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Fiber Bragg Gratings

Specifications Overview

Optromix manufactures various fiber optic products. We can accommodate your special requirements and design a fiber product catered specifically for your needs.
Central Wavelength (CW), nm530 - 2300
Wavelength Tolerance, nm< 0.1
Reflectivity, %0.1 … 99.9
Bandwidth (FWHM), nm0.03 - 3
Sidelobe Suppression Ratio (SLSR), dB> 20
FBG Length, mm0.1 - 50
CoatingAcrylate; Polyimide; No coating
Temperature range (acrylate), °C-20 … +85
Temperature range (polyimide), °C-200 … +350
ConnectorsFC/PC; FC/APC; any other

Types of FBGs

  • FBG writing into multicore fibers
  • Chirped FBGs
  • Apodized fiber Bragg gratings
  • Pi-phase-shifted fiber Bragg gratings
  • DFB lasers
  • FBGs inscription into non-photosensitive fiber (with a pure silica core) or writing through the coating. It is quite efficient to use them for the monitoring of facilities with harsh environment (for example, in oil & gas industry)
  • Long-period fiber gratings (LPFG)
  • Tilted fiber Bragg gratings
  • Customized fiber Bragg gratings
  • FBGs writing into special optical fibers (Panda, active, PCF, etc.)

Three Methods of FBGs Inscription

Currently, there are three known methods of FBGs inscription. Optromix is able to write fiber Bragg gratings by all 3 techniques, using 4 available laser stands.

Interferometric method. ​When fiber core is illuminated with a fringe pattern created by a phase mask (in this case FBG period is defined by a phase mask period)

Direct point-by-point method. When each FBG “pitch” is formed as a result of the nonlinear fs laser pulse absorption (in this case FBG period is defined by laser pulse repetition rate and by velocity of a fiber translation along its axis)

Continuous core-scanning method. When fiber position is modulated in transverse plane (in this case FBG period is defined by modulation frequency and by velocity of a fiber translation along its axis)

FBG Advantages

  • Narrowband optic emission reflection
  • Made of optical fiber
  • Low optical loss
  • Small size
  • Relatively simple and low-cost production

Fiber Bragg Gratings
Meaning and Principle

FBG (fiber Bragg grating) is a periodic circuit created in a fiber core. It has a capability to reflect certain emission wavelengths and transmit the others. The refraction index periodic variation in the fiber core causes the reflection generating a wavelength-specific dielectric mirror. Hence, fibre Bragg grating performs as an inline fiber optic filter blocking or reflecting specific wavelengths.

Fiber Bragg gratings may serve as:

  • Sensing elements in FBG sensors
  • High Reflector (HR) and Output Coupler (OC) mirrors in laser cavities
  • Spectral filters (optical fiber filters)
  • Dispersion compensators in telecommunications.

FBG spectral specifications are based on the periodic change of fiber core refractive index at different lengths and depend on the optical heterogeneity diffraction.

A fiber Bragg grating can be of different lengths from 0.1 to 50 mm.

The length of periodic fiber optic grating changes when mechanical compression and tension are applied; hence, the reflected wavelengths are adjusted as well.

FBG fabrication is a complex process. Bragg grating is usually written into a single mode fiber with an acrylate or polyimide coating. Unlike a multimode fiber, a single mode fiber has a much smaller core diameter.

Acrylate fiber is inexpensive, easy to clean up (with a mechanical or thermal stripper), but it is suitable only for regular operating conditions (it can withstand constant exposure to -20 … +85°C temperature range, and for a short period of time up to + 100°C).

Polyimide fiber is significantly more expensive, it is more difficult to clean up (with an electric arc or concentrated sulfuric acid), it is suitable for more aggressive environments with operating temperature -200 … +350°C. Some polyimide high temperature optical fibers can withstand temperatures up to 800°C.

We Are Here for Your Service

Competitive pricing

We deliver cutting-edge hi-tech fiber bragg gratings products and solutions, while offering one of the best prices on the market

Extensive experience

Established in 2004, Optromix has an extensive experience in the development of fiber optic products and solutions

Quality and reliability​

When producing fiber optic monitoring equipment, we always follow the world-class requirements and regulations