Date of Award

2010

Thesis Type

Masters

Document Type

Dissertation

Divisions

Faculty of Science

Department

Department of Physics

Institution

Universiti Malaya

Abstract

This dissertation describes the design and simulation of silica-on-silicon pump/signal multiplexer for hybrid passive-active optical devices. Uniform symmetric directional couplers and planar Bragg gratings were utilized in this work, forming the essential building blocks in a waveguide amplifier. Several designs in relation to the multiplexers are presented in this work, with the simplest application for the directional coupler as a pump/signal multiplexer. A 980/1550 nm and an 800/1310 nm pump/signal multiplexers for erbium doped and bismuth doped waveguide amplifier, respectively were modeled. These couplers were designed and simulated in Rsoft BeamPROP environment, utilizing 3D Finite Difference Beam Propagation Method (FD-BPM) to measure light propagation in the silica waveguide. Coupler parameters including edge-to-edge spacing, and the length of the central coupling region, were optimised in order to maximise the outputs. Both couplers are 11.5 mm and 8.4 mm long respectively with channel spacing of ≥125 m. Numerical results show that two broadly spaced wavelengths from both couplers were successfully coupled from two opposite inputs into the same output. For the purpose of broadening the amplification band for long haul optical fiber communications, a combined 800/1310 nm and 980/1550 nm pump/signal multiplexers which would be integrated into a broadband amplifier is proposed. These couplers were designed according to the silica based planar lightwave circuit fabrication tolerance and modeled using BeamPROP 3D FD-BPM. The influences of waveguide parameters such as edge-to-edge spacing, length of the central coupling region, and refractive index difference on the coupler characteristics were investigated in detail. The insertion loss for the transmission of 1310 nm and 1550 nm signal wavelengths are 0.23 dB and 0.87 dB, respectively after applying lateral offset. Furthermore, an optical chip consists of pump/signal multiplexer and planar Bragg grating is also presented. The chip was separate designed and modeled using BeamPROP 2D FD-BPM and GratingMOD. A 360 nm broad amplification band is obtained from this configuration in order to achieve higher data capacity and bandwidth.

Initial

khm

Additional Information

Dissertation (M.A.) – Faculty of Science, Universiti Malaya, 2010.

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