Variable optic attenuator

A variable optic attenuator comprising:

• a chassis defining a channel extending in a first direction;
• an attenuating device movably received in the channel, the attenuating device comprising a filter having a density varying from a low density region to a high density region in a filter moving direction that is substantially parallel to the first direction;
• a driving unit mechanically coupled to the attenuating device for reciprocally moving the filter in the filter moving direction;
• a mount attached to the chassis, the mount forming first and second primary bores extending parallel to the first direction and located on opposite sides of the channel, and a passage extending across the channel in a second direction perpendicular to the first direction and intersecting the first and second primary bores, the mount forming first and second flat surfaces at the intersection of the passage with the first and second primary bores, the surfaces being 45 degree inclined with respect to the first direction and perpendicular to each other, first and second reflectors being attached to the first and second flat surfaces of the mount;
• wherein the filter is located in the passage and thus between the reflectors, the movement of the filter by the driving unit bring different regions of the filter to the passage;
• and
• wherein the first and second bores primary are adapted to receive and retain ends of input optic fiber and output optic fiber, an optic signal transmitted through the input optic fiber is incident to the first reflector through the first primary bore and is then reflect to pass through filter along the passage toward the second reflector which reflects the signal to the output optic fiber through the second primary bore thereby forming a U-shaped optic path between the input and output optic fibers.