LCOS Optical Beam Routing with Wavefront Error Compensation

The patent applies parameter changes by modifying the phase pattern parameters displayed on the SLM. Specifically, it uses optimized phase patterns such as blazed gratings with specific duty cycles (e.g., 50%) and phase depths (e.g., π or 2π) to control diffraction efficiency. The patent also employs iterative algorithms like Gerchberg-Saxton to calculate optimal phase patterns that maximize coupling into desired output fibers while minimizing unwanted diffraction orders, thereby reducing insertion loss without changing the physical SLM structure.

The patent implements preliminary action by pre-calculating and storing optimized phase patterns in a lookup table before operation. The system pre-computes the ideal phase patterns using iterative algorithms that account for the specific optical geometry, fiber positions, and wavelength parameters. During switching operations, the system simply retrieves and displays the pre-optimized pattern corresponding to the desired input-output connection, eliminating the need for real-time calculation and ensuring optimal performance is achieved before the optical beam is routed.

The patent reduces crosstalk by changing the phase pattern parameters displayed on the SLM. It uses blazed grating patterns with specific spatial frequencies and phase modulations that concentrate diffracted power into the desired first-order maximum while suppressing higher-order diffraction. The patent also employs iterative optimization algorithms to calculate phase patterns that account for the specific geometry of the optical system, ensuring that unwanted diffraction orders do not couple into adjacent output fibers, thereby minimizing crosstalk without adding physical complexity to the optical train.

The patent converts the potentially harmful effect of diffraction into a beneficial phenomenon by using blazed grating patterns that deliberately shape the diffraction pattern. Instead of trying to eliminate diffraction, the patent harnesses it by designing phase patterns that steer the primary diffraction order precisely to the desired output fiber while pushing unwanted orders away from active fibers. This approach transforms diffraction from a source of crosstalk into a mechanism for precise beam steering and power concentration.

The patent addresses manufacturing limitations by changing the approach from requiring perfect physical SLM fabrication to optimizing software-controlled phase parameters. It uses iterative algorithms like Gerchberg-Saxton that can compensate for non-ideal SLM characteristics by calculating phase patterns that work around manufacturing imperfections. The system adjusts phase depth, spatial frequency, and duty cycle parameters to achieve optimal performance with commercially available SLMs that have typical pixelation and response characteristics, rather than requiring ultra-precise fabrication.

The patent implements feedback through iterative optimization algorithms that calculate phase patterns based on measured or specified system performance requirements. The Gerchberg-Saxton algorithm and similar methods iteratively refine the phase pattern by comparing the desired output field distribution with the actual result, adjusting the phase parameters to minimize errors. This feedback loop allows the system to achieve low insertion loss and crosstalk by software optimization rather than requiring perfect hardware fabrication, continuously adapting the phase pattern to compensate for SLM imperfections.