The Michelson Interferometer is probably the simplest and easiest interfeometer to use. It is hard not to get an interference pattern. But there are other types of interferometers. One of the most popular is the Mach-Zhender interferometer. Where the Michelson has a common beam splitter through which both light paths travel, the Mach=Zhender has two completely separate paths. This is a big deal for theorists as an argument can be made that the two beams in the Michelson could interfere with each other as they travel through the beam splitter. But with the Mach-Zhender the light paths are truly independent.
The Mach-Zhender is typically set up in a square or rectangular arrangement. One gets best results when each pair of legs is nearly exactly equal length. Light travels from the source (laser pointer) through one beam splitter where the light is split into two separate paths, oriented 90 degrees to each other. Each path is reflected by mirrors to a second beamsplitter that recombines the beams. There are now two exit rays. With a well set up system one can get interference patterns on both exit paths.
The Mach-Zhender interferometer is considerably more difficult to set up and can be a little frustrating until you are told the "tricks". Essentially you want to align both beams so they lie in the same plane and are exactly parallel to each other when they go through the final beam splitter (that acts to combine the beam. This means one must adjust both the mirrors and the beam splitters to obtain an interference pattern.
A good description of how to set up the Mach-Zhender will be included with the instructions for the device. I will also post the on this web site at my first oppportunity.
Polarizers and mica 1/4 wave plates are also available and can be ordered separately.
The Mach-Zhender is currently available with cube beam splitters. I am working on a universal mount that will accommodate a cube or plate beam splitter. I hope to have it available in the near future.