Optical signals have two basic components that are power and phase, which can be demonstrated in both time and frequency domains. The common diagnostics which are available in the market only measure power component in time or frequency domain. However in certain areas phase measurements are also required. The phase retrieval techniques are used to calculate phase measurements from different methods. There are a number of applications where phase measurements are required like astronomy, wavefront sensing technique (James Webb space telescope), x-ray crystallography, fiber optic telecommunications etc. Various phase retrieval algorithms have been used in retrieving phase measurements in temporal and frequency domains.
Gerchberg Saxton Algorithm technique is an iterative phase retrieval technique which has been used in phase retrieval methods. This iterative process involves iterative Fourier transformation back and forth between the object and Fourier domains with applications of the measured data or known constraints in each domain.
We worked on developing an iterative phase retrieval technique keeping
Gerchberg Saxton Algorithm as the basis of it and were able to successfully demonstrate phase retrieval in both temporal and spectral forms for a) Gaussian pulses having a wide range of initial educated guess phase; b) Chirped Gaussian pulses having various amounts of chirp; c) Chirped Super Gaussian pulses having various amounts of chirp. A metrics system was denied on which phase retrieval technique's success was based showing minimization of power, phase and instantaneous frequency metrics. During the study we found that chirped super Gaussian pulses of order 4 converge better than the chirped Gaussian pulses and also explored a way to choose a good edu-
cational phase without knowledge of the actual phase. Thus, this research provided a new foundation for further research on phase retrieval techniques of Gaussian and chirped Gaussian pulses.
Library of Congress Subject Headings
Signal theory (Telecommunication)--Mathematics; Fiber optics--Mathematics
Telecommunications Engineering Technology (MS)
Department, Program, or Center
Electrical, Computer and Telecommunications Engineering Technology (CAST)
Drew N. Maywar
Arif, Jamal, "Phase Retrieval using Power Measurements" (2013). Thesis. Rochester Institute of Technology. Accessed from
RIT – Main Campus