Optical module assembly, optical module, package for optical module and flexible printed board

1. A package for an optical module comprising:

a side wall; and

a substrate provided through the side wall in a first direction, the substrate including

a first wiring layer that is externally exposed, the first wiring layer including

a first signal terminal extending along the first direction,

a second signal terminal extending along the first direction, and

a first ground terminal extending along the first direction, the first ground terminal being provided between the first signal terminal and the second signal terminal, when viewed in a second direction perpendicular to the first direction,

a second wiring layer disposed under the first wiring layer, the second wiring layer including a first ground pattern, the first ground pattern being electrically coupled to the first ground terminal via a plurality of first vias,

a third wiring layer disposed under the second wiring layer, the third wiring layer including

a second ground layer electrically coupled to the first ground pattern via a plurality of second vias and a plurality of third vias;

a first insulating layer disposed between the first wiring layer and the second wiring layer, the first insulating layer including the plurality of first vias, the plurality of first vias being arranged at a first interval along the first direction, and

a second insulating layer disposed between the second wiring layer and the third wiring layer, the second insulating layer including

the plurality of second vias, the second vias being arranged at a second interval along the first direction, and

the plurality of third vias, the third vias being arranged at the second interval along the first direction,

wherein when viewed in the second direction, each first via of the plurality of first vias is provided between a corresponding second via among the plurality of second vias and a corresponding third via among the plurality of third vias, and

wherein when viewed in the first direction, each second via of the plurality of second vias is disposed at an offset by half of the second interval from the corresponding third via among the plurality of third vias.

2. The package according to claim 1 , wherein a first via of the plurality of first vias and the corresponding second via of the plurality of second vias of the substrate are separated by a first distance,

wherein the corresponding second via of the plurality of second vias and the corresponding third via of the plurality of third vias of the substrate are separated by a second distance, and

wherein the second distance is set to be equal to the first distance in the second direction.

3. The package according to claim 1 , wherein the first ground terminal has a first width in the second direction, and the first ground pattern has a second width in the second direction, and

wherein the first width is narrower than the second width.

4. The package according to claim 1 , wherein a centerline of the first ground terminal extends along the first direction, and

wherein the first vias are arranged so that centers of the first vias are on the centerline of the first ground terminal, when viewed in the first direction.

5. The package according to claim 4 , wherein the centerline of the first ground terminal and the first signal terminal are separated by a first distance in the second direction, and

wherein the centerline of the first ground terminal and the second signal terminal are separated by a second distance in the second direction, and

wherein the second distance is set to be equal to the first distance.

6. An optical module comprising:

the package according to claim 1 ; and

an optical semiconductor device included in the package.

7. A flexible printed board configured to be coupled to the package of the optical module according to claim 6 .

8. An optical module assembly comprising:

the optical module according to claim 6 ; and

a flexible printed board coupled to the optical module.