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