Non-selective optical wavelength-division multiplexing devices based on a-SiC:H multilayer heterostuctures
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1076-K09-02
Non-selective optical wavelength-division multiplexing devices based on a-SiC:H multilayer heterostuctures Manuela Vieira1,2, Miguel Fernandes1, Paula Louro1,2, Manuel Augusto Vieira1,3, Manuel Barata1,2, and Alessandro Fantoni1 1 Electronics Telecommunication and Computer Dept., ISEL, Rua Conselheiro Emídio Navarro, Lisbon, 1959-007, Portugal 2 CTS, UNINOVA, Monte da Caparica, Caparica, 2829-516, Portugal 3 Traffic Dept., CML, Lisbon, Portugal ABSTRACT In this paper we present results on the optimization of multilayered a-SiC:H heterostructures for wavelength-division (de) multiplexing applications. The non selective WDM device is a double heterostructure in a glass/ITO/a-SiC:H (p-i-n) /a-SiC:H(-p) /a-Si:H(-i’)/aSiC:H (-n’)/ITO configuration. The single or the multiple modulated wavelength channels are passed through the device, and absorbed accordingly to its wavelength, giving rise to a time dependent wavelength electrical field modulation across it. The effect of single or multiple input signals is converted to an electrical signal to regain the information (wavelength, intensity and frequency) of the incoming photogenerated carriers. Here, the (de) multiplexing of the channels is accomplished electronically, not optically. This approach offers advantages in terms of cost since several channels share the same optical components; and the electrical components are typically less expensive than the optical ones. An electrical model gives insight into the device operation. INTRODUCTION Until the late 1980s, optical fiber communications was mainly confined to transmitting a single optical channel. Because fiber attenuation was involved this channel required periodic regeneration, which included detection, electronic processing, and optical retransmission. Such regeneration causes a high-speed optoelectronic bottleneck and can handle only a single wavelength. Recently plastic optical fibers (POF) [1] are drawing the attention of the industry because they are produced at very low cost and easily installed by non-specially trained people both in home networking, industrial control networks and automotive applications [2]. To improve the transmission data rate, Wavelength Division Multiplexing (WDM) can be employed. WDM enables the use of a significant portion of the available fiber bandwidth by allowing many independent signals to be transmitted simultaneously on one fiber, with each signal located at a different wavelength. Routing and detection of these signals can be accomplished independently, with the wavelength determining the communication path by acting as the signature of the origin, destination or routing. Components are therefore required to be wavelength selective, allowing for the transmission, recovery, or routing of specific wavelengths. Although they are well known for infrared telecommunication, they must be completely renewed for the transmission with the POF fibers. So, the conception of new devices for signal (de)multiplexing in the visible spectrum is a demand in this field [3, 4, 5]. T
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