A wavelength tunable laser device includes a gain element positioned in an optical cavity that provides optical gain to an optical signal. A frequency shifter that generates a frequency shift as a function of time is positioned in the optical cavity. The optical cavity is configured so that a magnitude of the frequency shift as a function of time generated by the frequency shifter is substantially equal to a frequency separation of a cavity mode of the cavity such that an output of the cavity generates laser light having a wavelength that tunes as a function of time.

A swept light source of the present invention keeps a coherence length of an output beam long over an entire sweep wavelength range. A gain of a gain medium is changed with time in response to a wavelength sweep and the coherence length is kept maximum. The gain of the gain medium is kept close to a lasing threshold and an unsaturated gain range of the gain medium is narrowed over the entire sweep wavelength range. An SOA current waveform data acquiring method of driving while keeping the coherence length long, a novel coherence length measuring method, and an optical deflector suitable for the swept light source are also disclosed.

A digitizer and processor device for a swept-source optical coherence tomography (SS-OCT) imaging system, comprising: an input configured to receive an OCT signal; a control input configured to receive a k-clock signal; a combiner unit (130) receiving the OCT signal and the k-clock signal configured to output a composite signal; a digitizing unit (60) arranged to convert the composite signal into a digital composite signal (69); a data processing unit (70) arranged to determine a profile of optical density in a sample that generated the OCT signal based on the digital composite signal (69).

A digitizer and processor device for a swept-source optical coherence tomography (SS-OCT) imaging system, comprising: an input configured to receive an OCT signal; a control input configured to receive a k-clock signal; a combiner unit (130) receiving the OCT signal and the k-clock signal configured to output a composite signal; a digitizing unit (60) arranged to convert the composite signal into a digital composite signal (69); a data processing unit (70) arranged to determine a profile of optical density in a sample that generated the OCT signal based on the digital composite signal (69).

A method for compensating the artifacts generated by moving measurement objects in measurement signals of swept-source OCT systems by moving measurement objects. Signal reconstruction is implemented without the aid of additional reference signals in respect of the movement of the measurement object and only by way of especially adapted algorithms. Example methods relate firstly to the especially adapted, Fourier transform-based algorithms for processing the captured measurement signals and secondly to the measurement signals to be captured, in particular to the optical coherence interferometry-based measurement systems used for the production thereof. Although the proposed method is provided for applications in ophthalmology in particular, it can be used, in principle, wherever signals reflected by curved surfaces or backscattered from structures are analyzed.

A parameter measurement device of a light deflector includes a photodetector that receives output light from the light deflector, a biaxial translation automatic stage that moves the photodetector to a plurality of positions, and a signal processing device that calculates the wavelength of the output light of a wavelength sweeping light source for each time, calculates the wavelength of the light received from the light deflector by the photodetector based on the output signal of the photodetector and a previously-calculated wavelength, and calculates the incident angle of the output light beam of the wavelength sweeping light source onto the diffraction grating and an angle formed by an L-axis and a line perpendicular to the surface of the diffraction grating by performing fitting so that the coordinates of the photodetector that are obtained for each position of the photodetector and the wavelength of the light conform to a prescribed relational expression.

Provided is an optical interference measuring apparatus including a measuring unit for acquiring an interferogram of an interference wave obtained by irradiating a measuring target and a reference surface with electromagnetic waves and causing reflected waves from a reflecting surface of the measurement target and reflected waves from the reference surface to interfere and a signal processing unit for configuring an intensity profile in the depth direction by performing Fourier transform of the interferogram. The signal processing unit is configured to estimate a parameter for a model formula for an assumed surface count, based on the model formula of an interferogram when it is assumed that the measurement target has a predetermined structure, to select an optimal model by a statistical technique from the model formula to which a parameter estimated for the assumed surface count is applied, and to reconfigure an intensity profile based on the optimal model.

An optical distance measurer includes: a beam splitter splitting a laser beam and outputting as measurement light and reference light; a measurement light beam splitter splitting the measurement light and outputting as first measurement light and second measurement light; a reference light beam splitter splitting the reference light and outputting as first reference light and second reference light; a first optical system having a first Rayleigh length, the first optical system emitting the first measurement light to a target object; and a second optical system having a second Rayleigh length different from the first Rayleigh length, the second optical system emitting the second measurement light to the target object; a first receiver receiving the first reference light and first reflection light that is the first measurement light reflected by the target object and outputting a first receiving signal indicating the first reference light and the first reflection light; and a second receiver receiving the second reference light and second reflection light that is the second measurement light reflected by the target object and outputting a second receiving signal indicating the second reference light and the second reflection light.

An optical coherence tomography apparatus includes a branching and merging device that branches a light beam emitted from a wavelength sweeping laser light source into an object light beam and a reference light beam, a balanced photodetector that generates information about a change in an intensity ratio of interference light beams, which are generated by the interference between the object light beam and the reference light beam, wherein the object light beam is scattered from the measurement object after being transmitted through the transparent substrate including a structure that changes a thickness, and a control unit that acquires structural data of the measurement object in a depth direction based on the information about the change in the intensity ratio of the interference light beams and connects the structural data while moving an irradiation position of the object light beam with a position of the above structure as a reference.

OCT measuring device in the present exemplary embodiment includes: wavelength sweep light source that emits light of which a wavelength is swept; optical interferometer that divides the light into measurement light and reference light, emits measurement light toward measurement surface of measuring target object, and generates an optical interference intensity signal indicating an intensity of interference between measurement light reflected from measurement surface and reference light; electro-optic element which is a phase modulator arranged in a light path of optical interferometer; measurement processor which is a signal generator that derives a position of measurement surface and generates a phase amount indicator signal that indicates a phase amount of phase modulator based on the optical interference intensity signal; and electro-optic element controller which is a phase amount controller that controls the phase amount given to the light that is transmitted through phase modulator.