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This course is part of our Photonics Teaching Program.
TBC
TBC
TBC
ECTS credits: 3
This includes 30 hours of lectures, and an extra 60 hours for preparation and to work on the design study.
Prerequisites: Optics, electromagnetism
Compulsory program: Active participation, submission of report with design study.
Course assessment: A project report with a design study
Instructors: Nick Volet
1. Optical spectrum
Statistical description of laser phase and frequency fluctuations
Autocorrelation and power spectral density (PSD)
Wiener-Khintchine theorem
Ensemble averages, stationarity, and ergodicity
Connection between frequency noise and intrinsic linewidth
Lorentzian spectrum of an ideal laser
Broadening of real laser spectra by flicker and technical noise
2. Linewidth and frequency-noise measurement
Delayed self-heterodyne (DSH) interferometry for laser-linewidth measurement
Interference of delayed optical fields and generation of the RF beat signal
Autocorrelation of the detected intensity and connection to the RF spectrum
Role of phase noise, frequency-noise PSD, coherence time, and delay length
Linewidth extraction in the white-noise limit
Effect of finite delay length and interpretation of realistic DSH traces
Extension from linewidth measurements to full frequency-noise characterization
Unbalanced Mach-Zehnder interferometers (UMZI) as frequency discriminators
Phase reconstruction using coherent receivers and frequency-noise extraction
3. Optical feedback
Effective reflection coefficient.
The round-trip gain in the compound cavity.
Cavity resonance frequencies and emission frequencies.
Condition for emission frequencies in the presence of feedback
Change of emission frequency for weak feedback.
Criteria for single/multi-mode emission.
4. Photon density and laser phase
Rate equations for the photon density and for the laser phase.
Effect of optical feedback and spontaneous emission.
5. Langevin formalism
Stochastic rate equations.
Langevin equation.
6. Ensemble averages
Second moments and diffusion coefficients.
Power spectral density (PSD).
7. Frequency-noise plots
Intrinsic linewidth.
8. Stabilization
Pound-Drever-Hall (PDH) loops.
9. The MFB laser
Device design.
For registration and inquiries, please send an email to Nick Volet.
Slides and other files are available at this SharePoint site.
LaTeX files (for booklets and exercises) are available at this Overleaf project.
