Lensed Connector Cleanliness Specification Development

Transcription

1 Lensed Connector Cleanliness Specification Development Presented by: Doug Wilson FiberQA Optical Interconnects 2016 May 10, 2016 San Diego, California

2 Cleanliness Specification for Expanded Beam Connectors 10+ years of inemi research on the impact of contamination on fiber optic connector performance provides a quantitative approach to developing the first-ever industry cleanliness specification for expanded beam connectors. What does a cleanliness specification mean for Mega Data Centers? How clean must an expanded beam connector be to meet optical performance requirements? What is the impact of contamination/ scratches on the optical performance of expanded beam connectors? Photos above (clockwise from top left): Molex MT expanded beam connector; US Conec PRIZM LT Connector; US Conec MXC connector with PRIZM MT ferrules. How can Data Center costs (cleaning) be reduced by development of a cleanliness specification that is based on a quantitative approach and is accepted by the industry? 2

3 Experimental Measurement Flowchart M0 Record initial photos of the DUT and launch cable Mate Record IL De-Mate Add Dust Mn Repeat n = 1 to 5 Record photos of DUT. Clean launch cable if dust is present Mate Record IL De-Mate MC Clean DUT and launch cable Record photos of DUT and launch cable Mate Record IL De-Mate 3

4 Examples of Fine Dust S/N 005 F7 M0 M5 MC 0.42dB 0.76dB +0.34dB 0.42dB 4

5 Overview of the Data Only samples 0008, 0010 and 0011 have lenses with a significant dust loss. 5

6 Multimode Intensity Distribution The intensity distribution at the lens surface is approximated by a quadratic function of radius. [cf. This is the distribution at the endface of a graded-index multimode fiber with overfilled launch (OFL) conditions.] I( r, a) = ( r / a) 2 ì 1-0 r a í î 0 otherwise For this particular data set, the dust data is only valid within a maximum radius r max. This limit is therefore included in the intensity function: ( r / a) 2 ì 1-0 r min( a,rmax) I( r, a, rmax) = í î 0 otherwise Note that the launch conditions for the experiment meet encircled flux launch (EFL) conditions. A quadratic function is a reasonable, simple approximation to the actual intensity distribution. 6

7 Calculating the Multimode Dust Loss Calculated Intensity Distribution Measured Dust Distribution I(x,y) D(x,y) I(x,y)D(x,y) X = Sum over all pixels T Dust, MM = òò I( x, òò y) D( x, I( x, y) dxdy y) dxdy Sum over all pixels White: D(x,y) = 1 (no dust) Black: D(x,y) = 0 (dust) 7

8 Raytracing Modeling The lens material has an index of refraction n = 1.51; the numerical aperture (NA) of standard 50 μm graded index fiber is 0.2; and the distance from the fiber endface to the lens apex is L = 0.53 mm. The estimated beam diameter is therefore 2a 2L NA / n = 0.14 mm. 8

9 Calculated vs Simulated Data Excellent correlation between two modeling methods was achieved 9

10 Calculated Loss vs Measured Data 5 4 Calculated Loss (db) Measured Loss (db) Each data point represents the average of the loss measurements for the 5 matings; the agreement between analytical calculations and experimental measurements is relatively good. 10

11 Conclusions A simple analytical calculation is used to estimate the dust loss of an expanded beam connector. It is shown that this analytical result is nearly identical to an optical simulation using OFL or EFL launch conditions, and agrees reasonably well with experimental data. This calculation can be used as the foundation of an optical cleanliness specification by providing a calculated dust loss that can be compared against an acceptable loss limit. 11

12 Project Members Tatiana Berdinskikh Tom Coughlin Michael A. Kadar-Kallen, Mike Gurreri Christine Chen Ken Toyama Doug Wilson Tom Mitcheltree Kevin Chaloupka, George Megason Kevin Leigh 12

13 Author Information Michael A. Kadar-Kallen, CommScope Christine Chen, FIT Tom Coughlin, Molex Tatiana Berdinskikh, Celestica Doug Wilson, FiberQA 13