Plate-mounted optical splitters are connected by aligning the input fiber or beam to the splitter's coated surface, securing the plate in a mount, and coupling output fibers or detectors while minimizing insertion loss and reflections.

Mounting the Plate

Plate beamsplitters are typically thin, flat glass plates with a coated front surface and an anti-reflection coating on the back surface to reduce unwanted reflections . They are often designed for a 45° angle of incidence (AOI). To connect them:

• Use a precision optical mount or holder that can secure the plate without stress or bending.
• Ensure the mount allows fine angular adjustment to align the splitter with the incoming beam or fiber.
• For fiber-optic applications, the plate may be integrated into a fiber array or PLC chip assembly .

Optical Alignment

Proper alignment is critical to maintain the splitting ratio and minimize losses:

• For free-space beams, direct the input beam onto the coated surface at the designed AOI (commonly 45°).
• For fiber-coupled splitters, align the input fiber core with the splitter's input port or waveguide using a micrometer stage or fiber alignment fixture.
• Adjust the tilt and lateral position to ensure the reflected and transmitted beams are correctly directed to their respective output fibers or detectors.

Fiber Coupling

When connecting to optical fibers:

• Use fiber pigtails or connectors pre-aligned with the splitter's output ports.
• For PLC splitters, the fiber arrays are coupled to the planar waveguide chip and encapsulated in a protective housing .
• Ensure low insertion loss by polishing fiber ends, using index-matching gel if necessary, and avoiding angular misalignment.

Securing and Testing

• Once aligned, tighten the mount to prevent movement.
• Verify the splitting ratio and check for back reflections or ghost beams.
• For network applications, test the optical power distribution to ensure uniformity across all output channels .

Summary

Connecting a plate-mounted optical splitter involves mechanical mounting, precise optical alignment, and careful fiber coupling. Using adjustable mounts, alignment stages, and proper fiber handling ensures efficient signal splitting with minimal loss and reflection, whether in free-space optics or fiber-based networks. This method applies to both standard plate beamsplitters and fiber-integrated PLC splitters.