photonic devices - bragg gratings this graph shows typical experimental & theoretical grating...

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Photonic Devices - Bragg gratings 0 20 40 60 80 100 1430 1435 1440 1445 W avelength (nm ) R eflectivity (% ) 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 10 6 ), making Bragg gratings useful in fibre sensors. Theory Experimen t Peak shifts with temperature and / or strain Reflectivity (%) Victoria University Optical Techno Research Labora

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Page 1: Photonic Devices - Bragg gratings This graph shows typical experimental & theoretical Grating reflection spectra. The peak wavelength is sensitive to changes

Photonic Devices - Bragg gratings

0

20

40

60

80

100

1430 1435 1440 1445Wavelength (nm)

Ref

lect

ivity

(%

)

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

Page 2: Photonic Devices - Bragg gratings This graph shows typical experimental & theoretical Grating reflection spectra. The peak wavelength is sensitive to changes

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

Page 3: Photonic Devices - Bragg gratings This graph shows typical experimental & theoretical Grating reflection spectra. The peak wavelength is sensitive to changes

Planar optical waveguides

Planar waveguides written into a polymer on a silicon wafer using a focused laser

Microscope photo of a planar waveguide device

Page 4: Photonic Devices - Bragg gratings This graph shows typical experimental & theoretical Grating reflection spectra. The peak wavelength is sensitive to changes

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

Page 5: Photonic Devices - Bragg gratings This graph shows typical experimental & theoretical Grating reflection spectra. The peak wavelength is sensitive to changes

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