An official announcement about the link-up is expected on Friday but it is thought Alpine will replace the Nissan badges on the V8 engine in the team's ORECA 03 chassis.
Caterham boss Tony Fernandes, who claimed a 50 per cent stake in Alpine in November 2012, had hinted a deal was in the offing.
"There are lot of plans for other motorsport projects and things we can do together," he said. "We are working on plans that are good business and that showcase our companies."
Alpine will make a return to the event 35 years after securing a race victory with Renault.
Signatech has one entry for Le Mans and will also race the European Le Mans Series.
The team's partnership with Nissan dates back to 2011-12 when it received backing from the Japanese make, which placed winners of the PlayStation GT Academy with the team.