Methods for generation, manipulation and characterization of high repetition rate optical frequency combs
Abstract
In recent years, driven by metrological applications, there has been significant development in lasers producing very short pulses periodically with stabilized repetition rates and center frequencies. In frequency domain such lasers have discrete spectral lines with fixed frequency positions and are known as optical frequency combs. Utilizing such sources together with the well established techniques of Femtosecond pulse shaping, individual spectral lines can be controlled independently allowing for 100% duty factor very high complexity waveform generation. This is known as optical arbitrary waveform generation (OAWG) and promises to have significant impact in optical science and technology. The key components of an OAWG system primarily involves – (1) A source generating a high repetition rate frequency comb (2) An apparatus which can manipulate the comb on a line-by-line basis (3) Characterization techniques to analyze the modifications done to the comb. The work presented here has spanned all these three aspects. Firstly, a new class of pulse shapers which can achieve more than a magnitude improvement in achievable waveform complexities compared to previous techniques will be demonstrated. Next, two different characterization techniques (applicable in different situations) for high repetition rate frequency combs and arbitrary waveforms will be demonstrated. The last part of the dissertation would be on new ideas utilizing phase modulation for generating high stability, broadband optical frequency combs which are easily tunable in center frequency and repetition rate. Building upon recent ideas to generate frequency combs starting from continuous wave (CW) lasers, frequency comb sources with record spectral flatness and pulse quality are demonstrated. Techniques for significant enhancement in bandwidth of such sources using nonlinear optics in fibers will also be discussed.
Degree
Ph.D.
Advisors
Weiner, Purdue University.
Subject Area
Electrical engineering|Electromagnetics|Optics
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