Tunable filtering device for optical communications

DETAILED DESCRIPTION To solve the above problems, it is an objective of the present invention to provide a tunable filtering device for optical communications, which has a simple configuration and an enhanced optical transmission efficiency.
Accordingly, to achieve the above objective, there is provided a tunable filtering device comprising a base; first and second optical fibers installed on the base aligned and facing each other; a tunable filter installed on the optical path between the first and second optical fibers, for transmitting only a beam of a specific wavelength from the beam emitted from the first optical fiber toward the second optical fiber; an actuator driving the tunable filter; a beam splitter installed on the optical path between the tunable filter and the second optical fiber, for reflecting a portion of the beam transmitted through the tunable filter and transmitting the rest; an auxiliary optical fiber installed on the base, for receiving a beam reflected from the beam splitter for further transmission; and a controller detecting the beam transmitted through the auxiliary optical fiber and controlling the actuator according to the detected beam.
Here, the tunable filter is preferably a line filter to selectively transmit a beam of a specific wavelength according to the angle of the tunable filter with respect to an incident beam.
In this case, the actuator includes a DC servo-motor to rotate the tunable filter according to a signal from the controller, and an encoder detecting the angle of the tunable filter by measuring the rotational position of the DC servo-motor.
Further, the first and second optical fibers and the auxiliary optical fiber are preferably each installed in a groove formed in the base.
According to another embodiment of the present invention, the tunable filter is a gradient line filter installed at a constant angle to an incident beam for selectively transmitting a beam of a specific wavelength according to the horizontal and/or vertical position