A high-efficiency multi-beam splitter for optical pickups using ultra-precision manufacturing

• We propose a seven-port beam splitter grating with novel double-groove structure.
• High efficiency of 91.81% energy is designed to split into the −3T to +3T orders.
• The double-groove structure was fabricated using ultra-precision manufacturing.
• The deviation between the measured results and theoretically values is only 2.99%.
• It holds a high potential for mass production.

In this paper, we propose a compact seven-port beam splitter grating (BSG), based on a novel double-groove structure. The parameters of the grating are investigated by Fourier expansion and gradient algorithm. For an incident beam with TE mode normally passing through this BSG, high efficiency of 91.81% energy is theoretically split into the −3T ∼ +3T orders. The proposed double-groove blazed grating is fabricated using ultra-precision manufacturing. Therefore, the double-groove structure holds a high potential for mass production. The deviation of measured results from the simulated values is less than 3%, which proves that the experimental results are in good agreement with the theoretical values.

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