A wavelength tunable light source includes an optical pulse generating
section for generating an optical pulse; an amplitude control section for
controlling the amplitude of the optical pulse generated by the optical
pulse generating section by superimposing control light on the optical
pulse to output a short optical pulse; and an optical frequency converting
section for converting the frequency of the short optical pulse by
launching the short optical pulse output from the amplitude control
section into an optical nonlinear medium whose refractive index varies in
response to the electric-field intensity of the incident light. The
amplitude control section can be configured such that it carries out the
time division multiplexing and outputs the short optical pulse, thereby
constituting an optical pulse light source.
