High-precision optical and microwave signal synthesis and distribution

In this thesis, techniques for high-precision synthesis of optical and microwave signals and their distribution to remote locations are presented. The first topic is ultrafast optical pulse synthesis by coherent superposition of mode-locked lasers. Timing and phase synchronization of ultrabroadband Ti:sapphire and Cr:forsterite mode-locked lasers is studied. Subfemtosecond (<0.4 fs) timing synchronization over 12 h is demonstrated. In addition to the timing lock, phase synchronization to a local oscillator with subfemtosecond accuracy (<0.5 fs) over 1000 s is achieved. Drift-free subfemtosecond timing and phase synchronization enables a phase-coherent spectrum over 1.5 octaves that has a potential to generate single-cycle optical pulses at 1 pm. The second topic is long-term stable microwave signal synthesis from mode-locked lasers. Although mode-locked lasers can produce ultralow-noise microwave signals as a form of optical pulse trains, the transfer of stability from optical to electronic domain is a highly non-trivial task. To overcome the limitations of conventional photodetection, an optoelectronic phase-locked loop based on electro-optic sampling with a differentially-biased Sagnac-loop is proposed. Long-term (>1 h) 3-mrad level phase stability of a 10.225 GHz microwave signal extracted from a mode-locked laser is demonstrated. The third topic is timing stabilized fiber links for large-scale timing distribution. Precise optical timing distribution to remote locations can result in synchronization over long distances. In doing so, acoustic noise and thermal drifts introduced to the fiber links must be canceled by a length-correction feedback loop. A single type-II phase-matched PPKTP crystal is used to construct a compact and self-aligned balanced optical cross-correlator for precise timing detection.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Kim, Jung-Won, 1976-

Advisor dc:contributor.advisor

• Franz X. Kärtner.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/42230
• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Identifier URI

http://dspace.mit.edu/handle/1721.1/42230

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/42230