Performance & Intermateability

1. Performance & Intermateability Comparison between different ferrule technologies

2. Optical Interface • There are three main possibilities to have a fiber optic connection: • demountable connections (fiber optic connectors), • partly demountable connections (i.e. mechanical splices), • fixed connections (i.e. thermal “fusion” splices).

3. Different core diameter Different numerical aperture Different index profile Optical InterfaceIntrinsic Losses • Differences in the fiber specifications (Not correctable fiber imperfections). • core area mismatch • numerical aperture NA • refractive index profile • (profile parameter AN) • (elliptical fiber core) • (core eccentricity)

4. Reflection losses Surface quality End angle Lateral offset Angular misalignment End distance Optical InterfaceExtrinsic Losses Improper interface design or manufacture. • End face losses: • reflection • surface quality (smoothness) • end angle (flatness, perpendicularity) • Losses due to: • lateral offset (coaxiality) • angular misalignment • longitudinal distance (end gaps)

5. Fiber Optic ConnectorsTypical Requirements • There are many critical elements, technical and commercial, to be considered in an demountable fiber optic connection. The most important are : • Insertion Loss (IL) • Return Loss (RL) • mechanical reliability and long working life • thermal stability • packing density • possibility of field termination • sturdy, rugged and handy construction • prices

6. Fiber Optic ConnectorsPrinciple • High precision ferrules • High precision split ceramic sleeve • Does not utilize phosphor bronze or metal to reduce possibility of endface contamination • Ferrule and split sleeve maintain precise tolerances • enabling precise alignment of fiber and ferrule frontfaces

7. Fiber Optic Connectors Most important Parameters • The critical factor in a fiber optic junction is alignment. Loss is minimized when the two fibers - and especially the light carrying cores - are perfectly aligned. • Angular misalignment (Tilt Angle) • Insertion Loss • The end face geometry strongly affect light transmission. • Return Loss

8. Core eccentricity distribution according to DIAMOND factory specifications (measured values from production) Tilt angle distribution of centered plug according to DIAMOND factory specifications Fiber Optic Connectors Most important Parameters

9. Fiber Optic ConnectorsFerrule technologies • DIAMOND’s Multi-component ferrule with Cu-Ni alloy insert • Active Core Alignment • Geometrical parameters under control. • Monobloc ceramic ferrule • Tuning • Geometrical parameters are process dependent.

10. AB AB CB DB BB Active core aligned  0.5 m) Tuned connector  0.4 m  1.5m tuning within 30° area ! Fiber Optic ConnectorsStandards CECC 86275-802: 1998 Dimension Value Unit • AB max. 32 degrees • Theoretical: 30 degrees • BB 0.0004 mm • With BB  0.4 mm, is the position of the minimum attenuation no more detectable • CB 0.0015 mm • DB 0.0005 mm

11. Fiber Optic ConnectorsReference connectors A reference connector has to be characterized by clear, reproducible parameters, aiming to be perfect! • All the core characteristics of a reference connector have to be within the specified tolerances of each standard. • Taking the eccentricity into consideration, theoretically the only clearly reproducible value is 0 mm, being exactly the geometric center of the ferrule and also unequivocally defined. In practice today’s physics allow a value of 0.1 mm. Ferrule outer diameter (class 0) 2.499 -0/+0.0005 mm Eccentricity of the fiber core center to the ferrule center  0.0002 mm Deviation of axis of fiber to axis of ferrule  0.2 degree Eccentricity of spherically polished ferrule end-face  30 mm Visual examination of fiber end surface with 200x magnification No defects in core zone Attenuation between two reference plugs  0.15 dB Visual examination Every 50 matings Concentricity range using active aligned connectors against reference Concentricity range using tuned connectors against reference

12. Top of the fiber Top of the ferrule +h -h Fiber Ferrule Fiber Optic ConnectorsEnd-face geometry • POLISHING RADIUS (radius of curvature)  • FIBER HEIGHT • (fiber position)

13. 8° (+/- .5°) Polishing radius Fiber Ferrule Fiber Optic ConnectorsEnd-face geometry • APEX OFFSET • POLISH ANGLE

14. ZrO2 ferrule Epoxy glue ZrO2 Silica ZrO2 Cu-Ni Alloy Silica Used materials and their specifications Ferrule with Cu-Ni insert Epoxy glue E-Modules: ZrO2: 22.000 N/mm2 Cu-Ni Alloy 17.000 N/mm2 Silica 6.000 N/mm2 E-Modules: ZrO2: 22.000 N/mm2 Silica 6.000 N/mm2

15.  128m  is calibrated without glue before curing Geometry of the ferrules ZrO2 ferrule Ferrule with Cu-Ni insert  126m 150 m  125m 125 mm is the ideal fiber diameter. Within mono-block technology, the inside diameter of the hole must be changed in relation to the diameter of the fiber in order to achieve proper fit.

16.  128m 150 m  is calibrated without glue The role of the fiber position into the DIAMOND’s ferrule • The pressure at the fiber front face is absorbed by the glue, which is also deformed (see next figure). The larger the thickness, the higher possibility of deformation. • The thickness of the glue surrounding the fiber inside the ferrule still remains pretty large in relation to the fiber‘s outer dimensions, therefore, the fiber can easily adapt its position with respect to the pressure made by the opposite connector. The optical characteristics of the fiber are also controlled. • The lower E-modulus of silica and the higher adaptability of the fiber position permit larger tolerances for radius of curvature, fiber protrusion and apex offset.

17. Geometry of mated the ferrules • the contact area will show a diameter of approx. 200-220 mm and the end-surface will be nearly perpendicular to the fiber axis. • The lower E-modulus of the Cu-Ni insert allows a slightly higher deformation than the ZrO2 ferrule, therefore the radius of curvature at the front face of ferrules with Cu-Ni insert might be larger than the front radius of ZrO2 ferrules. • Regardless of the mentioned material differences, ferrules with Cu-Ni insert and ZrO2 ferrules are intermated worldwide with excellent results.

18. Area of reference plug Area of measured plugs Max offset:  = 0.6 m Estimated mean offset:  = 0.3-0.4 m Area of measured plugs Area of reference plug Max offset:  = 1.75 m Estimated mean offset:  = 0.7-0.8 m Test ResultsIL-Measurements • Reference Diamond / Test monobloc • Insertion loss @ 1550 nm Average 0.1 dB STD 0.06 dB Max 0.28 dB 80 measurements • Reference monobloc / Test Diamond • Insertion loss @ 1550 nm Average 0.08 dB STD 0.03 dB Max 0.18 dB 80 measurements

19. Test ResultsGeometry & Performance • The measured Insertion Loss values vary depending on geometry, which confirms that the mentioned parameters have to be rigorously controlled.

20. Test ResultsIL comparison • The measurement against reference plug according to the worldwide standards is the only repeatable condition which can be assumed as a universally valid requirement.

21. Area of Active Core Aligned 0.1 dB connectors Area for Active Core Aligned 0.5 dB connectors Area of Monobloc 0.1 dB connectors Area of Monobloc 0.5 dB connectors Measured monobloc sample plugs (various supplier) Test ResultsConclusion • There is a correlation between geometrical criteria and performance of fiber optic connectors. • The compatibility between connectors of different ferrule technologies is guarantied only using connectors that entirely fulfill the standard geometrical and surface quality requirements. LOW TILT ANGLE LOW ECCENTRICITY LOW ATTENUATION