Signal and Crosstalk Analysis Using Optical Convolution of Transmitted Optical Signals

Abstract

An optical system which consists of a transmitter array, a fiber array, and a receiver array, experience some signal loss and crosstalk as the signals travel from the transmitter to the receiver. Signal loss and crosstalk occur at the interface between the light source (Vertical Cavity Surface Emitting Laser, or the VCSEL) and the fiber array, and also at the interface between the fiber array and the detector (photodetector). In order to obtain the real-time analysis of the transmitted and crosstalk signals, optical convolution is employed in this work. Optical convolution of the radiated signals (from the VCSEL) and the fiber array is performed to determine the signal intensity at the receiver end and also the amount of crosstalk in the array system. Transmitted signal intensity and crosstalk are essential for defining signal integrity and reliability during the packaging of optoelectronic transmitter and receiver modules in an optical system. A theoretical analysis of transmitted and crosstalk signals is performed with various separation distances between the transmitter modules and the fiber array and with a zero separation distance between the fiber array and the photodetector. The analysis is also performed for a top-emitting VCSEL (for the planar transmitter module) and bottom-emitting VCSEL (for the multi-chip transmitter module). The optical convolution allows us to obtain the real-time and the actual transmitted and crosstalk signals at the receiver end of an optical array system. It also provides optical system performance analysis.