Self-Coherent Optical Chip Using Delay Interferometers
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Solution Overview
Problem
Conventional coherent receiving devices in optical communication systems require a local oscillator laser, increasing power consumption and complexity, and face stability issues due to random polarization changes in signal light after transmission through optical fibers, which affect demodulation.
Innovation Solution
An integrated self-coherent receiving optical chip using round-trip delay interferometers, incorporating a multi-port circulator array and two round-trip delay interferometers on a single substrate, which performs self-interference without a local oscillator, stabilizing signal reception by eliminating the need for active polarization control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional coherent receiving devices use a local oscillator laser to perform frequency mixing with signal light, then the demodulation capability is improved, but the power consumption and device complexity increase
Solution Approach 1:
The patent extracts and removes the local oscillator laser component from the coherent receiving device, replacing it with a self-coherent detection mechanism that uses the signal light itself as the local oscillator. This extraction eliminates the need for separate laser generation, frequency stabilization, and phase control systems, thereby reducing device complexity and power consumption while maintaining demodulation capability through self-interference of the signal light at the delay interferometer
Solution Approach 2:
The patent implements self-service by enabling the signal light to serve its own dual purpose: both as the information-carrying signal and as the local oscillator for coherent detection. The signal light is split into two paths, one delayed and one undelayed, then recombined to create self-interference patterns that enable demodulation without requiring an external local oscillator, thus reducing system complexity
2Reliability
If polarization controller is used to calibrate polarization state in real time, then the interference stability is improved, but the system complexity increases
Solution Approach 1:
The patent removes the polarization controller component from the system entirely. Instead of actively controlling and calibrating polarization states, the design accepts random polarization changes and uses polarization-diversity reception to capture both polarization components simultaneously, eliminating the need for real-time polarization calibration while maintaining interference stability
Solution Approach 2:
The patent introduces a polarization beam splitter as an intermediary element that automatically separates the incoming signal light into two orthogonal polarization components. These components are processed through separate delay interferometers and then recombined, allowing the system to handle arbitrary polarization states without active control, thus improving reliability without adding complexity
3Measurement precision
If polarization diversity technology is used to handle polarization randomization, then the demodulation accuracy is improved, but the device complexity increases due to requiring two pairs of delay interferometers and additional electronic processing
Solution Approach 1:
The patent merges the polarization diversity function with the delay interferometer structure by integrating polarization beam splitters and circulators within a single compact device. The two polarization components are processed through integrated optical paths that combine the delay interferometry and polarization handling in one unified structure, reducing the number of separate components and electronic processing modules while maintaining demodulation accuracy
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 reduces system complexity, enhances stability by managing polarization independently, and allows for efficient signal demodulation without the need for additional electronic processing, making it suitable for various optical communication systems and quantum key distribution.
Implementation Method 1
a first beam splitter configured to divide a signal light input to a first port of the optical chip into a first signal light component and a second signal light component
Implementation Method 2
perform a delayed self-interference before returning to a first port of the first round-trip delay interferometer, to generate a first interference optical signal and a second interference optical signal
Data Source
AI summary
The present application discloses an integrated self-coherent receiving optical chip based on round-trip delay interferometers, including a first beam splitter, a multi-port circulator array, a first round-trip delay interferometer and a second round-trip delay interferometer integrated on a same substrate, wherein the first beam splitter is connected to the multi-port circulator array, and the multi-port circulator array is connected to the first round-trip delay interferometer and the second round-trip delay interferometer, respectively.