If you get stuck like this, the first thing to do is to call the manufacturer sales rep. Almost all of the ones who are in this century have access to a distributor stock database, which will tell them not only which distributors worldwide have your part in stock, but also what's going on at the factory. They can also give you a heads-up about any distribution problems, or if the part is being obsoleted or phased out. Also, they may be able to suggest a cross (if you can accept a slightly different wavelength, or non-ROHS-compliant part, you may have other options). The problem is you may sometimes have to wait a bit for a response.
The Osram website is somewhat opaque ;-) about this, but their US sales office can be reached at
+1 888 446-7726
You might also want to try calling someone at DigiKey and ask when or if they expect delivery on these parts.
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