Optical Transmission Device Phase Estimation Circuit Scale
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Solution Overview
Problem
Conventional digital coherent reception systems are unsuitable for free space optics and short communication distance networks due to high power consumption and large circuit scale, particularly when handling multi-level phase-modulated signals like QPSK, which require phase compensation for both X and Y polarizations.
Innovation Solution
An optical transmission/reception device that suppresses phase changes by using a phase estimating unit to estimate the phase of one polarization and indirectly estimate the phase of another, reducing the need for separate phase compensation blocks and thus minimizing circuit scale, while employing polarization multiplexing and digital signal processing for efficient signal transmission and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional digital coherent reception systems are used for multi-level phase-modulated signals, then signal reception capability is improved, but circuit scale and power consumption increase
Solution Approach 1:
The patent merges the phase compensation functions for X and Y polarizations into a single shared phase compensation block. By estimating the phase shift for one polarization and applying it to both polarizations, the system eliminates the need for separate phase compensation blocks, thereby reducing circuit scale while maintaining signal reception capability
Solution Approach 2:
The shared phase compensation block serves multiple functions by compensating phase shifts for both X and Y polarizations simultaneously. This multi-functional approach allows a single block to perform what previously required separate dedicated blocks, reducing overall device complexity
2Measurement precision
If conventional digital coherent reception systems are used, then accurate phase compensation is achieved, but power consumption increases
Solution Approach 1:
The patent combines the phase compensation operations for both polarizations into a single shared block, reducing the total number of active circuit elements. This merging reduces power consumption while maintaining accurate phase compensation by using a unified phase estimation and compensation mechanism that serves both polarizations
3Measurement precision
If separate phase compensation blocks are used for X and Y polarizations, then phase accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges separate phase compensation blocks into a single shared block that processes both X and Y polarizations. The phase estimation unit estimates phase shifts and applies them to both polarizations through the shared compensation block, maintaining phase accuracy while eliminating redundant circuitry
Solution Approach 2:
Instead of creating separate physical compensation blocks for each polarization, the system uses a single shared block that is effectively 'copied' or reused for both X and Y polarizations. This approach maintains the functional equivalence of separate blocks while reducing physical circuit scale
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 the application of digital coherent reception systems to free space optics and short communication distance networks with a reduced circuit scale, improving power efficiency and adaptability.
Implementation Method 1
converting an optical signal that is obtained by causing interference between the received optical polarization multiplexed signal and a continuous wave local oscillation light oscillated by a local oscillator, into analog electric signals
Data Source
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AI summary
Provided is an optical transmission/reception device (1) for transmitting or receiving an optical signal via a communication path (2) in which a phase change of the optical signal is suppressed. The optical transmission/reception device (1) includes: a transmission device (10) including a framer generation unit (11), a symbol mapping unit (12), and an optical modulation unit (13); and a reception device (20) including an optical reception front end unit (21), an A/D conversion unit (22), a polarization separation unit (23), and a phase estimating unit (24) for estimating a phase of at least one of a plurality of polarizations from a plurality of polarization signals separated by the polarization separation unit (23) and estimating a phase of a remaining polarization on the basis of the estimated phase. The optical transmission/reception device (1), therefore, has a small circuit scale and allows a digital coherent reception system to be applied to free space optics or a communication system with a short communication distance such as an access network.