Certain Investigations and performance Analysis on newly developed optically gated fet based photodetectors for oeic receiver applications

Abstract

Optical communication becomes more successful since it offers the newlineloss of 0.0001 dB/km at a wavelength in the region like 1550nm, 1330nm, newlineetc,. The optical fiber communication is preferred due to its enormous newlinepotential bandwidth, small size and weight, electrical isolation, immunity to newlineinterference and crosstalk, signal security, low-transmission loss, ruggedness newlineand flexibility, system reliability and ease of maintenance and low cost. In newlinefiber optic communication, the information source provides an electrical newlinesignal to a transmitter which consists of an optical source that modulates the newlinelight wave carrier. The optical source which provides the electro-optical newlineconversion may be either a semiconductor laser or light emitting diode. The newlineoptical cable is used as transmission medium. The receiver consists of an newlineoptical detector which provides the demodulation of the optically modulated newlinesignal. Photodetectors like photodiodes (p-n, p-i-n, and avalanche types), newlinephototransistors and photoconductors are utilized for the detection of the newlineoptical signal and as opto- electrical conversion system. newlineMuch work has been reported for the two decades concerning the use newlineof field effect transistors in optically controlled applications. Complete newlinecharacterizations of the field effect transistors are yet to be done to examine newlinethe use of FET as high speed photodetectors. For certain applications, newlinecommercially available FETs do not have the desired photoresponse. newlineTherefore, it is necessary to improve the photosensitivity of FETs through newlineinnovative design technique. The optically gated FET structures have been newlinefound to have better photosensitivity as compared to the conventional newlinecounterpart (Chakrabarti (1994)). newline