Wide Passband Optical Interleaver Using Controllable Delay
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Solution Overview
Problem
Conventional optical interleavers have limited effective bandwidth ratios, leading to signal errors and high fabrication costs due to narrow frequency bands, which are not suitable for high-capacity data transmission in DWDM systems.
Innovation Solution
A wide passband optical interleaver design incorporating a first and second optical splitter, coupled with optical filters having specific transmission coefficients and delays, to achieve an improved effective group delay ratio, enhancing signal separation and reducing errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional interleaver design (AWG, thin-film filter, or multi-lattice MZI) is used, then the interleaver can separate odd and even wavelength groups, but the effective bandwidth ratio is limited to about 43% at 30 dB crosstalk
Solution Approach 1:
The patent changes the key parameter of effective group delay ratio T by introducing a controllable delay element in one optical path. By adjusting the delay parameter and transmission coefficients ρ1 and ρ2, the patent achieves a wide passband with 77% effective bandwidth ratio at 30 dB crosstalk, resolving the contradiction between signal separation accuracy and bandwidth efficiency
Solution Approach 2:
The patent introduces a dynamic delay element that can be adjusted to optimize performance. The delay element allows the system to adaptively control the phase difference between optical paths, enabling the interleaver to maintain high signal separation accuracy across a wider bandwidth range compared to static conventional designs
2Reliability
If a Gauss-type filter is used, then the filter provides signal filtering function, but the frequency band becomes narrow after multiple passes, reducing bandwidth within the channel
Solution Approach 1:
The patent changes the filtering mechanism by using interferometric filtering based on optical path difference rather than traditional Gauss-type frequency filtering. This approach maintains a wide frequency band even after multiple passes through the system, as the filtering is based on constructive and destructive interference patterns that are less sensitive to cumulative bandwidth narrowing
3Manufacturing precision
If the frequency band of the optical signal in a single wavelength becomes narrow, then the system can achieve precise signal filtering, but the system needs to be designed with high precision or the optical signal is easily operated at the range of stopband, resulting in signal error
Solution Approach 1:
The patent introduces a controllable delay element that allows dynamic adjustment of the interference pattern. This dynamic control enables the system to maintain robust signal separation with a wider frequency band, reducing sensitivity to manufacturing tolerances and minimizing signal errors without requiring extremely high precision in the fixed structural parameters
4Ease of manufacture
If conventional interleaver designs are used, then the interleaver can function with existing components, but the fabrication cost is high due to the need for high precision design to meet data transmission requirements
Solution Approach 1:
The patent changes the performance parameters achievable with standard components by introducing a simple delay element and optimizing transmission coefficients. This allows the system to achieve high data transmission capacity (80 channels) using off-the-shelf optical components rather than requiring custom high-precision manufactured elements, thereby reducing fabrication costs while maintaining high productivity
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
The design significantly increases the effective passband ratio from 43% to 77% at 30 dB crosstalk and maintains high performance across varying crosstalk levels, reducing signal errors and fabrication costs.
Implementation Method 1
Due to effect of the ring resonant filter 126 with coupler 128, the signal responses at the terminals S1 and S2 are different in frequency. As a result, an interleaver can be achieved.
Implementation Method 2
The present invention provides a wide passband optical interleaver, comprising a first optical splitter, having a first output terminal and a second output terminal.
Implementation Method 3
A second optical filter having a transmission coefficient ρ2 and a delay are coupled on the second optical route.
Data Source
AI summary
A wide passband optical interleaver includes a first optical splitter, having a first output terminal and a second output terminal. A first optical route is coupled to the first output terminal. A second optical route is coupled to the second output terminal. A delay is coupled on the second optical route. A second optical splitter having two input terminals is receiving the first optical route and the second optical route. A plurality of optical filter respectively having transmission coefficients ρi is coupled to the first optical route and the second optical route. The transmission coefficients ρi are determined by satisfying a desired quantity of effective group delay ratio T, defined asT=∑iSi1-ρi1+ρi,whereSiis+1or-1.where Si is +1 or −1.