An optical transmitter module that generates a signal multiplexing two or more optical signals each having optical power satisfying a preset magnitude is disclosed. The optical transmitter module includes laser diodes (LD), adjusting lenses coupled with the LDs to generate dispersive optical outputs, and a concentrating lens that concentrates the dispersive optical beams onto a coupling fiber. A feature of the optical transmitter module is that the adjusting lenses are set closer to the LDs to adjust the optical power coupled with the coupling fiber.