Abstract:
An optically pumped tunable VCSEL swept source module has a VCSEL and a pump, which produces light to pump the VSCEL, wherein the pump is geometrically isolated from the VCSEL. In different embodiments, the pump is geometrically isolated by defocusing light from the pump in front of the VCSEL, behind the VCSEL, and/or by coupling the light from the pump at an angle with respect to the VCSEL. In the last case, angle is usually less than 88 degrees. There are further strategies for attacking pump noise problems. Pump feedback can be reduced through (1) Faraday isolation and (2) geometric isolation. Single frequency pump lasers (Distributed feedback lasers (DFB), distributed Bragg reflector lasers (DBR), Fabry-Perot (FP) lasers, discrete mode lasers, volume Bragg grating (VBG) stabilized lasers can eliminate wavelength jitter and amplitude noise that accompanies mode hopping.
Abstract:
An optical coherence analysis system uses a laser swept source that is constrained to operate in a mode locked condition. This is accomplished by synchronously changing the laser cavity's gain and/or phase based on the round trip travel time of light in the cavity. Many high-speed wavelength swept laser sources emit pulses synchronized with the round trip time of the cavity as part of a nonlinear optical frequency red shifting process. Stable pulsation is associated with smooth tuning and low relative intensity noise. Addition of mode- locking methods to this class of lasers can control and stabilize these lasers to a low clock jitter and RIN state, and in specific cases allow long - to - short wavelength tuning in addition to the usual short - to - long (red shifting). The laser may comprise a SOA (410), a tunable Fabry- Perot - Filter (412) as one reflector and an Output coupler (405) in an optical fiber (406) to adjust the cavity lenght.
Abstract:
An integrated swept wavelength optical source uses a narrowband filtered broadband signal, such as a filtered amplified spontaneous emission (ASE) signal, with an optical amplifier and tracking filter and/or self-tracking filter. This source comprises a micro optical bench, a source for generating broadband light, a first tunable Fabry Perot filter, installed on the bench, for spectrally filtering the broadband light from the broadband source to generate a narrowband tunable signal, an amplifier, installed on the bench, for amplifying the tunable signal, and possibly a second tunable Fabry Perot filter, installed on the bench, for spectrally filtering the amplified tunable signal from the amplifier. In a self-tracking arrangement, a single tunable filter both generates the narrowband signal and spectrally filters the amplified signal. In some examples, two-stage amplification is provided. The use of a single bench implementation yields a low cost high performance system.
Abstract:
Integrated spectroscopy systems are disclosed. In some examples, integrated tunable detectors, using one or multiple Fabry-Perot tunable filters, are provided. Other examples use integrated tunable sources. The tunable source combines one or multiple diodes, such as superluminescent light emitting diodes (SLED), and a Fabry Perot tunable filter or etalon. The advantages associated with the use of the tunable etalon are that it can be small, relatively low power consumption device. For example, newer microelectrical mechanical system (MEMS) implementations of these devices make them the size of a chip. This increases their robustness and also their performance. In some examples, an isolator, amplifier, and/or reference system is further provided integrated.
Abstract:
A thin membrane (24) having a thin film optical coating thereon is formed from multiple layers of different materials in which the overall stress of the thin film is not more than 15 MPa. Such films can be formed through thermal evaporation with ion assist, by directing an electron beam (14) on a source (16) and evaporating material from the source (16) onto a thin flexible membrane (24) while directing an ion stream (44) onto the membrane device (34). The current of the source of the ion stream should be sufficient to provide a thin film coating that has substantially no porosity. Successive applications at constant current can be deposited, while varying the voltage of the ion stream (44). The stress of the thin films deposited under each different voltage can be evaluated and the voltage at which the stress is acceptably low can be determined.
Abstract:
Mounting and alignment structures for optical components allow optical components to be connected to an optical bench and then subsequently aligned, i.e., either passively or actively, in a manufacturing or subsequent calibration or recalibration, alignment or realignment processes. The structures comprise quasi-extrusion portions. This portion is "e;quasi-extrusion"e; in the sense that it has a substantially constant cross section in a z-axis direction as would be yielded in an extrusion manufacturing process. The structures further comprise at least one base, having a laterally-extending base surface, and an optical component interface. At least one armature connects the optical component interface with the base. In the preferred embodiment, the base surface is securable to an optical bench.
Abstract:
Optical coherence tomography (OCT) probe and system designs are disclosed that minimize the effects of mechanical movement and strain to the probe to the OCT analysis. It also concerns optical designs that are robust against noise from the OCT laser source. Also integrated OCT system-probes are included that yield compact and robust electro-opto-mechanical systems along with polarization sensitive OCT systems.
Abstract:
A microelectromechanical systems (MEMS)-tunable vertical-cavity surface-emitting laser (VCSEL) in which the MEMS mirror is bonded to the active region. This allows for a separate electrostatic cavity that is outside the laser's optical resonant cavity. Moreover, the use of this cavity configuration allows the MEMS mirror to be tuned by pulling the mirror away from the active region. This reduces the risk of snap down. Moreover, since the MEMS mirror is now bonded to the active region, much wider latitude is available in the technologies that are used to fabricate the MEMS mirror. This is preferably deployed as a swept source in an optical coherence tomography (OCT) system.
Abstract:
Methods and systems for increasing resolution and mitigating sidelobe artifacts on point spread functions in optical coherence tomography systems by addressing (1) the swept source's power variation across the scan band, (2) errors in sampling instances, and (3) window function selection.
Abstract:
An optical coherence analysis system uses a laser swept source that is constrained to operate in a stable mode locked condition by modulating a drive current to the semiconductor optical amplifier as function of wavelength or synchronously with the drive voltage of the laser's tunable element based on stability map for the laser.