A Photonic Integrated Circuit (PIC) includes N Ring and Disk type Microstructures (RDMs), N is an integer and greater than 1; at least one spare RDM, wherein each RDM operates spectrally in a periodic nature and has its spectral operation vary by temperature; and circuitry configured to handoff any of the N RDMs and the at least one spare RDM for spectral operation based on a current temperature. For the handoff, the at least one spare RDM is unlocked spectrally and is tuned and locked to a frequency of interest of a current RDM based on the temperature, and the current RDM is unlocked.

One embodiment provides an optical encoder. The optical encoder includes an optical comb source to generate a multi-wavelength optical signal; a number of optical filters sequentially coupled to the optical comb source, with a respective optical filter being tunable to pass or block a particular wavelength of the multi-wavelength optical signal based on a corresponding bit value of a multi-bit search word; and a common output for the optical filters to output the filtered multi-wavelength optical signal, which encodes the multi-bit search word and can be used as an optical search signal for searching an optical content-addressable memory (CAM).

Methods and devices that provide a variable-bandwidth optical filter with frequency tuning are disclosed. A universal variable bandwidth optical filter architecture is disclosed, based on microring resonators that can vary both operation wavelength and bandwidth with no extra complexity relative to conventional wavelength tunable filters. The filter architecture provides a universal filter design for any arbitrary shape of filter response, such as second-order, fourth-order, sixth-order, and so on. The filter characteristics—insertion loss, in-band ripple, and out-of-band rejection level—may be maintained over the bandwidth tuning range. There is no need for extra heaters to tune the filter's operating bandwidth, as the same heaters used to tune the filter frequency can be used to tune filter bandwidth. The device can be used as an add/drop filter.

A photon source includes a bus waveguide, a photon source pump laser coupled to the bus waveguide and a plurality of optical resonators coupled to the bus waveguide. Each optical resonator of the plurality of optical resonators has a respective resonance line width and a respective resonance frequency, wherein a bandwidth of the resonant center frequencies of the plurality of optical resonators is greater than a bandwidth of the photon source pump laser. The bus waveguide produces photons in response to receiving laser pulses from the pump laser.

Aspects of the present disclosure are directed to photon-pair sources based on an external-cavity laser comprising a gain element and a planar-lightwave circuit that includes a surface-waveguide-based mirror and a ring resonator that enables four-wave mixing, where the surface-waveguide mirror and the ring resonator reside within the gain cavity of the laser itself. As a result, photon-pair sources in accordance with the present disclosure can have: (1) a larger free-spectral range for the entire laser cavity to enable generation of a single wavelength to realize single-mode operation without additional stabilization; and (2) low laser noise, thereby enabling detection and use of the generated photon pairs.

An optical input polarization management device includes a polarization splitter and rotator (PSR) that directs a portion of incoming light having a first polarization through a first optical waveguide (OW). The PSR rotates a portion of the incoming light having a second polarization to the first polarization so as to provide polarization-rotated light. The PSR directs the polarization-rotated light through a second OW. Light within the first and second OW's is input to a first two-by-two optical splitter (2x2OS). A first phase shifter (PS) is interfaced with either the first or second OW. Light is output from the first 2x2OS into a third OW and a fourth OW. Light within the third and fourth OW's is input to a second 2x2OS. A second PS is interfaced with either the third or fourth OW. Light is output from the second 2x2OS into a fifth OW for further processing.

An electro-optic combiner includes a polarization splitter and rotator (PSR) that directs a portion of incoming light having a first polarization through a first optical waveguide (OW). The PSR rotates a portion of the incoming light having a second polarization to the first polarization to provide polarization-rotated light. The PSR directs the polarization-rotated light through a second OW. Each of the first and second OW's has a respective combiner section. The first and second OW combiner sections extend parallel to each other and have opposite light propagation directions. A plurality of ring resonators is disposed between the combiner sections of the first and second OW's and within an evanescent optically coupling distance of both the first and second OW's. Each of ring resonators operates at a respective resonant wavelength to optically couple light from the combiner section of the first OW into the combiner section of the second OW.

A multi-channel laser source, including: a bus waveguide coupled, at an output end of the bus waveguide, to an output of the multi-channel laser source; a first semiconductor optical amplifier; a first back mirror; a first wavelength-dependent coupler, having a first resonant wavelength, on the bus waveguide; a second semiconductor optical amplifier; a second back mirror; and a second wavelength-dependent coupler, on the bus waveguide, having a second resonant wavelength, different from the first resonant wavelength. In some embodiments the first semiconductor optical amplifier is coupled to the bus waveguide by the first wavelength-dependent coupler, which is nearer to the output end of the bus waveguide than the second wavelength-dependent coupler, the second semiconductor optical amplifier is coupled to the bus waveguide by the second wavelength-dependent coupler, and the first wavelength-dependent coupler is configured to transmit light, at the second resonant wavelength, along the bus waveguide.

An Optical Dispersion Compensator (ODC) is disclosed, the ODC being suitable for managing chromatic dispersion of an optical signal for transmission over an optical fiber. The ODC comprises a first ODC unit (202) arranged on a first optical bus (206), a second ODC unit (204) arranged on a second optical bus (208), parallel to the first optical bus (206), and a switching element (210) interconnecting the first and second optical buses (206, 208) between the first and second ODC units (202, 204). The first and second ODC units (202, 204) are operable to provide a delay to the optical signal that varies with frequency. The switching element (210) is configured, in a first state, to switch an optical signal received on one of the first or second optical buses (206, 208) to the other of the first or second optical buses (208, 206) and, in a second state, to maintain an optical signal received on one of the first or second optical buses (206, 208) on the optical bus on which it was received (206, 208). Reflective elements (710) may be included in the ODC, providing bidirectional propagation through one of more ODC units.

A method (100) is disclosed for filtering an optical signal to generate at least one electrical output. The method comprises receiving an optical signal (110) and directing at least a part of the optical signal through an n×m array of wavelength selective elements (120), the n×m array comprising n parallel groups, each group comprising m coupled wavelength selective elements. The method further comprises photodetecting an output from each of the n groups of coupled wavelength selective elements (130), and electrically selecting at least one of the photodetected outputs (140). Also disclosed are an optical filtering module (200, 300) a controller (400) for an optical filtering module and a computer program.