Optical characteristics of LEXEL 85 argon ion laser and Gsanger LM0202P modulator: application to AM-FM light conversion

Abstract

The purpose of this thesis is to examine the possibility of using a commercial electro-optical modulator, the LM0202P modulator manufactured by Gsanger Opto-Elektronic of Germany, to amplitude modulate an argon ion laser, the LEXEL model 85, for proving a theory of the conversion of amplitude to frequency modulation of light in fiber optics. The main focus is to analyze the spectral output of the laser both before and after being directed through the modulator. Also to be considered is launching the laser light down a length of optical fiber. It was determined that the laser does not produce a single mode, monochromatic spectral line. Further, it was determined that when the laser is directed through the modulator, the structure on the laser profile tends to blur. This effect increases when DC bias voltage is applied to the modulator. Additionally, when the modulator is driven with an AC modulation superimposed on the DC bias voltage, the resultant optical spectral profile does not correspond to that expected for sinusoidal amplitude modulation