In this paper, we present a design for an optical video transmission system employing a super wide-band FM modulation scheme. We focus on the design of optical transmitters and receivers, especially a wide-band electrical-to-optical converter and optical-to-electrical converter. With this system, it is important to develop optical and microwave devices which have a wide frequency response combined with flat group delay characteristics in order to improve the quality of the video signals after transmission. We also analyze theoretically the hybrid transmission capacity of AM analog video signals and 64QAM signals for digital video and data, and show the FM modulation parameters needed to realize high quality transmission. An experimental evaluation shows that our designed optical transmitter and receiver achieve high quality for the various channel plans for AM/64QAM hybrid transmission. The system has high received optical sensitivity and a wide optical dynamic range, allowing it to distribute analog video, digital video, and Internet data to many users over a wide area.

The thickness dependence of structure, magnetic properties and read-write characteristics has been studied for sputtered iron oxide thin films prepared by RF reactive sputtering. For sputter-deposited Fe3O4 films, [111] preferential orientation perpendicular to film surface is improved and crystal size increases with an increase in thickness (δ). Magnetic properties for Fe3O4 films are affected by thickness. In particular, saturation magnetization rapidly decreases at thicknesses less than about 0.07 µm. From this perspective, it is concluded that a thickness larger than about 0.07 µm is available for practical use. For oxidation-annealed γ- Fe2O3 media, signal-output and media transition length are proportional to δ0.7 and δ0.5, respectively. A γ-(Co0.025Cu0.03Fe0.945)2O3 medium with a 0.071 µm thickness shows 0.51 mV of Epp, 2000 frpm of D-6 dB, -35 dB of O/W and 38 dB of SNR.