OBR 4600: An Indispensable
Development Tool for Silicon
Photonics Research
www.lunainc.com
301 1
st
Street, SW, Suite 200 Roanoke, VA 24011
solutions@lunainc.com
540.769.8400
More Than Just a Reectometer
Tracks changes in polarization state, measures
group delay.
Component Characterization with
Unprecedented Visibility
See inside the component and evaluate each
interface for RL, IL dispersion, and more.
Accelerate Design Iterations
A full range of measurements in a single scan.
Up to 30 meters with 10 micron resolution in just
7 seconds.
• 0.05dBresolutionand0.10dBaccuracy
• 70dBdynamicrange
• Verylownoiseoor-130dB
• Measures30mwith10micronresolution
inlessthan7seconds
Key Specications
Making Silicon Work at the Speed of Light
“BlumenthalandBowers
OptoelectronicsResearchGroups”
Optimize Fabrication Methods to
Minimize Power Dissipation
Limiting total power dissipation is critical to
minimize heating and signal degradation.
Identify the Location of Power Loss
Inside the Chip
Characterize power loss across interfaces inside
the chip with micron resolution.
Polarization Mode Dispersion
Quantify the impact to polarization caused
by imperfections in physical dimensions and
characteristics of the light paths.
OBR4600
Connection
Spiral Delay Chip - Actual Size
Spiral Delay Chip - Schematic
One meter long spiral waveguide delay line
manufactured on a Si/Si
3
N
4
/SiO
2
Chip
A Spiral Delay Line Fabricated on a Silicon Platform -
An Analysis Using Luna’s OBR 4600
Total Distributed Loss Across 1 meter Silicon Photonics Spiral Delay Line
The high spatial resolution of the OBR 4600 is used to
illuminate a reective event near the entry point of the
spiral delay line. The detail in the lower plot reveals that
the broad reective event at the beginning of the trace is
in fact a series of 50 individual reections in the space of
2.5 mm correlating to the input waveguide leg crossing
the arms of the spiral path.
Using the same data set the average dispersion
accumulated by traveling through the device can
be determined by measuring the slope of the phase
derivative. In this case, the average dispersion is equal
to approximately 820 ps/nm.
Return Loss of Fiber and Face Reection Dispersion Measurement through Device
The Si photonics spiral delay chip compacts a 1 meter optical path length into an approximately 1 cm
2
area. The OBR 4600 can be optically coupled to the end of the spiral waveguide and the full 1 meter
path length scanned. In the data shown above, the reection at the chip input facet is at 5.486 meters
and the reection from the end facet is shown at 6.586 meters. The distributed loss across the entire
device can be measured and is approximately 30 dB/m. The data taken in a single scan contains a
remarkable level of detail with reective events due to waveguide crossing of the spiral clearly shown
with just 50 micron separation. Data from a single scan be reprocessed in different ways to support a
variety of analysis.
www.lunainc.com
301 1
st
Street, SW, Suite 200 Roanoke, VA 24011
solutions@lunainc.com
540.769.8400