摘要:
Methods and apparatus for coupling of pump light inside a laser cavity of a fiber laser. The optical elements of the cladding pumped laser are configured such that the pump laser is coupled within the laser cavity. An optical fiber laser includes a laser cavity comprising a lasing medium and first and second reflector devices, a pump source, and a combiner. The combiner has a first side, a second side and an input port that may be associated with one of the first and second sides. An output of the pump source is operatively coupled to the input port of the combiner, and the combiner is coupled at its first and second sides within the laser cavity.
摘要:
Raman fiber amplifiers are provided in which multiple pump wavelengths are used. A Raman fiber amplifier may be used to amplify optical signal channels over a range of wavelengths. Some of the pump wavelengths may be selected to create Raman gain in this range. Other pump wavelengths may be selected to create Raman loss in this range. Different pump powers may be used at each pump wavelength.
摘要:
A method and structure for terminating an optical fiber are disclosed that provide an optical fiber termination structure with a small volume and very low return loss, even when the termination is in close proximity to reflective surfaces. In one example embodiment, the optical fiber termination reduces reflections into the one or more cores to a return loss of −70 dB or less regardless of the presence of surfaces proximate the optical fiber termination. At the same time, a length of the optical fiber termination is less than 5 mm and a largest transverse dimension of the optical fiber termination is less than 325 um. The optical fiber termination is useful in fiber sensing applications in general and is particularly effective for terminating a multi-core fiber used in a distributed shape sensing application.
摘要:
Systems and methods for monitoring signals in an optical fiber amplifier system are provided. The optical amplifier system includes a tapered fiber bundle which couples optical energy into the cladding of an optical amplifier. A signal passing through the optical amplifier is amplified. To monitor the amplified signal, a single fiber of a tapered fiber bundle may be used as a monitor fiber. Alternatively, a monitor or coupler may be integrated into the tapered fiber bundle during manufacturing. The systems and methods disclosed allow for monitoring the amplified signal without increasing the length of the amplified signal's path, thus minimizing the introduction of additional non-linearities.
摘要:
A method and structure for terminating an optical fiber are disclosed that provide an optical fiber termination structure with a small volume and very low return loss, even when the termination is in close proximity to reflective surfaces. In one example embodiment, the optical fiber termination reduces reflections into the one or more cores to a return loss of −70 dB or less regardless of the presence of surfaces proximate the optical fiber termination. At the same time, a length of the optical fiber termination is less than 5 mm and a largest transverse dimension of the optical fiber termination is less than 325 um. The optical fiber termination is useful in fiber sensing applications in general and is particularly effective for terminating a multi-core fiber used in a distributed shape sensing application.
摘要:
Optical amplifiers and methods for manufacturing optical amplifiers are provided that allow amplifiers to be fabricated to match design expectations. Optical amplifiers may be manufactured by assembling passive optical components in the amplifier before assembling active optical components such as doped fiber coils. Passive losses may then be characterized and used to calculate the lengths of the fibers that should be used in the amplifier gain stages. Following corrections to the nominal doped-fiber lengths based on the measured passive losses, the passive and active components of the amplifier may be assembled and characterized. Final corrections may be made to the amplifier assembly based on these characterizations. For example, the lengths of one or more of the doped fibers may be adjusted. If desired, such length adjustments may be made to fiber coils in the mid-stage portion of the amplifier, so that the impact on the operating characteristics of the amplifier are minimized.
摘要:
A laser source comprises an optical fiber doped with a homogeneously broadened lasing medium, preferably with Erbium, pumped by a laser pump source and an intracavity acousto-optic modulator. When the acousto-optic modulator is driven by a variable frequency source, the Erbium fluorescence line emitted by the Erbium-doped optical fiber can be electronically tuned. In another embodiment, an electronic sweep waveform is used to frequency modulate the acoustic signal produced by the acousto-optic modulator. Without the low-rate frequency modulation, Erbium in a silica optical fiber is a mostly homogeneously broadened gain medium with a narrow laser linewidth. When measured on a long time scale, low-rate frequency modulation provides a broader spectral width, on the order of 19 nm, which makes such a source on an ideal source for certain optical applications such as fiber optic gyroscopes.
摘要:
An embodiment of a method of manufacturing a fiber optic cable includes selecting a cable support structure configured to support an optical fiber sensor, adhering the optical fiber sensor to the cable support structure by applying a temporary adhesive, and installing a protective layer around the cable support structure and the temporarily adhered optical fiber sensor. The method further includes removing a bond between the optical fiber sensor and the temporary adhesive, wherein removing the bond includes injecting a debonding material into a space formed between the cable support structure and the protective layer, and injecting a permanent adhesive into the space, the permanent adhesive configured to immobilize the optical fiber sensor relative to the protective layer and allow strain to be transferred from the protective layer to the optical fiber sensor.
摘要:
A temperature sensing arrangement includes a member having a first coefficient of thermal expansion, and an optical fiber having a second coefficient of thermal expansion. The optical fiber is strain transmissively mounted to the member. And the first coefficient of thermal expansion is greater than the second coefficient of thermal expansion such that strain measurable in the optical fiber is correlatable to temperature changes in the member.
摘要:
A twisted, multicore fiber communicates light input to each core to an output. The twisting mitigates relative time delays of the input light traveling through each of the cores in the multicore fiber to the output caused by bending of that multicore fiber. An example application is in an optical network that includes an optical input terminal and an optical sensor connected by a twisted multicore connecting fiber. One example of twisted multicore optical fiber is helically-wrapped, multicore fiber.