Optical module

Abstract

To provide an optical module capable of suppressing the deformation of a package.SOLUTION: The optical module includes: a package having an aperture surrounded by side walls; and a lid that is placed on the package to seal the aperture. The lid has: a welding part that is plate-shaped and fixed by welding to a top surface of the side wall of the package in which the aperture is formed; an easily deformable part that is formed at a distance from the welding part and is deformable in association with the welding; and a flat center part.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This disclosure relates to an optical module.

Background Art

[0002] Patent Document 1 describes a waveguide type optical module. The waveguide type optical module includes a package and a lid. The package houses a light emitting element, a lens, a waveguide substrate, and a single mode optical fiber. The lid hermetically seals the package by means such as welding. A notch is provided at the upper part of the side surface of the package. In the above-described waveguide type optical module, the bending stress generated on the side surface of the package due to temperature change when the lid is attached to the package is concentrated in the notch. Thereby, the influence on optical components such as a light emitting element is prevented.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described waveguide type optical module, there is a concern that cracks may occur when stress is concentrated in the notch. Further, when the lid is fixed to the package by welding as described above, the lid shrinks due to heat generation during welding, and deformation accompanying the shrinkage may occur in the package. When the optical system is complete inside the package, the positions of the components of the optical module may be displaced due to deformation of the package, and the light coupling efficiency may vary.

[0005] An object of this disclosure is to provide an optical module capable of suppressing deformation of a package.

Means for Solving the Problems

[0006] The optical module according to this disclosure comprises a package having an opening, and a lid that is placed on the package and seals the opening. The lid has a welded portion that is fixed by welding to the upper surface of the package in which the opening is formed, and a deformable portion that is formed at a position away from the welded portion and deforms in conjunction with welding. [Effects of the Invention]

[0007] According to this disclosure, deformation of the package can be suppressed. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a partial cross-sectional view of an optical module according to the first embodiment. [Figure 2] Figure 2 is a partial cross-sectional view showing the optical module from Figure 1 with the lid removed. [Figure 3] Figure 3 is a schematic cross-sectional view showing the package and lid of the optical module shown in Figure 1. [Figure 4] Figure 4 is a graph showing the relationship between the ratio of the length from the edge of the lid in Figure 3 to the easily deformable part and the coupling loss of light. [Figure 5] Figure 5 is a cross-sectional view showing the lid of Figure 1. [Figure 6] Figure 6 is an enlarged cross-sectional view of the easily deformable portion of the lid shown in Figure 5. [Figure 7] Figure 7 is an enlarged cross-sectional view of an easily deformable portion relating to a modified example different from that shown in Figure 6. [Figure 8] Figure 8 is a perspective view showing the package and lid of a modified optical module. [Figure 9] Figure 9 is a partial cross-sectional view of an optical module relating to a different modification from that shown in Figure 8. [Figure 10] Figure 10 is a partial cross-sectional view of an optical module relating to a different modification from that shown in Figures 8 and 9. [Figure 11] Figure 11 is a partial cross-sectional view showing the optical module from Figure 10 with the lid removed. [Modes for carrying out the invention]

[0009] [Description of Embodiments in this Disclosure] First, the contents of the embodiments of the optical module according to the present disclosure will be listed and described. The optical module according to the embodiment comprises (1) a package having an opening surrounded by side walls, and a lid that is placed on the package and seals the opening. The lid is plate-shaped and has a welded portion fixed by welding to the upper surface of the side wall of the package in which the opening is formed, a deformable portion formed at a position away from the welded portion and deforms with welding, and a flat central portion.

[0010] In this optical module, the opening of the package is sealed by a lid. The lid has a welded portion that is fixed to the upper surface of the package where the opening is formed by welding, and a deformable portion that deforms in conjunction with welding. The deformable portion is formed at a position away from the welded portion. Therefore, the deformation of the package can be suppressed by the deformation of the deformable portion, which is away from the welded portion of the package, in conjunction with welding. In other words, the deformation of the deformable portion reduces the stress on the package caused by welding, thus suppressing the deformation of the package. Therefore, even if the optical system is completed inside the package, the displacement of optical components due to package deformation can be suppressed, and the optical coupling efficiency can be stabilized.

[0011] (2) In (1) above, the lid may be plate-shaped, and the easily deformable portion may be a stepped portion that is convex or concave in the thickness direction of the lid relative to the welded portion. In this case, the easily deformable portion can be formed as a stepped portion, so the easily deformable portion can be formed easily.

[0012] (3) In (1) or (2) above, the lid may be plate-shaped, and the thickness of the lid in the easily deformable portion may be thinner than the thickness of the welded portion. In this case, the easily deformable portion can be made more easily deformed, so that deformation of the package can be suppressed more reliably.

[0013] (4) In any of (1) to (3) above, the lid may have a rectangular shape with a pair of short sides and a pair of long sides as its end sides, and the distance from the short side in the longitudinal direction of the lid to the easily deformable portion may be longer than the distance from the long side in the short transverse direction of the lid to the easily deformable portion. When the length from the end side of the lid to the easily deformable portion is long, the easily deformable portion can be made more easily deformable compared to the case where the length from the end side of the lid to the easily deformable portion is short. Therefore, when the distance from the short side in the longitudinal direction of the lid to the easily deformable portion is longer than the distance from the long side in the short transverse direction of the lid to the easily deformable portion, the easily deformable portions arranged along the longitudinal direction of the lid can be made more easily deformable, and the deformation in the longitudinal direction of the package can be more reliably suppressed. Accordingly, the deformation in the longitudinal direction of the package can be more reliably suppressed compared to the short transverse direction of the package, so that the optical coupling efficiency can be further stabilized.

[0014] (5) In any of (1) to (4) above, the lid may have end sides, and the package may have a cavity located below the lid. The distance from the end side to the easily deformable portion in the portion of the lid facing the cavity may be longer than the distance from the end side to the easily deformable portion in the portion of the lid not facing the cavity. In this case, the easily deformable portion in the portion of the lid facing the cavity can be made more easily deformable compared to the easily deformable portion in the portion of the lid not facing the cavity.

[0015] (6) In any of (1) to (5) above, a convex frame may be provided on the upper surface of the side wall of the package.

[0016] [Details of Embodiments of the Present Disclosure] A specific example of an optical module according to an embodiment of the present disclosure will be described below with reference to the drawings. It should be noted that the present invention is not limited to the following examples, and is intended to include all modifications within the scope shown in the claims and within the scope equivalent to the claims. In the description of the drawings, the same or corresponding elements are denoted by the same reference numerals, and duplicate descriptions are omitted as appropriate. In addition, for ease of understanding, some of the drawings may be drawn in a simplified or exaggerated manner, and dimensional ratios and the like are not limited to those described in the drawings.

[0017] FIG. 1 is a partial cross-sectional view showing an optical module 1 as an example. FIG. 2 is a partial cross-sectional view showing the internal structure of the optical module 1. As shown in FIGS. 1 and 2, the optical module 1 includes a rectangular parallelepiped package 2, and a transmission-side window 3 and a reception-side window 4 formed in the package 2. Each of the transmission-side window 3 and the reception-side window 4 has a rectangular shape. The package 2 is made of, for example, ceramic. The package 2 has a first side wall 2b extending along a first direction D1, a pair of second side walls 2c extending along a second direction D2 intersecting the first direction D1, and a bottom wall 2d on which each component of the optical module 1 is mounted. The first direction D1 is the longitudinal direction of the optical module 1, and the second direction D2 is the width direction of the optical module 1.

[0018] The first side wall 2b extends in both the first direction D1 and a third direction D3. The third direction D3 is a direction intersecting both the first direction D1 and the second direction D2, and corresponds to the height direction of the optical module 1. The pair of second side walls 2c are arranged along the first direction D1, and each second side wall 2c extends in both the second direction D2 and the third direction D3. The bottom wall 2d extends in both the first direction D1 and the second direction D2 at one end of the first side wall 2b and the second side wall 2c in the third direction D3. The pair of first side walls 2b and the pair of second side walls 2c form an opening 2g of the package 2 having a frame shape when viewed from the third direction D3. That is, the package 2 has an opening 2g surrounded by side walls (the pair of first side walls 2b and the pair of second side walls 2c).

[0019] The transmitting window 3 and the receiving window 4 have one of the pair of second side walls 2c penetrating them in the first direction D1. The transmitting window 3 and the receiving window 4 are aligned along the second direction D2. The receiving window 4 is the part into which input light L1 is input from the outside of the optical module 1 to the inside of the optical module 1. The transmitting window 3 is the part into which output light L2 is output from the inside of the optical module 1 to the outside of the optical module 1.

[0020] The optical module 1 includes a first temperature control device 11 mounted on the bottom wall 2d, a tunable light source base 12 mounted on the first temperature control device 11, and a tunable light source element 13 and a lens 14 mounted on the tunable light source base 12. For example, the tunable light source base 12 is made of either aluminum nitride or alumina. The tunable light source element 13 is made of, for example, indium phosphide (InP). The lens 14 is made of glass or silicon (Si). The tunable light source element 13 outputs light L3 to the lens 14, and the lens 14 outputs light L3 on the side opposite to the transmitting window 3.

[0021] The optical module 1 includes an intermediate substrate 21 mounted on a common lower substrate 88 of the first temperature control device 11 and the second temperature control device 31, and a beam splitter 22 mounted on the intermediate substrate 21. The intermediate substrate 21 is made of, for example, aluminum nitride and alumina. The beam splitter 22 includes, for example, glass and a dielectric multilayer film. The beam splitter 22 receives light L3 emitted from the lens 14 in a first direction D1. The beam splitter 22 transmits a portion of the light L3 in the first direction D1 and reflects the remainder of the light L3 in a second direction D2.

[0022] The optical module 1 includes a second temperature control device 31 mounted on the bottom wall 2d, a modulation element base 32 mounted on the second temperature control device 31, a modulation element carrier 33, a polarization multiplexing filter 34, a mirror 35, and a lens 36 mounted on the modulation element base 32, and a modulation element 37 mounted on the modulation element carrier 33. The modulation element base 32 and the modulation element carrier 33 are each made of, for example, either aluminum nitride or alumina.

[0023] The polarization multiplexing filter 34 is made of glass and a dielectric multilayer film. The polarization multiplexing filter 34 receives light L4 output from the modulation element 37 through the lens 36. The polarization multiplexing filter 34 transmits the light L4 in the first direction D1 and outputs it to the transmitting window 3. The mirror 35 reflects the light L5 output from the modulation element 37 through the lens 36 in the first direction D1 towards the polarization multiplexing filter 34 in the second direction D2. The polarization multiplexing filter 34 reflects the light L5 in the first direction D1 and outputs output light L2, which is the combined light of light L4 and light L5, to the transmitting window 3.

[0024] The lens 36 is made of, for example, glass and silicon (Si). The lens 36 has a first lens portion 36b, a second lens portion 36c, and a third lens portion 36d. The first lens portion 36b, the second lens portion 36c, and the third lens portion 36d are arranged in this order along the second direction D2. Light L5 emitted from the modulation element 37 in the first direction D1 is input to the first lens portion 36b. The first lens portion 36b transmits the light L5 toward the mirror 35. Light L4 emitted from the modulation element 37 in the first direction D1 is input to the third lens portion 36d. Light L3 transmitted through the beam splitter 22 is input to the second lens portion 36c. The second lens portion 36c inputs the light L3 to the modulation element 37.

[0025] The modulation element 37 is composed of, for example, indium phosphide (InP) and silicon (Si). As an example, the modulation element 37 includes indium phosphide (InP), silicon dioxide (SiO2), and benzocyclobutene (BCB). The modulation element 37 is, for example, a multimode interferometer having multiple optical waveguides. The modulation element 37 splits the input light L3 and applies phase modulation, combines a portion of the split light to emit light L4, and combines the remaining portion of the separated light to emit light L5.

[0026] The bottom wall 2d of package 2 includes a thin section 2h on which the first temperature control device 11 and the second temperature control device 31 are mounted, and a thick section 2j which is thicker in the third direction D3 than the thin section 2h. The optical module 1 has a first mirror 41, a polarization separation filter 42, a second mirror 43, a lens 44, and a receiving element carrier 45 mounted on the thick section 2j. Furthermore, the optical module 1 has a receiving element 46 mounted on the receiving element carrier 45.

[0027] The first mirror 41 reflects the light L3 reflected by the beam splitter 22 in the second direction D2 back to the first direction D1. The polarization separation filter 42 has, for example, a glass and dielectric multilayer film. The polarization separation filter 42 receives the input light L1 emitted from the receiving side window 4 in the first direction D1. The polarization separation filter 42 transmits a portion of the input light L1 in the first direction D1 and reflects the remainder of the input light L1 in the second direction D2. The second mirror 43 receives the input light L1 reflected from the polarization separation filter 42 in the second direction D2 and reflects the input light L1 back to the first direction D1.

[0028] The lens 44 has a first lens section 44b, a second lens section 44c, and a third lens section 44d. The first lens section 44b, the second lens section 44c, and the third lens section 44d are arranged in this order along the second direction D2. The receiving element carrier 45 is made of either aluminum nitride or alumina. The receiving element 46 is made of either indium phosphide (InP) or silicon (Si). The input light L1 that has passed through the polarization separation filter 42 is input to the first lens section 44b, and the first lens section 44b inputs the input light L1 to the receiving element 46. The light L3 reflected by the first mirror 41 is input to the second lens section 44c. The input light L1 reflected by the second mirror 43 is input to the third lens section 44d.

[0029] The optical module 1 includes a lid 5 that seals the package 2. The lid 5 is made of, for example, metal. For example, the lid 5 is made of Kovar. Alternatively, the lid 5 may be made of an iron-nickel alloy (Invar). The lid 5 has a rectangular shape. The lid 5 has, for example, a flat shape. The lid 5 has an upper surface 5b extending in both the first direction D1 and the second direction D2, a lower surface 5c facing the opposite side of the upper surface 5b, a first side surface 5d extending in the first direction D1 and the third direction D3, and a second side surface 5f extending in the second direction D2 and the third direction D3.

[0030] Lid 5 hermetically seals the opening 2g of package 2. For example, in package 2, a metal frame 2q is joined to the opening 2g, and lid 5 is joined to package 2 via frame 2q. Frame 2q is a convex frame provided on the upper surface of the side wall of package 2. For example, lid 5 is joined to package 2 by seam welding. In seam welding, a voltage is applied between lid 5 and the metal frame 2q in package 2, causing a current to flow, and the contact interface between lid 5 and frame 2q is heated by Joule heating due to contact resistance. This heat melts the Ni plating or Ni / Au plating applied to lid 5 and frame 2q, forming an Au brazing material that joins lid 5 to package 2.

[0031] The heating described above causes an overall temperature rise in the lid 5, and subsequently, thermal contraction of the lid 5 may generate residual stress in the lid 5. When residual stress is generated in the lid 5, the package 2 deforms and becomes distorted due to the thermal contraction of the lid 5, and warping of the package 2 may occur. Due to the effects of the deformation (strain) of the package 2, a decrease in the optical coupling efficiency of the optical components placed inside the package 2 may occur. Furthermore, in this embodiment, a problem may arise in that the internal optical system of the optical module 1 cannot be adjusted after the package 2 has been hermetically sealed. If the above decrease in optical coupling efficiency occurs, for example, the output power of the output light L2 may decrease.

[0032] Figure 3 is a schematic cross-sectional view of the package 2 and lid 5. As shown in Figures 1 and 3, the lid 5 has a welded portion 5g fixed by welding to the upper surface 2k of the side wall of the package 2 in which the opening 2g is formed, a deformable portion 5h formed at a position away from the welded portion 5g, and a flat central portion 5z. The deformable portion 5h is a part of the lid 5 that is more easily deformed by heating than the parts of the lid 5 other than the deformable portion 5h. Because the deformable portion 5h of the lid 5 is more easily deformed than the parts other than the deformable portion 5h, it is possible to deliberately deform the deformable portion 5h during welding while suppressing deformation of the package 2.

[0033] When viewed from a third direction D3, the welded portion 5g has a frame shape, and the easily deformable portion 5h is provided inside the welded portion 5g. The easily deformable portion 5h has a rectangular shape inside the welded portion 5g when viewed from a third direction D3. For example, the lid 5 has a lower portion 5j located on the bottom wall 2d side, and an upper portion 5k provided on the opposite side from the bottom wall 2d (upper side in Figure 3) from the lower portion 5j.

[0034] The easily deformable portion 5h is, for example, a stepped portion located between the lower portion 5j and the upper portion 5k. The easily deformable portion 5h is a concave stepped portion that is recessed in the third direction D3 relative to the welded portion 5g. Alternatively, the easily deformable portion 5h may be a convex stepped portion that protrudes in the third direction D3 relative to the welded portion 5g. The easily deformable portion 5h extends diagonally downward as it approaches the center of the lid 5. In the lid 5, after heating, the welded portion 5g is pulled toward the center of the lid 5. At this time, the upper side of the easily deformable portion 5h deforms so that it moves toward the center of the lid 5, thereby suppressing deformation of the package 2 toward the center. That is, the stress on the first side wall 2b and the second side wall 2c toward the center of the package 2 is reduced, thereby suppressing deformation of the package 2.

[0035] The lid 5 has an edge 5p facing in a direction intersecting the third direction D3 (either the first direction D1 or the second direction D2). The edge 5p includes a pair of short sides 5q extending along the second direction D2 and aligned with the first direction D1, and a pair of long sides 5r extending along the first direction D1 and aligned with the second direction D2. The distance K1 from the short side 5q to the easily deformable portion 5h in the first direction D1 is longer than the distance K2 from the long side 5r to the easily deformable portion 5h in the second direction D2.

[0036] Next, the effects and advantages obtained from the optical module 1 according to this embodiment will be described in more detail. In the optical module 1, the opening 2g of the package 2 is sealed by a lid 5. The lid 5 has a welded portion 5g that is fixed by welding to the upper surface 2k of the package 2 in which the opening 2g is formed, and a deformable portion 5h that deforms in conjunction with welding. The deformable portion 5h is formed at a position separated from the welded portion 5g. Therefore, the deformation of the package 2 can be suppressed by the deformation of the deformable portion 5h, which is separated from the welded portion 5g of the package 2, in conjunction with welding. In other words, since the stress on the package 2 due to welding can be reduced by the deformation of the deformable portion 5h, the deformation of the package 2 is suppressed. Therefore, even in this embodiment in which the optical system is completed inside the package 2, the displacement of the optical components due to the deformation of the package 2 can be suppressed, and the optical coupling efficiency can be stabilized.

[0037] In this embodiment, the lid 5 may be plate-shaped, and the easily deformable portion 5h may be a stepped portion that is convex or concave in the thickness direction (third direction D3) of the lid 5 relative to the welded portion 5g. In this case, the easily deformable portion 5h can be formed as a stepped portion, so the easily deformable portion 5h can be easily formed.

[0038] In this embodiment, the lid 5 may have a rectangular shape with a pair of short sides 5q and a pair of long sides 5r as its end sides 5p, and the distance K1 from the short side 5q to the easily deformable portion 5h in the longitudinal direction (first direction D1) of the lid 5 may be longer than the distance K2 from the long side 5r to the easily deformable portion 5h in the short direction (second direction D2) of the lid 5. When the length from the end side 5p to the easily deformable portion 5h of the lid 5 is long, the easily deformable portion 5h can be deformed more easily compared to when the length from the end side 5p to the easily deformable portion 5h of the lid 5 is short. Therefore, when the distance K1 from the short side 5q to the easily deformable portion 5h in the longitudinal direction of the lid 5 is longer than the distance K2 from the long side 5r to the easily deformable portion 5h in the short direction of the lid 5, the easily deformable portions 5h aligned along the longitudinal direction of the lid 5 can be deformed more easily, thereby more reliably suppressing deformation of the package 2 in the longitudinal direction (first direction D1). Therefore, deformation in the longitudinal direction of package 2 can be suppressed more reliably compared to the short direction of package 2 (second direction D2), thus further stabilizing the light coupling efficiency.

[0039] For example, distance K1 is 0.05 times or more the length of the long side 5r of lid 5. Distance K2 is 0.15 times or less the length of the short side 5q of lid 5. Figure 4 is a graph showing the relationship between the ratio of distance K1 to the length of the long side 5r of lid 5 and the optical coupling loss. The comparative example in Figure 4 shows an optical module having a lid in which the easily deformable portion 5h is not formed. As shown in Figure 4, when the easily deformable portion 5h is present, the optical coupling loss can be reduced compared to the comparative example without the easily deformable portion 5h. When distance K1 is 0.05 times or more the length of the long side 5r of lid 5, the optical coupling loss can be reduced to 0.2 dB or less. When distance K2 is 0.06 times the length of the short side 5q of lid 5, the optical coupling efficiency can be further reduced compared to when distance K2 is 0.15 times the length of the short side 5q of lid 5.

[0040] Next, an example of the details of the easily deformable portion 5h will be described with reference to Figures 5 and 6. Figure 5 is a cross-sectional view of the lid 5 when it is cut by planes extending in the first direction D1 and the third direction D3. Figure 6 is an enlarged cross-sectional view of the easily deformable portion 5h of the lid 5 in Figure 5. As shown in Figures 5 and 6, for example, the easily deformable portion 5h may be a thin-walled portion that is thinner than the other parts of the lid 5.

[0041] For example, the thickness T1 of the lid 5 in the part other than the easily deformable part 5h (welded part 5g) is 0.15 mm or less, and the minimum thickness T2 of the easily deformable part 5h is 0.1 mm or less. As an example, the depth H of the easily deformable part 5h (height of the upper surface 5k relative to the lower surface 5j) is 0.1 mm or more. The easily deformable part 5h has, for example, a first curved surface 5v that curves so that the lid 5 is recessed from the upper surface 5s of the upper surface 5k to the upper surface 5t of the lower surface 5j, and a second curved surface 5y that curves so that the lid 5 is recessed from the lower surface 5w of the upper surface 5k to the lower surface 5x of the lower surface 5j. The easily deformable part 5h having the first curved surface 5v and the second curved surface 5y is more easily deformed than the part of the lid 5 other than the easily deformable part 5h, so by deforming the easily deformable part 5h, the package 2 can be made less deformable.

[0042] As shown in the example in Figure 6, the thickness of the easily deformable portion 5h of the lid 5 may be thinner than the thickness T1 of the welded portion 5g. In this case, the easily deformable portion 5h can be made more easily deformable, so the deformation of the package 2 can be suppressed more reliably. Figure 7 is a cross-sectional view showing the easily deformable portion 55h of the lid 55 according to a different modification than that shown in Figure 6. As shown in Figure 7, the lid 55 may have an upper portion 55k and a lower portion 55j with different thicknesses. In this case, the upper portion 55k including the welded portion 5g of the lid 55 is thicker than the lower portion 55j not including the welded portion. The same effects as those of the lid 5 can be obtained from this lid 55 as from the lid 5.

[0043] Figure 8 is a perspective view showing a modified optical module 1A. Some of the components of optical module 1A are the same as some of the components of optical module 1 described above. Therefore, in the following, explanations that overlap with the explanation of optical module 1 will be omitted as appropriate, using the same reference numerals. As shown in Figure 8, optical module 1A comprises a package 2A, and package 2A has a cavity 2p that is recessed in a third direction D3. For example, cavity 2p is a portion that is recessed in a third direction D3 from the bottom wall 2d of package 2. Cavity 2p is a rectangular space that extends in a first direction D1, a second direction D2, and a third direction D3.

[0044] Optical module 1A has a lid 65 that is different from lid 5. In lid 65, the position of the easily deformable portion 5h is different from that of lid 5. In lid 65, the distance K3 from one short side 5q1 to the easily deformable portion 5h in the first direction D1 is longer than the distance K4 from the other short side 5q2 to the easily deformable portion 5h in the first direction D1. In lid 65, the portion 65b from one short side 5q1 to the easily deformable portion 5h faces the cavity 2p of package 2 along the third direction D3. In this way, the portion 65b is provided directly above the portion of package 2 with less volume (where the cavity 2p is formed).

[0045] As described above, in the optical module 1A, the package 2A has a cavity 2p located below the lid 65. The distance K3 from the edge 5p (one short side 5q1) in the portion 65b of the lid 65 facing the cavity 2p to the easily deformable portion 5h is longer than the distance K4 from the edge 5p (the other short side 5q2) in the portion of the lid 65 not facing the cavity 2p to the easily deformable portion 5h. In this case, the easily deformable portion 5h in the portion 65b of the lid 65 facing the cavity 2p can be deformed more easily than the easily deformable portion 5h in the portion of the lid 65 not facing the cavity 2p. Therefore, the peripheral portion of the cavity 2p of the package 2A can be made less deformable.

[0046] The lid 65, in which the position of the easily deformable portion 5h in the first direction D1 is asymmetrical, can also be applied to the package 2 according to the embodiment described above, as shown in Figure 9. Figure 10 is a partial cross-sectional view showing an optical module 1B according to a further modification. Figure 11 is a partial cross-sectional view showing the internal structure of the optical module 1B. For example, the optical module 1B includes the lid 5 described above.

[0047] The optical module 1B has a package 2B, and only a transmitting window 3 is formed in the package 2B. In other words, the optical module 1B is an optical transmitting module that only transmits optical signals. The optical module 1B comprises a first temperature control device 61 mounted on the bottom wall 2d of the package 2B, a base 62 for a tunable light source mounted on the first temperature control device 61, a tunable carrier 63 and a lens 64 mounted on the base 62 for the tunable light source, and a tunable light source element 66 mounted on the tunable carrier 63. The light L11 output from the tunable light source element 66 passes through the lens 64. The light L11 that passes through the lens 64 is output from the lens 64 to the side opposite the transmitting window 3.

[0048] Optical module 1B includes an intermediate substrate 71 mounted on a common lower substrate 89 of the first temperature control device 61 and the second temperature control device 81, and a beam splitter 72 mounted on the intermediate substrate 71. The beam splitter 72 transmits light L11 from the lens 64 in the first direction D1. Optical module 1B also includes a second temperature control device 81 mounted on the bottom wall 2d, and a modulation element base 82 mounted on the second temperature control device 81. Optical module 1B further includes a modulation element carrier 83, a polarization multiplexing filter 84, a mirror 85, and a lens 86 mounted on the modulation element base 82, and a modulation element 87 mounted on the modulation element carrier 83.

[0049] The lens 86 has a first lens section 86b, a second lens section 86c, and a third lens section 86d, which are arranged in this order along the second direction D2. The second lens section 86c transmits the light L11 emitted from the beam splitter 72 and outputs the transmitted light to the modulation element 87. The modulation element 87 outputs a first output light L12 and a second output light L13. The first output light L12 passes through the first lens section 86b and is reflected in the second direction D2 by the mirror 85. The second output light L13 passes through the third lens section 86d and reaches the polarization multiplexing filter 84. The polarization multiplexing filter 84 reflects the first output light L12, which has been reflected in the second direction D2 by the mirror 85, back in the first direction D1 and outputs it to the transmitting window 3, while also transmitting the second output light L13 and outputting it to the transmitting window 3.

[0050] The optical module 1B comprises a package 2B on which the aforementioned optical components are mounted, and a lid 5 that seals the package 2B. Therefore, the same effects and advantages as those of optical module 1 can be obtained from optical module 1B. Note that optical module 1B may have a lid 65 instead of lid 5.

[0051] The embodiments and various modifications of the optical module relating to this disclosure have been described above. However, the present invention is not limited to the embodiments or modifications described above. That is, it will be readily apparent to those skilled in the art that the present invention can be modified and altered in various ways without altering the essence described in the claims. For example, the shape, size, number, material and arrangement of each component of the optical module can be changed as appropriate, and are not limited to those described above. [Explanation of Symbols]

[0052] 1, 1A, 1B… Optical Modules 2.2A…Package 2b…First side wall 2B...Package 2c…Second side wall 2d…Bottom wall 2g…opening 2h...thin section 2j…thick part 2k…Top surface 2p…hollow 2q… slot 3…Transmitter side window 4…Receiving side window 5... Lid 5b…Top surface 5c…Bottom surface 5d…1st side 5f…Second side 5g...Welded area 5h... Easily deformable part 5j…Bottom part 5k…Top part 5p…Edge 5q, 5q1, 5q2... Short side 5r…long side 5s,5t…Top surface 5V... curved surface 5w,5x…Bottom side 5y…Curved surface 5z…Central part 11…Temperature control devices 12…Base for tunable light source 13... Wavelength-tunable light source element 14... Lens 21…Intermediate board 22... Beam Splitter 31... Temperature-controlled table 32…Base for modulation element 33...Carrier for modulation element 34…Polarization multiplexing filter 35...Mirror 36... Lens 36b...First lens section 36c...Second lens section 36d...Third lens section 37…Modulation element 41...Mirror 42…Polarization separation filter 43...Miller 44... Lens 44b...First lens section 44c...Second lens section 44d...Third lens section 45... Carrier for receiving element 46... Receiving element 55... Lid 55h... Easily deformable parts 55j…Bottom part 55k...Top part 61…Temperature control devices 62...Base for tunable light source 63... Wavelength tunable carriers 64... Lens 65... Lid 65b…part 66... ​​Wavelength tunable light source element 71…Intermediate board 72... Beam Splitter 81... Temperature control devices 82…Base for modulation element 83...Carrier for modulation element 84…Polarization multiplexing filter 85...Miller 86... Lens 86b...First lens section 86c...Second lens section 86d...Third lens section 87…Modulation element 88...Lower circuit board 89...Lower circuit board D1…first direction D2…Second direction D3...Third direction K1,K2,K3,K4…distance L1...Input light L2…Output light L3,L4,L5,L11…light L12, L13… Output light

Claims

1. A package having an opening surrounded by side walls, A lid placed on the package to seal the opening, Equipped with, The lid is plate-shaped and has a welded portion fixed by welding to the upper surface of the side wall of the package in which the opening is formed, a deformable portion formed at a position away from the welded portion and deformable in conjunction with the welding, and a flat central portion. The thickness of the lid of the easily deformable portion is thinner than the thickness of the welded portion. Optical module.

2. A package having an opening surrounded by side walls, A lid placed on the package to seal the opening, Equipped with, The lid is plate-shaped and has a welded portion fixed by welding to the upper surface of the side wall of the package in which the opening is formed, a deformable portion formed at a position away from the welded portion and deformable in conjunction with the welding, and a flat central portion. The lid has a rectangular shape with a pair of short sides and a pair of long sides as its edges. The distance from the short side to the easily deformable portion in the longitudinal direction of the lid is longer than the distance from the long side to the easily deformable portion in the short side direction of the lid. Optical module.

3. A package having an opening surrounded by side walls, A lid placed on the package to seal the opening, Equipped with, The lid is plate-shaped and has a welded portion fixed by welding to the upper surface of the side wall of the package in which the opening is formed, a deformable portion formed at a position away from the welded portion and deformable in conjunction with the welding, and a flat central portion. The lid has an edge, The package has a cavity located below the lid, The distance from the edge of the lid facing the cavity to the easily deformable portion is longer than the distance from the edge of the lid not facing the cavity to the easily deformable portion. Optical module.

4. The easily deformable portion is a stepped portion that is convex or concave in the thickness direction of the lid relative to the welded portion. The optical module according to any one of claims 1 to 3.

5. A convex frame is provided on the upper surface of the side wall of the package. The optical module according to any one of claims 1 to 3.

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