The main goal of this thesis is to develop a system to permit wide field operation of Michelson Interferometers. A wide field of view is very important in applications such as the observation of extended or multiple objects, the fringe acquisition and/ or tracking on a nearby unresolved object, and also to reduce the observation time. For ground-based arrays, the field of view should be at least equal to the isoplanatic patch. Optical Stellar Interferometry consists of using two or more telescopes to collect the light from a distant object in order to obtain information with very high angular resolution. When two apertures are separated by a distance B, called baseline, the flat wavefront that comes from a distant source at a certain angle from the baseline does not reach the apertures at the same time. This delay will introduce an Optical Pathlength Difference (OPD) at both arms of the interferometer; if this path length difference is larger than the coherence length, then the light from both apertures will not interfere. In order to detect fringes over an extended field of view the OPD needs to be compensated before the beam combination takes place. In most interferometers nowadays this is done by means of delay lines. The light coming from an off-axis direction has a different delay than the light coming onaxis, referred to as differential delay. In so-called Fizeau interferometers, the synthetic aperture of the telescope array is exactly reproduced in a down-scaled version at the recombination optics; this recombination scheme has intrinsic path length compensation and a correspondingly wide field. This technique is very promising, but it is not useful if the baselines are very large compared to the single collector's aperture. In this case, the central peak is narrow and the energy is spread over the sidelobes of the interference pattern, limiting the sensitivity of the instrument. For non-Fizeau interferometers, the beams from the telescope array are simply overlapped (pupil-plane recombination) or combined in the image plane without maintaining the input pupil configuration. At angles where the differential delay becomes higher than the coherence length, the fringes disappear and the high-resolution information on the objects that are off-axis is lost. One way to solve this problem and acquire a wide field of view is to introduce a correction to the OPD for every angle in the telescope's field. In order to avoid the serious drawback of Fizeau interferometry at a large ratio of baseline over aperture size, we thought of a new approach to the problem, i.e., a system that could use a Michelson pupil-plane combination scheme but acquiring a wide field of view in one shot, saving also observation time. The functional principle of our approach is the introduction of an equalised OPD. This extra OPD can be translated in first-order approximation in steps of constant width and variable height which can be achieved by setting a stair-shaped mirror in an intermediate image plane of the interferometer. The focal plane has the characteristic that the light from different parts of the sky is focused separately, and for this reason we use it to introduce the equalization of the OPD. An extra OPD is introduced as a function of the field angle, so that coherent interference over a wide field of view can be obtained. The dimensions of the steps and the orientation of the mirror depends on the baseline and the pointing direction. Because the projection of the baseline vector on the entrance pupil changes with the hour angle during an astronomical observation, the mirror has to be actuated to follow these changes: it has to be rotated to follow the rotation of the projected baseline in order to maintain the steps perpendicular to it, and the depth must vary as it has to be adapted to the modulus of the projected baseline. In a system formed by more than two telescopes, it is necessary to have a step mirror at the focal plane of each telescope and a common reference point for the different baselines. Each mirror will be perpendicular to the projection of its baseline on the entrance pupil of its telescope. In this thesis we have studied the problem of the field of view for non-Fizeau arrays analytically and experimentally. The complete analytical description of a pupilplane interferometer with a staircase mirror in the focal plane of one of its arms is developed, and the results are compared with the experiments. We have designed a stair-shaped mirror that was placed in the focal plane of one of the arms of a twoarm Michelson-type interferometer. With a Xenon arc-lamp and a starmask we simulate different configurations of objects in the sky, with several off-axis objects with a differential delay that should be compensated by the staircase mirror. For all configurations, the experimental results followed the analytical predictions, and the visibility of the on-axis and off-axis objects was retrieved simultaneously. Special attention was given to the case of a star focused on the edge of a step. Analytical calculations and experiments show that in that case two sets of fringes, each corresponding to one step, are detected. By adding the information contained in this two fringes it is possible to retrieve the visibility of the source, meaning that no information is lost due to the discontinuous nature of the mirror, and a continuous wide field can be reconstructed.