Analysis and Design of 2×4 90° Crystal Space Optical Hybrid for Coherent Optical Communication
Issue:
Volume 8, Issue 2, June 2020
Pages:
33-39
Received:
6 March 2020
Accepted:
24 March 2020
Published:
23 April 2020
Abstract: Based on the principles of crystal birefringence, wave plate phase delay and polarization transformation, a 2×4 90 degree crystal optical hybrid is presented. The beam splitting and coupling between signal and local oscillator lights of the hybrid is realized by two birefringent crystals and two half wave plates, and the required phase shift is produced by a quarter wave plate. Combined with the actual situation, the schemes of phase compensation and power ratio adjustment are given to optimize the performance of the device. And the feasibility of phase compensation and splitter ratio adjustment scheme is simulated and analysed through the establishment of mathematical model according to Jones matrix. The results show that the phase difference and splitter ratio can be set simply and accurately by the scheme of phase compensation and splitter ratio adjustment. Meanwhile, compared with the previous crystal spatial optical hybrid, this hybrid can improve the coupling effect of signal beam and local oscillator beam, and reduce the influence of crystal processing error between in-phase and quadrature branch. It has the advantages of simple and compact structure and good performance, and can be used in free-space optical coherent optical communication system.
Abstract: Based on the principles of crystal birefringence, wave plate phase delay and polarization transformation, a 2×4 90 degree crystal optical hybrid is presented. The beam splitting and coupling between signal and local oscillator lights of the hybrid is realized by two birefringent crystals and two half wave plates, and the required phase shift is pro...
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Paradoxa in the Blueprint of the Visual Organ: Their Contribution to ‘Intelligent’ Vision
Issue:
Volume 8, Issue 2, June 2020
Pages:
40-50
Received:
30 June 2020
Accepted:
24 July 2020
Published:
13 August 2020
Abstract: The development of the eyes is a product of the brain; the development of the central visual nerve tract which leads from the eyes to the brain is a product of the eyes and the development of the six extraocular muscles for the oculo-motoric control of the eyes is a further product of the brain. Therefore, the human visual system is a product of the brain and the eyes. Paradoxical constructions are part of the blueprint. These are not self-explanatory and are not immediately recognizable as intelligent solutions. Some of these solutions have been labelled as a ‘malperformance of nature’, others are paradoxically misinterpreted. Some paradoxa are discussed before the grating-optical 'cortical’ information processing in the three nuclear layers of the retina - the ‘brain in the eye’ - are looked at. The paradoxical construction of the visual nerve tract leading via the chiasm of the optic nerves (Chiasma Opticum) to the two CGL (Corpus Geniculatum Laterale) and to V1 (area 17) is based on this. At the same time, the ‘brain in the eye’ becomes the decisive basis of vision and the central visual nerve tract becomes a prominent organ of balance with a sensor and a motor function. Geometric optics and diffractive grating interference Near-field optics play an important part here as do the coordinate systems and the axis-centered symmetry operations.
Abstract: The development of the eyes is a product of the brain; the development of the central visual nerve tract which leads from the eyes to the brain is a product of the eyes and the development of the six extraocular muscles for the oculo-motoric control of the eyes is a further product of the brain. Therefore, the human visual system is a product of th...
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