FBG Research at I2R

Lim, Jun Long has been working on Fiber Bragg Grating (FBG) sensor as far back as 2010 when he first joined Institute for Infocomm Research (I2R) as a Research Officer (Research Associate). He researches on FBG simulations and experiments to gain insight on developing practical FBG sensors for Singapore industries (real world environment). Some of his FBG core competencies include, but not limited to,

  • Knowhow on FBG physics and material interaction with other particles,
  • Knowhow on managing tens of terabytes of FBG data for real world applications,
  • Supplychain of fabricating and deploying FBG sensors, etc.

Basic Principle

Most applications of FBG sensors operate in the reflective configuration. This means that the transmission medium is single ended and light propagate in and out at one end of the single mode fiber's core.

Coupled Mode Theory (CMT)

If you are interested in know how the spectrum of the FBG comes about, you can read more on CMT.

  1. M. McCall, " On the application of coupled mode theory for modeling fiber Bragg gratings," Journal of Lightwave Technology (JLT), vol. 18, no. 2, pp. 236-242, Feb. 2000. DOI: 10.1109/50.822798


FBG sensor has been widely used around the world for big infrastructure projects, security enhancement as well as research and development. Most of the time the deployment are of very large scale and concealed for very good reasons.


  1. Structural health monitoring
    1. Residential building
    2. Roof
    3. Bridges
  2. Healthcare (click here to read more on FBG Healthcare page)
  3. Security (Fence-Mount PIDS) [case study]

Niche Components

  1. Laser
  2. Optical components
  3. Maritime

Potentially FBG sensor can also work in many other industry and sector, many researches are currently in development to investigate their feasibility (proof of concept) and commercial viability (proof of value).

Research and Development (R&D)

  1. Biomedical / MedTech
  2. Safety
  3. Explosive
  4. Land movement
  5. Aerospace (click here to read more on FBG Aerospace page)

And many more!

FBG Supplier / Contractor

Note to all readers:

  1. Selected contractors are listed. There are many other contractors not shown. The list will change time to time without notice or reason.
  2. Disclaimer applies.
  3. This list is not in any form of paid advertisement. For the avoidance of any doubt, all paid advertisement will be explicitly marked or labelled 'paid ads'; all other not marked or labelled are published as free good will.

FBG Interrogator

  1. Micron Optics [link], part of Luna Innovations
  2. Smart Fibres [link]
  3. BaySpec [link]
  4. National Instruments [link] [listing] #singaporesupplier

FBG Sensor

  1. Micron Optics [link], part of Luna Innovations
  2. Smart Fibres [link]
  3. Proximion [link], part of the Hexatronic Group
  4. 3L Technologies [link] [listing]

System Integrator (SI) / Solution Provider

  1. ST Engineering [link] #singaporesupplier

Design Software

  1. Advanced Optics Solutions GmbH [link]
  2. Lumerical [link] [listing]
  3. Optiwave Systems [link] [listing]

And many more contractors! Contact us for more information

FBG People

World Renowned Influential FBG Researcher / Scientist

Notable FBG Researcher / Scientist in Singapore

  • Professor Tjin Swee Chuan, Associate Provost [NTU]
  • Dr. Hao Jianzhong Emily [LinkedIn]

FBG Publications

Highly cited FBG Basic Research

K. O. Hill, and G. Meltz, "Fiber Bragg grating technology fundamentals and overview," IEEE Journal of Lightwave Technology (JLT), vol. 15, no. 8, pp. 1263-1276, Aug. 1997. DOI: 10.1109/50.618320 [View at Publisher]

Abstract: The historical beginnings of photosensitivity and fiber Bragg grating (FBG) technology are recounted. The basic techniques for fiber grating fabrication, their characteristics, and the fundamental properties of fiber gratings are described. The many applications of fiber grating technology are tabulated, and some selected applications are briefly described.

K. O. Hill, B. Malo, F. Bilodeau, D. C. Johnson, and J. Albert, "Bragg gratings fabricated in monomode photosensitive optical fiber by UV exposure through a phase mask," Applied Physics Letters (APL), vol. 62, no. 10, pp. 1035, Jan 1993. DOI: 10.1063/1.108786 [View at Publisher]

Abstract: A photolithographic method is described for fabricating refractive index Bragg gratings in photosensitive optical fiber by using a special phase mask grating made of silica glass. A KrF excimer laser beam (249 nm) at normal incidence is modulated spatially by the phase mask grating. The diffracted light, which forms a periodic, high‐contrast intensity pattern with half the phase mask grating pitch, photoimprints a refractive index modulation into the core of photosensitive fiber placed behind, in proximity, and parallel, to the mask; the phase mask grating striations are oriented normal to the fiber axis. This method of fabricating in‐fiber Bragg gratings is flexible, simple to use, results in reduced mechanical sensitivity of the grating writing apparatus and is functional even with low spatial and temporal coherence laser sources.

G. Meltz, W. W. Morey, and W. H. Glenn, "Formation of Bragg gratings in optical fibers by a transverse holographic method," Optics Letters (OL), vol. 14, no. 15, pp. 823-825, Aug. 1989. DOI: 10.1364/OL.14.000823 [View at Publisher]

Abstract: Bragg gratings have been produced in germanosilicate optical fibers by exposing the core, through the side of the cladding, to a coherent UV two-beam interference pattern with a wavelength selected to lie in the oxygen-vacancy defect band of germania, near 244 nm. Fractional index perturbations of approximately 3 × 10−5 have been written in a 4.4-mm length of the core with a 5-min exposure. The Bragg filters formed by this new technique had reflectivities of 50–55% and spectral widths, at half-maximum, of 42 GHz.

Highly cited FBG Sensor Research

  • Coming soon.

Related Publication from I2R FBG Research

Jun Long Lim, Rebecca Yen-Ni Wong, Perry Ping Shum, Avellin Zi Xin Wong, Jing Xuan Chai, and Tasha Sonia Kaur, "Ruggedised low frequency range vibration sensor using fiber Bragg gratings," in Proc. of 2017 Opto-Electronics and Communications Conference (OECC) and Photonics Global Conference (PGC), Singapore, Jul. 2017. DOI: 10.1109/OECC.2017.8114949

Abstract: A fiber optic vibration sensor was developed from Fiber Bragg Grating (FBG) sensor. Three FBG vibration sensors are constructed and subjected to drop test, vibration test and mock train-railway positioning test. All the Bragg wavelengths of the sensors, as well as the Fast Fourier Transform (FFT) graphs are recorded by a computer via an FBG interrogator. Two commercially available FBG vibration sensors are also tested for comparison. The results show that the fabricated sensors are comparable commercially available FBG vibration sensors, certain level of robustness, picked up low frequency vibrations, and detected a mock train positioning on a mock railway.

Xueming Liu, Xiaoqun Zhou, Xiufeng Tang, Junhong Ng, Jianzhong Hao, Teck Yoong Chai, Edward Leong, Chao Lu , "Switchable and tunable multiwavelength erbium-doped fiber laser with fiber Bragg gratings and photonic crystal fiber," IEEE Photonics Technology Letters (PTL), vol. 17. no. 8, pp. 1626-1628, Jul. 2005. DOI: 10.1109/LPT.2005.851024

Abstract: We propose and report on a novel multiwavelength-switchable-tunable erbium-doped fiber laser with excellent stability and uniformity based on four-wave mixing (FWM) in a highly nonlinear photonic crystal fiber. By adjusting the attenuators, the single, dual, or triple wavelengths can be lasing simultaneously. Under the influence of the FWM, the spectrum is stabilized and the uniformity is less than 0.6 dB.

Jun Hong Ng, Xiaoqun Zhou, Xiufeng Yang, Jianzhong Hao, "A simple temperature-insensitive fiber Bragg grating displacement sensor," Optics Communications (OC), vol. 273, no. 2, pp. 398-401, May 2007. DOI: 10.1016/j.optcom.2007.01.040

Abstract: The study on fiber Bragg grating (FBG) displacement sensor based on monitoring the back-reflected power from an array of novelly embedded FBG sensors is presented. The sensor is a uniform FBG with three sections that are embedded in different layer in a composite lamina. Its bandwidth is displacement dependent and hence its reflected power varies almost linearly with displacement and it is insensitive to temperature variation. Thus, only low-cost photodetector (PD) is required to monitor displacement. This study demonstrates a novel fiber sensor, a method of fabricated the same, and a method to achieve simultaneous multi-sensor measurement.

JZ Hao, KM Tan, SC Tjin, CY Liaw, P Roy Chaudhuri, X Guo, Cu Lu, "Design of a foot-pressure monitoring transducer for diabetic patients based on FBG sensors," in Proc. of The 16th Annual Meeting of the IEEE Lasers and Electro-Optics Society (LEOS), Oct. 2003. DOI: 10.1109/LEOS.2003.1251581

Abstract: We report a novel fiber Bragg grating pressure sensor embedded in carbon fiber reinforced material that is capable of monitoring the foot pressure of diabetic patients.

Note: Disclaimer applies.

Note: Data retrieved from Google Scholar or public domain


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Affiliated: FBG Sensor Technology (www.fbgsensor.tech)