| 摘要 |
PROBLEM TO BE SOLVED: To provide miniaturized and inexpensive optical amplifier and optical transmitter reducing the number of comparatively expensive photodiodes and the number of light receiving circuits for amplifying an electric signal converted by the photodiode and having difficult design of a signal-to-noise ratio and a dynamic range. SOLUTION: The optical amplifier is provided with a single optical switch for selecting one of optical signals partially branched from a line for transmitting a main optical signal and outputting the selected signal, a photodiode for converting the output of the optical switch into an electric signal, a light receiving circuit for amplifying the electric signal outputted from the photodiode, and a sampling and holding circuit for holding the output of the light receiving circuit synchronously with the selection of the signal by the switch and outputting a plurality of electric signal and constituted so as to control the optical signals of two or more portions by the outputs from the sampling and holding circuit. |
