Ring-Modulated Laser With Integrated Cavity Modulators
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Solution Overview
Problem
Existing high-speed optical modulators in silicon photonics face challenges such as high power consumption, large control circuits, and the need for precise tuning in ring-resonator modulators, while Mach-Zehnder interferometers require strong phase modulation and are typically long and power-intensive.
Innovation Solution
A semiconductor optical amplifier with a reflective coating and a pair of ring-resonator modulators within an optical cavity, which modulates optical loss through push-pull modulation, eliminating the need for precise tuning and reducing power consumption by using a thermal tuning mechanism to adjust the carrier wavelength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ring-resonator modulators are used for high-speed optical modulation, then large extinction ratio can be achieved, but precise and dynamic tuning is required which consumes large electrical power and occupies large control circuit areas
Solution Approach 1:
The patent combines the laser cavity and ring-resonator modulators into a single integrated structure where the modulators are formed within the laser cavity itself. This merging eliminates the need for separate tuning control circuits and reduces power consumption while maintaining the high extinction ratio benefit of ring-resonator modulation.
Solution Approach 2:
The laser cavity serves multiple functions simultaneously: it provides optical amplification through the semiconductor optical amplifier and performs modulation through the integrated ring-resonator modulators. This multi-functionality eliminates the need for separate tuning mechanisms, reducing both power consumption and control circuit complexity.
2Measurement precision
If ring-resonator modulators are used for high-speed optical modulation, then large extinction ratio can be achieved, but control circuits occupy large areas on integrated circuits
Solution Approach 1:
The patent merges the modulation function directly into the laser cavity structure, eliminating the need for separate external control circuits. The ring-resonator modulators are formed as integrated structures within the laser cavity, reducing the area occupied by control circuits on the integrated circuit.
3Ease of operation
If MZI modulators are used instead of ring-resonator modulators, then precise and dynamic tuning is not needed, but much stronger phase modulation is required which makes them very long and requires high modulation voltage/power
Solution Approach 1:
The patent combines the advantages of both approaches by integrating ring-resonator modulators within the laser cavity, eliminating the need for external tuning mechanisms while keeping the device compact. The resonant enhancement within the cavity provides strong modulation effect without requiring long device lengths or high modulation voltages.
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 approach enables a compact, energy-efficient optical source with a high ON/OFF extinction ratio, suitable for inter- and intra-chip connections, without the need for precise tuning of the ring-resonator modulators, facilitating low-cost and high-speed silicon-photonic interconnects.
Implementation Method 1
a semiconductor optical amplifier, defined in a semiconductor other than silicon, which has a first edge and a second edge. This semiconductor optical amplifier includes a reflective coating on the first edge, and provides an optical signal at the second edge
Implementation Method 2
Ring-resonator modulators use strong resonances for modulation, and thus can achieve large ER even with a weak phase modulation
Implementation Method 3
a reflector optically coupled to an end of the optical waveguide, where the pair of ring-resonator modulators is included within an optical cavity defined by the reflective coating and the reflector
Implementation Method 4
an optical waveguide that conveys the optical signal
Data Source
AI summary
An optical source is described. This optical source includes a semiconductor optical amplifier, with a semiconductor other than silicon, which provides a gain medium. In addition, a photonic chip, optically coupled to the semiconductor optical amplifier, includes: an optical waveguide that conveys the optical signal; and a pair of ring-resonator modulators that modulate the optical signal. Furthermore, the pair of ring-resonator modulators is included within an optical cavity in the optical source. For example, the optical cavity may be defined by a reflective coating on one edge of the semiconductor optical amplifier and a reflector on one end of the optical waveguide. Alternatively, the optical cavity may be defined by reflectors on ends of the optical waveguide.