Octo™ Photodiodes
Enhanced Multi-Axis Detection
The GPD Optoelectronics Octo™ Position Sensitive Photodiode (PSD) is a monolithic optical sensor designed for dual-scale beam position detection using a concentric, segmented architecture. The device comprises eight active photodiode elements arranged as two nested quadrant detectors: a larger-area outer quad and a smaller, centrally located inner quad. This geometry enables both coarse and fine positional sensing within a single integrated component.
The outer quadrant detector provides a wide active area for initial beam acquisition and coarse alignment. Its larger segments allow detection of incident light over a broad spatial range, making it suitable for systems with significant beam misalignment or motion.
Position is determined by comparing photocurrent differences between opposing outer segments.
The inner quadrant detector, positioned at the center of the device, offers higher spatial resolution due to its reduced active area and tighter segmentation. Once the optical signal is sufficiently centered by the outer detector, the inner quad enables precise position measurement and fine alignment adjustments. This hierarchical sensing approach provides a large dynamic range, high accuracy, and seamless transition between coarse and fine alignment modes.
Features
- Standard LCC packaging
- Spectral response from 800 nm to 1700 nm
- Chip active diameters: 4.4mm
- High sensitivity
- Low crosstalk
- High shunt resistance
- Low dark current
- Low capacitance for high segment bandwidth
Applications
- Laser Guidance for Free Space Optical Communication
- Optical Tweezers
- Beam Profiling