Patent ID: 6452706
Filing Date: 2002-09-17
Classification: H04B

Abstract:
An FM signal optical transmission apparatus comprising:modulation means for converting a multiple signal obtained by subcarrier-multiplexing a plurality of signals into an FM signal having a predetermined carrier frequency; frequency conversion means for shifting an FM signal converted by said modulation means to a frequency lower than said carrier frequency; and optical modulation means for converting an optical signal into an FM optical signal by modulating said optical signal in accordance with an FM signal output from said frequency conversion means and transmitting said FM optical signal through an optical fiber cable, wherein said carrier frequency is higher enough than the frequency of said signals, conversion to said FM signal represents conversion of the carrier signal having said carrier frequency into a narrow-band FM signal by substantially FM modulating said carrier signal in accordance with a modulation index for substantially generating only a first-sideband, and shifting of said narrow-band FM signal to said low frequency side represents conversion of said narrow-band FM signal into a low-frequency-conversion narrow-band FM signal having a frequency lower enough than said carrier frequency.