Spectrally Interleaved Optical Transceivers for FSR-Limited WDM
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical transceivers face limitations in achieving fast, bidirectional communication due to the limited free spectral range (FSR) of on-chip resonant modulators, which restricts the number of WDM channels and leads to interference between signals traveling in opposite directions.
Innovation Solution
The transceiver is designed with separate transmit and receive bus waveguides, utilizing an optical interleaver, such as an asymmetric Mach Zehnder interferometer, to selectively couple wavelengths, preventing interference by employing π-shifted spectral responses and thermal stabilization techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If on-chip resonant modulators are used for WDM transmission, then optical signal modulation is achieved, but the free spectral range (FSR) is limited which restricts the number of WDM channels
Solution Approach 1:
The patent divides the single resonant modulator into multiple interleaved resonant modulators, each handling a subset of WDM channels. This segmentation allows each modulator to operate within its own FSR while collectively supporting a larger number of channels through wavelength interleaving, effectively resolving the channel number limitation imposed by single modulator FSR constraints
Solution Approach 2:
The patent introduces an additional dimension to the wavelength domain by implementing interleaved wavelength sets (e.g., odd and even channels). Instead of attempting to fit all channels within a single FSR, the system uses multiple modulators operating at different wavelength offsets, effectively adding a dimensional layer to the wavelength multiplexing scheme and doubling the channel capacity
2Productivity
If bidirectional communication is implemented over a single optical channel, then communication efficiency is improved, but signal interference occurs between opposite-direction signals
Solution Approach 1:
The patent segments the bidirectional communication channels by assigning different interleaved wavelength sets to different directions. For example, odd channels (λ1, λ3, λ5) are used for one direction while even channels (λ2, λ4, λ6) are used for the opposite direction. This segmentation eliminates interference between directions while maintaining full utilization of the optical fiber bandwidth
Solution Approach 2:
The patent introduces optical filters as intermediary components that selectively pass specific wavelength sets to each direction. These filters act as mediators that separate the bidirectional signals in the wavelength domain, allowing simultaneous transmission in both directions without interference while maintaining high communication efficiency
3Quantity of substance
If the number of WDM channels is increased in the same spectral band, then data transmission capacity is enhanced, but cross-talk between channels increases
Solution Approach 1:
The patent employs asymmetric wavelength spacing and interleaving patterns where different directional channels are offset by half the channel spacing. This asymmetric arrangement creates spectral separation between opposite-direction signals, reducing cross-talk while allowing doubled channel capacity. The asymmetric design ensures that transmit and receive wavelength sets do not overlap, eliminating the primary source of cross-talk
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 design allows for twice the number of WDM channels in the same spectral band without increasing FSR, reducing cross-talk, and enhancing data transmission efficiency.
Implementation Method 1
an optical interleaver configured to: selectively couple light having carrier wavelengths in a first wavelength set from the first waveguide bus to the I/O port, and selectively couple light having carrier wavelengths in a second wavelength set from the I/O port to the second bus waveguide
Implementation Method 2
utilizing an optical interleaver, such as an asymmetric Mach Zehnder interferometer, to selectively couple wavelengths, preventing interference by employing π-shifted spectral responses
Implementation Method 3
thermal stabilization techniques
Data Source
AI summary
Described herein are wavelength division multiplexing (WDM) transceivers configured to support fast, bidirectional communication over optical channels. An optical transceiver comprises a transmitter, a receiver, an input/output (I/O) port and an optical interleaver. The transmitter comprises a first bus waveguide and a plurality of optical modulators coupled to the first bus waveguide, each of the optical modulators being resonant at a respective wavelengths in a first wavelength set. The receiver comprises a second bus waveguide and a plurality of optical filters coupled to the second bus waveguide, each of the optical filters being resonant at a respective wavelength in a second wavelength set. The (I/O) port is coupled to an optical channel. The optical interleaver is configured to selectively couple light having wavelengths in the first wavelength set from the first waveguide bus to the I/O port, and selectively couple light having wavelengths in the second wavelength set from the I/O port to the second bus waveguide.