ORCID Identifier(s)

0000-0002-8344-5288

Graduation Semester and Year

Summer 2024

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Electrical Engineering

Department

Electrical Engineering

First Advisor

Michael Vasilyev

Abstract

The optical signal degradation by optical amplifier noise set the fundamental limit of link reach in the fiber-optics networks. The industrial solution is to use the optical-electrical-optical (OEO) regenerator to clean up the noise at the expense of high-speed electronics and extra cost of laser and photodetectors. All-optical signal processing, enabled by nonlinear optics and optical fiber, intrinsically provides 2-order of magnitude higher processing bandwidth and seamless interface to fiber communication channels. However, there is no robust phase-preserving regenerator that has been experimentally demonstrated without sophisticated polarization tuning and without instable interferometric structure. In this project, we explore the applications of parametric wavelength converter to amplify the wavelengths out of the range of erbium-doped fiber amplifier (EDFA) and realize the robust phase-preserving amplitude regenerator (PPAR), along with the investigation of stimulated Brillouin scattering (SBS) suppression to increase of the converter’s efficiency to support these two applications.

In the first part of the work, a hybrid S-band amplifier combining the parametric wavelength converters and EDFA is proposed and experimentally demonstrated first in separate stages, then as a stand-alone device, and finally with coherent modulation signal. This technology provides a competitive option to support multi-band communication outside of the C/L-bands supported by EDFA, without suffering from high noise figure and low reliability of the alternative such as a thulium-doped fiber amplifier.

In the second part of the work, in the effort to increase the wavelength conversion efficiency (CE) in a wavelength converter with continuous-wave pump, we investigated SBS suppression using temperature distribution along the fiber length while simultaneously aligning the zero-dispersion-wavelength (ZDW) along the fiber. The main distinction of our work from the prior research is that the temperature dependence of Brillouin frequency and ZDW of highly nonlinear fiber (HNLF) with practical ZDW variations are well characterized to choose fiber sections with different room-temperature ZDWs that can be brought together at higher temperature that detunes their Brillouin frequencies. Use two-segment dispersion-decreasing (DD)-HNLF, we increase the CE by 4 dB with temperature tuning. Then, combining two types of HNLFs together, we achieve similar conversion bandwidth and CE using temperature tuning to align their ZDWs. Finally, by combing the two methods together, we achieved another 6.5 dB CE improvement.

In the third part of the work, we proposed and experimentally demonstrated the single-channel phase-preserving Mamyshev regenerator to show that the robust PPAR is achievable by combining the robust Mamyshev amplitude regenerator and well-known optical phase conjugator in a 3-stage manner. This also paves the way for the future multi-channel PPAR experiments.

Keywords

Nonlinear optics, all-optical signal processing, fiber optics communication, parametric amplifier

Disciplines

Electromagnetics and Photonics | Signal Processing | Systems and Communications

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