A wavelength calibration method, apparatus, and system is disclosed. The method includes: selecting sonic wavelengths from a plurality of wavelengths, and performing the following operations on a microring filter for each of the some wavelengths, to obtain sets of calibrated voltages of the some wavelengths: (1) adjusting thermal tuning power of multiple microrings by using one set of voltages, and obtaining multiple sets of voltages that enable monitored optical power to have an extreme value, and (2) using the multiple of sets of voltages as a reference, adjusting the thermal tuning power of the multiple microrings by using another set of voltages, and determining one of the sets of calibrated voltages, which enables the monitored optical power to converge, from the multiple sets of voltages; and then, obtaining, through calculation based on the sets of calibrated voltages of the some wavelengths, sets of calibrated voltages of other wavelengths.

The present invention provides a wavelength control method, a system thereof and a shutoff depth control circuit. The method includes: enabling a current temperature of TEC (6) to be rapidly stabilized at a target temperature through a closed loop control of hardware PID (8); allowing the shut-off depth control circuit (11) to operate when a burst driver (5) that drives a light emitting assembly (3) is standby or operating, providing an input to the light emitting assembly (3) through the shut-off depth control circuit (11) so that the light-emitting assembly (3) can emit the light that does not affect the normal operations of other ONU, the light emitted allows the light emitting assembly (3) to be warmed up, which enables the light emitting assembly (3) to quickly stabilize the emitted light within the bandwidth required by each channel of the system during the time period from a non-light emitting state to a light emitting state.

A multi-path interference filter. The multi-path interference filter includes a first port waveguide, a second port waveguide, and an optical structure connecting the first port waveguide and the second port waveguide. The optical structure has a first optical path from the first port waveguide to the second port waveguide, and a second optical path, different from the first optical path, from the first port waveguide to the second port waveguide. The first optical path has a portion, having a first length, within hydrogenated amorphous silicon. The second optical path has a portion, having a second length, within crystalline silicon, and the second optical path has either no portion within hydrogenated amorphous silicon, or a portion, having a third length, within hydrogenated amorphous silicon, the third length being less than the first length.

An embodiment of the indention includes a passive, fiber optic, thermal insulator. The thermal insulator includes an inner sleeve defining a central access port. The thermal insulator includes an outer sleeve concentric to the inner sleeve. The inner sleeve and the outer sleeve are joined sufficient to define an annular void. The thermal insulator includes a first insulator located in the annular void. Optionally, the apparatus includes at least one optical fiber secured in the central access port.

An athermal optical waveguide structure such as an optical add drop multiplexer (OADM) or the like is fabricated by a method that includes forming a lower cladding layer on a substrate. A waveguiding core layer is formed on the lower cladding layer. An upper cladding layer is formed on the waveguiding core layer and the lower cladding layer a sol-gel material. The sol-gel material includes an organically modified siloxane and a metal oxide. A thermo-optic coefficient of the sol-gel material is adjusted by curing the sol-gel material for a selected duration of time at a selected temperature such that the thermo-optic coefficient of the sol-gel material compensates for a thermo-optic coefficient of at least the waveguiding core layer such that an effective thermo-optic coefficient of the optical waveguide structure at a specified optical wavelength and over a specified temperature range is reduced.

The present invention provides a wavelength control method, a system thereof and a shutoff depth control circuit. The method includes: enabling a current temperature of TEC (6) to be rapidly stabilized at a target temperature through a closed loop control of hardware PID (8); allowing the shut-off depth control circuit (11) to operate when a burst driver (5) that drives a light emitting assembly (3) is standby or operating, providing an input to the light emitting assembly (3) through the shut-off depth control circuit (11) so that the light-emitting assembly (3) can emit the light that does not affect the normal operations of other ONU, the light emitted allows the light emitting assembly (3) to be warmed up, which enables the light emitting assembly (3) to quickly stabilize the emitted light within the bandwidth required by each channel of the system during the time period from a non-light emitting state to a light emitting state.

A broadband light source apparatus, and corresponding method, includes a broadband light source configured to provide source light with a source wavelength spectrum having a centroid thermal sensitivity. The apparatus also includes a broadband optical filter characterized by a filter spectrum that has one or more spectral characteristics and a thermal sensitivity with magnitude and sign. The filter is configured to receive the source light and to deliver broadband output light with an output spectrum that is a function of the source and filter spectra and has an output centroid wavelength. The spectral characteristics and the magnitude and sign of the thermal sensitivity of the filter are configured to minimize a thermal sensitivity of the output centroid wavelength. The filter can be configured in view of a particular source spectrum to stabilize output centroid wavelength and maximize total output power passively with respect to ambient temperature fluctuations.

A multi-path interference filter. The multi-path interference filter includes a first port waveguide, a second port waveguide, and an optical structure connecting the first port waveguide and the second port waveguide. The optical structure has a first optical path from the first port waveguide to the second port waveguide, and a second optical path, different from the first optical path, from the first port waveguide to the second port waveguide. The first optical path has a portion, having a first length, within hydrogenated amorphous silicon. The second optical path has a portion, having a second length, within crystalline silicon, and the second optical path has either no portion within hydrogenated amorphous silicon, or a portion, having a third length, within hydrogenated amorphous silicon, the third length being less than the first length.

A broadband light source apparatus, and corresponding method, includes a broadband light source configured to provide broadband source light characterized by a source wavelength spectrum. The apparatus also includes a broadband optical filter including both a polarization changer with a length, as well as an exit polarizer. The broadband optical filter receives the source light and delivers broadband output light characterized by an output wavelength spectrum that is a function of the source wavelength spectrum and the polarization changer length and has an output centroid wavelength. The polarization changer length is configured to minimize a thermal sensitivity of the output centroid wavelength. The filter can be configured in view of a particular source wavelength spectrum to thermally stabilize the centroid wavelength and to maximize relative integrated output power passively with respect to ambient temperature fluctuations.

A pin hole or aperture is located or formed adjacent to the end surface of one or more of the input ports or fibers, or adjacent to one or more of the output ports or fibers, of a fiberoptic component. The aperture allows light to enter (or exit) the core of the associated fiber, and the non-transparent layer that surrounds the aperture blocks light from entering or exiting the cladding layer of the associated fiber. This blocking of the evanescent field in the cladding layer serves to reduce the polarization, wavelength, and temperature dependencies of the light coupling to the output port(s) or fiber(s) of the optical component. It can also reduce the passband width of the selected wavelength in tunable optical filter applications. The non-transparent layer surrounding the aperture can be made reflective, and light that is reflected by the non-transparent layer can be used for optical power monitoring.