Joe Novak
What Is An MZI? How Does It Work? Application In Biosensing Device Production Thoughts on Research
Mach-Zehnder Interferometer• Light based detection via interference
Power split into two equal beams• Reference beam• Sample Beam
Interference produces power at detector one(constructive) and no power at detector two(destructive)
Introduction of sample causes change in phase of sample beam, resulting in power differences at outputs
Output reduced to a single detector Light paths of same length Medium consisting of waveguide
materials
Power splitter
Power combiner
Phase shift reference arm
s
L
Bio-sensing arm
Several factors determine structure size• Device Functionality
Mode Selection Sensitivity
• Ease of Production Lithography Deposition/Etching
Si
h
H
W W = 3 μm
H = 250 nm
H = 20 nm
SiO2
Selected materials attach to biological handles
Presence of material changes effective refractive index of sample arm
Phase shift occurs in sample beam
WaveguideSurface Functionalization
Evanescent Wave
Recombination of sample beam with reference beam reduces power based on amount of phase shift
Observed output capable of inferring the presence of minute amounts of material
Pros• Detection by output power rather than
fringe patterns• Simple production, no moving parts• High theoretical sensitivity
Cons• Coupling misalignment introduces error• Larger waveguide structure increases
sensing area but introduces higher order modes
Sensors created on SOI(Silicon On Insulator) wafers
Various Etching, Photolithography, and Deposition steps
Processes utilizing Silicon and Silicon Dioxide have been researched for decades
(1) PR application
(2) development
(3) silicon etching
(5) silicon dioxide deposition
(6) PR application and development
Silicon dioxide
silicon PR
(4) strip PR
(7) silicon dioxide etch
Multidisciplinary benefits• Insights and different viewpoints are
invaluable Research Process
• Simulation and research during design can save months
Determination and endurance• Nothing is perfect, setbacks provide
experience
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