Abstract: Devices and methods for equalizing the gain of an optical amplifier are described. For devices including harmonic filters that are controllable by amplitude control voltages and phase control voltages, techniques for controlling the amplitude control voltages and phase control voltages are presented. Additionally, device architectures are described by which an incoming optical signal is equalized to compensate for uneven gain in prior amplifiers or other optical components, and in which the incoming optical signal is received at a beam displacer and separated into orthogonal component beams, wherein the beams are counter-propagated through the equalizer in opposite directions through the same spatial path so as to minimize or eliminate the effects spatially dependent imperfections in the equalizer.

Abstract: An optical processing device includes a polarization modulator operable to change a polarization state of an input optical signal based at least in part on a control voltage applied to a liquid crystal material associated with the polarization modulator. The control voltage is based at least in part on a temperature of the liquid crystal material.

Abstract: An optical device for demultiplexing an optical signal comprises a grating that receives an optical signal comprising a plurality of wavelength channels, and generates a plurality of spatially separated light beams. Each light beam is associated with a particular wavelength channel. The optical device further comprises an optical element that at least partially compensates a temperature based frequency shift associated with the spatially separated light beams. The optical device further comprises a plurality of lenses and a plurality of fibers. The plurality of lenses are arranged such that a spacing between at least a pair of lenses is determined to at least partially compensate a non-linearity introduced by the grating. Each fiber is associated with a corresponding lens and receives a corresponding light beam. At least one fiber is placed a distance that is less than a focal length associated with its corresponding lens.

Abstract: A wavelength division multiplexing/demultiplexing device is presented utilizing a polarization-based filter to separate odd and even wavelengths, or upper and lower channels of an input optical signal. The wavelength filter first converts the input signal to a predetermined polarization. A series of birefringent waveplates provide a polarization-dependent optical transmission function such that the polarized beam is decomposed into a first beam component carrying the first spectral band at a first polarization and a second beam component carrying the second spectral band at a second, orthogonal polarization. A beam displacer spatially separates the beam components into a pair of orthogonally-polarized beams. A quarter-wave plate converts these orthogonally-polarized beams into a pair of circularly-polarized beams, which are reflected by a mirror back along parallel optical paths through the quarter-wave plate, beam displacer, and waveplates.

Abstract: An optical wavelength router separates an input signal into two complementary output signals. A beamsplitter of the wavelength router separates the input signal into a first beam and a second beam. A first resonator reflects the first beam producing a group delay that is dependent on wavelength. Similarly, a second resonator reflects the second beam. The center wavelength of the second resonator is offset relative to that of the first resonator by one half of the free spectral range of the first resonator, so that the resonance frequencies of the second resonator are matched to the anti-resonance frequencies of the first resonator. The beams reflected by the resonators interfere within the beamsplitter to produce two output signals containing complementary subsets of the spectrum of the input signal (e.g., even optical channels are routed to a first output port and the odd optical channels are routed to a second output port).