In an example, an Echelle grating wavelength division multiplexing (WDM) device includes a first waveguide, a slab waveguide, multiple second waveguides, an Echelle grating, and a metal-filled trench. The first waveguide includes either an input waveguide or an output waveguide. The multiple second waveguides are optically coupled to the first waveguide through the slab waveguide. The multiple second waveguides include multiple output waveguides if the first waveguide includes the input waveguide or multiple input waveguides if the first waveguide includes the output waveguide. The Echelle grating includes multiple grating teeth formed in the slab waveguide. The metal-filled trench forms a mirror at the grating teeth to reflect incident light from the first waveguide toward the multiple second waveguides or from the multiple second waveguides toward the first waveguide.

In an example, an Echelle grating wavelength division multiplexing (WDM) device includes a first waveguide, a slab waveguide, multiple second waveguides, an Echelle grating, and a metal-filled trench. The first waveguide includes either an input waveguide or an output waveguide. The multiple second waveguides are optically coupled to the first waveguide through the slab waveguide. The multiple second waveguides include multiple output waveguides if the first waveguide includes the input waveguide or multiple input waveguides if the first waveguide includes the output waveguide. The Echelle grating includes multiple grating teeth formed in the slab waveguide. The metal-filled trench forms a mirror at the grating teeth to reflect incident light from the first waveguide toward the multiple second waveguides or from the multiple second waveguides toward the first waveguide.

A portion of an optical waveguide extending laterally within a photonic integrated circuit (PIC) chip is at least partially freed from the substrate to allow physical displacement of a released waveguide end relative to the substrate and relative to an adjacent photonic device also fabricated in the substrate. The released waveguide end may be displaced to modulate interaction between the photonic device and an optical mode propagated by the waveguide. In embodiments where the photonic device is an optical coupler, employing for example an Echelle grating or arrayed waveguide grating (AWG), mode propagation through the coupler may be modulated via physical displacement of the released waveguide end. In one such embodiment, thermal sensitivity of an integrated optical wavelength division multiplexer (WDM) is reduced by displacing the released waveguide end relative to the coupler in a manner that counters a temperature dependence of the optical coupler.

An optical module including a circuit board, a circuit adapter board disposed on and electrically connected to the circuit board, a silicon optical chip disposed on and electrically connected to the circuit adapter board, an optical fiber socket optically connected to the silicon optical chip through a first optical fiber ribbon, and a light source disposed on and electrically connected to the circuit board and optically connected to the silicon optical chip through a second optical fiber ribbon; wherein a thermal expansion coefficient of the circuit adapter board is lower than that of the circuit board, the silicon optical chip is provided with optical waveguide end facet on a side thereof configured to be butted with the first optical fiber ribbon and the second optical fiber ribbon, and the circuit adapter board has a notch on a side thereof proximate to the optical waveguide end facets.

An apparatus for alleviating a nonlinear temperature effect of an arrayed waveguide grating, comprising an integrated optical circuit base for an arrayed waveguide grating chip and an actuator. The integrated optical circuit base includes a first region, a second region connected by a hinge. The actuator includes two or more actuating rods having a thermal expansion coefficient different from that of the integrated optical circuit base. In different temperature ranges, the first region and the second region are driven by different actuating rods to rotate and/or translate relative to each other, so that the first region and the second region have a nonlinear displacement as the temperature changes, which brings the two parts of the arrayed waveguide grating chip to move relative to each other to accurately compensate drifting of a central wavelength of the arrayed waveguide grating chip in the different temperature ranges.

An optical module includes: a substrate and a waveguide element having a mount face opposed to the substrate, the waveguide element having an interference waveguide portion having an optical interference function. Further, the mount face includes a projection region to which the interference waveguide portion is projected on the mount face and a non-projection region, and the waveguide element is joined to the substrate with a joint material in the non-projection region.

An optical module includes: a substrate and a waveguide element having a mount face opposed to the substrate, the waveguide element having an interference waveguide portion having an optical interference function. Further, the mount face includes a projection region to which the interference waveguide portion is projected on the mount face and a non-projection region, and the waveguide element is joined to the substrate with a joint material in the non-projection region.

In an example, an Echelle grating wavelength division multiplexing (WDM) device includes a first waveguide, a slab waveguide, multiple second waveguides, an Echelle grating, and a metal-filled trench. The first waveguide includes either an input waveguide or an output waveguide. The multiple second waveguides are optically coupled to the first waveguide through the slab waveguide. The multiple second waveguides include multiple output waveguides if the first waveguide includes the input waveguide or multiple input waveguides if the first waveguide includes the output waveguide. The Echelle grating includes multiple grating teeth formed in the slab waveguide. The metal-filled trench forms a mirror at the grating teeth to reflect incident light from the first waveguide toward the multiple second waveguides or from the multiple second waveguides toward the first waveguide.

An apparatus for alleviating a nonlinear temperature effect of an arrayed waveguide grating, comprising an integrated optical circuit base for an arrayed waveguide grating chip and an actuator. The integrated optical circuit base includes a first region, a second region and connected by a hinge. The actuator includes two or more actuating rods having a thermal expansion coefficient different from that of the integrated optical circuit base. In different temperature ranges, the first region and the second region are driven by different actuating rods to rotate and/or translate relative to each other, so that the first region and the second region have a nonlinear displacement as the temperature changes, which brings the two parts of the arrayed waveguide grating chip to move relative to each other to accurately compensate drifting of a central wavelength of the arrayed waveguide grating chip in the different temperature ranges.

An optical module that implements an MMI device including an optical hybrid primarily made of semiconductor material is disclosed. The MMI device, which has a rectangular plane shape and includes multi-mode couplers, is mounted on a carrier. The carrier provides a step extending in a whole lateral width of a top surface thereof, where the step makes a gap against the MMI device in an area where the MMI couplers are formed.