An apparatus internal unit disposed inside a casing includes a fixed unit coupled to an opening portion forming member, a movable unit that is a unit including an incident light processing portion and is configured to be displaced with respect to the fixed unit in a first direction along an optical axis, and at least one elastic member that holds a position of the movable unit in the first direction with respect to the fixed unit by elasticity.

A tunable filter that may include a pair of optical components, wherein there is an optical gap between the pair of optical components; and a pair of actuating elements that are configured, once supplied with at least one actuating signal, to be positioned at an actuation gap from each other and to define the optical gap; and wherein the optical gap is substantially smaller than the actuation gap.

An optical filter device includes: a Fabry-Perot interference filter that includes: a first structural body having first and second surfaces; a second structural body having a third surface; a first mirror portion provided to the first structural body; a second mirror portion provided to the second structural body so as to face the first mirror portion via an air gap; a first driving electrode provided to the first structural body; a second driving electrode provided to the second structural body; first and third terminals electrically connected to the first driving electrode; and a second terminal electrically connected to the second driving electrode. A distance between the first driving electrode and the air gap is shorter than a distance between the second surface and the air gap. A resistance measurement unit is electrically connected to the first and third terminals and measures a resistance value of the first driving electrode.

A suction method is provided as a method of performing, by using a suction collet, suction of a Fabry-Perot interference filter including: a substrate; a laminated structure that is provided on the substrate and that includes a main surface facing a side opposite to the substrate; and a thinned portion that is located outside the laminated structure when viewed in a direction intersecting the main surface and that is recessed to a side of the substrate with respect to the main surface, the method including: a first step of arranging the suction collet so as to face the main surface; a second step of bringing the suction collet into contact with the Fabry-Perot interference filter after the first step; and a third step of suctioning the Fabry-Perot interference filter by using the suction collet after the second step.

A suction method is provided as a method of performing, by using a suction collet, suction of a Fabry-Perot interference filter including a substrate and a laminated structure that is provided on the substrate and that includes a main surface facing the side opposite to the substrate, the method including a first step of arranging the suction collet so as to face the main surface, a second step of bringing the suction collet into contact with the Fabry-Perot interference filter after the first step, and a third step of suctioning the Fabry-Perot interference filter by using the suction collet after the second step.

High-power light absorbers (HPLAs) can exhibit low back-scattered light, mitigate stray light, and withstand high optical power. The absorbers can be used with or without baffling as beam dumps for high-power lasers. An HPLA may include a substrate made of high thermally conductive material with an anti-reflection (AR) coating formed on the substrate. A thin layer of highly absorbing material may be located between the AR coating and substrate. The substrate can be cooled with a fluid, such as water or air.

Provided is a control device for controlling a Fabry-Perot interference filter having a pair of mirror parts and a pair of driving electrodes. The control device includes: a first driving source that is controlled by using a current as a control parameter, and changes the distance between the pair of mirror parts; a second driving source that is controlled by using a voltage as a control parameter, and changes the distance; and a control unit that controls the first driving source and the second driving source in such a way that the distance is changed by a first driving source in a first region and the distance is changed by the second driving source in at least one part of an region other than the first region when an region including a maximum of the voltage is defined as the first region.

A tunable notch filter for operation in reflection mode comprises an antenna layer positioned on a transmissive substrate and a mirror layer positioned on a support substrate. The antenna layer and the mirror layer are positioned on opposite sides of a gap and facing each other, the gap having a gap distance. The notch filter is tuned by adjusting the gap distance between the antenna layer and the mirror layer. Tuning the notch filter to a selected state can cause the filter to selectively attenuate the reflection of at least some electromagnetic radiation that is incident on the transmissive substrate and enters the notch filter.

An optical filter may comprise a first pair of mirrors, a second pair of mirrors, and a common spacer. The second pair of mirrors and the first pair of mirrors may reflect different portions of an electromagnetic spectrum. The common spacer may be positioned between the first pair of mirrors and between the second pair of mirrors.

Provided is a subminiature wavelength tunable liquid crystal etalon filter capable of minimizing damage during manufacturing, a light source and an optical transceiver including the same. According to one aspect of the present embodiment, a wavelength tunable liquid crystal etalon filter capable of minimizing damage that may be applied to a seal line during a curing process and a light source and an optical transceiver including the same are provided.