# \#wiki-fbg-tech **URL:** https://forum.ofscn.net/tag/wiki-fbg-tech/12.md [Latest](https://forum.ofscn.net/latest.md) · [Categories](https://forum.ofscn.net/categories.md) · [Tags](https://forum.ofscn.net/tags.md) --- ## [What is "production lead time for packaging"?](https://forum.ofscn.net/t/what-is-the-production-lead-time-for-packaging/2655)
**Author:** [@VoidWalker](https://forum.ofscn.net/u/VoidWalker)\ **Replies:** 1\ **Last updated:** [August 26, 2026, 2:47pm UTC](https://forum.ofscn.net/t/what-is-the-production-lead-time-for-packaging/2655 "2026-08-26T14:47:32Z")
How long does it take to make a specially packaged sensor? --- ## [What is the "thermo-optic effect"?](https://forum.ofscn.net/t/topic/1555)
**Author:** [@VoidWalker](https://forum.ofscn.net/u/VoidWalker)\ **Replies:** 1\ **Last updated:** [April 6, 2026, 1:19pm UTC](https://forum.ofscn.net/t/topic/1555 "2026-04-06T13:19:33Z")
Why does the refractive index of a material change with temperature? Is this the fundamental reason for using gratings for temperature measurement? --- ## [什么是“反射光谱”？](https://forum.ofscn.net/t/topic/1350)
**Author:** [@VoidWalker](https://forum.ofscn.net/u/VoidWalker)\ **Replies:** 1\ **Last updated:** [March 31, 2026, 12:41pm UTC](https://forum.ofscn.net/t/topic/1350 "2026-03-31T12:41:32Z")
为什么在屏幕上看到的是一个尖尖的峰，而不是一条直线？ --- ## [What is a "Picometer" (pm)?](https://forum.ofscn.net/t/what-is-a-picometer-pm/1336)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [March 31, 2026, 12:28pm UTC](https://forum.ofscn.net/t/what-is-a-picometer-pm/1336 "2026-03-31T12:28:14Z")
How many picometers correspond to a change of 1℃? Exactly how small is this unit—is it visible to the naked eye? --- ## [什么是布拉格波长（Bragg Wavelength）公式？](https://forum.ofscn.net/t/bragg-wavelength/672)
**Author:** [@kelvinchen](https://forum.ofscn.net/u/kelvinchen)\ **Replies:** 1\ **Last updated:** [March 2, 2026, 8:30am UTC](https://forum.ofscn.net/t/bragg-wavelength/672 "2026-03-02T08:30:35Z")
请给出基本的物理公式，并解释公式中各个参数的物理意义。@OFSCN\_CN\_PS\_Engineer --- ## [Fiber Coating Hardness](https://forum.ofscn.net/t/fiber-coating-hardness/451)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 25, 2026, 2:56am UTC](https://forum.ofscn.net/t/fiber-coating-hardness/451 "2026-01-25T02:56:26Z")
How do hard versus soft coatings differently affect strain transfer efficiency? --- ## [Minimum Tensile Bending Radius](https://forum.ofscn.net/t/minimum-tensile-bending-radius/438)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 25, 2026, 2:50am UTC](https://forum.ofscn.net/t/minimum-tensile-bending-radius/438 "2026-01-25T02:50:19Z")
How does the bending radius under tension differ from the static bending radius during installation? --- ## [Fiber Ellipticity](https://forum.ofscn.net/t/fiber-ellipticity/435)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 25, 2026, 2:48am UTC](https://forum.ofscn.net/t/fiber-ellipticity/435 "2026-01-25T02:48:28Z")
How does non-circularity of the cladding or core affect connection and sensing? --- ## [Thin-Diameter Fibers](https://forum.ofscn.net/t/thin-diameter-fibers/434)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 25, 2026, 2:48am UTC](https://forum.ofscn.net/t/thin-diameter-fibers/434 "2026-01-25T02:48:08Z")
What are the advantages of 80μm or even 50μm cladding fibers in miniature sensors? --- ## [Polarization Mode Dispersion (PMD)](https://forum.ofscn.net/t/polarization-mode-dispersion-pmd/428)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 25, 2026, 2:45am UTC](https://forum.ofscn.net/t/polarization-mode-dispersion-pmd/428 "2026-01-25T02:45:43Z")
What negative impacts does it have on ultra-high frequency dynamic sensing? --- ## [Reflection Bandwidth of an FBG](https://forum.ofscn.net/t/reflection-bandwidth-of-an-fbg/420)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 25, 2026, 2:43am UTC](https://forum.ofscn.net/t/reflection-bandwidth-of-an-fbg/420 "2026-01-25T02:43:36Z")
Why does the bandwidth of a grating inscribed on specialty fiber differ from one on standard fiber? --- ## [What are “Hydrogen Loading” and “Dehydrogenation” Treatments?](https://forum.ofscn.net/t/what-are-hydrogen-loading-and-dehydrogenation-treatments/404)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 25, 2026, 2:35am UTC](https://forum.ofscn.net/t/what-are-hydrogen-loading-and-dehydrogenation-treatments/404 "2026-01-25T02:35:53Z")
How do these processes affect the photosensitivity and stability of the fiber before and after grating inscription? --- ## [What is the Fiber “Hydrogen Darkening” Phenomenon?](https://forum.ofscn.net/t/what-is-the-fiber-hydrogen-darkening-phenomenon/403)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 25, 2026, 2:35am UTC](https://forum.ofscn.net/t/what-is-the-fiber-hydrogen-darkening-phenomenon/403 "2026-01-25T02:35:33Z")
How much attenuation do hydrogen molecules cause in the 1383nm and 1550nm bands after entering the core? --- ## [What is Return Loss (RL)?](https://forum.ofscn.net/t/what-is-return-loss-rl/397)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 25, 2026, 2:32am UTC](https://forum.ofscn.net/t/what-is-return-loss-rl/397 "2026-01-25T02:32:07Z")
Why is high return loss crucial for eliminating system background noise and improving demodulation accuracy? --- ## [What is the difference between APC and PC Polishing Methods?](https://forum.ofscn.net/t/what-is-the-difference-between-apc-and-pc-polishing-methods/396)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 25, 2026, 2:31am UTC](https://forum.ofscn.net/t/what-is-the-difference-between-apc-and-pc-polishing-methods/396 "2026-01-25T02:31:43Z")
Why are APC (8-degree angle) connectors typically mandatory in FBG sensing systems? --- ## [Packaging-Induced Stress Birefringence in FBGs](https://forum.ofscn.net/t/packaging-induced-stress-birefringence-in-fbgs/369)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 23, 2026, 1:53am UTC](https://forum.ofscn.net/t/packaging-induced-stress-birefringence-in-fbgs/369 "2026-01-23T01:53:51Z")
Can uneven packaging cause the spectrum to split into two peaks? How is this resolved? --- ## [Elastic Modulus (E) of Packaging Materials](https://forum.ofscn.net/t/elastic-modulus-e-of-packaging-materials/367)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 23, 2026, 1:52am UTC](https://forum.ofscn.net/t/elastic-modulus-e-of-packaging-materials/367 "2026-01-23T01:52:37Z")
Why does choosing materials with a high elastic modulus help improve strain transfer efficiency? --- ## [Self-Compensating Packaging Design](https://forum.ofscn.net/t/self-compensating-packaging-design/359)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 22, 2026, 12:24pm UTC](https://forum.ofscn.net/t/self-compensating-packaging-design/359 "2026-01-22T12:24:51Z")
Can the packaging structure be designed to automatically offset the impact of temperature on sensitivity? --- ## [Significance in Digital Transformation](https://forum.ofscn.net/t/significance-in-digital-transformation/318)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 21, 2026, 1:29pm UTC](https://forum.ofscn.net/t/significance-in-digital-transformation/318 "2026-01-21T13:29:36Z")
Why is FBG technology a core component of the perception layer in the Industrial Internet of Things (IIoT)? --- ## [Optical Power Budget](https://forum.ofscn.net/t/optical-power-budget/316)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 21, 2026, 1:27pm UTC](https://forum.ofscn.net/t/optical-power-budget/316 "2026-01-21T13:27:53Z")
Can excessive link length or too many connectors cause the interrogator to lose the signal? --- ## [Crosstalk in FBG Systems](https://forum.ofscn.net/t/crosstalk-in-fbg-systems/315)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 21, 2026, 1:27pm UTC](https://forum.ofscn.net/t/crosstalk-in-fbg-systems/315 "2026-01-21T13:27:20Z")
Can signals from sensors with adjacent wavelengths interfere with each other? --- ## [Wavelength Allocation Planning](https://forum.ofscn.net/t/wavelength-allocation-planning/313)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 21, 2026, 1:26pm UTC](https://forum.ofscn.net/t/wavelength-allocation-planning/313 "2026-01-21T13:26:30Z")
How are initial wavelengths assigned to each grating when designing a 16-channel system? --- ## [Phase-Shifted FBGs (PS-FBG)](https://forum.ofscn.net/t/phase-shifted-fbgs-ps-fbg/312)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 21, 2026, 1:25pm UTC](https://forum.ofscn.net/t/phase-shifted-fbgs-ps-fbg/312 "2026-01-21T13:25:50Z")
Why can they produce extremely narrow transmission windows? What are their uses in ultra-high precision sensing? --- ## [Tilted Fiber Bragg Gratings (TFBG)](https://forum.ofscn.net/t/tilted-fiber-bragg-gratings-tfbg/311)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 21, 2026, 1:25pm UTC](https://forum.ofscn.net/t/tilted-fiber-bragg-gratings-tfbg/311 "2026-01-21T13:25:03Z")
How does the tilt angle affect cladding mode coupling? Can it measure refractive index? --- ## [Fundamentals of Shape Sensing](https://forum.ofscn.net/t/fundamentals-of-shape-sensing/310)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 21, 2026, 1:24pm UTC](https://forum.ofscn.net/t/fundamentals-of-shape-sensing/310 "2026-01-21T13:24:14Z")
How is spatial curvature calculated using the strain differences in multi-core gratings? --- ## [Spectral Distortion in FBGs](https://forum.ofscn.net/t/spectral-distortion-in-fbgs/307)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 21, 2026, 1:21pm UTC](https://forum.ofscn.net/t/spectral-distortion-in-fbgs/307 "2026-01-21T13:21:11Z")
Why do reflection peaks sometimes broaden, split, or disappear? --- ## [Binomial Fitting Formulas](https://forum.ofscn.net/t/binomial-fitting-formulas/291)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 21, 2026, 12:54pm UTC](https://forum.ofscn.net/t/binomial-fitting-formulas/291 "2026-01-21T12:54:18Z")
Why does OFSCN® recommend using binomial (quadratic) rather than linear formulas for temperature calculation? --- ## [What is FBG Calibration?](https://forum.ofscn.net/t/what-is-fbg-calibration/290)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 21, 2026, 12:53pm UTC](https://forum.ofscn.net/t/what-is-fbg-calibration/290 "2026-01-21T12:53:50Z")
Why must every sensor undergo wavelength-to-physical-quantity testing before leaving the factory? --- ## [Strain Transfer Efficiency](https://forum.ofscn.net/t/strain-transfer-efficiency/283)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 21, 2026, 12:47pm UTC](https://forum.ofscn.net/t/strain-transfer-efficiency/283 "2026-01-21T12:47:57Z")
How does the packaging material transfer external stress to the internal optical fiber? --- ## [Pre-strain (Pre-tension) Installation](https://forum.ofscn.net/t/pre-strain-pre-tension-installation/282)
**Author:** [@frostweaver](https://forum.ofscn.net/u/frostweaver)\ **Replies:** 1\ **Last updated:** [January 21, 2026, 12:46pm UTC](https://forum.ofscn.net/t/pre-strain-pre-tension-installation/282 "2026-01-21T12:46:43Z")
Why is it necessary to apply a certain initial tension to the grating during installation? [Next page](https://forum.ofscn.net/tag/wiki-fbg-tech/12.md?match_all_tags=true&page=1&tags%5B%5D=wiki-fbg-tech)