A method and a controller for operating an array of variable optical retarders are disclosed. Neighboring pixels of the array of variable optical retarders are driven with disordered temporal bit sequences. An optical beam illuminating the pixels tends to integrate time-domain modulation caused by individual pixels driven in a non-coordinated or disordered fashion, which reduces the overall time-domain modulation amplitude of the optical beam.

An integrated optical device is mounted with two optical fibers that transmit a light and, as functional components in a space of a housing forming an optical path from one of the optical fibers to the other light, is provided with an optical power attenuator that attenuates, using vignetting, a light incident from the one optical fiber or a light emitted from the other optical fiber and a tunable filter that selects a light of a predetermined wavelength from among the light incident from the one optical fiber and emits this selected light from the other optical fiber.

An apparatus comprising at least: a first waveguide; a second waveguide; and a diffractive element. The first waveguide guides a first band of onto the diffractive element such that the first band is diffracted at an m.sup.th non-zero order over a first range of angles. The second waveguide guides a second band onto the diffractive element such that the second band is diffracted at the m.sup.th non-zero over the first range of angles. The second waveguide guides a third band onto the diffractive element such that the third band is diffracted at the n.sup.th non-zero order over the first range of angles. Wavelengths of the first band, the second band, and the third band do not overlap with each other. The m.sup.th order and the n.sup.th order are different from each other.

A wavelength division multiplexer is disclosed. The wavelength division multiplexer may include an input waveguide, in which a plurality of Bragg gratings for separating multiplexed optical signals into respective optical signals are provided, and a plurality of output waveguides connected to the input waveguide and configured to receive the optical signals separated by the plurality of Bragg gratings. The plurality of Bragg gratings may include a first Bragg grating including first protrusions each having a first width, and a second Bragg grating including second protrusions each having a second width larger than the first width. Each of the first and second protrusions may include a curved side surface, to which a corresponding one of the optical signals is incident.

A tunable optical device uses a diffraction grating to angularly disperse a collimated beam carrying multiple wavelengths into multiple individually collimated wavelength beams, and then refocuses each of the individual collimated beams to its own focusing point on a moving plate that is located in the region of the focus plane. One or more reflective dots on the moving plate then selectively reflect particular wavelength(s) back to a first output port. The unselected wavelengths are transmitted through the moving plate, where they are then recombined and sent to a second output port. In a typical optical network architecture, the selected wavelength(s) could be viewed as the dropped traffic at a node of the optical network, while the unselected wavelengths could be viewed as the express traffic that is being passed to another node of the network. The device can also be used as a wavelength or beam combiner as well as a splitter.

A tunable optical filter utilizes a pair of diffraction gratings and a rotating mirror to achieve a broad filter passband or wavelength bandwidth. By adjusting a small angle between the two diffraction gratings, such as less than approximately 15 degrees, the wavelength bandwidth of the tunable optical filter's passband may be arbitrarily adjusted or set. The two-grating system results in a narrower angular dispersion coefficient than could be achieved through the use of a single grating with similar properties. The narrower angular dispersion in turn results in a broader filter passband or wavelength bandwidth.

A method and a controller for operating an array of variable optical retarders are disclosed. Neighboring pixels of the array of variable optical retarders are driven with disordered temporal bit sequences. An optical beam illuminating the pixels tends to integrate time-domain modulation caused by individual pixels driven in a non-coordinated or disordered fashion, which reduces the overall time-domain modulation amplitude of the optical beam.

A method and a controller for operating an array of variable optical retarders are disclosed. Neighboring pixels of the array of variable optical retarders are driven with disordered temporal bit sequences. An optical beam illuminating the pixels tends to integrate time-domain modulation caused by individual pixels driven in a non-coordinated or disordered fashion, which reduces the overall time-domain modulation amplitude of the optical beam.

An end-capped optical fiber includes: an optical fiber including a first portion comprising a first core and a first cladding surrounding the first core, and a second portion comprising a second core and a second cladding surrounding the second core; and an end cap comprising a first face connected to an end face of the second portion and a second face located on a side opposite the first face, wherein: a diameter of the first core is constant along an optical axis of the first core; a diameter of the second core gradually increases toward the end cap; the end cap includes a convex lens; the second surface includes a convex lens surface of the convex lens; and a focal point of the convex lens is located inside the optical fiber and away from the end face of the second portion.