Characterization and nonlinear cleanup of noise in optical communication systems

In the first half of my thesis, I will present experimentally measured photon statistics of RZ/NRZ signals in an optically pre-amplified direct-detection receiver, and show that the results are in good agreement with quantum photodetection theory. Specifically, the ZEROs are described by a degenerate Bose-Einstein distribution, while the ONEs are described by a non-central-negative-binomial distribution. We will compare the exact quantum mechanical approach with the semiclassical Gaussian approximation in terms of evaluating the bit-error rate and the optimal decision threshold. I will then describe a nonlinear pulse filter that transmits incident pulses while rejecting cw background as well as ASE noise. The filter is realized by constructing a nonlinear optical Sagnac loop that is imbalanced by asymmetric dispersion. In the first demonstration at 30 Mb/s, a relative extinction of 22 dB (with respect to the pulse) is measured for the cw background. We also demonstrate cleanup of in-band ASE noise at 10 Gb/s. Other researchers have adopted my techniques and buHt similar pulse filters to clean up compressed pulses so as to build a pedestal-free, 5-ps 16-wavelength WDM source at 10 Gb/s and a 210-fs single-channel TDM source at 640 Gb/s.

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

1999

Author dc:creator

• Wong, William Shung-Kei

Advisor dc:contributor.advisor

• Hermann A. Haus and Erich P. Ippen.

• 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/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/9333

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/9333