Optical interference filters

A method performed using an optical device, the method comprising:

• emitting, by an emitter disposed in the optical device, a first light wave that results in an undesired light wave in the optical device;
• detecting, by a detector disposed in the optical device, a second light wave that is based on the first light wave, wherein the second light wave is susceptible to being coupled with the undesired light wave;
• and
• filtering, using an interference filter disposed on the detector, the undesired light wave caused by the first light wave, wherein filtering the undesired light wave comprises attenuating the undesired light wave based on at least one filter property of the interference filter, the at least one filter property being operable to cause the interference filter to:
• attenuate the undesired light wave;
• and
• have resistance to one or more environmental conditions that would otherwise cause physical deformation of the interference filter.

An optical device, comprising:

• an emitter operable to emit a first light wave;
• a detector operable to detect a second light wave that is based on the first light wave;
• and
• an interference filter disposed on the detector, the interference filter comprising:
• a first plurality of alternating layers that are formed using a first set of materials;
• and
• a second plurality of alternating layers that are formed using a second set of materials, the second plurality of alternating layers represents a protective layer stack of the interference filter.