JPH07117625B2 - Semiconductor laser module - Google Patents

Description

The present invention relates to a light source for optical communication, and more particularly to a semiconductor laser module having a function of efficiently coupling a semiconductor laser element and an optical fiber.

[Conventional technology]

Generally, the semiconductor laser module has already been put to practical use as a light source for optical communication, and the basic configuration shown in FIG. 3 is widely known. That is, this semiconductor laser module has a structure in which an outgoing beam from a semiconductor laser (hereinafter referred to as LD) pellet 1 is focused on the end face of the optical fiber 3 by the lens 2. By the way, since the LD has a characteristic that reflection noise is generated by re-injection of the near-end reflected light and the modulation characteristic is deteriorated, the near-end reflected light (broken line) is suppressed by obliquely polishing the end face of the optical fiber 3. There is.

FIG. 4 shows an example of the structure of a conventional semiconductor laser module. At one end of the holder 5 that houses the ball lens 4,
An LD package 6 that accommodates the LD pellet 1 is fixed, and a ferrule 8 obtained by terminal-treating an optical fiber core wire 7 is inserted from the other end and permanently fixed to a holder 5 with a screw 9. The end face of the ferrule 8 is obliquely polished for the reason described above.

[Problems to be Solved by the Invention]

As described above, in the prior art, it was necessary to polish the ferrule 8 obliquely. Therefore, it was not possible to adopt a structure in which a general-purpose standard connector whose tip was polished at a right angle was directly attached and detached. That is, as shown in FIG. 3, the conventional semiconductor laser module has a pigtail structure in which one end of the optical fiber core wire 7 is permanently fixed to the semiconductor laser module and the other end has a connector.

By the way, this semiconductor laser module is mounted on a circuit board together with a drive circuit, a digital circuit, etc., and constitutes an optical panel. Conventionally, because the semiconductor laser module is a pigtail type, the connector on the tip of the pigtail is connected to the adapter mounted on the side of the optical panel, the excess length of the optical fiber is processed, and then the semiconductor laser module body is mounted on the circuit board. It is supposed to be done. Therefore, the semiconductor laser module body cannot be mounted on the side surface of the optical panel. That is, there is a drawback that the degree of freedom of the mounting position is low. In addition, there is a drawback that the mounting space is taken up by the length of the optical fiber. Further, since the connector cannot be attached to and detached from the semiconductor laser module main body, an adapter, an optical connector at the tip of the pigtail, and a ferrule part in the semiconductor laser module are required, and there is a drawback that the cost becomes high. Furthermore, since the length of the optical fiber changes depending on the design of the optical panel, there is a drawback that the versatility is poor.

The object of the present invention is made in view of the above-mentioned drawbacks, and it is possible to increase the degree of freedom of the mounting position on the optical panel and reduce the mounting space, and further reduce the cost, and the semiconductor laser module is excellent in versatility. To provide.

[Means for Solving the Problems]

According to the present invention, in a semiconductor laser module including a semiconductor laser element, at least one lens housed and held in a holder and converging an emission beam of the semiconductor laser element, and a receptacle fixed to the holder, The stopper of the receptacle consists of a glass spacer with one optical surface polished to a spherical shape and the other optical surface polished obliquely to the optical axis, and the ferrule tip of the optical connector fitted into this receptacle is It is characterized in that it is configured so as to come into contact with the spherical optical surface of the glass spacer at one point near the optical axis.

[Action]

As described above, in the present invention, a glass spacer having one optical surface polished to a spherical shape and the other optical surface polished obliquely to the optical axis is used as the stopper of the receptacle to which the connector can be directly attached / detached. As a result, optical matching can be achieved with a simple configuration in which the tip of the ferrule of the optical connector fitted in the receptacle contacts the spherical optical surface of the glass spacer at one point near the optical axis. A semiconductor laser module can be realized. As a result, the adapter, the connector at the tip of the pigtail, and the ferrule inside the semiconductor laser module are not required, and the cost of the optical panel can be significantly reduced. Further, since there is no pigtail portion, the mounting space can be reduced, the degree of freedom of the mounting position on the optical panel can be increased, and the versatility does not deteriorate due to the change in pigtail length.

〔Example〕

The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 is a schematic configuration diagram showing the basic configuration of a semiconductor laser module according to the present invention. This semiconductor laser module includes an LD pellet 10, a lens 11 that converges an output beam of the LD pellet 10, a ferrule 13 that is a terminal processed optical fiber 12, and a detachable receptacle 14 for the ferrule 13. And a connector detachable type semiconductor laser module, characterized in that glass spacers (15) whose optical surfaces are not parallel to each other are used as stoppers of the receptacle (14).

When a PC (Physical Contact) type connector, which has become popular recently, is inserted into the receptacle 14, the end face of the optical fiber 12 is brought into close contact with the glass spacer 15 to be in a PC state. On the other hand, since the optical surface of the glass spacer 15 opposite to the optical fiber 12 is formed obliquely with respect to the optical axis, reinjection of reflected light (broken line) into the LD is suppressed. Therefore,
According to the present invention, a connector can be directly attached and detached, and a semiconductor laser module with small reflection noise can be realized.

Now, a specific configuration of the semiconductor laser module according to the present invention will be described with reference to FIG. The stopper 16 of the receptacle 14 is composed of a metal pipe 17 provided with a screw on the outer periphery and a glass spacer 15 provided inside the metal pipe 17, and one of the glass spacer 15 on the fiber ferrule side. The end face 15a is spherically polished and the other end face 15b is obliquely polished. The holder 19 containing the ball lens 18 and the receptacle 14 are fixed to each other via a screw on the outer circumference of the stopper 16.

The LD package 20 has its optical axis adjusted with respect to the optical fiber core portion of the PC connector connected to the receptacle 14, and is then fixed to the holder 19 by spot welding with a YAG laser or the like. In the experimental example, it was confirmed that the reflection at the contact portion between the glass spacer 15 and the PC connector tip was 35 dB or more in terms of return loss, which was about the same as the reflection at the connection portion of the PC connectors and was sufficiently small for practical use.

〔The invention's effect〕

As described above, the semiconductor laser module according to the present invention uses a glass spacer having one optical surface polished to a spherical shape and the other optical surface obliquely polished as a stopper of a receptacle to which a connector can be directly attached / detached. With this configuration, optical matching can be achieved with a simple configuration in which the ferrule tip of the optical connector fitted in the receptacle contacts the spherical optical surface of the glass spacer at a single point near the optical axis. A detachable semiconductor laser module can be realized. As a result, the adapter, the connector at the tip of the pigtail, and the ferrule in the semiconductor laser module can be eliminated as compared with the conventional pigtail type semiconductor laser module, whereby the cost of the optical panel can be significantly reduced. Also,
Since there is no pigtail part, the mounting space can be reduced and the degree of freedom of the mounting position on the optical panel can be increased,
Further, it has various effects that it is possible to surely prevent a decrease in versatility due to a change in pigtail length.

Further, in the present invention, one optical surface of the glass spacer is polished into a spherical shape, and the surface is in contact with the ferrule tip of the optical connector fitted to the receptacle at a single point in the vicinity of the optical axis. Compared to the case where the flat surfaces are in contact with each other, optical matching can be secured without using an adhesive. Therefore, not only is the matching agent unnecessary, but there is no room for problems such as evaporation, peeling, or deterioration when the matching agent is used, and the reliability of optical matching can be improved.

Therefore, the semiconductor laser module of the present invention is likely to be widely put into practical use, and its industrial value is very high.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a basic configuration of a semiconductor laser module according to the present invention, FIG. 2 is a sectional view showing an embodiment of a concrete configuration of the semiconductor laser module according to the present invention, and FIG. FIG. 4 is a schematic configuration diagram showing a basic configuration of the semiconductor laser module of FIG. 4, and FIG. 4 is a sectional view showing an example of a specific configuration of a conventional semiconductor laser module. 10 …… LD pellet, 11 …… Lens, 12 …… Optical fiber, 13 …… Ferrule, 14 …… Receptacle, 15 …… Glass spacer, 15a …… One end face, 15b …… Other end face, 16 …… Stopper, 18 …… ball lens, 19 …… holder, 20 …… LD package.

Claims (1)

[Claims] 1. A semiconductor laser module comprising a semiconductor laser element, at least one lens housed and held in a holder for converging an emission beam of the semiconductor laser element, and a receptacle fixed to the holder. The stopper of this receptacle is composed of a glass spacer with one optical surface polished to a spherical shape and the other optical surface polished obliquely to the optical axis, and the ferrule tip of the optical connector fitted to this receptacle. Is configured to contact the spherical optical surface of the glass spacer at one point in the vicinity of the optical axis.