AWG Optical Splitter for Flat Passband
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Solution Overview
Problem
Conventional synchronized AWG optical wavelength multiplexing/demultiplexing circuits face limitations in increasing passband width while maintaining flatness, leading to signal distortion and transmission quality deterioration in large communication systems.
Innovation Solution
The optical wavelength multiplexing/demultiplexing circuit employs an arrayed-waveguide grating with an interference circuit that includes an optical splitter with a splitting ratio that changes in accordance with the optical frequency, minimizing loss near the optical center frequency and extending the passband width, and incorporates temperature compensation grooves to stabilize the optical center frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the passband width is increased in a conventional synchronized AWG, then the transmission capacity is improved, but the passband flatness deteriorates causing signal distortion
Solution Approach 1:
The patent applies dynamics by making the splitting ratio of the optical splitter variable rather than fixed. The splitting ratio changes in accordance with optical frequency, being minimized near the optical center frequency. This dynamic adjustment compensates for the natural roll-off in the AWG response, maintaining passband flatness while extending the effective passband width to 80 GHz or more.
Solution Approach 2:
The patent changes the parameter of splitting ratio as a function of optical frequency. By controlling the splitting ratio to vary with frequency and reach minimum values near the center frequency, the invention compensates for the AWG's frequency response characteristics, achieving both wide passband (80 GHz or more) and maintained flatness simultaneously.
2Reliability
If the optical center frequency drifts due to temperature changes, then the transmission stability is improved, but the frequency accuracy deteriorates causing channel misalignment
Solution Approach 1:
The patent addresses thermal effects by incorporating temperature compensation grooves filled with material having a temperature coefficient of refractive index different from the waveguide material. This compensates for thermal expansion and refractive index changes in the AWG, stabilizing the optical center frequency against temperature variations while maintaining frequency accuracy for channel alignment.
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 achieves a wider passband with maintained flatness and reduced temperature dependence, enabling effective signal transmission through multiple stages without significant distortion, suitable for complex communication systems.
Implementation Method 1
an arrayed-waveguide grating which includes arrayed waveguides (102) and a first slab waveguide (101) and a second slab waveguide (103) which are respectively connected to ends of the arrayed waveguides
Implementation Method 2
the interference circuit includes a first arm waveguide (107), a second arm waveguide (108) extended adjacent to the first arm waveguide and having a different length
Data Source
AI summary
When a conventional synchronized AWG is employed to extend a transmission passband, an increase in loss near the optical center frequency can not be avoided. Because of passband width limit, a problem has existed in that the synchronized AWG could not be applied for a large, complicated communication system wherein a signal light passes a number of points. Therefore, an optical wavelength multiplexing/demultiplexing circuit of the present invention is a synchronized AWG, which includes an optical splitter arranged in an interference circuit that is connected on the side of one slab waveguide. The splitting ratio of the optical splitter varies, depending on the optical frequency, and the value becomes minimum near the optical center frequency of the synchronized AWG. The optical splitter is operated so that the splitting ratio is comparatively great at optical frequencies distant from the optical center frequency.