1. The document discusses the optimization of a characterization bench for micro and nano optical components such as waveguides. 2. A key part of the optimization is the automatic control of piezo controllers to precisely align the fiber and waveguide facets, which is important for evaluating propagation losses using the Fabry-Perot interferometric method. 3. The characterization bench uses a tunable laser, infrared camera, and power meter to visualize and measure the optical mode and propagation losses in lithium niobate waveguides.

1. Contacts
Nom: Omar IKEN
Courriel: omar.iken@edu.univ-fcomte.fr
INSTITUT FEMTO-ST
32 AVENUE DE L’OBSERVATOIRE
25044 BESANÇON CEDEX - www.femto-st.fr
The optimization of a characterization
bench of Micro and Nano Optical
Components
The optical characterization of waveguides represents a major step in the development of ultra-compact integrated photonic devices. It consists notably
in the evaluation of the propagation losses through the waveguide. The Fabry-Perot interferometric method appears as one efficient means of evaluating
the propagation losses [3]. However, it requires a high precision in the alignement between the fiber and the waveguide facets. Hence, one key feature
toward the optimization of the measurements is the automatic control of adjustable Piezo Controllers.
Power
meterCamera
1: The Piezo Actuators for the alignment between
the input and the output of the waveguide
(controlled by 2).
2: The Piezo Controllers for nanopositioning with
xyz axis (the automatisation of this component is
the main subject of this project).
Pictures showing the different components of the characterization bench
3
2
SampleOptical circulator
[1500,1600] nm
1 : Incident beam
2 : Transmitted beam
3 : Reflected beam
1
Nanopositioning stage
• Input
—We inject a laser beam in the LiNbO3 waveguide using a SMF28 optical fiber.
— We use a tunable laser source 1500-1600 nm.
• Output
— An infrared camera is used to visualize the light spot (wave) coming out from the
waveguide.
—A power meter with dual channel helps measuring the propagation losses.
A simplified schema describing the characterization bench
2
1
Experimental setup
Caracterization Results
Optical mode visualization @ (1550nm,0.2mW)
(output of a standard Ti:indiffused LiNbO3 waveguide, TE polarization)
Y
X
We use the Fabry-Perot interferometric method to measure the
propagation losses in the waveguide. A cavity is formed between the
input and the output of the waveguide. With this method we find the
unknown parameters in our theorical equations.
Reflected and Transmitted intensity
Using those two spectra ,we can find optical losses and group index [2]
with: - the Free spectral range
- Cavity length
The effective mode index :
Reflectivity :
The extinction ratio:
[3]Optical losses :
As a conclusion, we expect that the optimization of the bench will give more
possibilites to extract some important results, specialy about the waveguide
dimensions and their influence on the propagation.
References
X
Y
∆λ
Itmax
Itmin
Conclusion
Transmitted
beamReflected beam
L
[1]
[1] N.Courjal ECIO Conference 2012 Barcelona .
[2] H. Hu*, R. Ricken, and W. Sohler, Lithium niobate photonic wires Angewandte Physik/Vol
17,No.26/ OPTICS EXPRESS 24261.
[3] S. Taebi, M. Khorasaninejad, and S. Singh Saini, Modified Fabry–Perot interferometric
method for waveguide loss measurement / Vol. 47, No. 35 / APPLIED OPTICS 6625.
The waveguide us a Fabry-Perot cavity