JPH0633108U - Airtight structure of optical fiber of optical module - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the number of parts required for airtightness between the case and the optical fiber, and to facilitate its assembly. [Structure] In a case 11 accommodating an optical module body 12, an insertion hole 1 for extending an optical fiber 19 connected to the optical module body 12 to the outside of the case 11.
1a is provided. The optical fiber reinforcing sleeve 1 is fixed to the portion of the optical fiber 19 located in the insertion hole 11a. Then, an airtight plug 2 is press-fitted from the outside of the case 11 into the gap between the optical fiber reinforcing sleeve 1 and the insertion hole 11a to hermetically seal this portion.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an airtight structure of an optical fiber portion of an optical module used in an optical communication measuring instrument.

[0002]

[Prior art]

 For optical modules used in optical communication measuring instruments, chip carrier type optical elements such as LDs (Laser Diodes) and PDs (Photo Diodes) are used internally in order to reduce size and cost. Has been done. FIG. 2 shows a specific structure of the optical module. Here, the optical module body 12 is configured by mounting the LD 13, PD 14 and the lens 15 as optical elements, the ferrule 16 and the ferrule holding portion 17 on the substrate 18, and the optical module body 12 12 is disposed in the case 11. Further, at the opposite position of the portion of the ferrule holding portion 17 to which the ferrule 16 is attached, one end of an optical fiber 19 for guiding the light from the LD 13 to the outside or guiding the light from the outside to the PD 14 has a cap nut. It is attached by 20. Furthermore, the optical fiber 19 extends to the outside of the case 11 through an insertion hole 11a formed in one wall surface of the case 11.

By the way, the above-mentioned optical module M uses optical elements 13 and 14, and these optical elements 13 and 14 are oxidized by oxygen in the air to cause characteristic deterioration. It was necessary to arrange the optical module main body 12 on which 13 and 14 were placed in the case 11 and to make the case 11 airtight.

That is, in the optical module M, the airtightness is required in the opening portion in the upper part of the case 11 to which the cover (not shown) is attached and the optical fiber portion. The optical fiber portion is a part of the optical fiber 19 and is used when the optical fiber 19 is inserted into an insertion hole 11a formed in one wall surface of the case 11 and is extended to the outside of the case 11. Of the insertion hole 11a. The opening of the upper part of the case 11 is hermetically sealed by attaching a cover (not shown) to the upper part of the case by seam welding or the like.

Further, the conventional air-tightness in the optical fiber portion has the structure described below. That is, as shown in FIG. 3, the holder 21 and the hood 22 arranged so as to cover the periphery of the optical fiber 19 are tightened by tightening the two cap nuts 23 and 24 from the inside and the outside of the case 11. The two O-rings 25 and 26 provided in advance between the cap nuts 23 and 24 and between the cap nut 23 and the holder 21 are crushed and the optical fiber portion of the optical fiber 19 is hermetically sealed. .

On the other hand, the conventional procedure for assembling the airtight structure is such that the optical module main body 12 is externally assembled in advance and then housed in the case 11, as described below. That is, as shown in FIG. 4A, the optical module main body 12 is configured in a state where the respective components are attached to the substrate 18 in advance and the optical axes thereof are aligned. Further, one end of an optical fiber 19 is attached to the ferrule holding portion 17 attached on the substrate 18 by a cap nut 20.

Further, a cap nut 23, an O-ring 25, a holder 21 and a hood 22 which are parts for airtightness are attached near one end of the optical fiber 19 attached to the ferrule holding portion 17. A ferrule 27 connected to the outside of the optical module M is provided at the other end of the optical fiber 19.

Then, the optical module main body 12 having the above-described configuration is housed in the case 11 as follows. First, as shown in FIG. 4A, the ferrule 27 is inserted from the inside of the case 11 into the insertion hole 11 a formed in the side plate of the case 11. Then, as shown in FIG. 4B, the optical module body 12 is mounted in the case 11, and the cap nut 23 is brought into contact with the inner edge portion of the insertion hole 11a. Further, the end surface of the holder 21 is brought into contact with the cap nut 23, and the O-ring 25 between the cap nut 23 and the holder 21 is positioned in the groove 21a formed on the end surface of the holder 21.

Next, the cap nut 24 is inserted into the optical fiber 19 from the ferrule 27 side. An O-ring 26 is wound around the outer periphery of the cap nut 24. Then, the cap nut 24 and the cap nut 23 in the case 11 are screwed together and tightened. As a result, as shown in FIG. 3, the O-rings 25 and 26 between the cap nuts 23 and 24 and between the cap nut 23 and the holder 21 are crushed and the optical fiber portion of the optical fiber 19 is hermetically sealed.

[0010]

[Problems to be solved by the device]

 However, in the above-described airtight structure of the optical fiber portion of the optical module, since the number of parts for airtightness is large, some components are previously prepared before the optical fiber 19 is attached to the ferrule holding portion 17 of the optical module body 12. However, the work efficiency in the assembly process was poor. In addition, since the airtight component has a complicated shape, it is difficult to process it. Further, in assembling the airtight portion of the optical fiber portion, the O-rings 25 and 26 must be properly crushed, which causes a problem that the tightness of the cap nuts 23 and 24 must be constant. It was

In order to solve the above problems, the present invention reduces the number of parts required for hermetically sealing the case and the optical fiber, facilitates assembly, and improves the working efficiency of the optical module. The purpose is to provide an airtight structure for the optical fiber part.

[0012]

[Means for Solving the Problems]

 In order to achieve the above object, the optical fiber part airtight structure of the optical module according to the present invention has an insertion hole 11a formed in one wall surface of the case 11 in which the optical module body 12 is housed, and the optical module connected to the optical module body 12 is provided. In the optical fiber part airtight structure of the optical module M, which extends the fiber 19 from the insertion hole 11a to the outside of the case 11 and hermetically seals between the insertion hole 11a and the optical fiber 19, The optical fiber reinforcing sleeve 1 is fixed to a portion located in the insertion hole 11a, and the airtight plug 2 is deformably press-fitted into a gap between the optical fiber reinforcing sleeve 1 and the insertion hole 11a. It is characterized by that.

[0013]

[Action]

 An optical fiber 19 is connected to the optical module main body 12 housed in the case 11. The optical fiber 19 extends to the outside from an insertion hole 11a formed in the case 11. Then, the optical fiber reinforcing sleeve 1 is fixed to a portion of the optical fiber 19 located in the insertion hole 11a. Further, the airtight plug 2 is press-fitted into the gap between the optical fiber reinforcing sleeve 1 and the insertion hole 11a, and the optical fiber reinforcing sleeve 1 absorbs a load from the outside of the optical fiber 19 so that the optical fiber reinforcing sleeve 1 and the insertion hole 11a are not connected to each other. The airtightness with the fiber 19 is achieved.

[0014]

【Example】

 FIG. 1 is an enlarged side sectional view of a part of a hermetic structure of an optical fiber portion of an optical module according to an embodiment of the present invention. In the embodiments described below, the same or equivalent parts as those of the above-mentioned conventional example are designated by the same reference numerals and the description thereof will be omitted. As shown in FIG. 1, an optical fiber reinforcing sleeve 1 and an airtight stopper 2 are used for hermetically sealing an optical fiber portion of an optical module according to the present invention.

The optical fiber reinforcing sleeve 1 is formed of metal and is attached to the optical fiber 19 connected to the ferrule holding portion 17 of the optical module main body 12. The specific mounting position of the optical fiber reinforcing sleeve 1 is attached to the optical fiber portion of the optical fiber 19 when the optical module body 12 is housed in the case 11. Here, the optical fiber portion is a part of the optical fiber 19 and is used when the optical fiber 19 is inserted into the insertion hole 11a formed in one wall surface of the case 11 and is extended to the outside of the case 11. Of the insertion hole 11a. Further, the optical fiber reinforcing sleeve 1 is attached to the optical fiber portion 19a by an epoxy or silicone adhesive.

On the other hand, the airtight plug 2 is formed of fluororesin. This fluororesin is a plastic material that is softer than the case 11 and the optical fiber reinforcing sleeve 1, and is a material that can be deformed by pressure. When the airtight plug 2 made of a fluororesin is deformed by press-fitting described later, the airtightness for easily contacting the insertion hole 11a is easily obtained, and the weatherproofness is also excellent.

Further, a through hole 2 a is formed in the center of the airtight stopper 2, the inner diameter of which is set smaller than the outer diameter of the optical fiber reinforcing sleeve 1, and the outer diameter of the through hole 11 a of the case 11 is set. Is set larger than. Further, the inner diameter of the through hole 2a does not necessarily have to be set smaller than the outer diameter of the optical fiber reinforcing sleeve 1. For example, as will be described later, when the airtight plug 2 is press-fitted into the insertion hole 11a of the case 11, the inner diameter of the through hole 2a at the center of the airtight plug 2 is deformed and becomes smaller than the outer diameter of the optical fiber reinforcing sleeve 1. It may be a setting. Further, a flange 2b is formed at one end of the airtight plug 2.

Next, a procedure for assembling the optical fiber section to make it airtight will be described. First, the optical module main body 12 is previously assembled in the same manner as in the prior art, and the optical fiber 19 to which the optical fiber reinforcing sleeve 1 is fixed is attached to the ferrule holding portion 17. Then, after the optical module main body 12 is housed in the case 11, the airtight stopper 2 is inserted into the optical fiber 19 from the ferrule 27 side outside the case 11 with the flange 2b side facing backward.

Further, the airtight plug 2 is inserted between the insertion hole 11a and the optical fiber reinforcing sleeve 1 and press-fitted until the flange 2b abuts the outer edge of the insertion hole 11a. When the airtight stopper 2 is press-fitted, the load applied to the optical fiber 19 is absorbed by the optical fiber reinforcing sleeve formed of metal.

Therefore, in the airtight structure of the above-described embodiment, the airtight component is composed only of the optical fiber reinforcing sleeve 1 and the airtight plug 2, and the airtight plug 2 is easily press-fitted into the insertion hole 11a of the case 11. It can be assembled, and work efficiency in the assembly process when airtight can be improved. Moreover, since the shape of the airtight parts is simplified, the molding of these parts becomes easy. Further, in the process of attaching the optical fiber 19 to the ferrule holding portion 17 before airtightness, only the optical fiber reinforcing sleeve 1 is the component to be passed through the optical fiber 19, so that the troublesome assembling in this process is reduced as in the conventional case. It is possible to improve work efficiency.

[0021]

As described above, in the airtight structure of the optical fiber portion of the optical module according to the present invention, the parts for airtightness are composed only of the optical fiber reinforcing sleeve and the airtight stopper, and the airtight stopper is press-fitted even in the assembly procedure. Therefore, it is possible to easily assemble the respective parts without damaging the optical fiber, and it is possible to improve the work efficiency in each assembling process.

[Brief description of drawings]

FIG. 1 is a partially enlarged side sectional view of an airtight structure of an optical fiber portion of an optical module according to an embodiment of the present invention.

FIG. 2 is a plan view of an airtight structure of an optical fiber portion of a conventional optical module.

FIG. 3 is a partially enlarged side sectional view of FIG.

4A and 4B are partially enlarged side cross-sectional views showing a conventional assembly procedure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical fiber reinforcement sleeve, 2 ... Airtight stopper, 11 ... Case, 11a ... Insertion hole, 12 ... Optical module main body, 19
… Optical fiber, M… Optical module.

Claims (1)

[Scope of utility model registration request] 1. An insertion hole (11a) is formed in one wall surface of a case (11) accommodating an optical module main body (12), and an optical fiber (19) connected to the optical module main body is inserted through the insertion hole. In an optical fiber part airtight structure of an optical module (M) that extends to the outside of the case and hermetically seals between the insertion hole and the optical fiber, the optical module is fixed to a portion located on the insertion hole on the optical fiber. An optical fiber portion of an optical module, comprising: an optical fiber reinforcing sleeve (1); and an airtight plug (2) press-fitted in a gap between the optical fiber reinforcing sleeve and the insertion hole so as to be deformable. Airtight structure.