[INVITED] Nanofabrication of phase-shifted Bragg gratings on the end facet of multimode fiber towards development of optical filters and sensors

• Published in: Optics and laser technology 2018-05, Vol.101, p.49-56
• Main Authors: Gallego, E.E., Ascorbe, J., Del Villar, I., Corres, J.M., Matias, I.R.
• Format: Article
• Language: English
• Subjects: Additive manufacturing; Band-pass filters; Bragg gratings; Fiber DC sputtering; Gratings (spectra); Humidity; Nanofabrication; Optical fiber components; Optical fiber sensors; Optical filters; Phase shift; Propagation; Relative humidity; Sensors; Studies; Thin-films; Wave propagation
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/j.optlastec.2017.11.001

•Single-target sputtering nanodeposition of phase-shifted Bragg gratings on fiber.•Accurate control of the phase-shift corroborated with theoretical results.•Designs with modification of phase-shift and number of periods.•Development and characterization of a phase shifted Bragg grating humidity sensor. This work describes the process of nanofabrication of phase-shifted Bragg gratings on the end facet of a multimode optical fiber with a pulsed DC sputtering system based on a single target. Several structures have been explored as a function of parameters such as the number of layers or the phase-shift. The experimental results, corroborated with simulations based on plane-wave propagation in a stack of homogeneous layers, indicate that the phase-shift can be controlled with a high degree of accuracy. The device could be used both in communications, as a filter, or in the sensors domain. As an example of application, a humidity sensor with wavelength shifts of 12 nm in the range of 30 to 90% relative humidity (200 pm/% relative humidity) is presented.