Abstract: A non-confocal point-scan Fourier-domain optical coherence tomography, OCT, imaging system, comprising: a scanning system arranged to perform a two-dimensional point scan of a light beam across an imaging target, and collect light scattered by the imaging target; a light detector arranged to generate a detection signal based on an interference between a reference light and the light collected by the scanning system. The OCT imaging system further comprises hardware arranged to: generate complex volumetric OCT data of the imaging target based on the detection signal, the OCT data including a component which, when the OCT data is processed to generate an enface projection of the OCT data, provides a defocusing and/or distortion in the enface projection; and generate corrected OCT data by executing a correction algorithm which uses phase information in the OCT data to remove at least some of the component from the OCT data.

Abstract: An ophthalmic device for imaging an eye, wherein a scanning element scans a first portion of light beam across a region of an eye via a light guiding component and a second portion of the light beam is reflected back by the light guiding component. The ophthalmic device further comprises: a light detector to detect light reflected from eye and guided to the light detector by the light guiding component; and a dynamic amplitude mask which receives the light reflected from the eye and the light reflected back by the light guiding component, and has an unmasked portion to allow light reflected from the eye to reach the light detector, and a masked portion whose spatial distribution varies with a scan angle such that the masked portion prevents light reflected back by the light guiding component from reaching the light detector during the scan.

Abstract: An optical coherence tomography instrument suitable for imaging a retina is disclosed. In the instrument, an adjustable optical frequency shifter, which can be or include an acousto-optic modulator or electro-optic modulator, is arranged either (i) between a coupler and a reference optical system, (ii) in a reference optical system, (iii) between the coupler and a front-end optical system, or (iv) in a front-end optical system. The optical frequency of reference light or signal light may adjustably be increased or decreased. In operation, a subject is arranged such that its retina is in the focal depth of the front-end optical system. The increase or decrease in the optical frequency of the reference light or the sample light can be adjusted. Thereby, an interferogram representing a depth structure at the retina obtained between returning signal light and returning reference light may be brought to lie within a detection bandwidth of the instrument.

Abstract: A swept-source OCT imaging system for imaging a region of an object, comprising: a swept light source which generates a beam of varying wavelength; a scanning element which scans the beam across the object; an interferometer which generates interference light by combining light scattered by the object (owing to the scan) with reference light; a photodetector which generates an electrical signal (S) having frequency components spanning a frequency band and caused by interference of the scattered light with the reference light; a band-pass filter module which band-pass filters the electrical signal; and a sample acquisition module which samples the filtered electrical signal. The band-pass filter module extracts at least some of the frequency components spanning the frequency band from the electrical signal. The sample acquisition module band-pass samples the filtered electrical signal.

Abstract: An ophthalmic device for imaging an eye, wherein a scanning element scans a first portion of light beam across a region of an eye via a light guiding component and a second portion of the light beam is reflected back by the light guiding component. The ophthalmic device further comprises: a light detector to detect light reflected from eye and guided to the light detector by the light guiding component; and a dynamic amplitude mask which receives the light reflected from the eye and the light reflected back by the light guiding component, and has an unmasked portion to allow light reflected from the eye to reach the light detector, and a masked portion whose spatial distribution varies with a scan angle such that the masked portion prevents light reflected back by the light guiding component from reaching the light detector during the scan.

Abstract: A delay line interferometer comprising an optical waveguide having a distributed Bragg reflector, e.g. Bragg grating, fabricated therein. The distributed Bragg reflector has a refractive index modulation with a period variation ?(z) along its length z that is arranged to output in transmission an output optical signal fout(t) in response to a input optical signal fin(t), wherein the output optical signal fout(t) is the result of temporal interference between one or more time-delayed replicas of the input optical signal fin(t). In other words, the distributed Bragg reflector is operable to generate and permit temporal interference between two or more time-delayed replicas of the input optical signal fin(t). The invention may thus mimic the behaviour of one or more MZIs.

Abstract: A delay line interferometer comprising an optical waveguide having a distributed Bragg reflector, e.g. Bragg grating, fabricated therein. The distributed Bragg reflector has a refractive index modulation with a period variation ?(z) along its length z that is arranged to output in transmission an output optical signal fout(t) in response to a input optical signal fin(t), wherein the output optical signal fout(t) is the result of temporal interference between one or more time-delayed replicas of the input optical signal fin(t). In other words, the distributed Bragg reflector is operable to generate and permit temporal interference between two or more time-delayed replicas of the input optical signal fin(t). The invention may thus mimic the behaviour of one or more MZIs.