Adaptive Optical Receiver Using Low-Rate APD Bandwidth Compensation
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Solution Overview
Problem
High costs of optical network units (ONUs) in 10G PON systems are primarily due to the high costs of high-rate avalanche photodiodes (APDs), which are the most expensive components, and existing solutions do not effectively reduce these costs while maintaining signal quality.
Innovation Solution
An optical receiver design that uses a low-rate APD with a transimpedance amplification circuit and a controller to perform adaptive gain compensation, ensuring signal quality by extending the bandwidth of the optoelectronic detector and minimizing noise, and optionally includes an equalizer for further compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a photodetector array with multiple pixels is used to improve reception quality through spatial diversity, then reception quality is improved, but device complexity and cost increase due to requiring multiple independent photodetectors and associated readout circuits
Solution Approach 1:
The photodetector surface is segmented into multiple pixel regions (first pixel region, second pixel region, etc.) that share a common photosensitive layer but have independent readout circuits. This allows spatial diversity for improved reception quality while reducing complexity compared to fully independent photodetectors.
Solution Approach 2:
A single common photosensitive layer serves multiple pixel regions, allowing one photosensitive structure to perform multiple detection functions. This reduces the number of independent photodetector structures needed while maintaining spatial diversity benefits.
2Reliability
If multiple independent photodetectors are used to achieve spatial diversity, then reception quality is improved, but manufacturing cost increases due to multiple discrete components
Solution Approach 1:
Multiple pixel regions share a common photosensitive layer and substrate structure, merging what would otherwise be separate photodetector components. This integration reduces manufacturing steps, material usage, and assembly complexity while maintaining the spatial diversity needed for improved reception quality.
Solution Approach 2:
The common photosensitive layer serves multiple pixel regions simultaneously, reducing the total number of discrete photodetector components that need to be manufactured and assembled, thereby lowering manufacturing cost while maintaining reception quality.
3Reliability
If photodetectors are arranged in a specific geometric pattern to optimize signal reception, then reception quality is improved, but device complexity increases due to precise positioning requirements
Solution Approach 1:
Different pixel regions are positioned at specific locations (first pixel region, second pixel region) to optimize reception of signals from different directions or characteristics. This local optimization improves reception quality while the shared photosensitive layer reduces overall device complexity.
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 significantly reduces the component costs of the optical receiver while maintaining signal quality by using a low-rate APD and adaptive gain compensation, and provides a wider range of compensation for high frequencies without introducing additional noise.
Implementation Method 1
a first photodetector and a second photodetector in a photodetector array... each pixel comprising a photodetector
Data Source
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AI summary
This application discloses an optical receiver, including an optoelectronic detector, a transimpedance amplification circuit, a single-ended-to-differential converter, an I/O interface, and a controller. The optoelectronic detector is configured to convert a received optical signal into a current signal, where bandwidth of the optoelectronic detector is lower than a system transmission bandwidth requirement. The transimpedance amplification circuit is configured to: receive the current signal and a first control signal, and perform transimpedance gain on the current signal based on the first control signal, to obtain a voltage signal, where a frequency response value of the current signal within first bandwidth is greater than that within the bandwidth of the optoelectronic detector, and any frequency in the first bandwidth is not lower than an upper cut-off frequency of the optoelectronic detector. The single-ended-to-differential converter is configured to convert the voltage signal into a differential voltage signal. The I/O interface is configured to output the differential voltage signal. The controller is configured to generate, based on the differential voltage signal, a second control signal that is used to control the transimpedance amplification circuit to perform transimpedance gain on the current signal. According to the optical receiver disclosed in this application, costs are reduced while received signal quality is ensured.