Silicon Photonics Wavelength Locker Using Delay-Line Interferometer
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Solution Overview
Problem
Current data communication systems face challenges in achieving high data transfer rates due to fiber impairments like chromatic dispersion, which limit the bandwidth and efficiency of optical communication networks, especially beyond 10 Gbits/s, and require improved wavelength locking techniques for precise control in silicon photonic devices.
Innovation Solution
A wavelength locker integrated with a silicon photonics transmission system-on-chip using a delay-line-interferometer (DLI) on a silicon-on-insulator substrate, which splits the input signal into two paths, generates interference spectra, and uses detectors to create an error signal for locking laser frequencies to target frequencies, addressing the need for precise wavelength control and overcoming temperature drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If data transfer rate is increased beyond 10 Gbits/s, then bandwidth demand is met, but fiber impairments like chromatic dispersion cause distortion and attenuation
Solution Approach 1:
The patent implements a feedback control mechanism using a wavelength locker that continuously monitors the laser wavelength and generates an error signal when drift occurs. This error signal is fed back to the laser current control to adjust and maintain the wavelength at the target value, thereby compensating for fiber impairments and maintaining signal quality at high data rates
Solution Approach 2:
The patent replaces mechanical wavelength adjustment mechanisms with an integrated silicon photonic wavelength locker that uses optical interference and electronic feedback. The system uses photodetectors and electronic circuitry to sense and correct wavelength drift, substituting mechanical adjustment with an automated optical-electronic control system
2Measurement precision
If wavelength locking precision is improved to compensate for temperature drift, then frequency stability is maintained, but device complexity increases
Solution Approach 1:
The patent merges the wavelength locking function with the silicon photonic transmission system by integrating all necessary components (delay line interferometer, photodetectors, feedback circuitry) onto a single silicon chip. This integration consolidates multiple functions into one compact device, achieving high precision wavelength locking without proportionally increasing overall system complexity
Solution Approach 2:
The wavelength locker is designed to be universally applicable to different laser types and transmission conditions. The same integrated structure can lock wavelengths across different channels and adapt to temperature variations, providing multi-functional capability that reduces the need for separate correction mechanisms
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 solution enhances data transfer rates by maintaining precise wavelength locking, reducing distortion and attenuation, and enabling higher data rates beyond the limitations of existing systems, supporting increased internet and mobile application demands for multimedia data transfer.
Implementation Method 1
a first delay-line-interferometer (DLI) coupled to the second path to receive the second signal and configured to generate an interference spectrum
Data Source
AI summary
A wavelength locker integrated with a silicon photonics transmission system comprising a silicon-on-insulator (SOI) substrate and an input via a power tap coupler to receive a fraction of a transmission signal with one or more frequencies from a primary output path of the silicon photonics transmission system. The wavelength locker further includes a splitter configured to split the input to a first signal in a first path and a second signal in a second path and a first delay-line-interferometer (DLI) coupled to the second path to receive the second signal and configured to generate an interference spectrum and output at least two sub-spectrums tunable to keep quadrature points of the sub-spectrums at respective one or more target frequencies. The wavelength locker is configured to generate an error signal fed back to the silicon photonics transmission system for locking the one or more frequencies at the one or more target frequencies.