Optical Interconnect Pre-Filtering for Low-Loss Channel Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical interconnects face challenges in increasing bandwidth density while maintaining cost-effectiveness and reducing insertion loss and inter-channel crosstalk, often due to complex wavelength filtering designs that introduce penalties like narrow bandwidths and group velocity dispersion.
Innovation Solution
The solution involves performing wavelength filtering before optical modulation and optimizing the selection of encoded states to avoid overlapping channels in three dimensions, thereby reducing crosstalk and eliminating the need for narrowband filtering, which is typically done after modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wavelength filtering is performed after optical modulation using narrowband filters, then channel separation is achieved, but insertion loss increases and bandwidth is reduced
Solution Approach 1:
The patent performs wavelength filtering before optical modulation rather than after. The continuous wave light beam is filtered to select specific wavelengths prior to being modulated by the resonant modulators. This preliminary filtering action avoids the need for subsequent narrowband filtering of modulated signals, thereby reducing insertion loss and avoiding bandwidth reduction while still achieving proper channel separation.
2Productivity
If complex wavelength filtering designs are used to increase bandwidth density, then more channels are supported, but device complexity and cost increase
Solution Approach 1:
The patent utilizes the polarization dimension to multiplex optical channels. By employing resonant modulators that can operate with different polarizations and using polarization-maintaining fibers, the system achieves bandwidth density multiplication without requiring complex wavelength filtering designs. This dimensional approach to multiplexing simplifies the overall device architecture while supporting multiple channels.
Solution Approach 2:
The continuous wave light beam is pre-filtered to select specific wavelengths before modulation. This preliminary wavelength selection simplifies the filtering requirements compared to filtering modulated signals, as the unmodulated continuous wave signal is easier to filter with lower loss and simpler devices.
3Measurement precision
If narrowband filtering is applied to modulated optical signals, then channel isolation is improved, but group velocity dispersion and signal distortion increase
Solution Approach 1:
The patent performs wavelength filtering on the continuous wave light beam before it undergoes optical modulation. By filtering the unmodulated continuous wave signal, the system achieves channel isolation without subjecting the modulated signal to narrowband filtering that would cause group velocity dispersion and signal distortion. The filtered continuous wave then serves as the carrier for data modulation.
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 approach reduces device complexity and crosstalk, allowing for lower loss designs and maintaining high bandwidth without penalties from narrowband filtering or group delay, thus enhancing optical interconnect performance.
Implementation Method 1
a first optical add drop multiplexer demultiplexer connected to receive a continuous wave light beam and send a first filtered wavelength of the continuous wave light beam
Implementation Method 2
a first resonant modulator connected to receive the first wavelength and send a first modulated optical signal
Data Source
AI summary
An optical apparatus, with an optical interconnect, the optical interconnect including a first optical transceiver having a first notch filter, the first notch filter including first and second optical add drop multiplexer demultiplexers connected to receive a continuous wave light beam and send a first and second filtered wavelengths to first and second resonant modulators which send first and send modulated optical signals through a light propagation path. The second filtered wavelength is different from the first filtered wavelength, and the second modulated optical signal has a polarity that is orthogonal to a polarity of the first modulated optical signal. Methods of communicating using the apparatus and an optical filter for use in an optical transceiver are also disclosed.