The invention relates to a measuring device (10; 10a) for a machining system (12; 12a) for machining a workpiece (14; 14a) using a high-energy machining beam (16; 16a), wherein the measuring device (10; 10a) comprises a beam generating unit (18; 18a) configured to generate a sample beam (20; 20a) and a reference beam (22; 22a) that can be caused to interfere for the performance of optical interference measurements such as optical coherence tomography; a sample arm (24; 24a) that is optically connected to the beam generating unit (18; 18a) and in which the sample beam (20; 20a) is optically guided so that it can be projected onto the workpiece (14; 14a); a reference arm (26; 26a) that is optically connected to the beam generating unit (18; 18a) and in which the reference beam (22; 22a) is optically guided; and a measuring interface (28; 28a) that can be used to couple the sample beam (20; 20a) into the machining beam (16; 16a); the measuring device (10; 10a) comprising a base module (30; 30a) and an interchangeable module (32; 32a) that is connectable or connected thereto. The interchangeable module (32; 32a) comprises a beam guiding portion (48a) that includes optical components (50a) for guiding the sample beam (20a) and/or the reference beam (22a) and that is configured to form a central portion (52; 52a) of the sample arm (24; 24a) and/or the reference arm (26; 26a).

The invention further relates to a system comprising a measuring device (10; 10a) and a plurality of interchangeable modules (32, 32, 32), a machining system (12; 12a) and a method for adjusting a measuring device (10; 10a).

Disclosed is a heterodyne grating interferometry system based on secondary diffraction, including a single-frequency laser, an input optical fiber, an acousto-optic modulator, a reading head, and a measurement grating, an output optical fiber, a photoelectric conversion unit and an electronic signal processing unit, wherein the single-frequency laser emits a single-frequency laser, which enters the acousto-optic modulator through the input optical fiber, and is divided into a reference light and measurement light to be input to the reading head, wherein the reading head and the measurement grating convert the reference light and measurement light into a reference interference optical signal and a measurement interference optical signal and send them to the photoelectric conversion unit through the output optical fiber and wherein the photoelectric conversion unit converts the measurement interference optical signal and the reference interference optical signal into a measurement interference electrical signal and a reference interference electrical signal.

Disclosed is a heterodyne grating interferometry system based on secondary diffraction, including a single-frequency laser, an input optical fiber, an acousto-optic modulator, a reading head, and a measurement grating, an output optical fiber, a photoelectric conversion unit and an electronic signal processing unit, wherein the single-frequency laser emits a single-frequency laser, which enters the acousto-optic modulator through the input optical fiber, and is divided into a reference light and measurement light to be input to the reading head, wherein the reading head and the measurement grating convert the reference light and measurement light into a reference interference optical signal and a measurement interference optical signal and send them to the photoelectric conversion unit through the output optical fiber and wherein the photoelectric conversion unit converts the measurement interference optical signal and the reference interference optical signal into a measurement interference electrical signal and a reference interference electrical signal.

A laser interferometer includes a laser light source, a collimator generating collimated light, an optical modulator modulating the collimated light into reference light having a different frequency, and a light receiving element receiving object light and the reference light and outputting a light receiving signal. An optical axis of the collimated light is a first optical axis. When return light is generated, an optical axis of the return light is a second optical axis. A position at which the collimated light is generated is a reference position. The first and second optical axes at the reference position has a shift width y. The collimator has an effective diameter . The collimated light has a light diameter R. The reference position is away from the optical modulator by a distance L. The collimated light has a wavelength . These properties satisfy a specific equation (A).

A laser interferometer includes a laser light source, a collimator generating collimated light, an optical modulator modulating the collimated light into reference light having a different frequency, and a light receiving element receiving object light and the reference light and outputting a light receiving signal. An optical axis of the collimated light is a first optical axis. When return light is generated, an optical axis of the return light is a second optical axis. A position at which the collimated light is generated is a reference position. The first and second optical axes at the reference position has a shift width y. The collimator has an effective diameter . The collimated light has a light diameter R. The reference position is away from the optical modulator by a distance L. The collimated light has a wavelength . These properties satisfy a specific equation (A).

Aspects of the disclosure provide for automated self-inspection by an OCT imaging engine or device, to identify and resolve failures or inefficiencies in the hardware and/or software of the system or device during imaging. An OCT imaging engine can include a catheter connection check system for checking the quality of a physical connection point between a catheter and other components of an OCT imaging device or system. In some examples, the OCT imaging engine includes a self-inspection engine implemented to perform routine self-inspection by using a reference reflector internal to the OCT imaging engine to generate system performance data. The OCT imaging engine can use the system performance data to periodically search for and resolve failures or inefficiencies in the system. The OCT imaging engine can perform a self-calibration process to perform k-linearization and/or correct for chromatic dispersion using mirror measurements collected from an internal reference reflector.

Aspects of the disclosure provide for automated self-inspection by an OCT imaging engine or device, to identify and resolve failures or inefficiencies in the hardware and/or software of the system or device during imaging. An OCT imaging engine can include a catheter connection check system for checking the quality of a physical connection point between a catheter and other components of an OCT imaging device or system. In some examples, the OCT imaging engine includes a self-inspection engine implemented to perform routine self-inspection by using a reference reflector internal to the OCT imaging engine to generate system performance data. The OCT imaging engine can use the system performance data to periodically search for and resolve failures or inefficiencies in the system. The OCT imaging engine can perform a self-calibration process to perform k-linearization and/or correct for chromatic dispersion using mirror measurements collected from an internal reference reflector.

A three-dimensional profiler includes a broadband radiation source. An interferometric system receives the radiation and includes first and second beam splitters, a moving time delay-inducing reflector, and a stationary reflector. The interferometric system creates a time-delayed optical sample radiation source and an optical reference incident radiation source with the first beam splitter. A stationary sample holder receives the optical sample incident radiation. A reference plane receives the optical reference incident radiation. A detector receives an interference signal from reflected or scattered optical sample radiation and reflected or scattered optical reference radiation. A processor extracts an optical path difference between the reference plane and the sample and reconstructs a three-dimensional morphology of the sample.

A three-dimensional profiler includes a broadband radiation source. An interferometric system receives the radiation and includes first and second beam splitters, a moving time delay-inducing reflector, and a stationary reflector. The interferometric system creates a time-delayed optical sample radiation source and an optical reference incident radiation source with the first beam splitter. A stationary sample holder receives the optical sample incident radiation. A reference plane receives the optical reference incident radiation. A detector receives an interference signal from reflected or scattered optical sample radiation and reflected or scattered optical reference radiation. A processor extracts an optical path difference between the reference plane and the sample and reconstructs a three-dimensional morphology of the sample.

A method of determining residual intensity noise (RIN) of a sensor may comprise determining a first amplitude of a first harmonic of the sensor while a signal propagating through the sensor is modulated at a modulating frequency corresponding to twice an eigenfrequency of the sensor. The method may further comprise determining a second amplitude of a second harmonic of the sensor while the signal propagating through the sensor is modulated the modulating frequency, and determining the RIN of the sensor as a ratio of the first amplitude and the second amplitude.