Abstract

Optical front ends are crucial components for both direct detection and heterodyne systems. Serial tuning¹ has proved to be suitable for noise suppression without sacrificing a broadband frequency response^2-4 A thorough investigation of the noise performance of a serial tuned high impedance design² shows that, for a sufficiently high transconductance of the preamplifier transistor, three main sources are contributing to the total noise. In Fig. 1 the corresponding equivalent spectral input noise current densities are shown. Trace 1 is the total input noise density, which is in close agreement with measured values,² trace 2 represents the noise of the diode series resistance of the dual PIN diode.

© 1992 Optical Society of America