Sachs Wavy shifters are Shimano compatible and were introduced in late 1997. But in 1999 when SRAM took over Sachs things got a little complicated, so pay attention...
After the takeover the old Sachs range ie. Plasma, Quarz, Neos and Centera, was rebadged as the SRAM DIRT range. eg 'SRAM DIRT Plasma' and 'SRAM DIRT Quarz' etc.
'DIRT' stands for 'Direct Response Technology'
These all had the same 1:2 cable pull ratio as Shimano derailleurs and shifters, and as such were and are fully compatible and interchangeable.
Prior to the takeover in 1996 SRAM had introduced 'ESP' under their 'Gripshift' brand. ESP is basically a 1:1 cable pull ratio, so you must use ESP compatible shifters and mechs. SRAM have continued with this ratio set-up and still use it today.
So basically if it doesn't say 'ESP' or '1:1' anywhere on it, it should be Shimano compatible.