# US 2018/0024009 A1 · Method for measuring multi-channel mismatch of ultra-high speed photonic sampler and measurement compensation device thereof

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- Number: US 2018/0024009 A1
- Document ID: US20180024009A1
- Status: Published application
- Kind: A1
- Application number: 15/544,188
- Filed: 2014-10-30
- Published: 2018-01-25
- Earliest claimed: 2014-10-22
- Assignees: Shanghai Jiao Tong University
- Applicants: Shanghai Jiao Tong University
- Inventors: Weiwen ZOU; Guang YANG; Huajie ZHANG; Jianping CHEN
- Web page: https://patentgrep.com/patent/US20180024009A1

## CPC

- G01J 11/00: Measuring the characteristics of individual optical pulses or of optical pulse trains
- G01J 1/58: using luminescence generated by light
- G01J 3/28: Investigating the spectrum (using colour filters G01J3/51)
- G01R 27/28: Measuring attenuation, gain, phase shift or derived characteristics of electric four pole networks, i.e. two-port networks; Measuring transient response (in line transmission systems H04B3/46)
- G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

The present invention relates to a measuring and compensating method for channel mismatch of an ultra-high speed time-wavelength interleaved optical pulse sequence, by employing a generating module of the to-be tested ultra-high speed time-wavelength interleaved optical pulse sequence, an optical spectrum measuring module, an electrical frequency measuring module, and a data analyzing and processing module. The present invention obtains mismatch information of the pulse sequence for each channel by means of measurement and analysis of the ultra-high speed time-wavelength interleaved optical pulse sequence, thus overcoming the bottleneck of inadequate sampling of time-domain observation via an oscilloscope. The channel mismatch information obtained by the present invention may act as a basis for channel mismatch compensation and correction for the ultra-high speed time-wavelength interleaved optical pulse sequence.

## Claims

### Claim at position 1

1-2. (canceled)

### Claim 3

A method for measuring multi-channel mismatch of an ultra-high speed photonic sampler, comprising
splitting a multi-channel optical pulse signal sequence to be tested into a first path of the signal sequence and a second path of the signal sequence by a 1×2 optical fiber coupler,
inputting the first path of the signal sequence into a spectrometer to obtain a first measurement result,
passing the second path of the signal sequence through a photodetector and inputting the second path of the signal sequence into an electrical spectrum analyzer to obtain a second mesurement result,
outputting the first measurement result from the spectrometer and the second measurement result from the electrical spectrum analyzer respectively to a data analyzing and processing module,
calculating an amplitude αk as αk=|∫+∞−∞Ek(ƒ)df|2, wherein k equals to 1,2, . . . , M, of each channel, M is a total number of all the channels, and Ek(ƒ) is an optical spectrum as measured by the spectrometer for the kth channel,
calculating ũk(ƒ) as
u
~
k

(
f
)
=

E
k

(
f
)

2
max

{

E
k

(
f
)

2
}
as a Fourier transformation of uk(t), wherein the uk(t) is a normalized waveform of the kth channel, and
calculating a time delay τ1 as
{
10


log
10

P
M

(
τ
1
,
τ
2
,
…

,
τ
M
)
P
k

(
τ
1
,
τ
2
,
…

,
τ
M
)
=
C
M
-
C
k
,
k
=
1
,
2
,
…

,
M
-
1
τ
1
=
0
wherein Ckk=1,2, . . . , M are M spectrum peaks measured by the electrical spectrum analyzer, and Pk are M peaks of a radio frequency spectrum on an interval [0, ƒs]:
P
k
=
(
R
PD
MT
s
)
2


∑
l
=
1
M


a
l

u
~
l

(
kf
s
/
M
)

e
-
j


2


π

(
kf
s
/
M
)


τ
l


e
-
j


2


π


k

(
l
-
1
)
/
M

2
k
=
1
,
2
,
…

,
M
wherein Ts is a sampling period, ƒs=1/Ts, and RPD is a responsivity of the photodetector.

### Claim 4 (depends on 3)

A measurement compensation device for multi-channel mismatch of the ultra-high speed photonic sampler according to claim 3, comprising
the 1×2 optical fiber coupler having an input port,
the spectrometer having an input port and an output port,
the photodetector,
the electrical spectrum analyzer,
the data analyzing and processing module having an input port and an output port, and
a driving and feedback module having an input port and an output port;
wherein the input port of the 1×2 optical fiber coupler is connected to an output port of a generating module, and the generating module is for generating an ultra-high-speed time-and-wavelength-interleaved optical pulse sequence to be tested and has variable optical delay lines and variable attenuators;
the 1×2 optical fiber coupler splits the ultra-high-speed time-and-wavelength-interleaved optical pulse sequence into a first path and a second path,
the first path is connected to the input port of the spectrometer, the second path is successively connected to the photodetector and the electrical spectrum analyzer,
the output port of the spectrometer and the electrical spectrum analyzer are respectively connected to the input port of the data analyzing and processing module;
the output port of the data analyzing and processing module is connected to the input port of the driving and feedback module; and
the output port of the driving and feedback module is connected to the variable optical delay lines and the variable attenuators of the generating module.