A photonic integrated circuit (PIC) includes a waveguide in or over a semiconductor substrate. The waveguide has a terminal end. The PIC also includes an optical absorber having a curved shape adjacent to opposing sides and an endwall of the terminal end of the waveguide, i.e., it surrounds the terminal end of the waveguide. The optical absorber is multi-layered and includes a light absorbing layer. The light absorbing layer may include germanium or a vanadate. The optical absorber terminates or attenuates any stray optical signals from the waveguide while maintaining low back reflection.

In a photonic integrate circuit (PIC) architecture, non-guided stray light that is radiated from components, junctions, discontinuous and scattering points in an integrated optic device, may be received by an integrated waveguide structure in the path of the stray radiation. The integrated waveguide structure may comprise a plurality of collectors that are configured to collect the non-guided stray light from the radiating source. Each of the collectors may comprise an integrated waveguide with a front end that is tapered to increase the mode-field size and pointed toward the stray light source, and with a back end that is connected to a secondary waveguide. The collectors are placed in the path of the stray light and aligned in the propagation direction of the stray light. The collected stray light is guided to a light energy damper through the second waveguide for converting light energy into heat.

The present invention provides an optical module and an optical network system. A first chip is arranged on a lower cover plate, an upper cladding, which is close to a first PD, of the first chip is covered by a first upper cover plate; a first dividing groove divides the first chip into two parts, and a WDM and a light blocking material are arranged inside the first dividing groove, so as to block stray light transmitted inside the upper cladding, a sandwich layer, a lower cladding, and a base of the first chip; and a light blocking material is arranged on a side of the first upper cover plate facing the first LD, so as to block stray light transmitted on a surface of the first chip, thereby blocking the stray light that enters the first PD, and significantly reducing crosstalk of the optical module.

A low loss high extinction ratio on-chip polarizer is disclosed. The polarizer includes an input waveguide taper having an outer waveguiding region that widens in the direction of light propagation along at least a portion of the taper length, and a core waveguiding region that narrows in the direction of light propagation along at least a portion of the taper length, so as to selectively squeeze out light of undesired modes into the outer regions while preserving light of a desired mode in the waveguide core. An integrated light absorber/deflector may be coupled to the outer waveguiding regions.

A diffraction grating pattern is formed in the first insulating film on the active layer by electron beam lithography, and at the same time an end facet formation pattern whose end portion corresponds to a position of an emission end facet of the optical modulator is formed in the first insulating film on the optical absorption layer by electron beam lithography. A second insulating film is formed on the end facet formation pattern. The diffraction grating formation layer is etched using the first and second insulating films as masks to form a diffraction grating, and is embedded with an embedded layer. The second insulating film is removed. A third insulating film is formed on the diffraction grating and the embedded layer not to cover the end facet formation pattern. The optical absorption layer is etched using the first and third insulating films as masks to form the emission end facet.

A semiconductor photodetector comprising a closed loop configured to receive light from an external source adapted to trap light within said closed loop until absorption by the semiconductor.

A structure includes a polarization device such as a polarization splitter, a polarization combiner or a polarization splitter rotator including a waveguide having a light absorber at an end section with an at least hook shape, e.g., it can be hooked or spiral shape. The structure also includes another waveguide adjacent the stated waveguide. The hook or spiral shape acts as a light absorber that reduces undesired optical noise such as excessive light insertion loss and/or light scattering. The hook or spiral shape may also be used on supplemental waveguides used to further filter and/or refine an optical signal in one of the waveguides of the polarization device, e.g., downstream of an output section of the polarization splitter and/or rotator.

A passive on-chip optical long-pass filter for removing residual pump photons at short wavelengths after nonlinear generation of photons. A thin layer (<100 nm) of amorphous or poly-crystalline silicon is deposited onto a section of a waveguide to absorb light with a wavelength shorter than the silicon bandgap wavelength of 1.1 m, while the nonlinearly generated light in longer wavelengths than the silicon bandgap wavelength propagates in the waveguide with a negligible absorption loss. The filter is applicable to attain an on-chip optical pump light rejection ratio exceeding 120 dB for nonlinear and quantum photonic chips. The filter is conceptually simple to design and can be fabricated by a CMOS process with potentially a high wafer-level scalability and manufacturability at a low cost. The filter can be realized in various integrated photonic platforms, including silicon carbide, silicon nitride, lithium niobate and aluminum nitride.

A photonic integrated circuit (PIC) may be optically aligned to a plurality of optical components (e.g., an optical fiber array). Optical alignment may be facilitated by the use of an optical impedance element coupled between a first input/output (I/O) optical waveguide and a second I/O optical waveguide of the PIC. The optical impedance element me be configured to be transmissive during optical alignment and to be non-transmissive during the regular operation of the PIC.

A low loss high extinction ratio on-chip polarizer is disclosed. The polarizer includes an input waveguide taper having an outer waveguiding region that widens in the direction of light propagation along at least a portion of the taper length, and a core waveguiding region that narrows in the direction of light propagation along at least a portion of the taper length, so as to selectively squeeze out light of undesired modes into the outer regions while preserving light of a desired mode in the waveguide core. An integrated light absorber/deflector may be coupled to the outer waveguiding regions.