Self-aligning universal beam coupler

Optics Express (Impact Factor: 3.49). 03/2013; 21(5):6360-6370. DOI: 10.1364/OE.21.006360


We propose a device that can take an arbitrary monochromatic input beam and, automatically and without any calculations, couple it into a single-mode guide or beam. Simple feedback loops from detectors to modulator elements allow the device to adapt to any specific input beam form. Potential applications include automatic compensation for misalignment and defocusing of an input beam, coupling of complex modes or multiple beams from fibers or free space to single-mode guides, and retaining coupling to a moving source. Straightforward extensions allow multiple different overlapping orthogonal input beams to be separated simultaneously to different single-mode guides with no splitting loss in principle. The approach is suitable for implementation in integrated optics platforms that offer elements such as phase shifters, Mach-Zehnder interferometers, grating couplers, and integrated monitoring detectors, and the basic approach is applicable in principle to other types of waves, such as microwaves or acoustics.

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    • "However, large scale integration of several solid-state optical components on a single chip is still hampered by various technological challenges. One of the major limitations in Silicon photonics is the lack of transparent in-line monitors [3], in particular for tuning, dynamic reconfiguration and closed-loop control of photonic devices [4]. Fig. 1. "
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    Procedia Engineering 12/2014; 87:1545-1548. DOI:10.1016/j.proeng.2014.11.594
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    • "If at the inward " source " we impose some modulation of its scattering and we look in detectors D1–D4 for signals with that modulation , we can improve our ability to lock our channel onto this particular scatterer. Since the feedback sequence in this selfaligning beam coupler can be left running continuously [20], this approach could also be used even if the inward source and the self-aligning universal beam coupler are moving relative to one another, thus allowing this bidirectional channel to " track " relative movement. The inward and backward waves could be at the same frequency here, or they could be at different frequencies or with finite bandwidths of sources provided only that the relative phase delays for the different frequencies or bandwidth range in the different optical paths from grating couplers to the single-mode input/output waveguide are all substantially similar within the frequency or wavelength range of interest. "
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    ABSTRACT: We show how multiple optimal orthogonal channels for communicating or interconnecting with waves between two objects can be aligned and optimized automatically using controllable beamsplitters, detectors and simple local feedback loops, without moving parts, without device calibration, without fundamental beam splitting loss, and without calculations. Optical applications include multiple simultaneous orthogonal spatial communication channels in free space or multimode optical fibers, automatically focused power delivery with waves, multiple channel communication through scattering or lossy media, and real-time-optimized focused channels to and from multiple moving objects. The approach physically implements automatic singular value decomposition of the wave coupling between the objects, and is equivalent in its effect to the beam forming in a laser resonator with phase-conjugate mirrors with the additional benefits of allowing multiple orthogonal channels to be formed simultaneously and avoiding the need for any nonlinear optical materials.
    Journal of Lightwave Technology 12/2013; 31(24):3987-3994. DOI:10.1109/JLT.2013.2278809 · 2.97 Impact Factor
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