We have a bunch of very nice little Fujikura optical fiber splicers in house. It is my job this week to see that they are working-enough to sell. For the last two days I have been trying to get decent cleaves on optical fibers without a cleaver. Finally I have hit on a workable solution.
Trust me, this is BY FAR the best result I have found, and I tried at least a couple dozen different ways. NOTHING I have found is this easy and gives this-good a result, short of having a proper cleaving tool.
Note: this will get you close. A proper cleave angle is 0º with no chips or cracks. This got me single-digits or low double-digits cleave angles with only a few tries per fiber, which is close enough to tell if these arc fusion splicers work. It also was enough to make a joined fiber with a reasonable noise/transmission loss figure, according to the machine. If you have to join fibers that mean anything to your company for transmitting data, your company is stupid to do anything less than buy a cleaver. I'll be done with this job before a cleaver would arrive in the mail though, so here I go DIY'ing it.
YMMV. Some practice is required. This is NOT as good as having a proper precision cleaving tool! Everything else I tried either shatters the fiber or has better-than-even odds of a nasty break instead of a neat cleaving.
The bulk of the solution: a bulk pack of scraper razor blades.
Turn them edge-side up. Lay the fiber perpendicular to the blades and smartly lower your cutting razor so that it strikes between the supporting blades.
This is NOT going to get past any self-respecting Q.C. checker!
But if you just HAVE TO get the job done without a cleaver, the signal should at least be able to pass, which is light-years better than a broken fiber*.
*sorry, I wasn't trying to be punny!