To match the phase of a monitor voltage to that of a reference signal by setting the delay time of a delaying section to the sum of the delay time of a laser diode driving section and the light emission delay time of a laser diode.
The signal obtained by comparing an inversion signal and a non-inversion signal outputted from a data receiving signal 1 as the input signals of a laser diode driving section 2 is supplied to a reference voltage generating section 7 as a reference signal by delaying the signal by the time equal to the sum of the delay time of the driving section 2 and the light emission delay time of a laser diode 3. When the output signal of the data receiving section 1 is impressed upon the driving section 2, on the other hand, a monitor signal is outputted from a photodiode 4 with delay time which is equal to the sum of the delay time of the driving section 2 and the light emission delay time of the diode 3 and the outputs of the reference voltage generating section 7 and a monitor voltage generating section 8 simultaneously rise. Therefore, the output light level of the diode 3 becomes a prescribed value from the beginning of a burst signal and satisfies a pulse mask.
MIKI MAKOTO
YASUDA SHUICHI
NOBECHI KIYOTOSHI
MURAKAMI NORIO
SHIMIZU KAZUYOSHI
AKAZAWA YUKIO
ISHIHARA NOBORU
NAKAMURA MAKOTO
NIPPON TELEGRAPH & TELEPHONE
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