Optical filter and optical module having optical filter

Abstract

An optical filter comprising a first substrate, a first mirror formed on the first substrate, a second substrate coupled to the first substrate, the second substrate including a concave portion, and a second mirror formed on the concave portion and facing the first mirror, wherein the first substrate includes a first portion located on the first mirror, a second portion located around the first portion, a third portion located around the second portion, and a fourth portion located around the third portion, wherein both a thickness of the second portion and a thickness of the fourth portion are equal to or smaller than a thickness of the first portion.

Dependencies are inferred from the claim text.