The present invention is generally directed to integrated optical add/drop multiplexer devices in which light of a specific wavelength (or specific wavelengths) can be added to or dropped from a main fiber optic line. An actuation mechanism (e.g., heat) is used to tune and/or trim the devices. Some proposed architectures provide for tuning of the adding and dropping of channels in a hitless manner, a manner that is non-disruptive to other wavelength channels.