Do you have any experience With qsfp28 transceiver on 100g data center? have you ever make 100G QSFP28 to be Used for 40G? 100Gb/s QSFP28 IR4 PSM4 (Parallel Single Mode 4 lanes) Optical Transceiver, 2km would it be okay with 100g data center, anyone give me some advise please?
There's a wide (and growing) range of 100G PHYs. You need to get a transceiver that is compatible with the DC uplink, e.g. 100GBASE-SR4 or -LR4.
The transceiver you've linked to states "100GBASE-IR4" which seems to be a 1310 nm, single-mode variant of 100GBASE-SR4. It doesn't seem to be compatible with anything else.
Using a QSFP28 transceiver with 40 Gbit/s is possible but requires the port to support that mode with that transceiver. 40G normally uses QSFP+ transceivers which may or may not work in a QSFP28 slot, depending on the switch and transceiver's compatibility.
The usual way to connect is to get the DC's uplink options, look at the device(s) you've got and check out which kind of transceiver you need to connect. Then you go shopping.