High-Speed Photonic Functional Circuits Using Electrically Controllable PLZT Waveguides

Jiro ITO  Mitsuhiro YASUMOTO  Keiichi NASHIMOTO  Hiroyuki TSUDA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E92-C   No.5   pp.713-718
Publication Date: 2009/05/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E92.C.713
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Optoelectronics
Keyword: 
arrayed waveguide grating,  electro-optical devices,  planar lightwave circuit,  integrated optics,  

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Summary: 
We fabricated a high-speed wavelength tunable arrayed-waveguide grating (AWG) and an AWG integrated with optical switches using (Pb,La)(Zr,Ti)O3-(PLZT). PLZT has a high electro-optic (EO) coefficient, which means these devices have considerable potential for use in reconfigurable optical add drop multiplexers (ROADMs). The PLZT waveguides in this work have a rib waveguide structure with an effective relative index difference (Δ) of 0.65%. Both AWGs have 8 channels with a frequency spacing of 500 GHz. The fabricated wavelength tunable AWGs allows us to freely shift the output at a particular wavelength to an arbitrary port by applying voltages to 3 mm long electrodes formed on each of the waveguides. We confirmed that the maximum tuning range with driving voltage of 22 V was approximately 32 nm at 1.55 µm. With the integrated 8-ch PLZT waveguide switch array, we could also select the output port by setting the drive voltage applied to the switch array. 2 2 directional coupler switches were used for the switch array. The two devices exhibited insertion losses of 17 dB and 19 dB, adjacent crosstalk of -18.5 dB and -19.7 dB, and a maximum extinction ratio of 19.6 dB and 12.6 dB, respectively. The tuning speed of both devices was 15 ns and their physical sizes were 9.0 23.0 mm and 8.0 29.5 mm, respectively.