Characterizing 90° Optical Hybrid Units Using Phase-Shifted Signals
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Solution Overview
Problem
There is a need for a method to characterize optical devices with a 90° optical hybrid unit, photodetectors, and transimpedance amplifiers, specifically to measure their amplitude and phase response at specific intensity-modulation frequencies.
Innovation Solution
A method involving a 90° optical hybrid unit with multiple photodetectors and transimpedance amplifiers, where intensity-modulated optical signals with controlled phase differences are inputted to characterize the device's amplitude and phase responses, using a system with a signal source, optical phase shifter, measurement unit, and control unit to adjust and measure the optical phase differences and signal amplitudes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a 90° optical hybrid unit with multiple photodetectors and transimpedance amplifiers is used, then the optical device can process multiple optical signals with different phase relationships, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing an optical device that can simultaneously process multiple optical signals with different phase relationships (90° and 180°) using a unified structure comprising a 90° optical hybrid unit, photodetectors, and transimpedance amplifiers. This multi-functional design allows the same device architecture to handle various signal types without requiring separate dedicated circuits for each phase relationship.
Solution Approach 2:
The patent applies segmentation by dividing the optical device into distinct functional modules: the 90° optical hybrid unit for signal combination, photodetectors for optical-to-electrical conversion, and transimpedance amplifiers for signal amplification. This modular segmentation makes the complex device more manageable and allows each component to be optimized independently while maintaining overall system functionality.
2Measurement precision
If intensity-modulated optical signals with controlled phase differences are inputted to characterize the device, then precise amplitude and phase response measurement is achieved, but the measurement system complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the measurement system with a signal source that generates intensity-modulated optical signals with specifically controlled phase differences before they enter the device under test. The optical phase shifter is预先 set to establish the required phase relationships, allowing the characterization process to directly measure amplitude and phase responses without requiring complex real-time adjustments during measurement.
Solution Approach 2:
The patent introduces an optical phase shifter as an intermediary component between the signal source and the device under test. This mediator allows precise control of the phase differences between input signals, enabling accurate characterization of the device's phase response while keeping the measurement system architecture relatively simple and modular.
3Measurement precision
If the optical phase of input signals is phase-shifted to account for phase differences, then accurate phase response characterization is achieved, but the system requires additional phase control components
Solution Approach 1:
The 90° optical hybrid unit serves multiple functions: it combines optical signals with different phase relationships and simultaneously provides the necessary phase shifting functionality. This multi-functional component eliminates the need for separate phase shifters for each signal path, reducing the total number of phase control components while maintaining accurate phase response characterization 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
Enables precise characterization of optical devices by determining amplitude and phase response ratios and differences, effectively accounting for phase shifts and ensuring consistent signal amplitudes across outputs, thus providing comprehensive evaluation of optical device performance.
Implementation Method 1
a first photodetector connected to a first optical output and a second photodetector connected to a second optical output
Implementation Method 2
a first transimpedance amplifier connected to the first and second optical outputs of the 90° optical hybrid unit
Data Source
AI summary
An embodiment of the invention relates to a system comprising an optical device (10) and an evaluation device (20) for characterizing the optical device. The optical device comprising a 90° optical hybrid unit (30) having a first and second optical input (30E1, 30E2) and at least two optical outputs (30A1-30A4) wherein optical output signals (So1-So4) leaving the optical outputs have optical phase differences between each other of 90° or multiple thereof; a first photodetector (P1) connected to a first optical output (30A1) and a second photodetector (P2) connected to a second optical output (30A2), wherein the first optical output emits a first optical output signal (So1) and the second optical output emits a second optical output signal (So2), said second optical output signal having an optical phase difference of 180° relative to the first optical output signal; and a first transimpedance amplifier (Tr1) connected to the first and second photodetectors (P1, P2). The evaluation device (20) is characterized by a signal source (110) configured to generate a first and second intensity-modulated optical input signal (Sin1, Sin2); an optical phase shifter (120) adapted to phase-shift the optical phase of the second intensity-modulated optical input signal relative to the optical phase of the first intensity-modulated optical input signal; a measurement unit (160) adapted to measure the electrical output signal of the first transimpedance amplifier (Tr1); and a control unit (130) adapted to control the optical phase shifter.