Optical Receiver Adaptive Gain Compensation for Low-Cost APD Bandwidth
Find Innovative SolutionsGenerate Solutions
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 account for a large proportion of component costs, necessitating a reduction in APD costs to reduce overall component costs.
Innovation Solution
An optical receiver design utilizing a low-rate APD with a transimpedance amplification circuit and a controller to perform adaptive gain compensation, ensuring signal quality while reducing costs by using an optoelectronic detector with a bandwidth lower than the system transmission bandwidth requirement, and optionally incorporating an equalizer for further frequency compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a high-rate avalanche photodiode (APD) is used to meet system transmission bandwidth requirements, then the signal reception capability is improved, but the component costs increase significantly
Solution Approach 1:
The patent divides the bandwidth compensation function into two separate stages: first, the transimpedance amplification circuit provides initial bandwidth extension and signal amplification; second, the equalizer circuit performs further frequency compensation. This segmentation allows each circuit to be optimized independently, enabling the use of a lower-cost APD while achieving the required overall system bandwidth through coordinated multi-stage processing.
Solution Approach 2:
The patent introduces intermediate processing circuits (transimpedance amplification circuit and equalizer circuit) between the APD and the final signal output. These intermediary circuits act as mediators that compensate for the bandwidth limitations of the low-cost APD, transforming its insufficient frequency response into an acceptable signal quality that meets system requirements without needing an expensive high-rate APD.
2Ease of manufacture
If a low-rate APD with lower bandwidth is used to reduce costs, then component costs are reduced, but signal quality deteriorates due to insufficient bandwidth
Solution Approach 1:
The patent changes the electrical parameters (gain and frequency response) of the signal through active circuit processing. The transimpedance amplification circuit adjusts the gain across different frequency ranges, and the equalizer circuit further modifies the frequency response parameters to compensate for the APD's bandwidth limitations. These parameter changes transform the degraded signal from a low-rate APD into a high-quality signal that meets system requirements.
Solution Approach 2:
The patent employs feedback mechanisms where the controller monitors the signal characteristics and adjusts the equalizer circuit parameters accordingly. This feedback control ensures that the signal quality is maintained at the required level by dynamically compensating for any degradation, thereby ensuring reliable signal reception even when using a lower-cost low-rate APD.
3Reliability
If bandwidth extension is performed to compensate for APD limitations, then signal quality is improved, but device complexity increases due to additional circuits
Solution Approach 1:
The patent merges multiple functions into integrated circuits to reduce overall complexity. The transimpedance amplification circuit combines signal amplification, impedance transformation, and initial bandwidth extension in a single integrated stage. The equalizer circuit integrates frequency compensation and signal conditioning functions. This merging approach, while adding necessary complexity for bandwidth compensation, does so through optimized integrated designs that minimize the number of discrete components and simplify the overall system architecture.
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
The solution effectively reduces component costs by using a low-rate APD and transimpedance amplification circuit to remedy signal deterioration, ensuring received signal quality without introducing additional noise, and provides extended compensation range for higher frequencies when an equalizer is used.
Implementation Method 1
an optoelectronic detector, configured to convert a received optical signal into a current signal
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
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.