Opnext Japan, Inc.

Hirofumi Nakagawa

Mitsuo Akashi

Tetsuya Aoki

Fumitoshi Goto

Raju Kankipati

Hironori Saitoh

A relation between a light input power monitor value of an optical transmission signal before passing through a fiber and an input signal amplitude monitor value is recorded in advance in a storage device. Next, actual optical-transmission-waveform is inputted into an optical receiver module, and then comparisons between a light input power monitor value and an input signal amplitude monitor value, and respective monitor values in the case without having the waveform distortion as described above are performed in an operation device to calculate a waveform distortion value. According to the waveform distortion level calculated herein, an optimum threshold value and an optimum phase adjusting value, at which receiver sensitivity is maximized, are calculated in the operation device to control a threshold-value adjusting circuit and a phase-value adjusting circuit, thereby a threshold value and a phase value that are optimum for an input distortion level can be established.

Optical receiver module and optical receiver module system

The printed circuit board with the respective components of the optical transmitter-receiver mounted thereon is split into several parts, the fixing position of which respective parts with regard to the housing is set according to the standardized size of the respective components and which respective parts are interconnected through an electric connector and so forth, which makes the height of the transmitter-receiver lower. The split circuit boards are overlapped such that they make no contact with one another so as to enlarge the area of the circuit boards or practically increase the packaging area of the respective components, which realizes the structural compactness of the optical transmitter-receiver. The packaging side of the respective components is selected in an arbitrary manner according to the cooling direction of the respective ICs, which allows such direction to be oriented to the side of the heat sinks so as to enhance cooling behavior. When deteriorated parts are found, only the circuit board with such parts mounted is removed for repair or replacement, resulting in improving productivity and reducing production cost.

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Yokohama, Japan

Hirofumi Nakagawa