How well can the Point Source Microscope (PSM) locate the source of a single mode fiber?
In this case I was looking at the end of a single mode fiber patch cord to set it a particular distance above an optical breadboard.
With the laser turned on at a minimum intensity the light from the fiber looks like this zoomed in image of about 400 x 300 pixels of the whole 1.6 M pixel frame.
The laser spot (white dot) was purposely decentered from the magenta cross that is the origin of the PSM coordinate system so the shape of the spot could be clearly seen to get best focus. The centroid of the spot was measured to 0.2 μm in x and y using a 4x objective on the PSM.
Without touching anything other than turning off the laser source and shining a light past the objective to illuminate the front of the fiber I got this image of the 2.5 mm diameter fiber ferrule with the 125 μm core embedded in its center.
If you squint you can still see the magenta cross and the red scale bar to give a feel for the relative scale of the 2 pictures. The faint darker cross at 45 degrees gives a hint as to how the ceramic ferrule extrusion was made.
About the Author
Robert Parks received a BA and MA in physics from Ohio Wesleyan University and Williams College, respectively. His career started at Eastman Kodak Company as an optical engineer and then went on to Itek Corp. as an optical test engineer.
He learned about optical fabrication during a 4 year stay at Frank Cooke, Inc. This experience led to a position as manager of the optics shop at the College of Optical Sciences at the Univ. of Arizona and where he worked for 12 years and had a title of Assistant Research Professor. During that time he had the opportunity to write about the projects in the shop and the optical fabrication and testing techniques used there including papers about absolute testing and the installation and used of a 5 m swing precision optical generator.
Mr. Parks left the University in 1989 to start a consulting business specializing in optical fabrication and testing. Among the consulting projects was one working for the Allen Board of Investigation for the Hubble Telescope where he stayed in residence at HDOS for the duration of the investigation. In 1992 he formed Optical Perspectives Group, LLC as a partnership with Bill Kuhn, then a PhD student at Optical Sciences.
The consulting and experience with Optical Perspectives provided many more opportunities to publish work on optical test methods and applications. While still at Optical Sciences, Mr. Parks became involved in standards work and for twenty years was one of the US representatives to the ISO Technical Committee 172 on Optics and Optical Instruments. For two years he was the Chairman of the ISO Subcommittee 1 for Fundamental Optical standards. Recently Mr. Parks temporarily rejoined Optical Sciences part time helping support optical fabrication projects and teaching as part of the Opto-Mechanics program.
Bob is a member of the Optical Society of America, a Fellow and past Board member of SPIE and a member and past President of the American Society for Precision Engineering. He is author or co-author of well over 100 papers and articles about optical fabrication and testing, and co-inventor on 6 US patents. He remains active in development of new methods of optical testing and alignment.