This technical report is intended to characterize the microbend
\nsensitivity of optical fibers, thereby guiding fiber and cable
\nmanufacturers regarding the design of various coatings and basic
\nfibers as they apply to the design and performance of cable.<\/p>\n
For the purposes of this technical report, the term microbending
\nshould be properly distinguished from macrobending. The spirit of
\nthese two terms is to identify whether the bending is small or
\nlarge. Through many years, experiments with small and large bends
\nprovided a link between bend size and specific qualities of the
\nresulting loss spectra of the optical fiber under test, thereby
\nproducing new, functional definitions for micro- and macrobending.
\nThe following definitions will attempt to capture some of the art
\nand intuition behind these historic terms, while maintaining the
\nintegrity of their original intent. Moreover, since bend loss is a
\nfunction of wavelength, these terms should be defined in the
\ncontext of a given wavelength range. This report will use the
\ntypical wavelength region of interest for telecommunication fibers:
\n1200 to 1700 nm.<\/p>\n
Macrobending is usually characterized by a constant, moderately
\nlarge bend radius leading to an exponential increase in the loss as
\na function of wavelength. This loss in known to be physically
\ninduced by an optical tunneling phenomena, where the light from a
\npropagating mode leaks out toward the outside of the bend. In the
\nevent that the bend radius is not constant, the type of bending
\ncould still be considered macrobending provided the different bend
\nradii are all generally large, and the loss is still dominated by
\nthe optical tunneling phenomena with exponential wavelength
\ndependence. Microbending, on the other hand, is random microscopic
\nfiber axis perturbations along the length of the fiber. Such random
\nmicrobending is typically indicated by a uniform loss across the te
\nleco m mu n ica t io ns wave length band . Of cou rse , ce rtai n m
\nicro be nd scenarios can be created (small, periodic bending) where
\nthe loss response is not uniform, but these cases are typically not
\naccidental and may in fact be engineered into the fiber for a
\nspecific purpose. Regardless of the statistics of the microbends
\nhowever, they can generally be described by some form of
\ncoupled-mode theory, treating the bends as small perturbations to
\nthe otherwise straight fiber. Thus, micro- and macrobends can be
\ndistinguished both by the underlying physics and the appearance of
\nthe resulting loss spectra, provided the spirit of these terms is
\nmaintained. The transition from microbending to macrobending as
\nbend radius is increased is a continuous process, meaning that the
\nboundary typically contains features of both types of loss.
\nMoreover, such a boundary would be more appropriately described in
\nterms of the bend statistics (random versus constant, for example)
\nthan the absolute bend radius. Therefore this report will not
\nattempt to limit its scope with absolute specifications of bend
\nradii, but will rather leave this discrimination to those reviewing
\nthe above qualities of the fiber under test.<\/p>\n
For the purposes of this technical report, microbend and
\nmacrobend will be defined in terms of bend loss in optical fiber.
\nThe spirit of these two terms is to identify whether the bending is
\nsmall or large. Through many years, several different regions of
\nbend quality emerged. Since bend loss is a specified function of
\nwavelength, the typical region of interest for telecommunication
\nfibers is 1200 to 1700 nm.<\/p>\n
Macrobending is usually characterized by a constant moderately
\nlarge bend radius leading to an exponential increase in the loss as
\na function of wavelength physically induced by an optical tunneling
\nphenomena, where the light from a propagating mode leaks out toward
\nthe outside of the bend. Spectrally uniform microbending is
\nmicroscopic in nature, usually characterized as a collection of
\nrandom small bends, rapidly varying in both radius and orientation
\ninduced by factors that are usually described by coupled-mode
\ntheory. Microbend is dependent on the type of bend – usually
\nrandom, periodic. The boundary between microbend \/ macrobend
\n(combination region) is continuous and dependent on the wavelength
\nproperties usually in the mm range.<\/p>\n
Although they can be very useful tools for evaluating fiber and
\ncable designs, the current state-of-the-art of these test
\nprocedures are such that test results may prove to be misleading.
\nThese tests are not recommended for use in comparing different
\ntypes of optical fibers, nor should test results be compared from
\none facility to another nor from one technique to another.<\/p>\n
The ability of a coating to prevent microbend loss can be
\ndependent upon temperature. The temperature(s) at which this test
\nis to be performed for expandable drum, fixed drum and wiremesh
\nshall be specified in the Detail Specification. The basketweave
\ntechnique is a temperature dependent, microbend sensitivity test
\nwith the recommended temperatures defined within the text.<\/p>\n","protected":false},"excerpt":{"rendered":"
ITM-12 Microbend Sensitivity Test Methods<\/b><\/p>\n\n\n
\n Published By<\/td>\n Publication Date<\/td>\n Number of Pages<\/td>\n<\/tr>\n \n TIA<\/b><\/a><\/td>\n 2001<\/td>\n 26<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":692115,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2646],"product_tag":[],"class_list":{"0":"post-692105","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-tia","8":"first","9":"instock","10":"sold-individually","11":"shipping-taxable","12":"purchasable","13":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/692105","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media\/692115"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=692105"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=692105"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=692105"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}