Detection device

1. A detection device that detects a power of an input light, comprising:

a light-receiving module comprising a first light-receiving surface and that outputs an electrical signal according to the power of the input light received at the first light-receiving surface;

an optical lens comprising second and third light-receiving surfaces lying perpendicular to an axial direction of an optical fiber that transmits the input light, the second and third light receiving surfaces lying on opposites faces of the optical lens, and that collimates and guides to the first light-receiving surface the input light from the optical fiber; and

a condenser that:

is provided in a path of the input light between the optical lens and the first light-receiving surface,

decreases a beam diameter of the input light at the first light-receiving surface, and

is formed on a surface of the optical lens opposing the second light-receiving surface.

2. The detection device according to claim 1 , wherein

the condenser is a condensing lens made of a resin coated on the surface of the optical lens opposing the second light-receiving surface.

3. A detection device that detects a power of an input light, comprising:

a light-receiving module comprising a first light-receiving surface on a photodiode and that outputs an electrical signal according to the power of the input light received at the first light-receiving surface;

an optical lens, comprising second and third light-receiving surfaces lying perpendicular to an axial direction of an optical fiber that transmits the input light, the second and third light receiving surfaces lying on opposites faces of the optical lens, that collimates and guides to the first light-receiving surface the input light from the optical fiber; and

a condenser that is provided in a path of the input light between the optical lens and the first light-receiving surface and that decreases a beam diameter of the input light at the first light-receiving surface, wherein

the light-receiving module comprises a transparent covering body that encloses the photodiode, and

the condenser is formed on a surface of the covering body.

4. The detection device according to claim 3 , wherein

the condenser is a condensing lens made of a resin coated on the surface of the covering body.

5. The detection device according to claim 4 , wherein

the condensing lens made of the resin on the surface of the covering body comprises a potting material identical to that of the covering body.

6. The detection device according to claim 1 , wherein

a diameter of the first light-receiving surface is no more than 100 μm.

7. The detection device according to claim 1 , wherein

the input light is an optical communication signal;

the detection device further comprises an optical fiber pigtail including two optical fibers connected to an optical transmission line through which the optical communication signal is transmitted;

the optical lens collimates the input light from one end of one of the two optical fibers, separates the input light into a transmitted light and a reflected light, guides the transmitted light to the first light-receiving surface, and guides the reflected light as output to the other of the two optical fibers; and

the light-receiving module outputs the electrical signal according to the power of the input light that is the input light from the optical transmission line via the input fiber and received at the first light-receiving surface.

8. The detection device according to claim 1 , wherein

the optical lens collimates the input light from the outside and separates this input light into a transmitted light and a reflected light by a branching membrane provided on the surface of the optical lens opposing the second light-receiving surface, and guides the transmitted light to the first light-receiving surface, and

the condenser is formed adjacent to the branching membrane.