Abstract: Provided is a variable optical attenuator, including a pigtail, a spacer, a lens and a cap. The pigtail has a first waveguide and a second waveguide. The first waveguide transmits incident light, and the second waveguide receives the returned light. The pigtail is attached to one side of the space, and the lens is attached to another side of the space. Moreover, the cap includes a hollow portion, a first connecting portion and a second connecting portion. The lens is placed inside the hollow portion, and the space is connected to the first connecting portion of the cap.

Abstract: Provided is a variable optical attenuator, including a pigtail, a spacer, a lens and a cap. The pigtail has a first waveguide and a second waveguide. The first waveguide transmits incident light, and the second waveguide receives the returned light. The pigtail is attached to one side of the space, and the lens is attached to another side of the space. Moreover, the cap includes a hollow portion, a first connecting portion and a second connecting portion. The lens is placed inside the hollow portion, and the space is connected to the first connecting portion of the cap.

Abstract: A variable optical attenuator with wavelength-dependent loss compensation is provided, including: an optical fiber pigtail comprising at least a first waveguide and a second waveguide; a lens being disposed between the optical fiber pigtail and a reflector for focusing an emitted light from the first waveguide and returning a reflected light from the reflector to the second waveguide of the optical fiber pigtail; and the reflector being disposed at the focus of the lens to reflect the emitted light from the first waveguide passing the lens, and the reflected light passing through the lens to return to the second waveguide, the reflector having an initial position with a normal forming a pre-tilt angle with the axis of lens in the incident plane defined by the two axes, and the reflector tilting towards a larger tilt angle when an attenuation value increasing.