Performance Analysis of Directional Coupler Switches in the Presence of Noise from the Loss-Compensating Amplifiers

The performance of directional coupler (DC) based switches due to crosstalk in the presence of noise from the loss-compensating amplifier is analyzed using numerical calculations. It is shown that, by choosing an optimal decision threshold for a given amplified spontaneous noise (ASE) level and extinction ratio, the tolerance to switch element crosstalk levels can be greatly improved. Noise level improvement through distributed amplification for a given loss, further enhances the tolerance to element crosstalk levels at reduced receiver loss