Optical module
An optical module according to one embodiment includes: a beam splitter having a first surface, a second surface facing the first surface, a third surface intersecting with the first surface, a fourth surface facing the third surface, and an inner surface formed within a region defined by the first surface, the second surface, the third surface, and the fourth surface; and a light receiving unit arranged at a position facing the third surface of the beam splitter. The beam splitter splits first incident light incident from the first surface into first split light transmitted through the inner surface and emitted from the second surface and second split light reflected on the inner surface and emitted from the third surface. The optical module includes a light absorbing/reflecting unit provided on the fourth surface.
1 . An optical module comprising:
a beam splitter having a first surface, a second surface facing the first surface, a third surface intersecting with the first surface, a fourth surface facing the third surface, and an inner surface formed within a region defined by the first surface, the second surface, the third surface, and the fourth surface; and
a light receiving unit arranged at a position facing the third surface of the beam splitter,
wherein the beam splitter splits first incident light incident from the first surface into first split light transmitted through the inner surface and emitted from the second surface and second split light reflected on the inner surface and emitted from the third surface, and
wherein the optical module comprises a light absorbing/reflecting unit, and the fourth surface is coated with the light absorbing/reflecting unit.
2 . The optical module according to claim 1 ,
wherein the light absorbing/reflecting unit is coated with a light absorbing film or a light reflecting film.
3 . The optical module according to claim 1 , further comprising an optical modulation element,
wherein the optical modulation element is input with continuous light to an input port, and the first incident light is output from an output port as modulated signal light.
4 . The optical module according to claim 3 ,
wherein the light absorbing/reflecting unit absorbs or reflects the continuous light.
5 . The optical module according to claim 3 , further comprising another beam splitter having a fifth surface, a sixth surface facing the fifth surface, a seventh surface intersecting with the fifth surface, an eighth surface facing the seventh surface, and an inner surface formed within a region defined by the fifth surface, the sixth surface, the seventh surface, and the eighth surface,
wherein the other beam splitter is connected to the fourth surface of the beam splitter via the light absorbing/reflecting unit at the eighth surface and splits the second incident light incident from the fifth surface into third split light transmitted through the inner surface and emitted from the sixth surface and fourth split light reflected on the inner surface and emitted from the seventh surface.
6 . An optical module comprising:
an optical modulation element having an input port input with continuous light and an output port outputting modulated signal light;
a beam splitter having a first surface, a second surface facing the first surface, a third surface intersecting with the first surface, a fourth surface facing the third surface, and an inner surface formed within a region defined by the first surface, the second surface, the third surface, and the fourth surface and splitting the modulated signal light incident from the first surface into first split light transmitted through the inner surface and emitted from the second surface and second split light reflected on the inner surface and emitted from the third surface;
a light receiving unit arranged at a position facing the third surface of the beam splitter and receiving the second split light; and
a light absorbing/reflecting unit absorbing or reflecting the continuous light, wherein the fourth surface is coated with the light absorbing/reflecting unit.
7 . The optical module according to claim 1 ,
wherein a light transmittance of the light absorbing/reflecting unit is less than 0.1%, and a light reflectance of the light absorbing/reflecting unit is less than 2%.