Is it possible to call a Lightning Component from a Javascript function?
There is an event named force:navigateToComponent. You can use this event for going to another component. It is currently in the Beta version in the Winter '17 release.
Example:
var evt = $A.get("e.force:navigateToComponent");
evt.setParams({
componentDef: "c:componentName",
componentAttributes: {
// Attributes here.
}
});
evt.fire();
Source: https://resources.docs.salesforce.com/sfdc/pdf/lightning.pdf (Page number 411 in the document)