There is provided a fiber optic system comprising: a multi-wavelength
source adapted to generate frequency modulated signals having different
wavelengths, .lamda..sub.1, .lamda..sub.2, . . . , .lamda..sub.n; and an
arrayed waveguide grating adapted to convert the multiplicity of
frequency modulated signals into a multiplicity of substantially
amplitude modulated signals, and spatially combine the different
wavelengths .lamda..sub.1, .lamda..sub.2, . . . , .lamda..sub.n. And
there is provided a method for transmitting an optical signal through a
fiber comprising: operating a multi-wavelength source so as to generate
frequency modulated signals having different wavelengths, .lamda..sub.1,
.lamda..sub.2, . . . , .lamda..sub.n; passing the frequency modulated
signals through an arrayed waveguide grating so as to convert the
frequency modulated signals into substantially amplitude modulated
signals, and spatially combine the different wavelengths .lamda..sub.1,
.lamda..sub.2, . . . , .lamda..sub.n; and passing the substantially
amplitude modulated signals into the fiber. And there is provided a
fiber optic system comprising: a multi-wavelength source adapted to
generate frequency modulated signals having different wavelengths,
.lamda..sub.1, .lamda..sub.2, . . . , .lamda..sub.n; and a beam combiner
adapted to spatially combine the signals having different wavelengths and
pass them into a periodic optical spectrum reshaper (OSR) to generate a
plurality of substantially amplitude modulated signals having wavelengths
.lamda..sub.1, .lamda..sub.2, . . . , .lamda..sub.n.