Study on the characteristics of multi-wavelength sources using the phase-shifted fiber Bragg grating

Abstract

The characteristics of the phase-shifted fiber Bragg grating were analyzed and applications as multi-wavelength sources were presented. The phase-shifted fiber Bragg grating is fabricated by inserting phase-shift region in ordinary fiber Bragg grating. While the ordinary fiber Bragg grating generates only one reflection peak, the phase-shifted fiber Bragg grating generates the several narrow transmission peaks. This thesis describes the characteristics of the multi-wavelength sources through the following simulation results: the variation of the stopband by the transmission peak, the shift of the transmission peak by the amount of phase-shift, the variation of the transmission peak in asymmetrical condition, the variation of the transmission peakwidth, the variation of spacing, and expansion of the stopband. The phase-shifted fiber Bragg grating exhibits very narrow transmission peaks with different wavelengths simultaneously which can be selected in any wavelength by controlling the amount of phase-shift. The width of the transmission peaks was reduced as outermost subsection lengths were increased. When outermost subsection lengths were about $500\mum$ , the width of the transmission peak was about 0.5nm. It was also shown that spacing was increased as inner subsection lengths were reduced. When multi-wavelength source has the two transmission peaks and middle subsection length was about $300\mum$ , spacing was about 1nm. Multi-wavelength sources with the two and three transmission peaks were designed and analyzed. The source with two transmission peaks consists of two phase-shift regions inside ordinary fiber Bragg grating. In the case with the same interval of both sides of the Bragg wavelength, the simulation results deviated from the originally designed one were about 0.08nm in both transmission peaks. In the case with the different interval of both sides of the Bragg wavelength, the simulation errors of the first and the second transmission peaks...