Overwrite fabrication and tuning of long period gratings
Overwrite fabrication and tuning of long period gratings
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DOI：
10.1364/oe.24.022345
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发表时间：
2016-10-03
期刊：
影响因子：
3.8
通讯作者：
Tatam, Ralph P.
中科院分区：
文献类型：
--
作者：
Partridge, Matthew;James, Stephen W.;Tatam, Ralph P.
谐振带的中心波长是长周期光栅 (LPG) 作为传感器性能的关键方面，特别是对于设计在相位匹配转折点 (PMTP) 附近运行的设备，此时测量的灵敏度可能会快速变化。一般来说，LPG的特征在于其周期，但折射率调制的幅度也是决定谐振带波长的重要因素。 LPG 传感器的制造差异可能会增加或降低 LPG 对应变、温度或周围折射率的敏感度。在这里，演示了重写紫外激光制造技术。结果表明，在重复重写时，LPG 的谐振带表现出显着的波长偏移，可以对其进行监测，并可用于将谐振带调谐到所需的波长。该技术适用于 100 至 200 μm 范围内的周期，显示了多种包层模式的 PMTP 附近谐振带的周期演变。使用在线监测可将共振带传感器与传感器之间的中心波长变化从 10 nm 减少到 3 nm。
The central wavelengths of the resonance bands are critical aspect of the performance of long period gratings (LPGs) as sensors, particularly for devices designed to operate near the phase matching turning point (PMTP), where the sensitivity to measurements can vary rapidly. Generally, LPGs are characterized by their period, but the amplitude of the amplitude of the index modulation is also an important factor in determining the wavelengths of the resonance bands. Variations in fabrication between LPG sensors can increase or decrease the sensitivity of the LPG to strain, temperature or surrounding refractive index. Here, the technique of overwritten UV laser fabrication is demonstrated. It is shown that, on repeated overwriting, the resonance bands of an LPG exhibit significant wavelength shift, which can be monitored and which can be used to tune the resonance bands to the desired wavelengths. This technique is applied to periods in the range 100 to 200 mu m, showing the cycle-to-cycle evolution of the resonance bands near the PMTPs of a number of cladding modes. The use of online monitoring is shown to reduce the resonance band sensor-to-sensor central wavelength variation from 10 nm to 3 nm.