Wavelength-tuning optical filters are presented that also allows for the tuning or real-time adjustment of its bandwidth, or passband width. The bandwidth-adjustable tunable optical filters use one or more diffraction gratings that are fixed in place to provide angular dispersion of different wavelengths. A first rotatable or tilting mirror is used to adjust the angle of incidence of an input optical beam to the diffraction grating or diffraction grating system, while a second rotatable or tilting mirror is used to aim the diffracted optical beam back through the diffraction grating or diffraction grating system, so that a subset of the incoming wavelengths are optically aligned to the end face of an output fiber. The first rotatable or tilting mirror provides tuning or adjustment of the bandwidth or passband width of the tunable optical filter, while the second rotatable or tilting mirror tunes or adjusts the center wavelength of the passband.

Wavelength division multiplexing (WDM) has enabled telecommunication service providers to fully exploit the transmission capacity of optical fibers. State of the art systems in long-haul networks now have aggregated capacities of terabits per second. Moreover, by providing multiple independent multi-gigabit channels, WDM technologies offer service providers with a straight forward way to build networks and expand networks to support multiple clients with different requirements. In order to reduce costs, enhance network flexibility, reduce spares, and provide re-configurability many service providers have migrated away from fixed wavelength transmitters, receivers, and transceivers, to wavelength tunable transmitters, receivers, and transceivers as well as wavelength dependent add-drop multiplexer, space switches etc. However, to meet the competing demands for improved performance, increased integration, reduced footprint, reduced power consumption, increased flexibility, re-configurability, and lower cost it is desirable to exploit/adopt monolithic optical circuit technologies, hybrid optoelectronic integration, and microelectromechanical systems (MEMS).

A liquid crystal on silicon, a wavelength selective switch, an alignment direction obtaining method, and a method for manufacturing a liquid crystal on silicon. The liquid crystal on silicon has a first pixel area, and a first liquid crystal located in the first pixel area. The first liquid crystal is deflected in a plane perpendicular to a first panel, and is deflected towards a first direction in a plane parallel to the first panel. An alignment direction of the first partial alignment film located in the first pixel area is deflected towards a second direction relative to a polarization direction of an incident beam, and the second direction is opposite to the first direction to reduce a loss of a deflected beam.

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 liquid crystal on silicon, a wavelength selective switch, an alignment direction obtaining method, and a method for manufacturing a liquid crystal on silicon. The liquid crystal on silicon has a first pixel area, and a first liquid crystal located in the first pixel area. The first liquid crystal is deflected in a plane perpendicular to a first panel, and is deflected towards a first direction in a plane parallel to the first panel. An alignment direction of the first partial alignment film located in the first pixel area is deflected towards a second direction relative to a polarization direction of an incident beam, and the second direction is opposite to the first direction to reduce a loss of a deflected beam.

Optical systems and processes for calibrating and focusing optical systems are described. One embodiment of the invention includes an optical phase array (OPA) and an OPA controller that generates control signals to control phase shifters in the OPA. The OPA controller can calibrate the OPA by performing a plurality of phase sweeps using each of a plurality of different basis masks. Each phase sweep can involve performing a phase sweep across a phase sweep range at a plurality of phase step increments with respect to a first group of phase shifters identified in a basis mask. During the phase sweep, a calibration signal can be measured at each of the plurality of phase step increments and the measurements used to generate calibration phase state information. The calibration phase state information can be utilized to perform functions including (but not limited to) beamforming, focusing, and/or other waveform manipulation and control functions.

Wavelength division multiplexing (WDM) has enabled telecommunication service providers to fully exploit the transmission capacity of optical fibers. State of the art systems in long-haul networks now have aggregated capacities of terabits per second. Moreover, by providing multiple independent multi-gigabit channels, WDM technologies offer service providers with a straight forward way to build networks and expand networks to support multiple clients with different requirements. In order to reduce costs, enhance network flexibility, reduce spares, and provide re-configurability many service providers have migrated away from fixed wavelength transmitters, receivers, and transceivers, to wavelength tunable transmitters, receivers, and transceivers as well as wavelength dependent add-drop multiplexer, space switches etc. However, to meet the competing demands for improved performance, increased integration, reduced footprint, reduced power consumption, increased flexibility, re-configurability, and lower cost it is desirable to exploit/adopt monolithic optical circuit technologies, hybrid optoelectronic integration, and microelectromechanical systems (MEMS).

An optical filter includes a spectroscopic element configured to disperse input light, and emit the dispersed input light as spectrum light; and an optical fiber including an end face having a recess, a core having a first face in contact with a bottom of the recess and a second face sandwiched between the first face and a circumference end of the recess, and a clad surrounding the core, wherein in the optical fiber, the recess is irradiated with the spectrum light, the second face is inclined such that a second portion incident from the second face to the core out of the irradiated spectrum light is emitted to the clad, and a first portion incident from the first face to the core out of the irradiated spectrum light is outputted.

This invention provides a novel wavelength-separating-routing (WSR) apparatus that uses a diffraction grating to separate a multi-wavelength optical signal by wavelength into multiple spectral channels, which are then focused onto an array of corresponding channel micromirrors. The channel micromirrors are individually controllable and continuously pivotable to reflect the spectral channels into selected output ports. As such, the inventive WSR apparatus is capable of routing the spectral channels on a channel-by-channel basis and coupling any spectral channel into any one of the output ports. The WSR apparatus of the present invention may be further equipped with servo-control and spectral power-management capabilities, thereby maintaining the coupling efficiencies of the spectral channels into the output ports at desired values. The WSR apparatus of the present invention can be used to construct a novel class of dynamically reconfigurable optical add-drop multiplexers (OADMs) for WDM optical networking applications.

This invention provides a novel wavelength-separating-routing (WSR) apparatus that uses a diffraction grating to separate a multi-wavelength optical signal by wavelength into multiple spectral characters, which are then focused onto an array of corresponding channel micromirrors. The channel micromirrors are individually controllable and continuously pivotable to reflect the spectral channels into selected output ports. As such, the inventive WSR apparatus is capable of routing the spectral channels on a channel-by-channel basis and coupling any spectral channel into any one of the output ports. The WSR apparatus of the present invention may be further equipped with servo-control and spectral power-management capabilities, thereby maintaining the coupling efficiencies of the spectral channels into the output ports at desired values. The WSR apparatus of the present invention can be used to construct a novel class of dynamically reconfigurable optical add-drop multiplexers (OADMs) for WDM optical networking applications.