An integrated optical system includes a wavelength tunable optical source and a photonic integrated circuit (PIC). The PIC includes a set of spatial waveguide switches having an input optically coupled to the wavelength tunable optical source and a plurality of outputs. The PIC also includes an optical emitter having a plurality of inputs, each being coupled to a respective one of the plurality of outputs of the set of spatial waveguide switches, the optical emitter configured to produce at an output an optical beam having a wavelength dependent emission direction that changes as light is switched by the set of spatial waveguide switches such that the optical beam may be steered in two dimensions.

In one embodiment of the invention, a semiconductor optical amplifier (SOA) in a laser ring is chosen to provide low polarization-dependent gain (PDG) and a booster semiconductor optical amplifier, outside of the ring, is chosen to provide high polarization-dependent gain. The use of a semiconductor optical amplifier with low polarization-dependent gain nearly eliminates variations in the polarization state of the light at the output of the laser, but does not eliminate the intra-sweep variations in the polarization state at the output of the laser, which can degrade the performance of the SS-OCT system.

The source light having a range of optical wavelengths is split into sample light and reference light. The sample light is delivered into a sample, such that the sample light is scattered by the sample, resulting in signal light that exits the sample. The signal light and the reference light are combined into an interference light pattern having optical modes having oscillation frequency components respectively corresponding to optical pathlengths extending through the sample. Different sets of the optical modes of the interference light pattern are respectively detected, and high-bandwidth analog signals representative of the optical modes of the interference light pattern are output. The high-bandwidth analog signals are parallel processed, and mid-bandwidth digital signals are output. The mid-bandwidth digital signals are processed over an i number of iterations, and a plurality of low-bandwidth digital signals are output on the ith iteration. The sample is analyzed based on the low-bandwidth digital signals.

A wavelength-swept light source projects a light beam. An interferometer includes a splitting unit that splits the light beam projected from the wavelength-swept light source into light beams radiated toward a plurality of spots on a measurement target. Each of the interference beam is generated by interference between a measurement beam radiated toward the measurement target and reflected at the measurement beam, and a reference beam passing through an optical path that is at least partially different from an optical path of the measurement beam. A light-receiving unit receives the interference beams from the interferometer. A processor calculates distance to the measurement target by associating a detected peak of the interference beams with one of the spots. The optical path length difference between the measurement target and the reference beam is made different among the light beams split in correspondence with the plurality of spots.

A light source projects a light beam. An interferometer includes a splitting unit that splits the light beam. The interferometer generates interference beams with the respective split light beams. Each of the interference beam is generated by interference between a measurement beam radiated toward the measurement target and reflected at the measurement beam and a reference beam passing through an optical path. A light-receiving unit receives the interference beams. A processor calculates a distance to the measurement target by associating at least one detected peak with at least one of the spots in accordance with a mirror surface mode or a rough surface mode. The optical path length difference is made different among the split light beams. In the mirror surface mode, the processor uses a distance calculated based on a peak corresponding to a spot for which the optical path length difference is shortest.

This application discloses a measurement apparatus that does not use a femtosecond laser light source and a delay stage. The measurement apparatus mixes a first laser light from a first CW laser light source and a second laser light from a second CW laser light source to generate an interference light having a beat in a range from GHz to THz and demultiplexes the interference light into a pump light and a probe light. A generating photoconductive antenna is irradiated with the pump light, and a detecting photoconductive antenna is irradiated with the probe light. A current value of an electromagnetic wave propagating through a waveguide connecting the generating photoconductive antenna and the detecting photoconductive antenna is measured using a current system connected to the detecting photoconductive antenna.

A method for determining characteristics of a test cavity, the method includes for each of a plurality of optical frequencies within a bandwidth of a tunable laser, measuring interference signals from the test cavity and a reference cavity having a known characteristic. The method includes determining values for the plurality of optical frequencies from the measured interference signals from the reference cavity and the known characteristic of the reference cavity, and determining the characteristic of the test cavity using the determined values of the plurality of optical frequencies.

An optical interrogation system, e.g., an OFDR-based system, measures local changes, of index of refraction of a sensing light guide subjected to a time-varying disturbance. Interferometric measurement signals detected for a length of the sensing light guide are transformed into the spectral domain. A time varying signal is determined from the transformed interferometric measurement data set. A compensating signal is determined from the time varying signal which is used to compensate the interferometric measurement data set for the time-varying disturbance. Further robustness is achieved using averaging and strain compensation. The compensation technique may be applied along the length of the light guide.

Methods for synchronizing an Optical Coherence Tomography (OCT) system including detection when a plurality of A-line scans obtained from reflected light of a cantilever scanning fiber within a probe oscillating along a scanning path that increases in amplitude over time are no longer being obtained at a point along the oscillating scanning path when the scanning fiber reaches a minimum speed, determining a value by which a phase angle of the oscillating scanning path is out of synchronization with the plurality of A-line scans, and adjusting a trigger clock for the obtaining the plurality of A-line scans based on the value.

A method comprises: splitting laser light into sample light, reference light, and monitor light; routing the reference light into a reference arm of an OCT interferometer; routing the monitor light into a monitor device, which generates at least one optical monitor signal representing at least one time-dependent property of the monitor light; generating at least one electric monitor signal from the at least one optical monitor signal; illuminating in a point-shaped manner a sample with sample light, wherein the illumination point is guided on the surface of the sample along a predetermined trajectory; superimposing the light scattered by the sample with the reference light emerging from the reference arm to generate an electric OCT signal; wherein the at least one electric monitor signal and the electric OCT signal are AD-converted in alternating sequence, in each case equidistantly in time, to form a single digital data stream.