Study Of A Hybrid Beam Splitter-wavelength Multiplexer Based On Arrayed Waveguide Grating

Rapid development of the internet has fueled the great demand of bandwidth in opticalacess network. To meet the increasing bandwidth requirement in future, wavelength divisionmultiplexing(WDM) is applied in passive optical network(PON). However, its high costplays a main role in stopping it from been widely used. So far, a number of approaches havebeen investigated to reduce the cost. Among them, hybrid WDM PON can achieve a properbalance between performance and cost of future PON networks.In hybrid WDM PON, WDM transmission is used only for downstream signals wherewavelength demultiplexer is required. The upstream signals carried by single wavelength iscombined by a beam splitter. So in hybrid WDM PON, hybrid beam splitter-wavelengthdemultiplexer is very important.In this thesis, we propose an approach to realize a hybrid beam splitter-wavelengthdemultiplexer based on arrayed waveguide grating. Different wavelength from thedownstream signal incident from the center of the input slab waveguide grating circle, andfocus on the output slab waveguide circumference of Roland circle. That’s how thewavelength demultiplexer part works. The beam to be split is launched away from the centerof the circle which insures the beam won’t focus on a spot in the image plane. If the beamspot in the image plane is big enough, then it will be able to couple into all outputwaveguides. That’s how the beam splitter part works.In this thesis, we designed and simulated a1×32hybrid beam splitter-wavelengthdemultiplexer. For the beam splitting part, the excess loss is about2.7dB (not including thecoupling loss between optical fiber and silica waveguide), the maximum nonuniformity isabout2.2dB. For the wavelength demultiplexer part, the loss is2.5dB. The crosstalk for thecenter channel is-31.4dB. And the side channels suffer from increased crosstalk. Thecrosstalk of the outboard channel is-22.8dB. And the1dB bandwidth is19.1GHz.