In one implementation, a method is provided for frequency tuning of a
photonic oscillator. The method includes supplying an optical signal, for
example laser light, which is modulated, delayed, and then converted to
an electrical signal. The electrical signal is amplified, and used in
modulating the optical signal. With this implementation, the frequency of
the an output signal of the photonic oscillator is shifted by adjusting a
bias voltage of the amplifier. In some implementations, shifting the
frequency of the output signal further includes using a frequency lock
loop circuit. In some implementations, shifting the frequency of an
output signal of the photonic oscillator further comprises adjusting at
least one of an phase shifter in series with the amplifier, an optical
fiber stretcher, or a bias voltage of a second amplifier.