Fusion Splice Loss from Fiber and Geometry Mismatch

ScopeThe worked 9.2/8.6 micron fiber mismatch costs only 0.020 dB, while 2 degrees of axial tilt between the cores costs 0.92 dB (a fusion splice does not tilt by the cleave angle; under 2 degrees of cleave is acceptable). A core-alignment splicer can correct offset; fiber, splicer, and acceptance-test requirements govern.

Formula or tableMFD mismatch = -20 log10(2 w1 w2/(w1^2+w2^2)); lateral loss = 4.343 x 2 d^2/(w1^2+w2^2); angular loss = 4.343(pi n theta/lambda)^2 x 2 w1^2 w2^2/(w1^2+w2^2), which are 4.343(d/w)^2 and 4.343(pi n w theta/lambda)^2 for matched fibers; small losses add approximately.

Source and editionGaussian single-mode splice-loss approximations for mode-field mismatch and geometric misalignment.

Free accessThree Gaussian coupling approximations.

What governsEstimate. AHJ and licensed professional govern.

API field namesmfd_1_um, mfd_2_um, lateral_offset_um, cleave_angle_deg, wavelength_nm, fiber_index, mfd_mismatch_loss_db, lateral_offset_loss_db, angular_loss_db, angular_2deg_loss_db, total_loss_db

• Single-mode Gaussian approximation not applicable to multimode fiberthe coupling model
• Independent small losses real fusion also depends on contamination, arc parameters and core geometrythe splicer data
• One-direction intrinsic estimate dissimilar fibers require bidirectional OTDR averagingthe acceptance test standard