Optical Receiver Circuit for Multilevel Signal Gain and Offset Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical communication systems face challenges in efficiently transmitting both high-speed and low-speed signals over the same optical link without requiring additional costly components or power, as they typically rely on two-level signalling which is inadequate for distinguishing between these signals.
Innovation Solution
A circuit arrangement and method that utilize a transimpedance amplifier with automatic gain control, an integrator, a voltage-controlled current source, a limiter, and a second transimpedance amplifier in parallel, along with an automatic offset controller, to enable multilevel signalling by maintaining a constant output amplitude and using a higher optical power level to differentiate between signal levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two-level signalling is used in optical communication systems, then the system structure remains simple, but the ability to transmit multiple signal types (high-speed and low-speed) over the same link is lost
Solution Approach 1:
The patent applies parameter changes by transitioning from two-level signalling to multi-level signalling, where optical power levels are varied to represent different signal states. This allows high-speed data transmission and low-speed status signal transmission to be multiplexed over the same optical link by encoding status changes as specific power level transitions, thereby improving adaptability without proportionally increasing device complexity.
2Reliability
If an extra optical link is dedicated for low-speed signal transmission, then signal transmission reliability improves, but system cost and power consumption increase significantly
Solution Approach 1:
The patent merges high-speed data transmission and low-speed status signal transmission into a single optical link by using multi-level signalling. Status changes are encoded as specific optical power level transitions within the same data stream, allowing both signal types to share the same physical medium, light source, and detector, thereby maintaining reliability while eliminating the need for separate transmission paths and reducing overall power consumption.
Solution Approach 2:
The optical link is designed to perform multiple functions simultaneously: it transmits high-speed data signals and low-speed status signals through the same infrastructure. The multi-level signalling scheme enables the system to differentiate between data transmission modes and status indication modes, making the single optical link universal for both purposes and avoiding the need for dedicated separate links.
3Measurement precision
If optical power levels are increased to transmit additional signal information, then signal-to-noise ratio improves, but power consumption and potential signal distortion increase
Solution Approach 1:
The patent employs dynamic optical power level adjustment where the transmitter varies power levels based on the signal being transmitted. During normal high-speed data transmission, standard power levels are used. When low-speed status signals need to be transmitted, the system dynamically transitions to specific power level patterns that encode status information. This dynamic approach allows the system to optimize signal-to-noise ratio when needed while avoiding excessive power levels that would cause distortion, as power is only increased transiently and selectively rather than continuously.
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 solution allows reliable transmission of slow-speed signals over shared optical links using multilevel signalling, improving signal-to-noise ratio and reducing the need for additional components or power, while maintaining desired signal integrity.
Implementation Method 1
at least one light-receiving component for converting the optical signals into electrical current signals
Data Source
AI summary
In order to further develop a circuit arrangement (CR; CR′) for receiving optical signals (SI) from at least one optical guide (GU), said circuit arrangement (CR; CR′) comprising:at least one light-receiving component (PD) for converting the optical signals (SI) into electrical current signals (IPD),at least one transimpedance amplifier (TA), being provided with the electrical current signals (IPD) from the light-receiving component (PD),at least one automatic gain controller (AG) for controlling the gain or transimpedance (R) of the transimpedance amplifier (TA),at least one integrator (IN) in a feedback path (FP), said integrator (IN) generating a control signal (Vint),at least one voltage-controlled current source (CS), being provided with the control signal (Vint) from the integrator (IN),at least one limiter (LI) acting as a comparator and generating in its output a logic level for positive or negative voltages in its input,and a corresponding method in such a way that a multilevel optical link can be provided,at least one second transimpedance amplifier (TA2) arranged in parallel to the transimpedance amplifier (TA), andat least one automatic offset controller (AO) for setting the voltage (Voffset) for the second transimpedance amplifier (TA2)are proposed.