An in-packaged multi-channel light engine is packaged for four or more sub-assemblies of optical-electrical sub-modules. Each is assembled with at least four laser chips, one or more driver chip, and one or more trans-impedance amplifier (TIA) chip separately flip-mounted on a silicon photonics interposer and is coupled to an optical interface block and an electrical interface block on a sub-module substrate. The in-packaged multi-channel light engine further includes a first frame fixture holding the four or more sub-assemblies and a second frame fixture configured to hold the first frame fixture with the four or more sub-assemblies. The in-packaged multi-channel light engine further includes an interposer plate inserted between the sub-module substrates and a module substrate and is compressed between a backplate member attached to a bottom side of the module substrate and a top plate member configured as a heatsink with a plurality of fin structures.

An on-chip interferometer and a spectrometer including the interferometer are provided. An on-chip interferometer includes a waveguide for propagation of an optical signal including an input waveguide; at least two interferometer arms having one or more slot waveguides; and an output waveguide; wherein the input waveguide is split into the at least two interferometer arms which are recombined into the output waveguide; and a control mechanism configured for controlling a relative time delay between optical signals propagating in the two interferometer arms by modifying one or more slot widths of one or more of the slot waveguides; and wherein the relative time delay is at least 1, 2, 5, or at least 10 fs or at least one optical period of the longest optical wavelength of the optical signal.

There is described a resonant interferometric coupler generally having: a substrate; a bus waveguide having in serial connection an input section, a bent section and an output section; a first resonator having a first evanescent coupling point with the input section and a second evanescent coupling point with the output section, the first resonator having first resonances; an interferometer having a first arm path extending along the bent section between the first and second evanescent coupling points, and a second arm path extending along the first resonator between the first and second evanescent coupling points; and a second resonator having a third evanescent coupling point with the bent section, the second resonator having a second resonance overlapping with one of the first resonances and across which a first phase shift is imparted, thereby causing interference at the second evanescent coupling point.

This application provides an example light source switching apparatus. The apparatus includes first and second multi-mode interference (MMI) couplers, and a phase modulator. The first MMI coupler includes four ports, where first and second ports are located on one side, and third and fourth ports are located on the other side. The second MMI coupler includes three ports, where fifth and sixth ports are located on one side, and a seventh port is located on the other side. The first and the second ports connect to the fifth and the sixth ports, respectively, to form two connections. The phase modulator is disposed on one of the two connections, and the seventh port connects to an optical modulator. Both the third and the fourth ports connect to a light source emitting continuous light, and the phase modulator selects one of the two light sources for output from the seventh port.

A radio frequency generator has first and second lasers configured to emit first and second optical outputs; a reference module configured to receive at least part of the first and second optical outputs from the first and second lasers; a control module connected to the first and second lasers and to the reference module; and an optical-to-electrical (O/E) converter configured to process optical signals, originating from the first and second single-frequency lasers, to provide a radio frequency output.

Another radio frequency generator has a control module; and a reference module connected to the control module. The reference module includes a photonic integrated circuit (PIC) having first and second single-frequency lasers configured to emit first and second optical outputs; an unbalanced Mach-Zehnder interferometer (UMZI) with first and second 3×3 optical splitter/combiners; first and second peripheral splitter/combiners; and an output splitter/combiner.

A signal generator includes a photonic circuit configured to output a sequence of solitons at a known rate. The solitons illuminate a high-speed photodiode that, in response, generates an electrical signal, such as a sinusoidal signal, which can be provided as input to a direct digital synthesizer configured to output successive phases of a selected waveform in response to electrical stimulus.

Optical circuits support reconfigurable spatial rearrangement (also referred to as “spatial multiplexing”) for a group of photons propagating in waveguides. According to some embodiments, a set of 2×2 muxes can be used to rearrange a pattern of photons on a first set of waveguides into a usable input pattern for a downstream optical circuit.

An expanded Bell state generator can generate a Bell state on four output modes of a set of m output modes, where m is greater than four. Some expanded Bell state generators can receive inputs on any four of a set of 2m input modes. Subsets of the m output modes can be multiplexed to reduce the number of modes to four. According to some embodiments, a set of 2×2 muxes can be used to rearrange the output modes prior to reducing the number of modes.

A photonic chip has at least one input waveguide, at least one output waveguide, one of at least one Mach-Zehnder interferometer and at least one resonator, and a one-sided optical port enabling in and out coupling of light where the input waveguide begins and the output waveguide ends.

Various polarization rotator splitter (PRS) configurations are disclosed. In an example embodiment, a system includes a PRS that includes a silicon nitride (SiN) rib waveguide core that includes a rib and a ridge that extends vertically above the rib, the SiN rib waveguide core having a total height h.sub.SiN from a bottom of the rib to a top of the ridge, a rib height h.sub.rib from the bottom of the rib to a top of the rib, a rib width w.sub.rib, and a top width w.sub.SiN of the ridge. The rib width w.sub.rib varies along at least a portion of a length of the SiN rib waveguide core.