| Project/Area Number |
09650387
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
電子デバイス・機器工学
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| Research Institution | Department of Electrical Engineering, Faculty of Science and Technology, Keio University |
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Principal Investigator |
KANNARI Fumihiko Department of Electrical Engineering, Keio University Associate Professor, 理工学部, 助教授 (40204804)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1998: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1997: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Spatial Light Modulator / Phase Encoding / Light Routing / Optical Interconnection / Space Variant Router / スペースバリアント型光ルータ / 光ル-タ / スペースバリアント型光ル-タ |
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| Research Abstract |
A novel space variant optical interconnection, where the spatial routing pattern among nodes is variable only by changing the phase encoding pattern embedded on a spatial light modulator (SLM), is proposed and experimentally examined its basic performance for one-dimensional routing patterns. The spatial phase profile of a coherent light is shaped with a segmented liquid crystal SLM so that the far-field pattern matches to a desired routing pattern. At the same time, the laser beam is encoded with a M-series code and converted to a quasi noise spatial pattern. Various routing patterns encoded with different M-series are multiplexed and send in space. At a receiver, only a desired routing pattern can be selected with an identical M-series phase mask. The rest of multiplexed signals remain as noise and eliminated by some threshold detectors. We obtained following conclusions through theoretical and experimental studies.
(1) Assuming a 128x128 segmented SLM at 16 gray levels, one can multiplex more than 100 routing patterns using length-127 M-series phase codes.
(2) Proof-of-concept experiments was conducted with a 128 one-dimensional SLM and a HeNe laser. Doubly encoded spatial routing pattern embedded on the SLM was successfully decoded with another SLM phase mask. The signal-to-loss ratio were evaluated for different M-series code lengths.
(3) We demonstrated that a spatial pattern encoded for the spectral phase of an incoherent light can be sent through a fiber and recovered by forming a spectral holography. This time-to-space conversion scheme can open up new optical interconnections and communications.
(4) In order to use spectral holography technologies in fiber delivered interconnections and communications, we demonstrated holography at 1.3mm wavelength. The hologram was first written by a SHG of 1.3mm laser and then read by the fundamental beam.
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