Techniques are described for implementing an out-of-band communication channel used to exchange control channel information in sub-carrier-based optical communication systems. In an example implementation, an optical communication system includes a primary transceiver, a component, and secondary transceivers. The primary transceiver is operable to supply first optical subcarriers to an optical communication path, the first optical subcarriers being amplitude modulated at a first frequency to carry first control information and amplitude modulated at a second frequency to carry second control information. The component is operable to be coupled to the optical communication path and includes circuitry operable to detect the first control information. The secondary transceivers are coupled to a terminal end of the optical communication path. At least one of the secondary transceivers is operable to detect the second control information and block the first control information.

The present invention discloses a directional photonic coupler (1) with independent tuning of the coupling factor and phase difference. The coupler comprises: two waveguides (4, 5), with respective propagation constants “β.sub.1, β.sub.2”, on which phase shifters (6, 7) configured to modify the propagation coefficients are located. Both phase shifters are configured such that, by independent modification (differential or unique) of the propagation coefficients, the power coupling factor (K) between an input signal (2a or 2b) and the output signals (3b and 3a) is tuned, and by equal and simultaneous modification of the propagation coefficients, the common phase difference of the optical output signals (3 a, 3b) is tuned. A third phase shifter (15) can be used to retune the phase difference at the input/output of one of the waveguides. The coupler is of particular interest in PIC circuits, coupled resonators, Mach-Zehnder interferometers and mesh structures.

Described herein are hybrid IC assemblies that include multiple stacked layers of electronic and/or photonic circuit elements. For example, a first layer of the IC assembly includes a waveguide formed of a substantially monocrystalline material, and a second layer of the IC assembly includes at least one electronic circuit element. A bonding material between a front face of the first layer and a back face of the second layer attaches the first layer to the second layer. The bonding material has a lower crystallinity than the waveguide.

Embodiments of this application disclose an optical switch. The optical switch includes at least one first port, at least one second port, a first wavelength division multiplexing WDM apparatus, an optical splitter, an optical monitoring apparatus, and an optical switching apparatus. The first port is configured to transmit an input first optical signal to the first WDM apparatus, where the first optical signal is a multi-wavelength signal. The first WDM apparatus is configured to demultiplex the first optical signal. The optical splitter is configured to split a demultiplexed first optical signal to obtain a first sub-signal and a second sub-signal. The optical switching apparatus is configured to perform optical switching on the first sub-signal. The second port is configured to output a first sub-signal obtained after optical switching. The optical monitoring apparatus is configured to perform optical performance monitoring on the second sub-signal.

A thermally tunable waveguide including an optical waveguide and a heater is provided. The optical waveguide includes a phase shifter. The heater is disposed over the optical waveguide. The heater includes a heating portion, pad portions and tapered portions. The heating portion overlaps with the phase shifter of the optical waveguide. The pad portions are disposed aside of the heating portion. Each of the pad portions is connected to the heating portion through one of the tapered portions respectively.

A line-shaped heater and an optical resonator with portions on opposite sides of the line-shaped heater are provided. In particular a device provided herein includes: one or more inputs; one or more outputs; one or more optical waveguides configured to: receive an optical signal from at least one of the one or more inputs; and convey the optical signal to at least one of the one or more outputs; an optical resonator configured to modulate or filter the optical signal; and a heater configured to heat the optical resonator, the heater being line-shaped and having a first side and a second side opposite the first side, and the optical resonator comprising a first portion at the first side of the heater and a second portion at the second side of the heater.

An optical device has a first photonic waveguide provided on a substrate, a second photonic waveguide provided on the substrate and extending side by side with the first photonic waveguide, and a looped waveguide continuously connecting the first photonic waveguide and the second photonic waveguide on the substrate, wherein a width of at least one of the first photonic waveguide or the second photonic waveguide varies continuously along an optical axis, between a first position located at a side opposite to the looped waveguide and a second position connected to the looped waveguide, and wherein cross sections of the first photonic waveguide and the second photonic waveguide are congruent at the second position, and are incongruent at the first position.

A MEMs and/or NEMs measurement system includes a resonant assembly comprising: an input and an output, a plurality of N optical resonators Ri indexed i each having a resonance wavelength λr,i, at least one waveguide to which the optical resonators are coupled, at least one element coupled to each resonator Ri, an emission device, a modulation device, an injection device configured to superpose the N light beams to form an input beam and to inject the beam as input to the resonant assembly, at least one detector configured to detect a light beam arising from the beam at the output of the resonant assembly and to generate an output signal, a demodulation device comprising at least N synchronous-detection demodulation modules.

A silicon photonic integrated chip and a wavelength division multiplexer that includes at least two polarization control structures and at least one polarization-independent Mach-Zehnder interferometer on a silicon substrate are provided. The polarization control structure includes two input ports and one output port. The Mach-Zehnder interferometer includes two input ports and one optical signal output port for outputting a multiplexed optical signal. The output ports of the polarization control structures are connected to the input ports of the Mach-Zehnder interferometer. The polarization control structures have large bandwidths for increasing an optical bandwidth of the wavelength division multiplexer and reducing an optical loss. A quantity of phase shift arms that require tuning feedback is reduced to lower overall power consumption of the wavelength division multiplexer. Reliability and yields of the wavelength division multiplexer are enhanced due to a large manufacturing tolerance and good stability of the polarization control structures.

An integrated circuit includes an electronic circuit. The integrated circuit further includes a photonic device. The photonic device includes a first photodetector (PD) electrically connected to the electronic circuit. The photonic device further includes a second PD electrically connected to the electronic circuit. The photonic device further includes a first waveguide configured to receive an optical signal input, wherein the first waveguide is optically connected to the first PD. The photonic device further includes a second waveguide optically connected to the second PD. The photonic device further includes a resonant structure between the first waveguide and the second waveguide, wherein the resonant structure is configured to optically couple the first waveguide to the second waveguide.