<title>Irregular virtual optical phased array</title>

The concept of irregular virtual phased-array overcomes some fundamental and practical obstacles in developing an optical phased-array with large scanning angle. In the irregular phased-array, array elements assume random positions; thus, an irregular phased-array can always produce only one beam, with no extra grating lobe, regardless the (average) center-to- center spacing between elements. Therefore, large size phase- modulator and large spacing can be used, which enhances the performance and simplify the structure of the phase-array. A virtual array is generated by an array of lenses that is coupled with an array of the phase-modulators such that the virtual array become the effective representation of the phased-array, and the physical size, shape and positions of the phase-modulators and lenses are no longer directly relevant. Thereby, the array of the phase-modulators and the array of the lenses can all be regular array, and only the virtual array needs to be an irregular array, which makes the structure of an irregular phased-array very simple. An irregular sub-array technique is also applied for further simplification. Computer simulation results are reported to illustrate some characteristics of the irregular phased-array.