Patent ID: 7991029

Claim:
An optical module comprising: a header; a grounding pin connected to said header; a signal pin penetrating and electrically insulated from said header; glass filling space between said header and said signal pin; a laser diode connected to said signal pin; a flexible circuit board facing said header; a ground conductor on a first surface of said flexible circuit board, directly facing said header, and connected to said grounding pin; a signal line on a second surface of said flexible circuit board, opposite said first surface, and connected to said signal pin; and a cut-out portion where said ground conductor is not present on said first surface of said flexible circuit board, located in a region where said header faces said flexible circuit board, and extending from a junction of said signal pin and said signal line, wherein said cut-out portion has a size determined so that impedance of said signal pin is matched to impedance of said signal line, wherein said cut-out portion has a length in an extending direction, which extends along said signal line, from said junction where said signal pin is connected to said signal line, in a range from 1 mm to 4 mm.