photonic devices - bragg gratings this graph shows typical experimental & theoretical grating...
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Photonic Devices - Bragg gratings
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Ref
lect
ivity
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This graph shows typical experimental & theoretical Grating reflection spectra. The peak wavelength is sensitive to changes in temperature (0.01nm/ degree C) as well as changes in strain (0.001 nm if the fibre stretches by 1 part in 106), making Bragg gratings useful in fibre sensors.
Theory
Experiment
Peak shifts with temperature and / or strain
Reflectivity (%)
Victoria University
Optical TechnologyResearch Laboratory
Special fibres for special applications
Current sensing on HV powerlines
“Non-zero dispersion-shifted fibre” for long haul high bit rate links
Optical fibre wound around conductor can safely sense magnetic fields
Erbium-doped fibre amplifier for all-optical repeaters in long haul communication links
Planar optical waveguides
Planar waveguides written into a polymer on a silicon wafer using a focused laser
Microscope photo of a planar waveguide device
Planar Optical Waveguides
Planar waveguides can also be built up layer by layer, as has been done for silicon chipsSequence of processing steps:
• Cladding deposition
• Core deposition
• Masking
• Etching
• Cladding deposition
This allows quite complex waveguide structures to be fabricated over a large area in a short time
Microscope photo of a buried channel waveguide showing the ~ 6 micron core (bright) against a darker cladding
Microphotonics - a new frontier
Micro-electro-mechanical systems (MEMS)In recent years, new kinds of moving objects such as tiny motors, pumps and moving mirrors have been fabricated on micrometer scales. This tiny electronically tiltable mirror is a building block in devices such as all-optical cross-connects and new types of computer data projectors.
MEMS array configured as an optical crossconnect