SiPM Local Light Biasing for Distortion-Controlled OWC Reception
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Solution Overview
Problem
SiPM-based photodetectors in optical wireless communication systems suffer from receiver-side distortions due to inadequate DC biasing, leading to performance degradation, especially in conditions where eye-safety standards limit the modulation bandwidth.
Innovation Solution
Implementing a local, controllable light biasing mechanism using a controllable light source to provide explicit automatic gain control (AGC) for SiPM-based photodetectors, where a digital signal processor performs distortion and intensity analysis to adjust the biasing light intensity accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If DC biasing is increased to improve signal detection, then detection sensitivity improves, but eye-safety standards are violated
Solution Approach 1:
The patent segments the biasing function into two independent components: a fixed DC bias component and a controllable AC biasing light component. This segmentation allows the system to achieve adequate total biasing for signal detection while keeping the DC component below eye-safety thresholds, using the AC component to provide additional gain control without violating safety standards.
Solution Approach 2:
The patent changes the biasing parameter from a static DC voltage approach to a dynamic optical biasing approach using controllable light sources. By modulating the biasing light intensity based on signal conditions, the system can adaptively adjust the photodetector gain without being constrained by fixed DC bias limitations imposed by eye-safety requirements.
2Productivity
If modulation bandwidth is increased to improve communication performance, then data transmission rate improves, but receiver-side distortions increase
Solution Approach 1:
The patent implements feedback control where the controllable light source's biasing intensity is dynamically adjusted based on real-time analysis of the received signal characteristics. This feedback mechanism allows the system to optimize detection performance for high-bandwidth signals while compensating for receiver-side distortions, maintaining reliability even at higher data transmission rates.
Solution Approach 2:
The patent transforms the static biasing system into a dynamic one where the biasing light intensity can be continuously adjusted in response to varying signal conditions. This dynamic adaptability enables the receiver to handle high-modulation-bandwidth signals effectively by optimizing the biasing level for each signal condition, thereby reducing distortions while maintaining high data transmission rates.
3Reliability
If automatic gain control is implemented to reduce distortions, then signal quality improves, but device complexity increases
Solution Approach 1:
The patent introduces a controllable light source as an intermediary element that provides automatic gain control functionality. This intermediary component mediates between the incoming optical signal and the photodetector, dynamically adjusting the biasing light to compensate for signal variations and reduce distortions, thereby improving signal quality without requiring complex electronic gain control circuits.
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
Mitigates receiver-side distortions and improves the performance of SiPM-based OWC receivers by optimizing gain control, enhancing signal detection and reducing interference, thereby improving communication quality.
Implementation Method 1
a controllable light source positioned to emit a biasing light signal within a field of view of the input sensor, wherein the controllable light source is configured to emit the biasing light signal within a sensitivity range of the SiPM
Implementation Method 2
detecting a plurality of photons at an input sensor of a SiPM-based photodetector, wherein the plurality of photons includes zero or more input photons received from an OWC transmitter and one or more biasing photons received from a controllable light source
Data Source
AI summary
This disclosure provides systems, methods, and devices for wireless communication that support local light biasing for silicon photomultiplier (SiPM)-based photodetectors used in optical wireless communication (OWC). In a first aspect, a photodetector may include a silicon photomultipier (SiPM) having an input sensor configured to detect a light signal and an output interface configured to produce an output signal proportional to an intensity of the light signal detected at the input sensor, and a controllable light source positioned to emit a biasing light signal within a field of view of the input sensor, wherein the controllable light source is configured to emit the biasing light signal within a sensitivity range of the SiPM. When such photodetector is implemented in an OWC receiver, an analysis of the output signal allows the OWC receiver to adjust the biasing light at the controllable light source. Other aspects and features are also claimed and described.