Optical Modulator Curved Phase Shifter RF Uniformity
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Solution Overview
Problem
Optical modulators face challenges such as non-uniform application of RF signals, large device area consumption, and inadequate compensation for wavelength changes in laser diodes, particularly in fiber optic communications where high-bandwidth chirping occurs during direct modulation of laser diodes.
Innovation Solution
The optical modulator design incorporates a 1*m or 2*m optical coupler, waveguides, phase shifters, and loop mirrors to uniformly apply electromagnetic fields, reducing device area and compensating for wavelength changes by using curved or arced phase shifters and low-speed phase shifters to adjust refractive indices, enabling efficient phase modulation and amplitude control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If linear phase shifters are used in conventional optical modulators, then the device can perform phase modulation, but the RF signal is not uniformly applied along the length of the phase shifter, leading to non-uniform electromagnetic field application and reduced modulation efficiency
Solution Approach 1:
The patent applies curved or arced phase shifters instead of linear phase shifters. The curved geometry allows the RF signal to be applied more uniformly across the phase shifter structure, improving electromagnetic field distribution and modulation efficiency while maintaining manufacturing feasibility through standard fabrication processes
2Productivity
If conventional linear waveguide-phase shifter combinations are used, then phase modulation can be achieved, but the device consumes a relatively large area or amount of device real estate
Solution Approach 1:
The curved phase shifter design reduces the device area by compacting the phase modulation path. The arc-shaped configuration allows the light beam to traverse a shorter distance while still achieving the required phase shift, thereby reducing the overall footprint of the optical modulator
Solution Approach 2:
The patent implements a nested structure where the phase shifter is integrated within the waveguide structure, and the entire modulator is compacted into a smaller footprint. This nesting approach allows multiple functional elements to share space, reducing the total device area while maintaining all necessary modulation functions
3Device complexity
If simple non-tunable laser diodes are used, then the device is simpler and cheaper, but the output wavelength drifts with temperature changes and requires inadequate compensation techniques
Solution Approach 1:
The patent incorporates feedback mechanisms through the use of loop mirrors and phase shifters that actively compensate for wavelength drift. The system monitors phase changes and adjusts the phase shifter control signals to maintain stable operation despite temperature variations, providing automatic correction without requiring complex laser diode structures
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 enhances the efficiency of phase shifting, reduces modulator area, and compensates for phase drifts due to temperature changes, allowing for more precise control of optical signals and reduced reflection back to the laser, facilitating the generation of multiple optical signals from a single laser.
Implementation Method 1
the first phase shifter is configured to shift a phase of the similar or substantially identical continuous light beam in the first waveguide in a first applied electromagnetic field
Implementation Method 2
first and second low-speed phase shifters 210a-b, first and second high-speed phase shifters 212a-b... operating by applying a controlled amount of thermal energy to the corresponding waveguide, thereby changing the temperature and the refractive index of the waveguide
Implementation Method 3
The first and second loop mirrors are configured to return the similar or substantially identical continuous light beam to the first and second waveguides, respectively
Implementation Method 4
A beam splitter divides the laser light into two paths... The beams are then recombined. Changing the electric field on the phase modulating path determines whether the two beams interfere constructively or destructively at the output
Data Source
AI summary
Embodiments of the disclosure pertain to an optical modulator including an m*n optical coupler, first and second waveguides coupled or connected to the m*n optical coupler, a first phase shifter coupled to the first waveguide, and first and second loop mirrors at respective ends of the first and second waveguides opposite from the m*n optical coupler. The m*n optical coupler is configured to combine substantially similar or identical continuous light beams (at least one of which may be phase-shifted) returned through the first and second waveguides by the first and second loop mirrors to form a modulated optical signal. A compound optical modulator, a modulated or modulatable laser, and methods of using and manufacturing the optical modulators, are also disclosed.