An optical apparatus includes a waveguide-based frequency-selective structure with one or more input ports and N1 output ports where N1 is 2 or more. If input signals in a pair of input signals are separated in frequency by an integer multiple of the structure's free spectral range, and one of the pair is routed onto one output port, the other in the pair is also routed onto that port. The apparatus also includes: N2 waveguides, where N2<=N1, each having an input port coupled to a corresponding one of the N1 output ports, and a waveguide output port; N3 frequency-selective elements where N3<=N2, each having an input port coupled to a corresponding one of the N2 waveguide output ports and an output surface from which optical emission occurs at an optical frequency-dependent angle; and an element receiving optical emission from the N3 output surfaces, detecting a corresponding intensity pattern.

A device for performing unitary matrix computations comprises a light source configured to generate first optical signals; an array of waveguides, including: inputs that receive the first optical signals from the light source; a plurality of channels positioned in parallel for transmitting the first optical signals along a length of the waveguides; and outputs for outputting second optical signals generated according to a matrix multiplication operation from the first optical signals. The device further comprises phase shifters constructed and arranged in a cascade structure at the channels of the waveguides, the waveguides include sections or directional couplers between adjacent phase shifter. The matrix multiplication operation includes coupling coefficient values between adjacent waveguides and length values of the sections of the waveguides. General non-unitary matrix computations are implemented by interlacing two embodiments of the device together with an array of amplitude modulators.

A multi-path interference filter. The multi-path interference filter includes a first port waveguide, a second port waveguide, and an optical structure connecting the first port waveguide and the second port waveguide. The optical structure has a first optical path from the first port waveguide to the second port waveguide, and a second optical path, different from the first optical path, from the first port waveguide to the second port waveguide. The first optical path has a portion, having a first length, within hydrogenated amorphous silicon. The second optical path has a portion, having a second length, within crystalline silicon, and the second optical path has either no portion within hydrogenated amorphous silicon, or a portion, having a third length, within hydrogenated amorphous silicon, the third length being less than the first length.

A densely-spaced wavelength division multiplexing (DWDM) transceiver utilizes a comb laser source to provide a multi-channel system capable of supporting at least twenty separate channels. The optical transmitter portion of the transceiver utilizes a double-pass (e.g., reflective) modulator configuration. The double-pass arrangement allows for a single grating (or other suitable dispersive element) to be used as a demultiplexer in combination with the comb laser source to separate the input optical beams into individual wavelength components, as well as a multiplexer for combining the plurality of separate modulated optical signals into a single, multi-channel DWDM optical output signal. The optical receiver portion of the transceiver includes a grating element to direct the multi-channel received optical signal into separate, wavelength-based channels, with the signal propagating along each channel directed into a separate photodiode.

A multi-beam optical phased array on a single planar waveguide layer or a small number of planar waveguide layers enables building an optical sensor that performs much like a significantly larger telescope. Imaging systems use planar waveguides created using micro-lithographic techniques. These imagers are variants of phased arrays, common and familiar from microwave radar applications. However, there are significant differences when these same concepts are applied to visible and infrared light.

A method of forming an emitting array of waveguides, comprising providing a plurality of waveguides that exhibit different propagation constants so as to ensure that nearby waveguides do not couple evenly over parallel propagation lengths by varying a length in one or more dimensions of respective waveguides, whereby the respective waveguides are phasemismatched with at least their nearest neighbor.

An optical apparatus includes a waveguide-based frequency-selective structure with one or more input ports and N1 output ports where N1 is 2 or more. If input signals in a pair of input signals are separated in frequency by an integer multiple of the structure's free spectral range, and one of the pair is routed onto one output port, the other in the pair is also routed onto that port. The apparatus also includes: N2 waveguides, where N2<=N1, each having an input port coupled to a corresponding one of the N1 output ports, and a waveguide output port; N3 frequency-selective elements where N3<=N2, each having an input port coupled to a corresponding one of the N2 waveguide output ports and an output surface from which optical emission occurs at an optical frequency-dependent angle; and an element receiving optical emission from the N3 output surfaces, detecting a corresponding intensity pattern.

A multi-path interference filter. The multi-path interference filter includes a first port waveguide, a second port waveguide, and an optical structure connecting the first port waveguide and the second port waveguide. The optical structure has a first optical path from the first port waveguide to the second port waveguide, and a second optical path, different from the first optical path, from the first port waveguide to the second port waveguide. The first optical path has a portion, having a first length, within hydrogenated amorphous silicon. The second optical path has a portion, having a second length, within crystalline silicon, and the second optical path has either no portion within hydrogenated amorphous silicon, or a portion, having a third length, within hydrogenated amorphous silicon, the third length being less than the first length.

The application discloses a polymer-based optical splitter on a silicon surface. A trench is formed on the silicon surface and a polymer waveguide having three 45 degree reflectors is patterned in the trench. The trench has two slanted side walls opposite to each other. Two reflectors of the polymer waveguide are arranged on the two slanted side walls. An intrusion structure with a slanted front wall is located in the middle of the waveguide and the third reflector is formed on the slanted front wall. The first reflector receives an optical input source, the second reflector is aligned to return light to the end optical receiver. The third reflector functions as a light splitter and is aligned to an intermediate optical receiver. Light splitting ratio is determined by the third reflector size relative to the waveguide cross section near the third reflector. A fabrication method is disclosed thereof.

The present disclosure is generally directed to an optical transceiver that includes a multi-channel on-board ROSA arrangement that includes an optical demultiplexer, e.g., an arrayed waveguide grating (AWG) and an array of photodiodes disposed on a same substrate. The array of photodiodes may be optically aligned with an output port of the optical demultiplexer and be configured to detect channel wavelengths and output a proportional electrical signal to an amplification circuit, e.g., a transimpedance amplifier. Each of the photodiodes can include an integrated lens configured to increase the alignment tolerance between the demultiplexer and the light sensitive region such that relatively imprecise bonding techniques, e.g., die bonding, may be utilized while still maintaining nominal optical power.