A semiconductor laser has a mirror formed in a gain chip. The mirror can be placed in the gain chip to provide a broadband reflector to support multiple lasers using the gain chip. The mirror can also be placed in the gain chip to have the semiconductor laser be more efficient or more powerful by changing an optical path length of the gain of the semiconductor laser.

A semiconductor laser has a mirror formed in a gain chip. The mirror can be placed in the gain chip to provide a broadband reflector to support multiple lasers using the gain chip. The mirror can also be placed in the gain chip to have the semiconductor laser be more efficient or more powerful by changing an optical path length of the gain of the semiconductor laser.

A method includes: forming a first plurality of tiers that each comprises first and second dummy layers over a substrate, wherein within each tier, the second dummy layer is disposed above the first dummy layer; forming a second plurality of recessed regions in the first plurality of tiers, wherein at least one subgroup of the second plurality of recessed regions extend through respective different numbers of the second dummy layers; and performing an etching operation to concurrently forming a third plurality of trenches with respective different depths in the substrate through the at least one subgroup of the second plurality of recessed regions.

A method includes: forming a first plurality of tiers that each comprises first and second dummy layers over a substrate, wherein within each tier, the second dummy layer is disposed above the first dummy layer; forming a second plurality of recessed regions in the first plurality of tiers, wherein at least one subgroup of the second plurality of recessed regions extend through respective different numbers of the second dummy layers; and performing an etching operation to concurrently forming a third plurality of trenches with respective different depths in the substrate through the at least one subgroup of the second plurality of recessed regions.

A method of forming a semiconductor structure includes: providing an initial substrate having a first region and a second region; forming a first substrate on the initial substrate; forming a first insulating layer on the first substrate; forming a second substrate on the first insulating layer; removing the second substrate in the second region to form a second insulating layer on the first insulating layer in the second region; and forming a plurality of passive devices on the second insulating layer in the second region and forming a plurality of active devices on the second substrate in the first region.

An optical coupler includes a substrate, a mirror layer, a plurality of coupling gratings, a plurality of waveguides, and an oxide layer. The substrate includes a first surface, a second surface opposite to the first surface, and a concave portion exposed from the first surface. The mirror layer is disposed in the concave portion. The coupling gratings are disposed above the mirror layer. The waveguides are laterally aligned with the coupling gratings. The concave portion faces both the coupling gratings and the waveguides. The oxide layer is bonded on the first surface. The coupling gratings and the waveguides are disposed on the oxide layer.

A method of transfer printing. The method comprising: providing a precursor photonic device, comprising a substrate and a bonding region, wherein the precursor photonic device includes one or more alignment marks located in or adjacent to the bonding region; providing a transfer die, said transfer die including one or more alignment marks; aligning the one or more alignment marks of the precursor photonic device with the one or more alignment marks of the transfer die; and bonding at least a part of the transfer die to the bonding region.

A compact silicon waveguide mode converter, a dielectric meta-surface structure based on periodical oblique subwavelength perturbations, including a top silicon structure with oblique subwavelength perturbations etched in certain periods with period length of Λ, a duty cycle and an oblique angle θ on the SOI substrate. The invention adopts an all-dielectric meta-surface structure with oblique subwavelength perturbation, which can achieve a compact mode conversion from fundamental mode to arbitrary high-order mode of silicon waveguide, and can improve the optical communication capacity greatly.

A compact silicon waveguide mode converter, a dielectric meta-surface structure based on periodical oblique subwavelength perturbations, including a top silicon structure with oblique subwavelength perturbations etched in certain periods with period length of Λ, a duty cycle and an oblique angle θ on the SOI substrate. The invention adopts an all-dielectric meta-surface structure with oblique subwavelength perturbation, which can achieve a compact mode conversion from fundamental mode to arbitrary high-order mode of silicon waveguide, and can improve the optical communication capacity greatly.

A photonic structure is provided. The photonic structure includes a first oxide layer in a semiconductor substrate, a second oxide layer over an upper surface of the semiconductor substrate and an upper surface of the first oxide layer, and an optical coupling region over an upper surface of the second oxide layer. The optical coupling region is made of silicon, and an area of the optical coupling region is confined within an area of the first oxide layer in a plan view.