Micromachined Polarization Beam Splitter with Adjustable Leak Ratio for Optical Pickup

In this letter, we propose the optomechanical design and fabrication of a novel batched-processed polarization beam splitter (PBS) with an adjustable leak ratio for optical recording applications. The micro-PBS was fabricated by a 410-nm low stress silicon nitride Si₃N₄membrane integrated with a bimorph actuator. A dc drive voltage was applied to allow an adjustable leak ratio (0-0.24) with incident angle from 65° to 75° for operation in the different optical requirements (phase-change and magneto-optical disks) at A = 633 nm. The characteristics of the fabricated PBS are in close agreement with the theoretical calculations and confirm its feasibility.