Design of a Franz–Keldysh effect electroabsorption waveguide modulator for millimetre-wave generation

• Published in: Optics and laser technology Vol. 34; no. 6; pp. 475 - 478
• Main Author: Leeson, M.S
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.09.2002; Elsevier Science
• Subjects: Applied sciences; Circuit properties; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Franz–Keldysh electroabsorption; Frequency conversion ; harmonic generation, including high-order harmonic generation; Fundamental areas of phenomenology (including applications); Harmonic generation, frequency conversion; Integrated optics. Optical fibers and wave guides; Millimetre waves; Nonlinear optics; Optical and optoelectronic circuits; Optical elements, devices, and systems; Optical processors, correlators, and modulators; Optical waveguides and couplers; Optics; Physics; Waveguide modulator; Waveguide modulator; Millimetre waves; Franz–Keldysh electroabsorption; Millimeter wave radiation; Mode coupling; Electroabsorption modulators; Franz-Keldysh effect; Theoretical study; Multimode waveguide; Optical harmonic generation; Nonlinear optics; Optical waveguides
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/S0030-3992(02)00045-2

An analysis of the generation of harmonics for millimetre-wave signals using a Franz–Keldysh effect waveguide modulator is presented. The Franz–Keldysh electroabsorption is obtained via a method known to provide accurate results in comparison with experimental data. This is followed by an optimisation of the drive voltage in terms of the d.c. bias for a sinusoidal input. A spectrum rich in harmonics is produced and the fifth is considered in detail for device optimisation. The modulator considered is based on a large core multimode waveguide designed to yield a high coupling efficiency to single-mode fibres. The confinement factor, and hence the length, of the structure are determined via the effective index method. The resulting device could be used for the cost-effective production of millimetre-wave carriers via the harmonics generated whilst enabling the employment of electronics running at the speed of the fundamental.