An integrated quasi-collinear coupled acoustooptical mode converter

• Published in: Optics communications 2002-07, Vol.208 (1), p.79-83
• Main Authors: Hu, H.Z, Lin, H.Y, Yang, J.S, Zhang, M, Chen, J, Geng, F
• Format: Article
• Language: English
• Subjects: Acousto-optical devices; Acoustooptical coupling; Acoustooptical tunable filter; Applied sciences; Circuit properties; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Integrated optics; Integrated optics. Optical fibers and wave guides; Optical and optoelectronic circuits; Optical elements, devices, and systems; Optics; Physics; Waveguides, couplers, and arrays
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/S0030-4018(02)01561-4

TE/TM mode converter is a key element of integrated acoutooptical tunable filter (AOTF). Based on the quasi-collinear acoustooptical coupling, a new design configuration of mode converter has been proposed, in which a SiO 2/In 2O 3 film is used as acoustical waveguide and the acoustical waveguide is at a small angle to optical waveguide. This configuration not only has good performance of suppressing sidelobes but also has simple fabrication technique. The theory of this configuration has been discussed and a real mode converter has been fabricated. As the acoustooptical coupling length is 25 mm and the angle between acoustical and optical waveguides is 0.42°, the measured FWHM is 1.46 nm and the measured sidelobes level is −13.2 dB, as compared to the theoretical values of 1.44 nm and −13.4 dB, respectively. The RF drive power is measured to be 40 mw at mode-conversion efficiency of 99%.