Silicon OPA Delay Line for Optical Signal Processing
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Solution Overview
Problem
Existing optical delay systems face limitations in adjustability, signal distortion, and complexity, particularly in high-speed optical communication networks, where they require electrical conversions and have limited delay adjustment ranges due to material properties and size constraints.
Innovation Solution
An integrated optically adjustable delay line using an optical phased array (OPA) that generates an angle-adjustable light beam through beam forming, allowing flexible delay adjustments by changing the propagation path in a waveguide, featuring a combination of optical phased array transmitting and receiving units, couplers, phase shifters, and waveguide structures for low loss and high integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical-to-electrical (O/E) and electrical-to-optical (E/O) conversions are used for data buffering, then data buffering function can be achieved, but system complexity increases and electrical power consumption increases
Solution Approach 1:
The patent replaces electrical conversion mechanisms with a purely optical solution. An optical phased array modulates the phase of optical signals to control propagation paths through interferometric coupling, eliminating O/E and E/O conversions entirely. This substitution of optical control for electrical conversion reduces system complexity and power consumption while maintaining data buffering functionality.
Solution Approach 2:
The patent introduces an optical phased array as an intermediary device between optical input and optical output. This intermediary modulates optical signals directly through phase control, avoiding the need for electrical conversion intermediaries. The optical phased array acts as a mediator that enables data buffering purely through optical phase manipulation and interferometric path control.
2Adaptability or versatility
If the length of the waveguide is increased to achieve larger delay adjustment range, then delay adjustment range increases, but device size increases and loss increases
Solution Approach 1:
The patent transitions from one-dimensional delay adjustment (changing waveguide length) to two-dimensional control by manipulating the propagation angle in the x-direction. The optical phased array controls the incident angle of optical signals entering the waveguide, thereby controlling the propagation path length without changing the physical waveguide length. This angular dimension enables delay adjustment without increasing device size.
Solution Approach 2:
The patent changes the propagation parameter from waveguide length to propagation angle. By modulating the phase difference between adjacent waveguides in the optical phased array, the incident angle of optical signals is controlled, which in turn controls the propagation path length within the fixed-size waveguide. This parameter substitution enables delay adjustment without physical expansion of the device.
3Adaptability or versatility
If the effective refractive index of the medium is changed to adjust delay amount, then delay adjustment can be achieved, but the changeable range is small and optical absorption loss increases
Solution Approach 1:
The patent avoids changing the refractive index parameter and instead controls delay by manipulating the propagation angle in spatial domain. The optical phased array adjusts the incident angle of optical signals, which changes the effective propagation path length through geometric control rather than material property modification. This dimensional shift from material parameter to geometric parameter eliminates the need to change refractive index, avoiding associated absorption losses.
4Adaptability or versatility
If large dispersion is used to achieve continuous delay adjustment, then adjustability improves, but signal distortion increases and working bandwidth decreases
Solution Approach 1:
The patent replaces dispersion-based delay adjustment with phase-based interferometric control. Instead of relying on material or waveguide dispersion to achieve continuous delay adjustment, the system uses the optical phased array to modulate phase and control propagation angles. This substitution eliminates the inherent signal distortion and bandwidth limitations associated with dispersion while maintaining continuous adjustability through phase control.
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 solution provides a wide range of adjustable delay amounts with low loss and dispersion, enabling flexible and efficient optical signal processing, suitable for high-speed systems, and simplifies the structure and control, with potential for low-cost mass production.
Implementation Method 1
an optical phased array transmitting unit (101) which transmits a wave beam with directivity through beam forming
Implementation Method 2
different delay amounts obtained by multiple total reflection transmission in the waveguide
Data Source
AI summary
A silicon- and optical phased array-based integrated optically adjustable delay line, comprising, an optical phased array transmitting unit, a slab waveguide transmitting unit, and an optical phased array receiving unit that are sequentially arranged. By the optical phase control transmitting unit, the phase difference between channels is regulated and controlled via a phase shifter to change a far-field interference light spot and form a wave beam with directivity to regulate and control an incident angle of an optical signal entering the slab waveguide, thus changing the propagation path length of the optical signal. Finally, the optical signal is received by a corresponding optical phased array receiving unit to obtain different delay amounts. Large adjustable delay amount is realized and the delay line has the advantages of simple structure and control and high integration level with high application value in optical communication and microwave photonic and optical signal processing.