Detection apparatus and method for noise intensity and coherent optical receiver
A detection apparatus and method for noise intensity and a coherent optical receiver where the detection method includes: preprocessing a received signal to obtain a pilot sequence contained in the received signal; removing a phase noise of a receiving pilot sequence by using a known transmitting pilot signal; calculating a noise power density of the receiving pilot sequence with no (or without) phase noise within a predetermined spectral width near a pilot frequency; and calculating power of a linear noise of the received signal based on a bandwidth of the received signal and the noise power density within the predetermined spectral width. Hence, linear noises and nonlinear noises may be split efficiently without introducing much complexity, and information on intensities of various noises may be obtained.
1. A detection apparatus for noise intensity, configured in a coherent optical receiver, the detection apparatus comprising:
a digital signal processor
configured to preprocess a received signal to obtain a pilot sequence contained in the received signal;
remove a phase noise of a receiving pilot sequence by using a known transmitting pilot signal;
calculate a noise power density of the receiving pilot sequence without phase noise within a predetermined spectral width near a pilot frequency; and
calculate power of a linear noise of the received signal based on a bandwidth of the received signal and the noise power density within the predetermined spectral width,
the digital signal processor further configured to:
calculate total power of received signal noise of the received signal, and
calculate power of a nonlinear noise of the received signal based on the total power of the received signal noise and the power of the linear noise.
2. The detection apparatus according to claim 1 , wherein the linear noise comprises amplified spontaneous emission (ASE) noise, and the nonlinear noise comprises cross phase modulation (XPM) noise.
3. The detection apparatus according to claim 2 , wherein the digital signal processor is configured to calculate power of the amplified spontaneous emission noise using:
P ASE =n 0 _ ASE ·BW;
where, P ASE is the power of the amplified spontaneous emission noise of the received signal, n 0 _ ASE is the noise power density within the predetermined spectral width, and BW is the bandwidth of the received signal.
4. The detection apparatus according to claim 2 , wherein the digital signal processor is configured to calculate power of the cross phase modulation noise using:
P XPM =P total −P ASE ;
where, P ASE is the power of the amplified spontaneous emission noise of the received signal, P XPM is the power of the cross phase modulation noise of the received signal, and P total is the total power of the noise of the received signal.
5. The detection apparatus according to claim 1 , wherein the digital signal processor is configured to:
obtain the phase noise of the receiving pilot sequence symbol by symbol by using the transmitting pilot signal and the receiving pilot sequence, and
remove the phase noise from the receiving pilot sequence.
6. The detection apparatus according to claim 5 , wherein the digital signal processor is configured to perform the phase noise removal using:
r
(
n
)
PN
_
removal
=
r
(
n
)
·
exp
[
-
j
·
angle
(
r
(
n
)
s
(
n
)
)
]
;
where, r(n) is the receiving pilot sequence, r(n) PN _ removal is the receiving pilot sequence with no phase noise, s(n) is the transmitting pilot signal, and
angle
(
r
(
n
)
s
(
n
)
)
denotes a phase angle between the receiving pilot sequence and the transmitting pilot signal.
7. The detection apparatus according to claim 1 , wherein the linear noise is used for one of failure diagnosis and system positioning.
8. A detection method for noise intensity, applicable to a coherent optical receiver, the detection method comprising:
preprocessing a received signal to obtain a pilot sequence contained in a received signal;
removing a phase noise of a receiving pilot sequence by using a known transmitting pilot signal;
calculating a noise power density of the receiving pilot sequence without phase noise within a predetermined spectral width near a pilot frequency; and
calculating power of a linear noise of the received signal based on a bandwidth of the received signal and the noise power density within the predetermined spectral width,
the detection method further comprising:
calculate total power of received signal noise of the received signal; and
calculate power of a nonlinear noise of the received signal based on the total power of the received signal noise and the power of the linear noise.
9. The detection method according to claim 8 , wherein the detection method further comprises:
calculating total power of received signal noise of the received signal; and
calculating power of a nonlinear noise of the received signal based on the total power of the received signal noise and the power of the linear noise.
10. A non-transitory computer readable storage medium storing a method according to claim 8 .
11. A coherent optical receiver, comprising:
an optical-to-electrical converter configured to convert a received optical signal into an electrical signal; and
a digital signal processor configured to preprocess the electrical signal to obtain a pilot sequence contained in the electrical signal, remove a phase noise of a receiving pilot sequence by using a known transmitting pilot signal, calculate a noise power density of the receiving pilot sequence without phase noise within a predetermined spectral width near a pilot frequency, calculate power of a linear noise of the received signal based on a bandwidth of the received signal and the noise power density within the predetermined spectral width, calculate total power of received signal noise of the received signal, and calculate power of a nonlinear noise of the received signal based on the total power of the received signal noise and the power of the linear noise.
12. A coherent optical receiver method, comprising:
converting a received optical signal into an electrical signal;
preprocessing the electrical signal to obtain a pilot sequence contained in the electrical signal;
removing a phase noise of a receiving pilot sequence by using a known transmitting pilot signal;
calculating a noise power density of the receiving pilot sequence without phase noise within a predetermined spectral width near a pilot frequency; and
calculating power of a linear noise of the received signal based on a bandwidth of the received signal and the noise power density within the predetermined spectral width the coherent optical receiver method further comprising:
calculate total power of received signal noise of the received signal; and
calculate power of a nonlinear noise of the received signal based on the total power of the received signal noise and the power of the linear noise.
13. A detection apparatus for noise intensity, configured in a coherent optical receiver, the detection apparatus comprising:
a signal preprocessor configured to preprocess a received signal to obtain a pilot sequence contained in the received signal;
a phase noise remover configured to remove a phase noise of a receiving pilot sequence by using a known transmitting pilot signal;
a power density calculator configured to calculate a noise power density of the receiving pilot sequence without phase noise within a predetermined spectral width near a pilot frequency;
a linear noise calculator configured to calculate power of a linear noise of the received signal based on a bandwidth of the received signal and the noise power density within the predetermined spectral width;
a total power calculator configured to calculate total power of received signal noise of the received signal; and
a nonlinear noise calculator configured to calculate power of a nonlinear noise of the received signal based on the total power of the received signal noise and the power of the linear noise.