spot size of the emitted light is made to match the spot size of the SMF to form an optical coupling circuit.

FIG. 4 shows an example of such a coupling system. The light emitted from the LDl is condensed by the second lens 4, becomes a nearly parallel light beam, and enters the second lens 4 integrated with the SMF 3. In this incident plane, the spot size of the SMF 3 is expanded by the second lens 4, so an integrated part formed by the SMF 3, the second lens 4, and the holder 5 that holds these SMF 3 and the second lens 4 is formed. This coupling system has the advantage that even if the axis of the first lens 2 is misaligned with respect to the first lens 2, the amount of decrease in coupling efficiency is small.

[Problem to be solved by the invention]

However, in the conventional LD module for SMF described above, there are two lenses (second lens 4, second lens 4) that are much larger than the outer diameter of LDl or SMF3.
It is difficult to miniaturize the module because S
There is a drawback that the sensitivity to axis misalignment between the MF 3 and the second lens 4 is high, and alignment of these parts is difficult.

SUMMARY OF THE INVENTION An object of the present invention was made in view of the above-mentioned drawbacks, and it is an object of the present invention to provide a semiconductor laser module that can be miniaturized and whose components can be easily aligned.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention provides a semiconductor laser module configured to input light emitted from a semiconductor laser into a single-mode optical fiber through one or more lenses. A multimode optical fiber having the same outer diameter is connected to the single mode optical fiber, and the tip of the multimode optical fiber is spherical and has an outer diameter larger than the outer diameter of the multimode optical fiber. It is structured as follows.

[Effect]

In this way, in the present invention, precise adjustment can be performed by connecting a multimode optical fiber (hereinafter abbreviated as MMF) whose tip is processed into a spherical shape larger than the outer diameter of the SMF to the end face of the SMF. The spot size of the SMF can be expanded without any problem.

Therefore, alignment between SMF and MMF can be easily performed,
At the same time, since there is no need for a large lens, SMF-L
The assembly cost and size of the D module can be reduced.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an embodiment of an LD module according to the present invention, and FIGS. 2(A) and (B) are diagrams showing the manufacturing process of the same LD module.

In Fig. 1, the light emitted from the LD 6 is focused by the lens 7 and expanded to a spot size of W at the tip of the MMF 8, and the spot size of the end face of the SMF 9 is expanded to W2 at the tip of the MMF 8. When W+ = W2, the coupling efficiency from LD6 to SMF9 is highest. At this time, the spherical processing 8158a at the tip of the MMF 8 has a lens effect.

That is, as shown in FIG. 2(A), the MMF8 is cut short in advance, the tip is processed into a spherical shape by thermal processing such as electrical discharge, and this is then cut into SMF8 as shown in FIG. 2(B).
9 is inserted halfway and has an inner diameter slightly larger than the outer diameter of the SMF 9, and is inserted from the opposite side of the lary 10 and fixed. In this case, MMF8 and SMF
By making the outer diameters of MMF 9 the same, MMF 8 can be combined with SMF 9 simply by inserting it into glass capillary 10.

For example, the outer diameter of MMF8 and SMF9 is 125 μm.
1. The inner diameter of the glass capillary 10 is 126 μm.

3(A>, (B), and (C) show other embodiments of the LD module of the present invention. MMF8 and SMF9 are connected by a discharge splice (see FIG. 3(A)), and MM
After cutting the F8 part, the tip part is machined into a spherical shape by electric discharge, and 8a is the spherical machined part>, glass capillary 10
to strengthen the bond between MMF8 and SMF9 (Figure 3 (B)
)reference).

FIG. 3(C) shows an SM constructed using such means.
An example of an F-LD module is shown. On the front side of the MMF 8, the LD 6 and the LD 7 are arranged.

〔Effect of the invention〕

As explained above, according to the semiconductor laser module of the present invention, by connecting the MMF whose tip is machined into a spherical shape larger than the outer diameter of the SMF to the end face of the SMF, the SMF can be used without making precise adjustments. The spot size can be expanded.

Therefore, alignment between SMF and MMF can be easily performed,
At the same time, there is no need for a large lens as in the prior art, which brings about the excellent effect of reducing the assembly cost and downsizing of the semiconductor laser module.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of the LD module according to the present invention, FIGS. 2(A) and (B) are diagrams showing the manufacturing process of the LD module, and FIGS. 3(A) to C ) is a diagram showing the manufacturing process of another embodiment of the same LD module, No. 4
The figure is a schematic configuration diagram showing an example of a conventional LD module. 6...LD,?・・・・・・Runs, 8...
...MMF, 8a... Spherical processing part, 9...
...SMF, 10...Glass capillary.

Claims (1)

[Claims] The light emitted from the semiconductor laser is connected to a single mode optical fiber.
In a semiconductor laser module configured to allow input through more than one lens, a multimode optical fiber having the same outer diameter as the single mode optical fiber is connected to the tip of the single mode optical fiber, and the multimode optical fiber is connected to the tip of the single mode optical fiber. A semiconductor laser module characterized in that the tip of an optical fiber is spherical with an outer diameter larger than the outer diameter of the multimode optical fiber.