Optical module, optical module substrate and optical coupling structure

An optical module, comprising:

• a substrate including a first ceramic substrate member having a plurality of insulating layers laminated together in a first layer lamination direction and a second ceramic substrate member having a plurality of insulating layers laminated together in a second layer lamination direction, the first and second ceramic substrate members allowing electrical connection therebetween and being joined together in such a manner that the first and second layer lamination directions are substantially perpendicular to each other;
• an optical element mounted to the first substrate member;
• and
• a coupling element arranged on the first substrate to provide a positional reference for optical axis alignment of the optical element with a counterpart optical device;
• wherein the first ceramic substrate member further comprises a mount portion to which the optical element is mounted and a hole formed by precision machining so as to receive therein the coupling element.

A substrate for an optical module, the optical module having an optical element and a coupling element, the substrate comprising:

• a first ceramic substrate member having a plurality of ceramic insulating layers laminated together in a first layer lamination direction, a mount portion to which the optical element is mounted and a hole formed by precision machining so as to receive therein the coupling element;
• and
• a second ceramic substrate member having a plurality of ceramic insulating layers laminated together in a second layer lamination direction,
• the first and second ceramic substrate members allowing electrical connection therebetween and being joined together in such a manner that the first and second layer lamination directions are substantially perpendicular to each other.

A process of producing a ceramic substrate for use in an optical module, the optical module being adapted to mate with an optical connector plug upon fitting of a guide pin into the optical module and the connector plug, the process comprising:

• providing a ceramic substrate body having a main substrate surface and opposite side surfaces extending perpendicular to the main substrate surface;
• forming a recess in one of the side surfaces of the ceramic substrate body;
• preparing a filler having better machinability than that of the ceramic substrate body;
• packing the filler in the recess;
• and
• after said packing, subjecting the filler to precision machining to define at least part of a guide hole into which the guide pin is inserted.