Experimental and Small-signal Analysis of Microwave Photonic Phase Shifter based on Slow and Fast Light using Linear and Nonlinear Semiconductor Optical Amplifiers

This paper investigates the performance differences obtained by using four different SOAs as microwave phase shifters. All performances are evaluated in terms of measured phase shift, radiofrequency gain penalty and 3 dB bandwidth. A microwave phase shift as high as 89.3° is achieved by slow and fast light effects in a high gain extra-nonlinear SOA. In the same SOA a different response of the phase from usual CPO is observed experimentally at low frequencies for particular operating points in saturated regime. This phenomenon is theoretically analyzed by means of a small-signal analysis.