JP2014075536A - Optical module and cap for optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage to a laser element at the time of attaching a cap.SOLUTION: An optical module 1 includes a stem 20, a semiconductor laser element 11 provided on the stem 20, and a cap 30 covering the semiconductor laser element 11 on the stem 20. The stem 20 has a first screw portion 22s provided on an outer peripheral surface 22c of the stem 20. The cap 30 has a cylindrical side-wall portion 30a, a ceiling portion 30b covering one end of the side-wall portion 30a, and a second screw portion 30s provided on an inner peripheral surface 30d of the other end of the side-wall portion 30a. The first screw portion 22s and the second screw portion 30s are fitted into each other.

Description

  The present invention relates to an optical module and an optical module cap.

  Conventionally, in an optical module, a laser element provided on a stem is sealed by a cap having a window portion. This cap is bonded to the stem by welding (see Patent Document 1 and Patent Document 2).

JP-A-7-176825 Japanese Patent Laid-Open No. 11-251688

  However, in the welding process, since the cap is bonded to the stem using arc discharge or the like, heat is generated during welding. This heat may damage the laser element.

  Accordingly, the present invention has been made to solve such problems, and provides an optical module having a structure capable of suppressing damage to a laser element when the cap is attached, and an optical module cap. With the goal.

  In order to solve the above problems, an optical module according to the present invention includes: (a) a stem; (b) a semiconductor laser element provided on the stem; and (c) a cap that covers the semiconductor laser element on the stem. And comprising. The stem includes a first screw portion provided on an outer peripheral surface of the stem, and the cap includes a cylindrical side wall portion, a ceiling portion covering one end of the side wall portion, and the other end of the side wall portion. A second screw portion provided on an inner peripheral surface, and the first screw portion and the second screw portion are fitted together.

  In this optical module, the first screw portion is provided on the outer peripheral surface of the stem, and the second screw portion is provided on the inner peripheral surface at the other end of the side wall portion of the cap. Then, the first screw portion and the second screw portion are fitted together. In this way, the cap can be attached to the stem by screwing. For this reason, it is possible to attach the cap to the stem without performing welding, and it is possible to suppress damage to the semiconductor laser element when the cap is attached.

  The stem may include a first member and a second member provided on the first member, and the first member, the second member, and the semiconductor laser element include: The first member may be disposed in order along the axial direction of the side wall, and the first member includes a first portion provided with the second member, and a second portion surrounding the first portion with the axial direction as an axis. The first screw portion may be provided on the outer peripheral surface of the second member. In this case, the first screw portion and the second screw portion can be fitted together and tightened until the other end of the cap contacts the second portion of the first member of the stem. For this reason, it becomes possible to prescribe | regulate the position of the cap with respect to a stem.

  The other end of the cap may be in contact with the second portion. In this case, when the other end of the cap and the second portion of the first member of the stem are in contact, the airtightness of the space surrounded by the cap and the stem can be improved.

  The optical module may further include a sealing member. In this case, the sealing member may be sandwiched between the other end and the second portion. In this case, the sealing member can further improve the airtightness of the space surrounded by the cap and the stem.

  The cap may be made of metal. Even when a metal cap is used, it can be attached to the stem without welding, and damage to the semiconductor laser element during attachment of the cap can be suppressed.

  The optical module may further include a lens provided on the ceiling. Even when a cap having a lens on the ceiling is used, the cap can be attached to the stem without welding, and damage to the semiconductor laser element when the cap is attached can be suppressed.

  The second screw portion may be a convex portion extending in a spiral shape, and the second screw portion may be a concave portion extending in a spiral shape.

  The cap for an optical module according to the present invention is a cap for covering the semiconductor laser element on the stem. The optical module cap includes a cylindrical side wall, a ceiling that covers one end of the side wall, and a screw provided on the inner peripheral surface of the other end of the side wall.

  In this optical module cap, a second screw portion is provided on the inner peripheral surface of the other end of the side wall portion. When this optical module cap is attached to a stem having a first screw portion on the outer peripheral surface, the optical module cap can be attached to the stem by screwing. For this reason, it is possible to attach the optical module cap to the stem without performing welding, and it is possible to suppress damage to the semiconductor laser element when the cap is attached.

  ADVANTAGE OF THE INVENTION According to this invention, the damage to the laser element at the time of attachment of a cap can be suppressed.

It is an upper perspective view which shows roughly the optical module which concerns on this embodiment. It is a figure which shows schematically the cross section along the axis | shaft of the optical module of FIG. It is process drawing which shows the manufacturing method of the optical module of FIG. It is a lower perspective view which shows schematically the modification of the cap for optical modules.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a diagram schematically showing an optical module according to the present embodiment. As shown in FIG. 1, the optical module 1 is a coaxial optical module having an axis X as an axis, for example, and includes a package 10, a semiconductor laser element 11, a submount 12, and a mounting member 13. I have.

  The package 10 is provided so as to cover the semiconductor laser element 11, the submount 12 and the mounting member 13. The semiconductor laser element 11, the submount 12, and the mounting member 13 are accommodated in an airtight space provided by the package 10. The package 10 includes a stem 20, a plurality of lead pins 23, a cap 30, and a lens 31.

  The stem 20 has a surface 20a intersecting the axis X, and the semiconductor laser element 11, the submount 12, and the mounting member 13 are mounted on the surface 20a. The stem 20 is made of, for example, iron. The stem 20 is provided with a plurality of through holes 20d extending in the axis X direction. Lead pins 23 are passed through these through holes 20 d, and the gap between the lead pins 23 and the stem 20 is sealed by a sealing member 24. As the sealing member 24, low melting point glass or the like is used.

  The cap 30 is a hollow cylindrical member provided on the stem 20 and having an axis X as an axis. The cap 30 is made of, for example, an iron nickel alloy. The cap 30 has a cylindrical side wall portion 30a with the axis X as an axis, and a ceiling portion 30b that covers one end of the side wall portion 30a. Further, the other end of the side wall 30 a is fixed to the stem 20. An opening 30c is provided around the axis X in the ceiling 30b. The lens 31 is fitted and held in the opening 30c, and the lens 31 and the opening 30c are sealed with a sealing member such as low melting point glass.

  The semiconductor laser element 11 is a group III nitride semiconductor laser element, for example, and includes an active layer. The semiconductor laser element 11 outputs light along the axis X. The submount 12 mounts the semiconductor laser element 11. The semiconductor laser element 11 and the submount 12 are fixed to each other via a conductive adhesive. The mounting member 13 is a heat sink, for example, and is made of a metal having excellent thermal conductivity. The mounting member 13 is provided on the stem 20. The mounting member 13 is joined to the surface 20 a of the stem 20. The mounting member 13 has a mounting surface 13a along the axis X, and the submount 12 is mounted on the mounting surface 13a.

  Next, the structure for fixing the stem 20 and the cap 30 will be described in more detail. FIG. 2 is a diagram schematically showing a cross section along the axis X of the optical module of FIG. As shown in FIG. 2, the stem 20 includes a first member 21 and a second member 22. The first member 21 is a disk-shaped member having the axis X as an axis, and includes a support surface 21a intersecting the axis X and a back surface 21b opposite to the support surface 21a. The length H1 of the first member 21 in the axis X direction is, for example, about 0.5 mm, and the outer diameter D1 of the first member 21 is, for example, about 5.6 mm. Further, the first member 21 includes a first portion 211 and a second portion 212. The first portion 211 includes the axis X and has an outer diameter of, for example, about 3.2 mm. The first portion 211 is provided with a plurality of through holes 21d extending in the axis X direction. The second portion 212 is an annular portion that surrounds the first portion 211 around the axis X.

  The second member 22 is a columnar member having the axis X as an axis, and is provided on the first portion 211 of the first member 21 and is not provided on the second portion 212. The second member 22 has a support surface 22 a that intersects the axis X and a fixed surface 22 b that joins the support surface 21 a of the first member 21. The support surface 22a forms a surface 20a. That is, the first member 21, the second member 22, and the semiconductor laser element 11 are sequentially arranged along the axis X direction. The length H2 of the second member 22 in the axis X direction is, for example, about 1 to 3 mm, and the outer diameter D2 of the second member 22 is, for example, about 3.2 mm. A distance D12 from the outer peripheral surface 21c of the first member 21 to the outer peripheral surface 22c of the second member 22 is, for example, about 1.15 mm. The second member 22 is provided with a plurality of through holes 22 d extending in the axis X direction at positions corresponding to the through holes 21 d of the first member 21. The through hole 22d of the second member 22 and the through hole 21d of the first member 21 are connected to form a through hole 20d that penetrates the stem 20 in the axis X direction. The second member 22 has a first screw portion 22s provided on the outer peripheral surface 22c. The first screw portion 22s is a screw groove (concave portion) that is recessed from the outer peripheral surface 22c, and extends spirally over the entire outer peripheral surface 22c.

  The cap 30 has a second screw portion 30s provided on the inner peripheral surface 30d at the other end of the side wall portion 30a. The second screw portion 30s is a screw thread (convex portion) protruding from the inner peripheral surface 30d, and extends spirally along the inner peripheral surface 30d. The outer diameter Dout of the side wall 30a is, for example, about 3.6 mm, and the inner diameter Din is, for example, about 3.2 mm. The first screw portion 22s of the second member 22 and the second screw portion 30s of the cap 30 are screwed together and fitted together. With the first screw portion 22 s and the second screw portion 30 s being screwed together, the other end of the cap 30 is in contact with the support surface 21 a of the second portion 212 of the first member 21.

  The distance W between the bottom portion of the first screw portion 22s and the through hole 20d is such a size that the force applied for screwing does not affect the sealing member 24, and is about 0.3 mm, for example. is there. Depending on the distance W, the depth of the first screw portion 22s and the height of the second screw portion 30s are determined.

  Next, a method for manufacturing the optical module 1 will be described. FIG. 3 is a diagram illustrating a method of manufacturing the optical module of FIG. As shown in FIG. 3, first, in the stem preparation step S01, the stem 20 is prepared. Specifically, first, the first member 21 and the second member 22 are prepared. The first member 21 is formed by preparing a plate material having a predetermined size made of iron, for example, and forming a plurality of through holes 21d at predetermined positions of the plate material. The first member 21 includes a first portion 211 provided with a through hole 21d and a second portion 212 surrounding the first portion 211. The second member 22 is formed by preparing a plate material having a predetermined size made of iron, for example, and forming a plurality of through holes 22d at predetermined positions of the plate material. Then, the first screw portion 22s is formed on the outer peripheral surface of the second member 22 by, for example, cutting using a die. Next, the second member 22 is joined to the first portion 211 of the first member 21 using, for example, silver solder while aligning the plurality of through holes 21d and the plurality of through holes 22d. Thereby, the stem 20 is formed. The through hole 20d is formed by the through hole 21d and the through hole 22d.

  Next, in the cap preparation step S02, the cap 30 is prepared. For example, the cap 30 is formed by attaching the lens 31 to the opening 30c provided in the ceiling 30b of the cap 30 using a solid welding agent. At this time, the lens 31 is fixed to the opening 30c by heating and melting the solid welding agent. Then, the second screw portion 30s is formed on the inner peripheral surface 30d at the other end of the cap 30 by, for example, cutting using a tap. In the lead pin mounting step S03, the plurality of lead pins 23 are inserted into the plurality of through holes 20d, respectively, and the lead pins 23 are fixed to the stem 20 by the sealing member 24. In the mounting member and submount mounting step S04, the mounting member 13 is disposed on the support surface 22a of the second member 22, and the support surface 22a and the mounting member 13 are joined. Then, the submount 12 is mounted on the mounting surface 13 a of the mounting member 13. In the semiconductor laser element mounting step S05, the semiconductor laser element 11 is fixed to the submount 12 using, for example, a conductive adhesive. In the wire bonding step S06, the lead pin 23 and the semiconductor laser element 11 or the submount 12 are connected using a wire.

  In the cap attachment step S07, the stem 20 and the cap 30 are fixed to each other by screwing. More specifically, the first screw portion 22s provided on the outer peripheral surface 22c of the second member 22 and the second screw portion 30s provided on the inner peripheral surface 30d of the cap 30 are screwed and fitted to each other. Match. Then, the cap 30 is screwed until the other end of the cap 30 comes into contact with the second portion 212 of the first member 21. The optical module 1 is produced as described above.

  In the optical module 1, the first screw portion 22 s is provided on the outer peripheral surface 22 c of the second member 22 of the stem 20, and the second screw portion 30 s is provided on the inner peripheral surface 30 d of the other end of the side wall portion 30 a of the cap 30. Yes. Then, the first screw portion 22s and the second screw portion 30s are fitted together. Thus, the cap 30 can be attached to the stem 20 by screwing. For this reason, since the cap 30 can be attached to the stem 20 without performing welding, damage to the semiconductor laser element 11 due to heat and arc discharge during welding can be prevented. As a result, it is possible to suppress damage to the semiconductor laser element 11 during cap sealing.

  Further, the other end of the cap 30 is in contact with the second portion 212 of the first member 21 of the stem 20. For this reason, even if the gas in the package 10 leaks to the outside from between the first screw portion 22 s and the second screw portion 30 s, the contact between the other end of the cap 30 and the second portion 212 leads to the inside of the package 10. The amount of leakage of gas to the outside can be reduced. As a result, the airtightness of the space provided by the package 10 can be improved.

  Further, when the other end of the cap 30 is in contact with the second portion 212, the position of the cap 30 with respect to the stem 20 can be defined. That is, the position of the lens 31 with respect to the semiconductor laser element 11 can be defined. Accordingly, the cap 30 and the stem 20 may be screwed until the cap 30 contacts the second portion 212, and fine adjustment of the screwing is not necessary.

  FIG. 4 is a lower perspective view schematically showing a modified example of the cap 30. As shown in FIG. 4, the cap 30 is different from the cap 30 of the above-described embodiment in that it further includes a sealing member 32.

  The sealing member 32 is an annular member, and is provided on the cap 30 along the lower peripheral edge of the other end of the cap 30. The sealing member 32 is made of, for example, resin. In the optical module 1 using the modified cap 30, the sealing member 32 is sandwiched between the other end of the side wall 30 a and the second portion 212 of the first member 21 of the stem 20.

  Even when the cap 30 of the above modification is used, the same effect as the optical module 1 of the above-described embodiment can be obtained. When the cap 30 according to the modification is used, the sealing member 32 is sandwiched between the other end of the side wall portion 30 a and the second portion 212 of the first member 21 of the stem 20. For this reason, the space between the stem 20 and the cap 30 can be sealed by the sealing member 32, and the airtightness of the space provided by the package 10 can be further improved.

  The optical module and the optical module cap according to the present invention are not limited to those described in the above embodiment. For example, in the above embodiment, the first screw portion 22s is a spiral concave portion and the second screw portion 30s is a convex portion, but the first screw portion 22s is a convex portion and the second screw portion 30s is a concave portion. Good.

  Further, the first screw portion 22s and the second screw portion 30s do not need to be continuous in a spiral shape, and the stem 20 and the cap 30 can be screwed together by the first screw portion 22s and the second screw portion 30s. If it is.

  DESCRIPTION OF SYMBOLS 1 ... Optical module, 11 ... Semiconductor laser element, 20 ... Stem, 21 ... 1st member, 22 ... 2nd member, 22c ... Outer peripheral surface, 22s ... 1st screw part, 30 ... Cap, 30a ... Side wall part, 30b ... Ceiling part, 30d ... inner peripheral surface, 30s ... second screw part, 31 ... lens, 32 ... sealing member, 211 ... first part, 212 ... second part, X ... axis.

Claims (9)

Stem,
A semiconductor laser element provided on the stem;
A cap that covers the semiconductor laser element on the stem;
With
The stem has a first screw portion provided on the outer peripheral surface of the stem,
The cap includes a cylindrical side wall, a ceiling that covers one end of the side wall, and a second screw provided on the inner peripheral surface of the other end of the side wall.
The optical module, wherein the first screw part and the second screw part are fitted together. The stem includes a first member and a second member provided on the first member,
The first member, the second member, and the semiconductor laser element are sequentially arranged along the axial direction of the side wall portion,
The first member includes a first portion provided with the second member, and a second portion surrounding the first portion with the axial direction as an axis,
The optical module according to claim 1, wherein the first screw portion is provided on an outer peripheral surface of the second member.   The optical module according to claim 2, wherein the other end of the cap is in contact with the second portion. A sealing member,
The optical module according to claim 2, wherein the sealing member is sandwiched between the other end and the second portion.   The optical module according to any one of claims 1 to 4, wherein the cap is made of metal.   The optical module according to claim 1, further comprising a lens provided on the ceiling portion.   The optical module according to claim 1, wherein the second screw portion is a convex portion extending in a spiral shape.   The optical module according to claim 1, wherein the second screw portion is a concave portion extending in a spiral shape. A cap for covering the semiconductor laser element on the stem,
A cylindrical side wall,
A ceiling portion covering one end of the side wall portion;
A screw portion provided on the inner peripheral surface of the other end of the side wall portion;
An optical module cap comprising:

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