Fiber Bragg gratings (FBG) may be used to perform phase adjustment for optimal phase-sensitive amplification. Specifically, FBGs may be used between the idler stage and the amplification stage of an optical phase-sensitive amplifier for phase shifting or tuning. The phase shifting or tuning may be applied to at least one of an input optical signal, an idler signal, and an optical pump. A feedback control loop may be used in the phase-sensitive optical amplifier with respect to an output optical signal for optimal phase adjustment.

A communication apparatus for a fibre-optic communication system for an aircraft that includes: an optical coupler; an input port optically coupled to the optical coupler via a first waveguide, the input port arranged to receive light; a modulator optically coupled to the optical coupler via a second waveguide, the modulator having a logic input and a fibre having a fibre Bragg grating (FBG) receiving light from the input port via the optical coupler, the modulator operable to vary a strain force applied to the fibre according to a logic signal received at the logic input to modulate a wavelength of a modulated light signal reflected by the FBG back to the optical coupler; and an output port optically coupled to the optical coupler via a third waveguide to receive the modulated light signal therefrom, the output port being operable to output the modulated light signal.

An apparatus for sensing acoustic waves below a surface of the earth includes an optical fiber disposed below the surface of the earth and having a series of sensing units along the optical fiber with each sensing unit having three or more reflectors and an optical interrogator in optical communication with the optical fiber. The reflectors in each sensing unit are positioned to provide a linearized response that approximates a sawtooth wave better than a sinusoidal wave to sense the acoustic waves in a desired dynamic range. The optical interrogator is configured to transmit an input light signal into the optical fiber and receive a reflected light signal from the optical fiber due to the input light signal in order to measure a strain on each sensing unit due to interaction with the acoustic waves and to determine a location of the sensing unit corresponding to the sensed strain.

An optical force sensor along with an optical processing apparatus and method are disclosed. The optical force sensor includes an optical fiber, a core included in the optical fiber, an instrument including the optical fiber, the instrument having a distal region, and a tubular structure encasing an end of the optical fiber and secured to the first conduit at the distal region of the instrument. When an optical interferometric system is coupled to the optical fiber, it processes reflected light from a portion of the core included within the tubular structure that does not include Bragg gratings to produce a measurement of a force present at the distal region of the instrument.

A communication apparatus includes an optical fiber along which radiation can be transmitted; an optical fiber grating formed within the optical fiber, the optical fiber grating having a structure, and configured to reflect radiation at a particular wavelength; and an instrument coupled to the grating and configured to controllably modify the structure of the grating, thereby changing the wavelength at which the grating reflects radiation. A communication system including the communication apparatus is also described, along with a method of communicating a signal.

A fiber optic transducer is provided. The fiber optic transducer includes a fixed portion configured to be secured to a body of interest, a moveable portion having a range of motion with respect to the fixed portion, a spring positioned between the fixed portion and the moveable portion, and a length of fiber wound between the fixed portion and the moveable portion. The length of fiber spans the spring. The fiber optic transducer also includes a mass engaged with the moveable portion. In one disclosed aspect of the transducer, the mass envelopes the moveable portion.

Application of non-uniform strain to discrete segments of a fiber grating mechanically changes the structure type of the associated device, e.g., the refractive index perturbation profile of the fiber grating is changed from uniform to phase shifted superstructured, or from chirped to superstructured. The strain may be applied with one or more deformable corrugated slides which are bonded to the fiber grating between the discrete segments. The applied strain changes the local period of fiber grating. Complex changes may be achieved via variations of corrugated slide dimensions. An LPFG may be provided with bare fiber by applying periodically longitudinal axial strain to fiber at multiple discrete segments on the fiber.

A measurement system for assisting in guiding a tubular-shaped medical device in a body includes a multicore fiber for insertion into a tubular-shaped medical device such that a position of the tip of the multicore fiber corresponds with a position near the tip of the tubular medical device. A plurality of Bragg gratings is inscribed in the multicore fiber. The plurality of Bragg gratings is spaced apart from each other and positioned along the length of the multicore fiber. A measurement device for reading out optical signals is obtained as a function of a total length of a multicore fiber portion inserted in the body. The measurement device is adapted for deriving shape information of the multicore fiber when the multicore fiber is inserted.

A garment for real time detection of body deformation during an image scan includes a front portion, made of a compression material and having a plurality of fiber Bragg gratings (FBGs). The garment includes a plurality of light emitters, each light emitter configured to pulse light waves through a corresponding FBGs and a plurality of light sensors, each light sensor attached to a corresponding FBG and configured to receive pulsed light waves. A processor obtains data through a data acquisition module configured to receive from the light sensors peak wavelengths reflected by the FBG Based on the effective shifts of the Bragg wavelengths of the FBGs aligned along the cartesian coordinate system, the processor may correct acquired image data or re-direct an external beam treatment to compensate for body deformation during an image scan.

A method for compensating for dynamic changes in a body of a patient during a controlled interaction with the body includes acquiring data from at least one sensing device disposed on the body and detecting a change along at least one optical fiber of the sensing device caused by dynamic changes associated with the body during the controlled interaction. A respiratory gating signal is generated based on the change along the at least one optical fiber of the sensing device measured over time. The method further comprises controlling relative movement between the body and an interactive device in response to the respiratory gating signal to compensate for the dynamic changes associated with the body during the controlled interaction.