Filter for reducing optical cross-talk

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

• emitting, by an emitter disposed in the optical device, a first light wave, wherein the first light wave causes 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 detectable by the detector is susceptible to being coupled with an undesired light wave caused by the first 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 a filter property of the interference filter.