Normal mode analysis of waveguide devices. II. Device output and crosstalk

For pt.I see ibid., p.1051 (1988). A normal mode analysis is applied to Mach-Zehnder interferometers and directional couplers for the purpose of calculating device output and crosstalk, while including a rigorous treatment of the device transition structures. For devices whose transition structures are both nonsynchronous and nonabrupt the parameters of the transition structure are shown to affect both crosstalk (or modulation index) and the zero voltage bias. For synchronous directional couplers dephasing of the normal modes in the transition structures is shown to require different voltages to achieve zero crosstalk in the cross state with reverse phase mismatch and in the bar state with uniform phase mismatch