Troubleshooting Complicated Optics

[OpticsEngineer]

In my school days, we heard one of our professors had a lucrative side business going into optical labs, finding problems and fixing them. So we asked him about it one day before class, which covered first order layout. (Drawing optical diagrams and applying calculations to them.)

We imagined him going into a room full of electronics with a table full of lenses, mirrors and lasers, studying it intently for a few days and then pointing and saying, “There’s the problem.” We told him it sounded really hard.

He scoffed and said, “No, it’s really easy. It’s always the same problem. I ask to see their first order layout. And they never have one.”

We said, “They must have something.” He said, “Oh, they always have some drawings with optical rays drawn on them. But no equations. So the rays just go all over in unphysical ways”

We asked, “Aren’t they embarrassed to show that to you?” He said, “No, not at all. They’re always really proud of themselves. I just tell them to give me what they have, and I work from that.

“Don’t you go into the lab and look at the equipment?”

“Never for more than five minutes. Speaking of time, nine o’clock, time for lecture."

Throughout my career I ran into the same thing many times. Seeing lots of effort expended on mathematically unsound projects. I am sure many others on this forum have seen similar situations. I would really like to hear about them,

 

[JimKasson]

In my school days, we heard one of our professors had a lucrative side business going into optical labs, finding problems and fixing them. So we asked him about it one day before class, which covered first order layout. (Drawing optical diagrams and applying calculations to them.)

We imagined him going into a room full of electronics with a table full of lenses, mirrors and lasers, studying it intently for a few days and then pointing and saying, “There’s the problem.” We told him it sounded really hard.

He scoffed and said, “No, it’s really easy. It’s always the same problem. I ask to see their first order layout. And they never have one.”

We said, “They must have something.” He said, “Oh, they always have some drawings with optical rays drawn on them. But no equations. So the rays just go all over in unphysical ways”

We asked, “Aren’t they embarrassed to show that to you?” He said, “No, not at all. They’re always really proud of themselves. I just tell them to give me what they have, and I work from that.

“Don’t you go into the lab and look at the equipment?”

“Never for more than five minutes. Speaking of time, nine o’clock, time for lecture."

Throughout my career I ran into the same thing many times. Seeing lots of effort expended on mathematically unsound projects. I am sure many others on this forum have seen similar situations. I would really like to hear about them,

I don't remember ever encountering something similar in my professional life. Sure, I've seen projects that were conceptually flawed, and ones in which mathematically or physically based limits were encountered, like propagation velocity causing timing budgets to be exceeded, race conditions discovered, COGs too high, feature set poorly chosen, too little known about the psychology of the user (see color matching work), computation speed too slow for the algorithms, thermal budgets exceeded, worst-case design too rigid, worst case design too lax (not really worst case), can't package product in form factor specified, etc.

 

[OpticsEngineer]

"I don't remember ever encountering something similar in my professional life."

I am kind of surprised by that. But there is the problem that there are relatively few universities with a good optics program. So there is a shortage and it is pretty common to run into people trained in other areas like chemistry or mechanical engineering doing optics work who have never had a full three semester hour geometric optics course. Often at most they had a couple of weeks of geometric optics in an introductory optics course that covered a lot of topics quite thinly. So they are basically self-taught and make a lot of mistakes with the basics.

By the way, a three-semester hour geometric optics course is significantly easier than a junior level EE network analysis course that would cover resistors, inductors, capacitors, Kirchoff's law and second order differential equations.

 

[JimKasson]

"I don't remember ever encountering something similar in my professional life."

I am kind of surprised by that. But there is the problem that there are relatively few universities with a good optics program. So there is a shortage and it pretty common to run into people trained in other areas like chemistry or mechanical engineering doing optics work who have never had a full three semester hour geometric optics course. Often at most they had a couple of weeks of geometric optics in an introductory optics course that covered a lot of topics quite thinly. So they are basically self-taught and make a lot of mistakes with the basics.

By the way, a three-semester hour geometric optics course is significantly easier than a junior level EE network analysis course that would cover resistors, inductors, capacitors, Kirchoff's law and second order differential equations.

Most of the engineers that I worked with had at least MSEE's. If they didn't, we paid for them to get those degrees on the Stanford Honors Coop program. I never assigned a task to an engineer unless I thought that he (and they were mostly men) had the theoretical skills to do the job. EE schools are light on the fine points of unwanted analog interactions, and when they ran into trouble, wwe had a EE professor from Berkeley who helped them out. He and one of my engineers got together and wrote a book on that part of digital design.

https://www.amazon.com/High-Speed-Digital-Design-Handbook/dp/0133957241

By the way, our development engineer college recruiting program for EEs, EECS grads, and CS students was highly targeted. We had a college recruiter who was a good EE. He went made friends with the faculty on about 8 college campuses (Cal, Stanford, CalTech, MIT, CMU, Champaign-Urbana, Ann Arbor) and at the very beginning of the school year identified the most promising grads. We didn't wait for them to come to us. We went to them. For production engineers, we added Cal Poly.

--
https://blog.kasson.com

 

[OpticsEngineer]

A typical path for someone to end up doing optics is they had a diagnostic problem for chemistry, mechanical engineering fluid flow, or quality inspections and they set up optics to do it. Then got deemed a resident company optic expert and kept on going. Sometimes they would have a Phd in their original field so people assumed they knew what they were doing.

Particularly a problem in government work. One place I left the guy who took my place had a Phd in Economics, which made the company happy because they could bill Phd rates, but pay him not so much because they knew he was unqualified. I heard the projects fell apart pretty quickly after that.

** edit **

Funny thing about the guy with the Phd in Economics. I overlapped with him for two weeks and taught him what I could and gave him all my spreadsheets and programs. I asked why he had chosen optics. He said he applied his economics training and selected a field where data indicated there was a high percentage of people working in the field without a college degree in the subject.