Transmitter Side ROPA Pumped via Bidirectional Fiber
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Solution Overview
Problem
Current amplification technologies for unrepeatered optical transmission links face challenges in improving noise performance, especially at higher data rates, due to signal distortions from nonlinear fiber effects and increased costs associated with complex amplifier setups.
Innovation Solution
A method involving a bidirectional optical link with a transmitter side remote optically pumped amplifier (ROPA) where at least part of the transmitter side pump power is provided via a second transmission link, allowing counterdirectional pump signal propagation to minimize signal distortions and reduce costs by using a broadband WDM coupler for pump power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If codirectional Raman amplification is used to supply pump power to the ROPA, then the amplifier can be supplied with power easily, but signal distortions occur due to nonlinear fiber effects
Solution Approach 1:
The patent applies counterdirectional Raman amplification where the pump light propagates in the opposite direction to the signal light, reversing the conventional codirectional approach. This inversion eliminates nonlinear fiber effects while still providing effective pump power supply to the ROPA, resolving the contradiction between ease of operation and signal quality
2Object-affected harmful factors
If additional fibers are used for supplying pump power to the ROPA cassette, then signal distortions are avoided, but the cost of the cable increases significantly
Solution Approach 1:
The patent makes the existing transmission fiber serve dual functions: carrying signal light in one direction and carrying pump light in the opposite direction. This multi-functionality approach eliminates the need for additional dedicated pump fibers, avoiding increased cable costs while still providing counterdirectional pump supply that prevents signal distortions
3Reliability
If counterdirectional Raman amplification is used to improve OSNR, then noise performance improves, but device complexity increases
Solution Approach 1:
The system uses the existing bidirectional transmission infrastructure to automatically provide counterdirectional pump supply. The ROPA cassette itself generates and directs the pump light through the same fiber that carries signals, eliminating the need for separate complex amplifier setups while achieving improved OSNR through counterdirectional Raman amplification
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 approach enhances the noise performance of unrepeatered links by reducing signal distortions and maintaining cost-effectiveness, enabling efficient amplification for higher data rates without the need for complex setups.
Implementation Method 1
Raman amplification is based on the stimulated Raman scattering (SRS) phenomenon, according to which a lower frequency 'signal' photon induces the inelastic scattering of a higher-frequency 'pump' photon in an optical medium in the nonlinear regime. As a result of this inelastic scattering, another 'signal' photon is produced, while the surplus energy is resonantly passed to the vibrational states of the medium.
Data Source
AI summary
The invention discloses a method of amplifying an optical signal, in particular a data signal, transmitted from a first location (A) to a second location (B) via a first transmission link (10a), wherein said optical signal is amplified by means of a transmitter side remote optically pumped amplifiers (ROPA) (18) comprising a gain medium (24), wherein the gain medium (24) of said transmitter side ROPA (18) is pumped by means of transmitter side pump power (20) provided from said first location (A), characterized in that at least a part of said transmitter side pump power (20) is provided by means of light supplied from said first location (A) to said transmitter side ROPA (18) via a portion of a second transmission link (10b) provided for transmitting optical signals from said second location (B) to said first location (A).