Multiband WSS for Quantum Entangled Photon Distribution
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Solution Overview
Problem
Current optical communication technologies face challenges in increasing transmission capacity due to bandwidth limitations, particularly in the C-Band, and suffer from nonlinear effects such as cross-phase modulation and four-wave mixing.
Innovation Solution
A system for distributing entangled photon pairs using a source with a pump laser and a nonlinear medium to produce polarization-entangled frequency-correlated photons across the C-Band and L-Band, utilizing wavelength division multiplexing (WDM) and wavelength-selective switches (WSS) to manage and direct these photons effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dense wavelength division multiplexing is used to increase transmission capacity, then the number of channels increases, but nonlinear effects such as cross-phase modulation and four-wave mixing are exacerbated
Solution Approach 1:
The patent segments the optical spectrum into multiple bands (C-band, L-band, S-band) and uses separate wavelength-selective switches for each band. This segmentation allows independent control of channels in different bands, reducing nonlinear interactions between channels while maintaining high transmission capacity through multi-band operation.
Solution Approach 2:
The patent transitions from single-band operation to multi-band operation, adding the spectral dimension to the transmission system. By utilizing multiple optical bands simultaneously, the system increases transmission capacity without increasing channel density within a single band, thereby avoiding exacerbation of nonlinear effects.
2Productivity
If channel spacing is reduced to increase the number of channels, then transmission capacity increases, but nonlinear effects increase
Solution Approach 1:
The patent divides the optical spectrum into distinct bands (C-band, L-band, S-band) and manages each band separately using dedicated wavelength-selective switches. This segmentation allows the system to use larger channel spacing within each band while compensating for the reduced number of channels per band through the addition of multiple bands, thereby avoiding cross-phase modulation issues.
3Productivity
If wavelength division multiplexing is used to increase capacity, then more channels can be transmitted, but device complexity increases
Solution Approach 1:
The patent segments the wavelength management function into separate wavelength-selective switches for each optical band (C-band, L-band, S-band). Each switch independently manages its designated band, simplifying the control logic and reducing the complexity of wavelength management compared to a single comprehensive switch that would handle all bands simultaneously.
Solution Approach 2:
The patent employs wavelength-selective switches that are designed to handle multiple bands (C-band, L-band, S-band) with a single device, making the system more compact and easier to manage. This multi-functional approach reduces the total number of separate devices needed while maintaining the ability to independently control channels across all bands.
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 system enables efficient distribution of entangled photon pairs across multiple optical communication bands, enhancing transmission capacity while minimizing nonlinear effects, thereby supporting the development of a commercially viable quantum network.
Implementation Method 1
a pump laser and a nonlinear medium that are configured and operated to produce, when the pump laser pumps the nonlinear medium, pairs of polarization-entangled frequency-correlated photons
Implementation Method 2
The WDM is configured to direct photons of the entangled pairs having frequencies in the C-band frequency range to the first port, and photons of the entangled pairs having corresponding frequencies in the L-band frequency range to the second port
Data Source
AI summary
An on-demand distribution of pairs of polarization-entangled frequency-correlated photons is provided. The pairs are frequency-correlated in different bands of a multiband spectrum which may include the C-Band and the L-Band. The pairs are provided to wavelength selective-switches (WSS), which may be simultaneously controlled to provide the pairs to different receivers that are respectively connected to the output ports of the WSSes. Each WSS has a plurality of frequency channels of δf-width bins aligned to the ITU grid. A network controller receives a request for the distribution of one or more pairs to a pair of receivers and controls frequency-correlated channels in the WSSes to provide the pair(s) to the receivers.