Development of efficient FPGA-based
phase meters for IR-Interferometers.
Optimizations for multichannel
interferometers
L. Estebana), M.Sáncheza), J.Sáncheza)
a) Laboratorio Nacional de Fusión, Asociación EURATOM-CIEMAT, Avd
Complutense Nº22, Madrid, Spain.
J. A. Lópezc), O. Nieto-Taladriz c)
c) Departamento de Ingeniería Electrónica, ETSI Telecomunicación, Universidad
Politécnica de Madrid, Avd Complutense Nº20, Madrid, Spain.
P. Pedreirac), P. Acedoc)
c) Departamento de Opto-Electrónica y Tecnología Laser, Universidad Carlos III de
Madrid, Avd de La Universidad SN, Leganés, Spain.
Online processing concept
• Pre-processing
–
De-noising of input carrier signals (interference signals) (TJ-II, W7-X)
–
Digital Diplexing (W7-X)
–
Crosstalk elimination...
• Processing
–
Phase demodulation of the input signals with a proper algorithm
• Post-processing
–
Control signals
–
Operations over the demodulated signals
Compensation results TJ-II, W7-X
0.09
0.6
NdYAG
CO2
0.06
Optical path-lengths [m]
Optical path-lengths [m]
0.4
0.2
0.0
-0.2
0.1
0.2
0.00
-0.03
0.3
Time [s]
0.4
0.5
0.6
-0.09
0.000
0.010
0.020
Time [s]
0.030
0.040
0.01
0.02
Time [s]
0.03
0.04
0.08
0.04
Path-length difference [m]
Path-length
difference [m]
0.08
0.00
-0.04
-0.08
0.08
Path-length
difference [m]
0.03
-0.06
-0.4
-0.6
0.0
CO
CO2
0.04
0.00
0.04
0.00
-0.04
-0.04
-0.08
0
0.1
0.2
0.3
Time [s]
0.4
0.5
0.6
-0.08
0.00
Electron density computation, example TJ-II
λ1ΔΦ1, λ2ΔΦ2 Optical pathlength
differences
Average electronic density
≈2 μm







1
1
22
n
d
l

e r
2
2





e 1
2
Maximun phase shift ≈ 10 fringes (periods) CO2
Maximun phase shift ≈ 100 fringes (periods) NdYAG
PFE10
THANKS!