
480 Laser-based measurements for time and frequency domain applications
where R is the responsivity of the photodiode. Hence, the demodulated time-averaged
microwave power is
P
mw
= 8ρr
2
R
2
P
LO
P
B
e
−2α
(1 −r
2
) (7.14)
where ρ is the resistance at the output of the photodiode. Thus, the generated microwave
power is proportional to the power of the optical sidebands. Finally, the phase nois e of the
oscillator can be characterized by a modified Leeson formula
S
φ
=
1 +
ηP
mw
2ρR
2
P
2
P D
P
P D
P
B
γ
2
f
2
2~ω
0
ηP
P D
≃
1 + 4ηe
−2α
r
2
γ
2
f
2
2~ω
0
ηP
LO
(1 −r
2
)
(7.15)
where γ is the HWHM of the loaded WGM resonance and η is the quantum efficiency
of the detector. The above equation shows that ...