Application of fiber amplifiers to fiber lasers and terahertz spectroscopy

Citation

Park, Namkyoo (1994) Application of fiber amplifiers to fiber lasers and terahertz spectroscopy. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/ZK03-KN91. https://resolver.caltech.edu/CaltechETD:etd-12212006-102347

Abstract

Starting with a review of the Erbium doped fiber amplifier, this thesis will describe the construction, intensity noise, linewidth, stabilization techniques, and spectroscopic applications of the Erbium doped fiber ring laser developed as a part of the thesis research activity. This laser, which uses the Erbium doped fiber amplifier as its gain module within fiber based ring resonator, exhibits excellent sidemode suppression (>70dB) and intensity noise properties (shot noise limited beyond GHz regime) with ultranarrow linewidth (<4kHz).

To measure and improve these performance, several new techniques were developed. A new interferometer based on a loss-compensated recirculating delayed self heterodyne technique, for the measurement of ultranarrow linewidth. A novel intracavity filtering technique to make the laser operate at the shot noise floor of intensity noise. Extension of Pound-Drever locking technique into the laser cavity, to enable the laser be stabilized and locked to an external reference at the same time.

The laser was also applied as a spectroscopic tool to study the four wave mixing process in semiconductor optical amplifiers. Because of the ultranarrow linewidth and intensity noise characteristics of fiber laser, it was possible to resolve THz intraband dynamics in a quantum well amplifier.

This thesis will also cover mode locked operation of the fiber laser and related issues briefly in the appendix.

Thesis Files