Single-Pump Multi-Wavelength Raman Laser for Flat Gain
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Solution Overview
Problem
Current Raman pump lasers for optical fiber communication systems require multiple pump lasers with different wavelengths to achieve flat gain, leading to increased power consumption and cost due to the need for multiple pumps and gain flatten filters.
Innovation Solution
A single pump multi-wavelength semi-conductor Raman pump laser and pump combination apparatus using at least two fiber Bragg gratings with different central pump wavelengths on the output pigtail to achieve flat Raman gain across multiple pump wavelengths, reducing the number of pumps and simplifying control circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple pump lasers with different wavelengths are used to achieve flat Raman gain, then the gain flatness is improved, but the device complexity and power consumption increase
Solution Approach 1:
The patent combines multiple pump wavelengths into a single laser source by using a single laser diode to pump multiple Raman fibers with different core diameters. Each fiber generates Raman gain at a different wavelength, and these wavelengths are combined to achieve flat overall gain across the C-band, eliminating the need for multiple separate pump lasers
Solution Approach 2:
A single laser diode performs multiple functions by pumping multiple Raman fibers simultaneously. The same pump source generates multiple Raman wavelengths through different fibers, making the system more versatile and reducing component count while maintaining flat gain performance
2Manufacturing precision
If multiple pump lasers are used to achieve flat gain, then the gain flatness is improved, but the power consumption increases
Solution Approach 1:
The patent merges multiple pump functions into a single laser diode source that simultaneously pumps multiple Raman fibers. This consolidation reduces total power consumption because a single optimized pump source is more efficient than multiple separate pump lasers, while still achieving flat gain through the combined Raman wavelengths from different fibers
3Manufacturing precision
If multiple pump lasers and gain flatten filters are used, then the flat gain is achieved, but the cost and device size increase
Solution Approach 1:
The patent extracts and eliminates the need for gain flatten filters from the system architecture. By carefully selecting Raman fibers with different core diameters that generate complementary Raman gain spectra, the system achieves flat gain naturally through the physics of Raman scattering, removing the need for additional filtering components and reducing overall device volume
Solution Approach 2:
The patent combines multiple Raman fibers with different core diameters in parallel, each contributing a different portion of the Raman gain spectrum. The smaller core fiber provides gain at shorter wavelengths while the larger core fiber provides gain at longer wavelengths, and their combined output naturally flattens the overall gain spectrum without requiring external filters
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 the number of pumps, lowers power consumption, increases energy transfer efficiency, and decreases the size and cost of the amplifier while maintaining performance, by using a single pump laser with multiple wavelengths to achieve flat Raman gain.
Implementation Method 1
uses a reflected light reflecting to the laser diode with narrow wavelength range to realize wavelength locking
Implementation Method 2
the TEC to stabilize the die temperature
Data Source
AI summary
A single-pump multi-wavelength lasing semiconductor Raman pump laser comprises a thermoelectric cooler arranged in a shell; a heat transition bearing platform arranged in the thermoelectric cooler; a semiconductor Raman pump laser tube core arranged on the heat transition bearing platform; and a coupling lens group, a thermistor and a backlight detector that are arranged on the heat transition bearing platform respectively. The pump laser tube core, the backlight detector, the thermistor and the thermoelectric cooler are electrically connected to pins outside a laser tube shell. A pump combination apparatus comprises a first signal transmission fiber, a pump signal combiner and a second signal transmission fiber that are sequentially connected to each other. An input terminal of the pump signal combiner is connected to an output terminal of an isolated polarization beam combiner and depolarizer. Two polarization maintaining fiber input terminals of the isolated polarization beam combiner and depolarizer are correspondingly connected to one single pump multi-wavelength lasing semiconductor Raman pump laser respectively.