In accordance with an embodiment, a bandpass transmission filter having a center wavelength of transmission includes: a waveguide structure comprising a grating structure having changing grating pitch values configured to diffract radiation in the waveguide structure having a first wavelength lower than the center wavelength of transmission, and configured to reflect radiation in the waveguide structure having a second wavelength higher than the center wavelength of transmission; and a radiation absorbing structure configured to absorb radiation guided by the waveguide structure having a third wavelength higher than the second wavelength, wherein the radiation absorbing structure is an integrated part of the waveguide structure or comprises a layer arranged adjacent to the waveguide structure.

A laser inspection system is provided. A laser source emits a laser with a first spectrum and the laser is transmitted by a first optical fiber. A gain optical fiber doped with special ions is connected to the first optical fiber, and a light detector is provided around the gain optical fiber. When the laser with the first spectrum passes through the gain optical fiber, the gain optical fiber absorbs part of the energy level of the laser with the first spectrum, so that the laser with the first spectrum is converted to generate light with a second spectrum based on the frequency conversion phenomenon. The light detector detects the intensity of the light with the second spectrum, so that the power of the laser source can be obtained.

Implementations disclosed describe a system comprising a first optical device to receive an input beam of light, the input beam having a plurality of spectral components of light, and cause the input beam to disperse into a plurality of spectral beams, wherein each of the plurality of spectral beams corresponds to one of the plurality of spectral components and propagates along a spatial path that is different from spatial paths of other spectral beams, and a second optical device to collect a portion of each of the spectral beams, wherein the collected portion depends on the spatial path of the respective spectral beam, and form an output beam of light from the collected portion of each of the spectral beams, wherein a spectral profile of the output beam is different from a spectral profile of the input beam of light.

An optical fiber filter has an ultra-wide tuning range and includes a two-dimensional mechanical rotating mirror, a collimating and beam expanding system, and two grating. An input fiber emits a multi-wavelength optical signal into the rotating mirror, which reflects the signal to the system to form collimated beams. In turn, the collimated beams are incident on the gratings that disperse the light of different wavelengths to different angles. Lights of different diffraction angles are input into an output fiber by adjusting the rotating mirror. The rotating mirror can be used to switch between gratings of different wavebands to tune optical wavelengths in an ultra-wide range.

An optical fiber filter has an ultra-wide tuning range and includes a two-dimensional mechanical rotating mirror, a collimating and beam expanding system, and two grating. An input fiber emits a multi-wavelength optical signal into the rotating mirror, which reflects the signal to the system to form collimated beams. In turn, the collimated beams are incident on the gratings that disperse the light of different wavelengths to different angles. Lights of different diffraction angles are input into an output fiber by adjusting the rotating mirror. The rotating mirror can be used to switch between gratings of different wavebands to tune optical wavelengths in an ultra-wide range.

A delivery fiber assembly suitable for delivering broad band light and including a delivery fiber and a connector member. The delivery fiber has a length, an input end for launching light, and a delivery end. The delivery fiber includes along its length a core region and a cladding region surrounding the core region, the cladding region includes a cladding background material having a refractive index N.sub.bg and a plurality of microstructures in the form of inclusions of solid material having refractive index up to N.sub.inc and extending in the length of the longitudinal axis of the delivery fiber, wherein N.sub.inc<N.sub.bg. The plurality of inclusions in the cladding region is arranged in a cross-sectional pattern including at least two rings of inclusions surrounding the core region. The connector member is mounted to the delivery fiber at a delivery end section of the delivery fiber including the delivery end.

A tunable wavelength filtering device is presented in which the tuning mechanism is based on altering the incident angle to an optical thin film coating stack, or thin film optical filter. Rotating mirrors, such as Micro-Electro-Mechanical Systems (MEMS) tilt-mirrors, are used to alter the incident angle of the optical beam coming from an input fiber, and also to aim or align the exiting beam to an output optical fiber. The optical thin film coating stack can be implemented onto a glass substrate, to form a thin film filter chip. The thin film filter chip can be fixed in place, and the incident angle and exiting angle of the optical beam is varied by adjusting the tilt angle of the two rotating mirrors.

A sensor system comprises a pulsed light source, and a passive sensor head chip in communication with the light source. The sensor head chip includes a first photonics substrate, a transmitting optical component on the first photonics substrate and configured to couple a pulse, transmitted through a first optical fiber from the light source, into a region of interest; and a receiving optical component on the first photonics substrate and configured to couple backscattered light, received from the region of interest, into a second optical fiber. A signal processing chip communicates with the sensor head chip and light source. The signal processing chip includes a second photonics substrate and comprises a passive optical filter array that receives the backscattered light from the second optical fiber. The filter array includes notch filters in communication with each other and operative for frequency selection; and optical detectors respectively coupled to the notch filters.

An optical filter assembly comprising: a tuneable optical filter; a beam splitter assembly configured to split an input beam into an output beam, a reference beam, and a probe beam, and to direct the output beam and the probe beam through the tuneable optical filter, such that the probe beam is at an angle α to the output beam; a first detector configured to measure the intensity S0 of the reference beam; a second detector configured to measure the intensity S1 of the probe beam after it has passed through the filter; a controller configured to adjust the tuneable optical filter on the basis of the measured intensities of the reference and probe beams.

The invention comprises a delivery fiber assembly suitable for delivering broad band light. The delivery fiber assembly comprises a delivery fiber and a connector member. The deliver has a length, an input end for launching light and a delivery end for delivering light, where the delivery fiber comprises along its length a core region and a cladding region surrounding the core region. The cladding region comprises a cladding background material having a refractive index N.sub.bg and a plurality of inclusions of solid material having refractive index up to N.sub.inc and extending in the length of the longitudinal axis of the delivery fiber, wherein N.sub.inc<N.sub.bg and the plurality of inclusions in the cladding region is arranged in a cross-sectional pattern comprising at least two rings of inclusions surrounding the core region. The connector is mounted to the delivery fiber at a delivery end section of the delivery fiber comprising said delivery end. The delivery fiber has a transmission bandwidth of about 200 nm or more, such as of about 300 nm or more, such as of about 400 nm or more, such as of about 500 nm or more.