Optical communication module and flexible printed circuit board

An optical communication module, comprising:

• an optical device;
• a main board incorporating a signal generation circuit for generating a high frequency signal corresponding to an optical signal converted by the optical device;
• and
• a flexible printed circuit board for connecting the optical device with the main board,
• wherein the flexible printed circuit board comprises:
• a signal wiring pattern comprising:
• a first transmission line for connecting an end of the optical device with an end of the signal generation circuit;
• and
• a second transmission line for connecting another end of the optical device with another end of the signal generation circuit;
• a thin film resistor layer formed in a region including at least a part of a region facing the signal wiring pattern so as to constitute a first microstrip line together with each of the first transmission line and the second transmission line;
• a ground layer formed in a region except a part of a region facing the thin film resistor layer within a region including a region facing the signal wiring pattern so as to constitute a second microstrip line together with the each of the first transmission line and the second transmission line;
• and
• an insulating layer formed between each two of the signal wiring pattern, the thin film resistor layer, and the ground layer.