Semiconductor optical amplifier as a phase modulator for short-pulse synthetic aperture ladar and vibrometry

Date of Award


Degree Name

Ph.D. in Electro-Optics


Department of Electro-Optics and Photonics


Advisor: Bradley D. Duncan


The use of a saturated Semiconductor Optical Amplifier (SOA) as both a phase modulator and an amplifier for long range laser radar applications is explored. As will be discussed, this concept could reduce the hardware necessary to transmit high bandwidth pulses and allow for the transmission of shorter pulses that are less sensitive to the detrimental effects of target motion. After reviewing the concepts governing ranging, vibrometry, and synthetic aperture ladar, the nature of the phase and amplitude modulation from saturating an amplifier with a high peak power Gaussian pulse is explored. The key SOA parameters affecting the modulation of the output pulse are addressed and optimized, and their impact on the ideal pulse response of a laser radar system is explored. Proof of concept laboratory demonstrations using phase modulated pulses to interrogate stationary, vibrating, and translating targets are also presented. The concept of using a saturated SOA to enable short-pulse synthetic aperture ladar and vibrometry is also explored. This research will show that the range resolution of a ladar system can be optimized by saturating a SOA with a carrier lifetime that is one half the FWHM Gaussian input pulse duration, yielding a substantial improvement in range resolution that is highly insensitive to variations in the input pulse duration and energy.


Optical amplifiers, Optical radar, Phase modulation

Rights Statement

Copyright 2012, author