Patent ID: 7616845

Claim:
An optical module comprising: a member having first and second planar surfaces opposed to each other, wherein said member has a cavity therein and the cavity has opposing third and fourth planar surfaces therein and said third planar surface is parallel to the fourth planar surface; wherein an extended line of a first line belonging to the first planar surface is intersected by an extended line of a third line belonging to said third planar surface in one cross section of said member at a position of presence of said cavity and smaller one of intersection angles between said first and third lines is φ 1 ; wherein an extended line of a second line belonging to said second planar surface is intersected by an extended line of a fourth line belonging to said fourth planar surface and smaller one of intersection angles between said second and fourth lines is φ 1 ; wherein at least one reflecting film is provided on a part of said third planar surface; at least one optical wavelength filter is provided on a part of said fourth planar surface; said reflecting film and said optical wavelength filter are opposed at least partly to each other; said optical wavelength filter transparent to a wavelength λ 1 and reflects light having a wavelength λ 2 ; and λ 1 and λ 2 satisfy a relationship λ 1 >λ 2 or λ 1 <λ 2 ; and a substrate provided with a laser diode and a photo detector; wherein at least part of said substrate and at least part of said second surface of said member are fixed; wherein first output light having the wavelength λ 1 emitted from said laser diode is passed through the part of said member, said optical wavelength filter, said cavity and another part of said member, and directed into an optical fiber provided above said first surface of said member; and second output light output from said optical fiber and having the wavelength λ 2 is passed through another part of said member and said cavity, reflected by said optical wavelength filter and said reflecting film, passed through said cavity and the part of said member, and directed onto said photo detector.