Wavelength Selective Switch Port Arrangement for Noise Reduction
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Solution Overview
Problem
Wavelength selective switches face issues with -1st order light noise due to its incidence on other light input/output ports, causing interference, as existing designs fail to effectively manage the diffraction patterns and port arrangements to minimize this noise.
Innovation Solution
The proposed wavelength selective switch incorporates a specific port arrangement and phase modulation pattern where the 1st order light is directed to a designated output port, while the -1st order light is spaced away from other ports, utilizing a wavelength dispersive element and phase modulation element with a diffraction-grating-shaped phase modulation pattern to ensure minimal -1st order light incidence, potentially using a condensing lens and isolator to further reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a diffraction-grating-shaped phase modulation pattern is used to control optical paths, then wavelength selective routing is achieved, but -1st order light is generated and incident on other ports causing noise
Solution Approach 1:
The patent applies asymmetry by arranging light input/output ports asymmetrically with respect to the optical axis of the -1st order light. Specifically, the first port and third port are positioned at different distances from the -1st order optical axis, breaking the symmetry that would otherwise cause equal incidence of -1st order light on multiple ports. This asymmetric arrangement ensures that -1st order light does not incident on other ports, eliminating noise while maintaining wavelength selective routing capability
Solution Approach 2:
The patent converts the harmful -1st order diffraction light into a beneficial element by using its predictable optical path and symmetrical angle to design the port arrangement. By intentionally positioning ports based on the -1st order light's trajectory, the design ensures that while -1st order light is generated, it is directed away from active ports. The harmful diffraction effect is thus transformed into a design parameter that enables noise-free operation
2Productivity
If light input/output ports are arranged to receive 1st order light, then efficient wavelength routing is achieved, but -1st order light symmetrically generated may incident on other ports
Solution Approach 1:
The patent positions the second port (output port) asymmetrically relative to the first port (input port) with respect to the optical axis of the -1st order light. The second port is arranged to receive the 1st order light efficiently, while the first and third ports are spaced from the -1st order optical axis. This asymmetric configuration ensures that -1st order light, which travels at a symmetrical angle to the 1st order light, does not incident on other ports, thereby maintaining signal integrity while preserving routing efficiency
Solution Approach 2:
The patent introduces the optical axis of the -1st order light as an intermediary reference for port arrangement. By using this optical axis as a design benchmark, the patent ensures that ports are positioned at specific distances from it, creating a buffer zone that prevents -1st order light from reaching active ports. This intermediary reference enables precise control over light paths and eliminates noise interference
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration significantly reduces the -1st order light noise incident on other ports, achieving a light intensity ratio of less than -30 dB relative to the 1st order light, thereby minimizing noise and improving the reliability of optical communication systems.
Implementation Method 1
a phase modulation element which includes a plurality of pixels performing phase modulation and diffractively deflects an optical path of the light arriving from the first port via the wavelength dispersive element by presenting a diffraction-grating-shaped phase modulation pattern
Implementation Method 2
a wavelength dispersive element optically coupled to the light input and output part
Data Source
AI summary
A wavelength selective switch includes a light input and output part in which light input/output ports are arranged in a predetermined direction, the light input/output ports including a first port for inputting light, a second port for outputting the light, and at least one third port for inputting or outputting the light, a wavelength dispersive element optically coupled to the light input and output part, and a phase modulation element which includes a plurality of pixels performing phase modulation and diffractively deflects an optical path of the light arriving from the first port via the wavelength dispersive element by presenting a diffraction-grating-shaped phase modulation pattern, and the light input/output ports are arranged so that a 1st order light of the light is incident on the second port, and the first port and the third port are spaced from an optical axis of a −1st order light of the light.