I ordered one of the Chinese lasers last week before reading this info. From what I saw of them in my searching, anything that is sold new is the exact same part no matter the source: eBay, aliexpress, electronics parts suppliers, etc. You can tell from the pictures and specs. $13/shipped is the cheapest you can get it.
Here is that link.
One thing that I know from repairing several Sega CD Model 1 & 2s is that almost everyone online misdiagnoses disc-reading problems as laser issues, when in fact a recap is what's actually needed. Many Sega CDs won't read discs before a recap, but after they come back to life with no pot adjusting or laser replacement needed.
If I had a Duo or CD with disc reading problems (read errors, discs not spinning, etc), I would start by recapping it and then move on to replacing the laser as a second resort. That's just me though. You are probably better off following the advice of long-time PCE CD experts.