Optical Fiber Parametric Amplifier for Pulse Extinction Ratio
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Solution Overview
Problem
Existing distributed optical fiber sensing methods face challenges in maintaining signal-to-noise ratio and pulse power amplification due to optical fiber loss and noise, with current amplification techniques either increasing transmission loss or causing signal crosstalk, and none effectively enhance both pulse power and extinction ratio simultaneously.
Innovation Solution
A distributed pulsed light amplifier based on optical fiber parametric amplification, utilizing high-power pump light near the zero-dispersion wavelength to amplify sensing pulsed light power while maintaining low leakage outside the pulse duration, thereby enhancing signal-to-noise ratio and pulse extinction ratio without increasing transmission loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If distributed amplification using stimulated Brillouin scattering or stimulated Raman scattering is used to amplify sensing pulse power, then the pulse power is amplified, but the leakage light outside pulse duration is also amplified causing extinction ratio reduction
Solution Approach 1:
The patent changes the operating parameters by using optical fiber parametric amplification near the zero-dispersion wavelength instead of stimulated Brillouin or Raman scattering. This parameter change enables selective amplification of the sensing pulse while avoiding amplification of leakage light, thereby resolving the contradiction between pulse power amplification and extinction ratio maintenance
Solution Approach 2:
The patent employs dynamic control by synchronizing the pump pulse with the sensing pulse and using time-gated detection. The pump pulse is activated only during the sensing pulse duration, creating a dynamic amplification window that amplifies the signal while leaving the inter-pulse period unaffected, thus preserving extinction ratio
2Length of stationary object
If optical fiber loss and environmental noise are present during long-distance transmission, then transmission distance is extended, but signal-to-noise ratio is degraded
Solution Approach 1:
The patent applies preliminary amplification by placing the parametric amplification effect within the transmission path itself (distributed amplification). The sensing pulse is amplified continuously along the fiber length before the signal degrades significantly, pre-compensating for transmission losses and maintaining high signal-to-noise ratio over long distances
Solution Approach 2:
The patent introduces pump light as an intermediary that transfers energy to the sensing pulse through four-wave mixing in the optical fiber. This intermediary mechanism enables long-distance transmission by continuously replenishing the sensing pulse energy without directly affecting the signal-to-noise ratio measurement
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 effectively increases the signal-to-noise ratio and pulse power of sensing signals in long-distance optical fiber sensing systems, reducing power loss and extinction ratio degradation, while minimizing chromatic dispersion and transmission loss, particularly effective in OTDR-based systems.
Implementation Method 1
a Rayleigh scattering effect in the parametric amplification optical fiber causes the pump pulsed light and the sensing pulsed light to generate scattered light in a direction opposite to a pulse transmission direction
Implementation Method 2
high-power pulsed light is used as pump light to generate an optical fiber parametric amplification effect near a zero-dispersion wavelength of an optical fiber, thereby amplifying a power of another sensing pulsed light
Data Source
AI summary
The present invention discloses a distributed pulsed light amplifier based on optical fiber parametric amplification, comprising a pump pulsed light source, a sensing pulsed light source, a synchronization device, a two-in-one optical coupler, an optical circulator, a parametric amplification optical fiber, a first optical filter, a photoelectric detector and a signal acquisition device. According to the distributed pulsed light amplifier, high-power pulsed light is used as pump light to generate an optical fiber parametric amplification effect near a zero-dispersion wavelength of an optical fiber, thereby amplifying a power of another sensing pulsed light. Meanwhile, due to the fact that effective optical fiber parametric amplification cannot be achieved through low-power light leakage outside a duration interval of the pump pulsed light, leaked light from the sensing pulsed light cannot be amplified, and the effect of amplifying a pulse extinction ratio can be achieved at the same time.