Optical inputs to photonic switches may incorporate a polarization controller in order to change the polarization of the input signal to a pre-determined polarization for operation with the silicon photonics. A last stage of components of the polarization controller may overlap with a first input switching stage. A polarization controller that overlaps with the first stage of the switch input may provide lower insertion loss and power consumption for the photonic switch.

An optical waveguide for optical signals is formed in a semiconductor layer of an SOI substrate, a heater for heating the optical waveguide is formed on a silicon oxide film which covers the optical waveguide, and wirings for supplying power to the heater are connected to both ends of the heater. Each of the wirings is constituted of a laminated film of a bottom barrier metal film, an aluminum-copper alloy film serving as a main conductive film and a top barrier metal film, and the heater is constituted integrally with the bottom barrier metal film constituting a part of each of the wirings.

A relay device includes: a first port, a plurality of second ports, a splitter configured to branch first optical signals input from the first port into the plurality of second ports; and a plurality of optical modulators configured to modulate shared carrier light by multiplexing the carrier light with a plurality of second optical signals with different frequencies input from the plurality of second ports and by inputting the multiplexed carrier light into a plurality of nonlinear optical mediums, and to transmit the carrier light to the first port.

A dual-ring-modulated laser includes a gain medium having a reflective end coupled to an associated gain-medium reflector and an output end, which is coupled to a reflector circuit through an input waveguide to form a lasing cavity. The reflector circuit comprises: a first ring modulator; a second ring modulator; and a shared waveguide that optically couples the first and second ring modulators together. The first and second ring modulators have resonance peaks that are tuned to be offset in alignment from each other to provide an effective reflectance having a flat-top response, which is aligned with an associated lasing cavity mode. The first and second ring modulators are driven in tandem based on the same electrical input signal, whereby the resonance peaks of the first and second ring modulators shift wavelengths in the same direction during modulation, and an effective reflectance stays within the flat-top wavelength range.

A photonic integrated circuit comprises an input interface adapted for receiving an optical input signal and splitting it into two distinct polarization modes and furthermore adapted for rotating the polarization of one of the modes for providing the splitted signals in a common polarization mode. The PIC also comprises a combiner adapted for combining the first mode signal and the second mode signal into a combined signal and a decohering means adapted for transforming at least one of the first mode signal and the second mode signal such that the first mode signal and the second mode signal are received by the combiner in a mutually incoherent state. A processing component for receiving and processing said combined signal is also comprised.

A second optical modulator is provided between a semiconductor laser and a first optical modulator. Further, a second optical waveguide branched from a first optical waveguide is provided between the semiconductor laser and the second optical modulator, and a light receiving element which converts received laser light into a second electrical signal is provided at an end of the second optical waveguide. Furthermore, the second optical modulator adjusts a light intensity of the laser light entering the first optical modulator to a fixed light intensity, based on data transmitted as the second electrical signal. Still further, the first optical modulator modulates the laser light based on data transmitted as a first electrical signal, and converts the first electrical signal into an optical signal.

An optical switch has four optical ports; a first optical waveguide coupled between a first of said ports and a second of the ports; a first switch element provided between the first waveguide and a second optical waveguide that is coupled to a third of the ports; a second switch element provided between the first waveguide and a third optical waveguide that is coupled to a fourth of the ports. Each switch element has a micro-ring resonator having an active state in which it is coupled to the first waveguide and to a respective one of the second and third waveguides for optical signals at a preselected wavelength, and an inactive state in which no coupling occurs. Each switch element has a control element arranged to receive a respective control signal configured to cause it to switch the micro-ring resonator between said states.

An optical frequency shifter includes a splitter that branch a first optical signal having a first frequency component, a first mutual phase modulator that generate a second optical signal having a second frequency component and a third optical signal having a third frequency component with mutual phase modulation of the first optical signal and a first optical beat signal, a phase converter that change a phase of an output of the first mutual phase modulator, a second mutual phase modulator that generate the second optical signal and the third optical signal with mutual phase modulation of the first phase converter of output signal and a second optical beat signal, and a combiner that interfere between an output of the second mutual phase modulator and another optical signal obtained by branching of the splitter.

An optical waveguide which has sufficient orientation characteristics and its manufacturing processes are simple to be suitable for the manufacture of electro-optic elements and that can be reduced the power consumption by its large electro-optic characteristics and further can be thinned and stacked, and the material thereof. This material is characterized in a polymer compound that includes an oxazoline structure in a side chain, and an acid generator or a polyvalent carboxylic acid.

A display device includes: an optical waveguide (15) comprising an optical waveguide body (151) and a light outputting section (152) disposed on the optical waveguide body (151); M lens assemblies (13, 14) disposed adjacent to an end of the optical waveguide body (151), wherein at least two lens assemblies (13, 14) of the M lens assemblies (13, 14) have different focal lengths, and M is a natural number greater than one; and M display screens (11, 12) corresponding to the M lens assemblies (13, 14) in one-to-one correspondence, each of the M display screens (11, 12) configured to emit light with image information through a corresponding lens assembly (13, 14) to the optical waveguide body (151) for transmission; wherein the light outputting section (152) is configured to output the light from the M display screens (11, 12) out of the optical waveguide body (151) for imaging, the light from the M display screens (11, 12) form M images, respectively, and at least two images of the M images have different image distances.