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Polarization Compensation And Loss Equalization In Arrayed Waveguide Grating

Posted on:2016-03-26Degree:DoctorType:Dissertation
Country:ChinaCandidate:X XiaFull Text:PDF
GTID:1108330491962865Subject:Optical Engineering
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With the rapid development of large servers and supercomputers, a huge demand is raised for communication bandwidth. The available bandwidth of electronic interconnection technology has encountered a bottleneck, so people have paid attention to the optical interconnect technology. Wavelength division multiplexing (WDM) has become one of most promising solution to deal with the huge bandwidth. Arrayed waveguide grating (AWG) is a typical WDM device, which is already playing an important role in optical communication systems. In this thesis, we aim at improving two key performances of AWG:polarization dependence and loss uniformity.A birefringence compensation technique based on angled star couplers in AWG is theretically and experimentally investigated based on silica-on-silicon waveguide with B-Ge codoped upper cladding. This material platform has the best coupling loss to fiber. A 16-channel AWG with 100GHz channel spacing is designed and fabricated. The star couplers are designed according to Rowland circle construction with an oblique incident/diffraction angle. Five AWGs with different polarization compensation parameters are designed corresponding to different incident/diffraction angles to investigate the stress-induced birefringence. The experimental results confirm that the polarization dependent wavelength shift (PDλ,) can be tuned by varying the incident/diffraction angle at the star couplers. The polarization dependent shift decreases from 0.265nm to 0.03nm.This birefringence free AWG can be achieved without any additional fabrication process.A uniform channel insertion loss design over entire free speactral range (FSR) on silicon waveguide is proposed and experimentally demenstrated. Based on Rowland circle layout, by changing direction of arryed waveguides at the output star coupler to the entire output waveguide instead of the central output waveguide alone in conventional design, the insertion loss variation of all channels can be reduced. Using Kirchhoff diffraction formula simulation method, the direction of arrayed waveguides is optimizaed. Finally, the experimental results show this design can reduce the nonuniformity from 2.7dB to 1.1 dB without increasing the fabrication process steps or device size.
Keywords/Search Tags:waveguide, arrayed waveguide grating, integrated optics, wavelength division multiplexing, silica waveguide, silicon nano wire waveguide
PDF Full Text Request
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