To provide the cut-off frequency of a light-receiving module for optical communication for mounting an APD element to be set within a specified range.
To sort the APD element in the light-receiving module for optical communication, which has the APD element for outputting a received optical signal as a electrical signal, an amplifier for amplifying the electrical signal of the output of the APD element and outputting it, and a low-pass filter connected to the output side of the amplifier, the above APD elements are sorted, so that a second difference is within a predetermined range, based on the relation between the first difference of the cut-off frequency between the first and second values out of the multiplication factor within the prescribed range and the applied bias voltage, in each of a plurality of APD elements and the second difference of the cut-off frequency between the first and second values at using each of the plural APD elements as the APD element of the light-receiving module.
TOSHIBA CORP