There have been a number of threads about making DIY optical cable on this forum. One of weak points of most of these DIY's is getting the right connectors. The solutions range from buying connectors (at about $10 a pop or $20 per cable), re-using connectors from old cables (which may require drilling them out and gluing fiber) to using random bits of off the shelf hardware which may have poor fit and finish. I've tried all of these solutions.
A few months ago, I bought my first 3D Printer and have been making a bunch of Scuba/Camera related parts. My latest project is a set of custom designed connectors for Optical fiber strobe cables. I think these are at least as good as the OEM cables I've seen from Nauticam, Inon, etc. And it had the added benefit of being really fun to design, print, test, and refine. I've been testing these connectors for the last several weeks and have done a bunch of dives with good results.
If you have a 3D printer with some TPU and PETG or PLA material, you can print these out at a very low unit cost. You will need some M3x6mm nuts and bolts and 2mm fiber to complete.
I've just uploaded the design and STL print templates to the public sharing site Thingiverse: https://www.thingiverse.com/thing:6134211
Thingiverse Details:
Inon Style Optical Fiber Cable Connectors
https://www.thingiverse.com/thing:6134211
Make your own optical fiber cables using these connectors paired with 2mm fiber. I used both 613 multi-core fiber cables and cheap TosLink cables. The design assumes 2.2mm OD for the cables.
This design contains two styles of connectors: A 90deg elbow and 180deg straight connectors. The elbow part is printed with PETG. PLA will work but may not stand up as well to the elements. The actual connector parts are printed with TPU. These parts must be soft rubber, so no material substitutes are possible.
The 90deg Elbow part snaps together and is secured with two M3x6mm nuts/bolts. These can be purchased from many sources like Amazon. The TPU connector and strain relief parts fit in the groves of the elbow. Thread the optical fiber through the TPU parts and align them into the elbow before screwing them together.
The TPU parts should be snug enough to hold the cable secure with no adhesive. If it is not secure, you can apply a small amount of silicone-based glue to the cable as you thread it into the TPU parts. Using glue may make it difficult to reuse the connectors should a cable get damaged.
Use the connectors in combinations that work for your camera rig. I like a 90deg connector on the top of my Nauticam housing and a 180deg connector on an Inon or Backscatter strobe. With a Retra strobe a 90deg connector will work better.
I have found these connectors to work well with a firm connection that is installed or removed with appropriate resistance.