Abstract: Arrayed waveguide grating (AWG) circuits are disclosed, having different radii in the slab regions to supplement and/or replace other mechanical techniques which enable athermal AWGs. Dual band, interleaved pairs of athermal AWGs are also disclosed, with improved cost, space and center wavelength properties, for, e.g., optical line terminal (OLT), and remote node (RN) applications.

Abstract: A transform spectrometer measurement apparatus and method for a planar waveguide circuit (PLC). The spectrometer typically includes an input optical signal waveguide carrying an input optical signal; a plurality of couplers, each connected to the input optical signal waveguide, and each including a coupler output for carrying a coupled optical signal related to the input optical signal; and an array of interleaved, waveguide Mach-Zehnder interferometers (MZI), each having at least one input MZI waveguide, each MZI input waveguide receiving a coupled optical signal from a respective coupler output. A phase shifting circuit is applied to at least one arm of the MZIs to induce an active phase shift on the arm to thereby measure phase error in the MZIs. Light output from the MZIs is measured under intrinsic phase error conditions and after an active phase shift by the phase shifting circuit.

Abstract: A transform spectrometer implemented on a planar waveguide circuit (PLC), having an input optical signal waveguide carrying an input optical signal to be analyzed; a plurality of couplers, each connected to the input optical signal waveguide, and each including a coupler output for carrying a coupled optical signal related to the input optical signal. An array of interleaved, asymmetrical waveguide Mach-Zehnder interferometers (MZI) is formed on the PLC, each having at least one input MZI waveguide, each MZI input waveguide receiving a coupled optical signal from a respective coupler output; wherein at least some of the input MZI waveguides intersect in a common layer of the PLC, at an angle which allows their respective coupled optical signals to transmit without unacceptable attenuation. This arrangement improves spatial efficiency of the PLC, allowing more MZIs to be implemented, resulting in increased spectral resolution.

Abstract: A technique for monitoring optical power in a fiber array unit having a plurality of optical transmission waveguides terminating at an edge thereof for carrying optical signals to and/or from a PLC. A tapping filter is placed within a slit formed in the substrate and interrupting the transmission channels, thereby tapping at least some of the optical power from the channels and directing the tapped optical power toward respective photodetector channels for detection, while allowing other optical power to continue transmission in the at least one channel of the fiber array unit.

Abstract: A fiber array unit (FAU) having plurality of optical transmission channels (e.g., fiber optics) terminating at a side surface thereof for carrying optical signals to and/or from waveguides in a planar lightwave circuit (PLC). The optical transmission channels of the FAU terminate at the side surface thereof in a non-linear, cross-sectional pattern (e.g., a curved pattern). The non-linear pattern is determined by a pattern of grooves formed in a substrate of the FAU, in combination with a lid which may also have an inverse, non-linear pattern, to thereby rigidly, reliably and permanently hold the optical transmission channels in place.

Abstract: A funnel-type planar lightwave circuit (PLC) optical splitter having an input optical waveguide, a slab waveguide receiving the input optical signal from the input optical waveguide, and output waveguides projecting from the slab region. The region connecting the slab waveguide to the output waveguides is characterized by a segmented taper structure. In another additional, or alternative aspect of the present invention, a cladding mode absorption region runs along either or both sides of the input optical waveguide. A funnel-type splitter with both a cladding mode absorption region and a segmented taper structure provides a “super” low loss splitter design, when considering both insertion loss and polarization dependent loss. Advantageously, the disclosed funnel-type PLC splitter does not require a quartz substrate due to its very low PDL, and a silicon substrate can be used. Silicon substrates are known to be lower cost, with a higher resistance to fracture.