Integrated Ring Resonator Modulator and APD Monitoring
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Solution Overview
Problem
Traditional optical ring resonators require additional structural elements like drop bus waveguides and photodiodes for monitoring, which increase footprint, reduce modulation efficiency, and introduce power loss, and the use of silicon-based photodiodes is limited by their bandgap, making it difficult to detect longer wavelengths.
Innovation Solution
An integrated ring resonator design that incorporates a modulator and an avalanche photodiode along different sections of the ring waveguide, allowing for light modulation and monitoring within a single device structure, using a higher reverse bias voltage to enable detection of lower energy photons and reduce the effective potential barrier, thus increasing modulation efficiency and eliminating the need for additional space-consuming components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional optical ring resonators use drop bus waveguides and photodiodes for monitoring, then light monitoring function is achieved, but device footprint increases and modulation efficiency decreases
Solution Approach 1:
The patent combines the light monitoring function directly into the ring waveguide structure by forming an avalanche photodiode along a section of the ring waveguide, eliminating the need for separate drop bus waveguides and external photodiodes. This integration achieves light monitoring while reducing device footprint.
Solution Approach 2:
The ring waveguide structure is designed to serve multiple functions: it acts as both the optical transmission path and the integration platform for the avalanche photodiode monitoring element. This multi-functionality eliminates the need for dedicated monitoring components, reducing overall device complexity and footprint.
2Adaptability or versatility
If traditional optical ring resonators use drop bus waveguides and photodiodes for monitoring, then light monitoring function is achieved, but modulation efficiency decreases
Solution Approach 1:
By integrating the avalanche photodiode monitoring function directly along the ring waveguide, the patent eliminates the need for separate drop bus waveguides that would divert optical power. This maintains full optical power for modulation while achieving monitoring functionality, thus preserving modulation efficiency.
3Ease of manufacture
If silicon-based photodiodes are used, then standard silicon technology is utilized, but detection of longer wavelengths is limited by bandgap
Solution Approach 1:
The patent employs avalanche photodiodes with adjustable reverse bias voltage to change the detection parameters. By applying higher reverse bias voltages, the effective potential barrier is reduced, enabling detection of lower energy photons (longer wavelengths) while still using silicon-based technology.
4Adaptability or versatility
If additional structural elements are added for monitoring, then light monitoring capability is improved, but fabrication complexity increases
Solution Approach 1:
The patent merges the monitoring function into the existing ring waveguide structure by forming the avalanche photodiode along a section of the ring waveguide. This eliminates the need for separate drop bus waveguides and external photodiodes, thereby reducing fabrication complexity while maintaining monitoring capability.
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 modulation efficiency, reduces fabrication complexity and cost, and allows for compact, integrated optical systems capable of detecting a wider range of wavelengths without power loss, while maintaining high responsivity.
Implementation Method 1
an avalanche photodiode isolated from the modulator and formed along a second section of the circumference of the ring waveguide to detect an intensity of the light inside the ring waveguide
Data Source
AI summary
Examples described herein relate to an optical device, such as, a ring resonator, that includes a ring waveguide. The ring resonator includes a ring waveguide to allow passage of light therethrough. Further, the ring resonator includes a modulator formed along a first section of the circumference of the ring waveguide to modulate the light inside the ring waveguide based on an application of a first reverse bias voltage to the modulator. Moreover, the ring resonator includes an avalanche photodiode (APD) isolated from the modulator and formed along a second section of the circumference of the ring waveguide to detect the intensity of the light inside the ring waveguide based on an application of a second reverse bias voltage to the APD. The second section is shorter than the first section, and the second reverse bias voltage is higher than the first reverse bias voltage.