Optical multiplexer for short range communications

Multiplexers are useful tools for the transmission of signals that can share the same physical transmission path. At the end of the connection it is necessary to have a demultiplexer that performs the inverse operation, and allows the recovery of each input signal. In this paper we present results obtained by using multilayered a-SiC:H heterostructures as wavelength-division multiplexing device (WDM) operating in the visible region of the electromagnetic spectrum. The WDM is a glass/ITO/a-SiC:H (p–i–n)/a-SiC:H(-p)/Si:H(-i)/SiC:H(-n)/ITO heterostructure in which the generated photocurrent at different values of the applied bias can be assigned to the different optical signals. The device was characterized through spectral response measurements, under different electrical bias and frequencies. Results show that in the multiplexing mode the output signal is balanced by the wavelength of each incoming optical carrier and modulated by their frequencies.