© DIAMOND SA / / 1 Performance & Intermateability Comparison between different ferrule technologies

© DIAMOND SA / / 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).

© DIAMOND SA / / 3 Optical Interface Intrinsic 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) Different core diameter Different numerical aperture Different index profile

© DIAMOND SA / / 4 Optical Interface Extrinsic 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) Lateral offset Angular misalignment End distance End angle Reflection losses Surface quality

© DIAMOND SA / / 5 Fiber Optic Connectors Typical 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

© DIAMOND SA / / 6 Fiber Optic Connectors Principle  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

© DIAMOND SA / / 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

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

© DIAMOND SA / / 9 Fiber Optic Connectors Ferrule 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.

© DIAMOND SA / / 10 Fiber Optic Connectors Standards CECC : 1998 DimensionValueUnit  ABmax. 32degrees Theoretical: 30degrees  BB0.0004mm With BB  0.4 mm, isthe position of the minimum attenuation no more detectable  CB0.0015mm  DB0.0005mm AB BBDB CB Active core aligned   0.5  m) Tuned connector   0.4  m  1.5  m  tuning within  30° area !

© DIAMOND SA / / 11 Fiber Optic Connectors Reference 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. Concentricity range using active aligned connectors against reference Concentricity range using tuned connectors against reference Ferrule outer diameter (class 0) / mm Eccentricity of the fiber core center to the ferrule center  mm Deviation of axis of fiber to axis of ferrule  0.2 degree Eccentricity of spherically polished ferrule end-face  30  m Visual examination of fiber end surface with 200x magnificationNo defects in core zone Attenuation between two reference plugs  0.15 dB Visual examinationEvery 50 matings

© DIAMOND SA / / 12 Fiber Optic Connectors End-face geometry POLISHING RADIUS (radius of curvature) FIBER HEIGHT (fiber position) Fiber Ferrule Top of the ferrule Top of the fiber +h -h

© DIAMOND SA / / 13 Fiber Optic Connectors End-face geometry APEX OFFSET POLISH ANGLE Polishing radius 8° (+/-.5°) Fiber Ferrule

© DIAMOND SA / / 14 Epoxy glue E-Modules: ZrO 2: N/mm 2 Cu-Ni Alloy N/mm 2 Silica N/mm 2 Ferrule with Cu-Ni insert ZrO 2 Cu-Ni Alloy Silica Epoxy glue ZrO 2 Silica ZrO2 ferrule E-Modules: ZrO 2: N/mm 2 Silica N/mm 2 Used materials and their specifications

© DIAMOND SA / / 15 Ferrule with Cu-Ni insert ZrO2 ferrule 150  m  126  m  125  m 125  m 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.  128  m  is calibrated without glue before curing Geometry of the ferrules

© DIAMOND SA / / 16  128  m  is calibrated without glue 150  m 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.

© DIAMOND SA / / 17 Geometry of mated the ferrules  the contact area will show a diameter of approx 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.

© DIAMOND SA / / 18 Test Results IL-Measurements  Reference Diamond / Test monobloc Insertion 1550 nm Average 0.1 dB STD 0.06 dBMax 0.28 dB80 measurements  Reference monobloc / Test Diamond Insertion 1550 nm Average 0.08 dB STD 0.03 dBMax 0.18 dB80 measurements Max offset:  = 0.6  m Estimated mean offset:  =  m Area of reference plug Area of measured plugs Max offset:  = 1.75  m Estimated mean offset:  =  m Area of measured plugs Area of reference plug

© DIAMOND SA / / 19 Test Results Geometry & Performance  The measured Insertion Loss values vary depending on geometry, which confirms that the mentioned parameters have to be rigorously controlled.

© DIAMOND SA / / 20 Test Results IL 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.

© DIAMOND SA / / 21 Test Results Conclusion 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)  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