Abstract: A measuring device and an optical fiber strain measuring jig thereof appropriately measure an attraction force distribution on a wafer held by an electrostatic chuck. The measuring jig includes a substrate configured to be held by the electrostatic chuck; and an optical fiber including therein reflection elements capable of reflecting light having a wavelength corresponding to strain of the substrate due to stress, and fixed to one surface of the substrate in a state in which the reflection elements are disposed at plural positions, respectively, on the one surface of the substrate.

Abstract: A method for constructing a six-degree-of-freedom ROV operation simulation platform comprises an integrated control platform, an instructor control system, a marine environment simulation system, a simulation platform calculation system, an ROV control system, a display system and a database storage system; wherein the construction method comprises (1) calculating a hydrodynamic coefficient and a time delay function of a mother ship according to a profile of the mother ship; (2) establishing a finite difference model of umbilical cables and tethers by adopting a beam model, and calculating a shape and tensions at both ends; step (3) establishing boundary conditions of the umbilical cables and the tethers in a coupling model; (4) modeling a tether management system by using a bar element model; (5) establishing a nonlinear ROV maneuverability equation; and (6) establishing a dynamic model of the manipulator considering a pose of the ROV.

Abstract: An information processing device includes a storage configured to store a first film thickness model or a first refractive index model defining an amount of change in a film thickness or a refractive index at each position of a first wafer when a film forming processing is performed by changing an output of each of a plurality of plasma sources provided in a film forming device by a predetermined amount and a calculator configured to calculate, based on the first film thickness model or the first refractive index model, a correction value of the output of each of the plurality of plasma sources to achieve a target value of a film thickness or a target value of a refractive index at each position of a second wafer.

Abstract: Analysis of residual stress in materials is often done in static conditions in a laboratory. Accurate systems and methods for performing these analyses in a dynamic, non-laboratory environment are notoriously difficult and can be very inaccurate. A method using a portable, field deployable apparatus having greater accuracy than currently available is disclosed whereby accurate and repeatable residual stress analysis may be implemented in non-laboratory environments leading to greatly improved diagnostics, maintenance and life limit prediction.

Abstract: A wavelength selective switch, including: an optical fiber array, an optical signal processing device and an output selection device. The optical fiber array includes multiple dual-core optical fibers arranged in parallel, one dual-core optical fiber being used for inputting two optical signals; the optical signal processing device is located at an output end of the optical fiber array and is used for splitting the two optical signals into sub-signals of different wavelengths and projecting the sub-signals of different wavelengths to different spectral band regions in the output selection device; and the output selection device is located at the rear end of the optical signal processing device, and is used for processing the sub-signals projected to the spectral band regions, so as to respectively perform output selection on the sub-signals split from two optical signals, thereby achieving a dual-switch function.

Abstract: A stretchable strain sensor includes a light-emitting element, an optical structure, and a photo-detective element. The stretchable strain sensor is located in a path of light emitted from the light-emitting element. The optical structure is configured to have optical properties that change in response to stretching of at least a portion of the stretchable strain sensor. The photo-detective element is configured to detect light transmitted through the optical structure or reflected through the optical structure.

Abstract: A monitoring system for a power grid includes one or more power transformer monitors. Each power transformer monitor includes a plurality of optical sensors disposed on one or more optical fibers that sense parameters of the power transformer. Each optical sensor is configured to sense a power transformer parameter that is different from a power transformer parameter sensed by at least one other sensor of the plurality of optical sensors. An optical coupler spatially disperses optical signals from the optical sensors according to wavelength. A detector unit converts optical signals of the optical sensors to electrical signals representative of the sensed power transformer parameters.

Abstract: Methods of characterizing ion-exchanged chemically strengthened Li-containing glasses include: a) measuring a mode spectrum of the glass sample; b) using the mode spectrum, estimating a first contribution to the center tension associated with a spike region and estimating a second contribution to the center tension due to a deep region only, wherein the deep region is assumed to follow a power-law stress profile; and c) determining a total center tension by adding of the first and second contributions to the center tension. The methods can be used for quality control during manufacturing of glass samples by comparing the total center tension to a center tension specification that provides optimum strength and durability.

Abstract: A posture control system for a hull, and a marine vessel including the posture control system, allows crew members to fish more comfortably and includes a posture control tab attached to a stern of the hull to control a posture of the hull, a driver to drive the posture control tab, and a controller to control the driver. When it is determined that the hull has changed to a fishing mode, the controller causes the driver to raise the posture control tab to a predetermined position.

Abstract: Analysis of residual stress in materials is often done in static conditions in a laboratory. Accurate systems and methods for performing these analyses in a dynamic, non-laboratory environment are notoriously difficult and can be very inaccurate. A method using a portable, field deployable apparatus having greater accuracy than currently available is disclosed whereby accurate and repeatable residual stress analysis may be implemented in non-laboratory environments leading to greatly improved diagnostics, maintenance and life limit prediction. Especially the analysis of a pipe or channel can be facilitated with this invention.

Abstract: Provided is a displacement measurement system including: a sensor that is contactable with a measurement target object and includes a first spacer that has at least a one-dimensional spread, and two or more types of light emitting particles that are distributed over the spread of the first spacer and emit light at different wavelengths by an excitation energy; an excitation energy source that causes the two or more types of light emitting particles included in the sensor to emit light; and a light receiver that receives light emitted from the sensor.

Abstract: Provided are three dimensional, stretchable, optical sensor networks that can localize deformations. The devices described herein are suitable for uses in soft robots to determine the position of external contact, such as touching, and possibly internal deformations that may be caused by actuation. Sensor networks of the present disclosure contain a substrate, such as a 3D lattice, and cores having a cladding, such as air. Light passes through the cores and upon deformation of the substrate, cores may come into contact, allowing light to couple between cores due to frustrated total internal reflection. The resulting changes in intensity in the cores can be used to determine the placement and magnitude of deformation.

Abstract: The prism-coupling systems and methods include using a prism-coupling system to collect a 2D digital mode spectrum of an IOX article. The mode line and critical angle positions and orientations are found by performing a weighted fit to mode line and critical angle images and are used to define a compensated mode spectrum. If mode line tilt is found, it is removed from the 2D digital mode spectrum to define the compensated mode spectrum. The compensated mode spectrum is then processed using techniques known in the art to provide a more accurate estimate of stress-related characteristics of the IOX sample versus using the uncompensated mode spectrum. Derivative-based methods of accurately establishing positions of intensity transitions in a mode spectrum of an IOX sample using a derivative spectrum and curve fitting are also disclosed.

Abstract: Methods of characterizing ion-exchanged chemically strengthened Li-containing glasses include: a) measuring a mode spectrum of the glass sample; b) using the mode spectrum, estimating a first contribution to the center tension associated with a spike region and estimating a second contribution to the center tension due to a deep region only, wherein the deep region is assumed to follow a power-law stress profile; and c) determining a total center tension by adding of the first and second contributions to the center tension. The methods can be used for quality control during manufacturing of glass samples by comparing the total center tension to a center tension specification that provides optimum strength and durability.

Abstract: An environmental property measurement apparatus includes a unit configured to receive probe light in a desired mode from one end of a measurement optical fiber, a unit configured to receive, from the other end of the measurement optical fiber, a light pulse in the desired mode as a pump light pulse with respect to the probe light, the light pulse having a frequency difference corresponding to a Brillouin frequency shift of the measurement optical fiber relative to the probe light on a high frequency side, and a unit configured to receive second probe light having the frequency difference corresponding to the Brillouin frequency shift of the measurement optical fiber relative to the probe light on a low frequency side from the other end of the measurement optical fiber, the second probe light being probe light with respect to the probe light in another mode different from the desired mode.

Abstract: A system for detecting sound comprising a laser beam transmitter transmitting at least two parallel modulated laser beams through a medium having a measurable index of refraction, a beam termination mechanism configured to terminate the laser beams' transmission through the medium, a guide mechanism used to guide the terminated laser beam to at least one beam combiner, an envelope detector optically coupled to the beam combiner, wherein the envelope detector is configured to receive the terminated laser beam from the beam combiner, creating an angle modulated signal; a processor used to process the angle modulated signal to recover the sound.

Abstract: A borescope may include a housing including a transparent viewing window, a bumper surrounding at least a portion of a periphery of the transparent viewing window, wherein the bumper is configured to be pressurized by a fluid, and at least one imaging assembly configured to visualize a field of view exterior of the housing through the transparent viewing window.

Abstract: A method is provided for facilitating a vacuum bagging operation during fabrication of a composite laminate. The method comprises applying a vacuum bag over a composite part to fabricate the composite laminate from the composite part. The method also comprises drawing a vacuum in the vacuum bag, and monitoring one or more portions of the vacuum bag for strain within the vacuum bag when the vacuum is drawn. The method further comprises manipulating the vacuum bag to even out strain within the vacuum bag.

Abstract: The invention relates to a seal containing a substrate which can be applied to an object to be sealed, so that said seal is changed when it is removed without authorization, wherein the substrate contains or comprises a polymer and/or a glass and at least one optical waveguide is arranged in the substrate, at least one first Bragg grating being arranged in said optical waveguide, wherein the substrate has a thickness of less than 200 ?m. The invention further relates to a system having a seal of this kind and having an evaluation device, and also to a sealing method.

Abstract: Using the systems and methods discussed herein, CMAS corrosion is inhibited via CMAS interception in an engine environment and/or is prevented or reduced by the formation of a metal oxide protective coating on a hot engine section component. The CMAS interception can occur while the engine is in operation in flight or in a testing or quality control environment. The metal oxide protective coating can be applied over other coatings, including Gd-zirconates (GZO) or yttria-stabilized zirconia (YSZ). The metal oxide protective coating is applied at original equipment manufacturers (OEM) and can also be applied in-situ using a gas injection system during engine use in-flight or during maintenance or quality testing. The metal oxide protective coating contains a rare earth element, aluminum, zirconium, chromium, or combinations thereof, and is from 1 nm to 3 microns in thickness.

Abstract: Methods of characterizing ion-exchanged chemically strengthened Li-containing glasses include: a) measuring a mode spectrum of the glass sample; b) using the mode spectrum, estimating a first contribution to the center tension associated with a spike region and estimating a second contribution to the center tension due to a deep region only, wherein the deep region is assumed to follow a power-law stress profile; and c) determining a total center tension by adding of the first and second contributions to the center tension. The methods can be used for quality control during manufacturing of glass samples by comparing the total center tension to a center tension specification that provides optimum strength and durability.

Abstract: Disclosed is a method of measuring a surface refractive index of a strengthened glass including causing light to enter a surface layer of the strengthened glass through a liquid provided with a refractive index equivalent to that of a surface of the surface layer; a process of causing the light to be emitted from the strengthened glass through the liquid; converting two types of light components into two types of emission line sequences; capturing an image of the two types of emission line sequences; measuring positions of respective emission lines of the two types of emission line sequences from the image; and calculating refractive indexes of a surface of the strengthened glass corresponding to the two types of light components, or refractive index distributions of the strengthened glass in a depth direction from the surface corresponding to the two types of light components.

Abstract: A system for monitoring parameters of an object is described. The system comprising: a monitoring unit configured for performing one or more monitoring sessions on an object and collecting data from an inspection region on the object over time and generating monitored data indicative of the inspected region, a stimulation unit configured and operable for applying at least one selected external stimulation field on the object during said one or more monitoring sessions, and a control unit configured for receiving the monitored data from the monitoring unit and determining one or more selected parameters. The stimulation unit is configured for providing said at least one selected external stimulation field directed toward said inspection region from two or more different directions.

Abstract: An FBG element is configured to apply a phase shift to at least one of an input optical signal, a first pump light, and an idler signal between stages of a phase sensitive amplifier. The FBG element is apodized using a trapezoidal apodization function over the length of the first FBG element to enable tuning of the phase shift over a range of 2? radians.

Abstract: Rotor thrust balancing systems for turbomachines and methods of using the same are generally disclosed. For example, a rotor thrust balancing system for a turbomachine, wherein the turbomachine defines a centerline extending the length of the turbomachine. The system includes a rotating drive shaft, a thrust bearing, and a first waveguide sensor. The rotating drive shaft couples a turbine section and a compressor section of the turbomachine. The thrust bearing supports the rotating drive shaft of the turbomachine. The thrust bearing includes a plurality of ball bearings, an inner race coupled to the rotating drive shaft, and an outer race coupled to a fixed structure. The first waveguide sensor is coupled to the outer race at a first end of the waveguide sensor. The waveguide sensor communicates a vibrational frequency from the thrust bearing to a second end of the waveguide sensor.

Abstract: A true stress testing system broadly comprising a force input machine, an imaging system, and a computer. The imaging system includes a light source for projecting a light beam at the specimen in a first direction and a camera positioned on an opposite side of the specimen for receiving portions of the light beam not blocked by the specimen such that a shadow image of the specimen is created via the camera. The computer may determine a minimum dimension of the specimen perpendicular to the first direction at a point in time over a plurality of points along the force axis via the shadow image of the specimen such that the processor accounts for changes in position of the minimum dimension along the specimen. A true stress of the specimen may then be determined according to the minimum dimension of the specimen perpendicular to the first direction at the point in time.

Abstract: Conventional optical-transmission-type residual stress measuring apparatus cannot be used for completing the measurement of residual stress in an optical film having light reflective property, and conventional optical-reflection-type residual stress measuring apparatus is known failing to achieving the measurement of residual stress in an optical thin film having transparent or translucent property. In view of that, the present invention discloses a system for measuring residual stress in optical thin films, which is able to be utilized for achieving the residual stress measurement of respective optical thin film having transparent or translucent property and that of respective optical thin film having light reflective property.

Abstract: A multicore fiber for communication 10 which allows propagation of an optical signal includes: a clad 12; a core 11a which is arranged in a center of the clad 12; and seven to ten cores 11b which are arranged at equal intervals surrounding the core 11a, and the cladding diameter is 230 ?m, distances between centers of the mutually neighboring cores 11a and 11b are 30 ?m or more, distances between the centers of the cores 11b and an outer peripheral surface of the clad 12 are 35 ?m or more and a mode field diameter of light propagating in the cores 11a and 11b is 9 ?m to 13 ?m.

Abstract: A system for monitoring smoke and/or temperature of an electronic device includes a fiber harness having at least one fiber optic cable terminating at a node. The node is located to measure one or more conditions at the electronic device, and a control system operably connected to the fiber harness. The control system includes a light source configured to transmit light through the fiber harness, a light sensitive device configured to receive scattered light associated with the node, and a control unit configured to analyze the scattered light to determine at least one of a presence and magnitude of the one or more conditions at the node of one or more conditions at the electronic device, wherein the control unit is further configured to transmit a signal in response to the one or more conditions, wherein the one or more conditions are one or more of smoke, fire, and temperature.

Abstract: A metrology device includes a sound sample holder and an optical system. The sound sample holder is provided for applying sound waves to a first substrate stack surface of the substrate stack. The optical system include a source, a lens field, a beam splitter, and a detector. The source is provided for outputting electromagnetic radiation, which is split into at least one first beam path and one second beam path. The lens field is provided for applying the first beam path to a substrate stack measuring surface of the substrate stack. The beam splitter is provided for forming an interference radiation made up of the first and second beam paths of the electromagnetic radiation. The detector is provided for detecting the interference radiation.

Abstract: A method and apparatus are disclosed for determining a bending radius of a flexible pipe. The apparatus includes at least one bend sensor element comprising an elongate flexible substrate and at least one bend sensitive element on the substrate that has at least one electrical characteristic that is responsive to angular displacement of the substrate. The apparatus also comprises a flexible crush resistant elongate housing that supports and surrounds the bend sensor element.

Abstract: An optical system and method for connecting two optical fibers is described in the present disclosure. An example optical system includes a first optical fiber embedded in an embedding material, the first optical fiber comprising side walls extending in a longitudinal direction in contact with the embedding material, a second, external, optical fiber, and a self-written waveguide in optical contact with the first and second optical fibers. Only a cross section perpendicular to the side walls of the first optical fiber is outside the embedding material, in contact with the self-written waveguide.

Abstract: The system includes a movement sensor and a core contraction sensor in communication with a processor. The core contraction sensor is placed on the core muscles of a user and transmits core contraction signals to the processor. The processor receives movement signals from the movement sensor and identifies user movements that are qualifying movements that benefit from core contractions. The processor also monitors the timing between the qualifying movements and the core contractions to identify protected and unprotected qualifying movements. The system can also include a memory for storing core scores that are calculated from the protected and unprotected qualifying movements, exercise information and core sensor calibration information. The core contraction information can be used to calibrate the core contraction sensor. The core contraction and movement information can be transmitted to a therapist who can monitor the user's activities and provide instructional feedback.

Abstract: A strain amount calculation system includes an imaging unit, and a strain amount calculation device that acquires an image taken by the imaging unit, measures luminescent brightness from the acquired image, calculates an amount of strain on the object caused by a load on the object, based on a temporal change in the measured luminescent brightness, and outputs information on the calculated strain amount.

Abstract: A full-duplex borehole communication system includes a single light source to generate a light signal. A downlink modulator is coupled to the light source to modulate the light signal in response to downlink data using a first protocol to generate a first modulated light signal. An uplink modulator is coupled to the downhole modulator to modulate the first modulated light signal in response to uplink data using a second protocol to generate a second modulated light signal. A downlink receiver is coupled to the downlink modulator to demodulate the first modulated signal to recover the downlink data. An uplink receiver is coupled to the uplink modulator and configured to demodulate the second modulated light signal to recover the downlink data and the uplink data. Asymmetric protocols are used between the downhole portion of the system and the uphole portion.

Abstract: The disclosed technology includes, among others, methods and devices for measuring distributed fiber bend or stress related characteristics along an optical path of fiber under test (FUT) uses both a light input unit and a light output unit connected to the FUT at one single end.

Abstract: A strain sensor includes a marker, detectors and a calculator. The marker is disposed on a surface of a measurement object and includes a strain body and surface plasmon generating particles. In the strain body, a strain is formed by a load. The surface plasmon generating particles are arranged in two directions which are parallel to two in-plane directions of a light receiving surface of the strain body. The first detector detects a spectral intensity of a light which has been reflected on the marker or has passed through the marker. The second detector detects absorption spectral peaks corresponding to the respective array directions of the particles from the spectral intensity. The calculator calculates the quantity of the strain of the marker based on a difference in wavelength of the two absorption spectral peaks.

Abstract: A pressure sensing device including a light source, at least one resonant structure, a cladding body, a first substrate and a second substrate is provided. The light source is configured to provide an original broadband light. The resonant structure includes a plurality of semiconductor rod structures arranged into a row at intervals along a single arranging direction, and each of the semiconductor rod structures has a lattice constant on the arranging direction. The original broadband light is transmitted between the semiconductor rod structures, and a resonant light is produced, wherein each of the semiconductor rod structures has a length perpendicular to the arranging direction and has a width parallel to the arranging direction, the length and the width are less than the wavelength of the resonant light. The cladding body completely covers the semiconductor rod structures of the at least one resonant structure.

Abstract: An illustrative distributed acoustic sensing system includes a multi-mode optical fiber cable for distributed sensing and a distributed acoustic sensing interrogator coupled to the multi-mode optical fiber cable via a single mode optical fiber. The interrogator derives distributed acoustic measurements from Rayleigh backscattering light that is initiated with a substantially under-filled launch configuration that is designed to excite only the lowest-order modes of the multi-mode optical fiber. Mode conversion within the multi-mode optical fiber is anticipated to be negligible. For elastic scattering (i.e., Rayleigh scattering), it is further anticipated that the scattered light will be primarily returned in the incident propagation mode, thereby escaping the extraordinarily large coupling loss that would otherwise be expected from coupling a single-mode optical fiber to a multi-mode optical fiber for distributed sensing. Experiments with graded index multi-mode optical fiber have yielded positive results.

Abstract: In the field of monitoring the aging of parts subjected to a rotary movement and, more precisely, of monitoring the deformation to which a peripheral surface of a rotating part is possibly subject, an improved method is provided. The method includes: a step of emitting a light signal at a first end of an optical fiber at least one section of which runs between two points of the surface of the part; a step of measuring a characteristic of the light signal received at a second end of the optical fiber, the characteristic varying as a function of the length of the optical fiber between its ends; and a step of comparing the characteristic of the light signal to a reference signal.

Abstract: The present invention relates to a method for evaluating a SERS sensor substrate, comprising the steps of: a) measuring, through a dark-field microscope, the color of nanoparticles positioned on the SERS sensor substrate; b) converting the measured color into a distance between the nanoparticles; c) acquiring the Raman signal intensity of the SERS sensor substrate; d) acquiring the standard Raman signal intensity of a standard SERS sensor substrate including the nanoparticles having the distance that is the same as the converted distance; and e) comparing the Raman signal intensity and the standard Raman signal intensity.

Abstract: In order to provide a simplified inspection of an aircraft for the pilot, an aircraft inspection system is provided which includes at least one movable inspection unit, a position detection arrangement, and at least one data transfer interface. The at least one moveable inspection unit is moveable relative to an aircraft to be inspected. The at least one movable inspection unit includes at least one sensor for detecting a characteristic value, for verifying a characteristic and/or for determining a defect of an aircraft. The movable inspection unit is configured to generate monitoring data. When a defect or a characteristic value is detected, the position detection arrangement detects position data of the movable inspection unit in relation to the aircraft to be inspected, and assigns the position data to the monitoring data. The data transfer interface provides the position data with the assigned monitoring data as inspection data.

Abstract: An optical fiber cable assembly which includes an optical fiber cable which includes at least a first core and a second core positioned spaced apart from one another within a cladding material, wherein the at least first core and the second core and the cladding material extend in a direction of a length of the optical fiber cable. The assembly further includes material positioned at a predetermined location along the length of the optical fiber cable, wherein the material is associated with the optical fiber cable such that when the material is exposed to an environment change, the material transmits a force onto the optical fiber cable, changing a shape of the optical fiber cable.

Abstract: In a strain sensor and a method for installing a strain sensor according to the present invention, a first base fixes and supports one side of an optical fiber. A second base fixes and supports another side of the optical fiber. A connecting member is constituted of a separate member from the first base and the second base and is detachably mounted between the first base and the second base. Tension is applied to the optical fiber in a state in which the connecting member is mounted between the first base and the second base, and the optical fiber is fixed to and supported by the first base and the second base in a state in which tension is applied.

Abstract: A multiple sensor fiber optic sensing system includes an optical fiber having at least first fiber optic sensors and second fiber optic sensors deployed along its length. In response to an interrogating pulse, the first fiber optic sensors generate responses in a first optical spectrum window, and the second fiber optic sensors generate responses in a second, different optical spectrum window. The responses in the first optical spectrum window are measured in a first optical spectrum channel, and the responses in the second optical spectrum window are measure in a second, different optical spectrum channel and provide simultaneous indications of one or more parameters, such as temperature and pressure, in the environment in which the sensors are deployed.

Abstract: For processing eye tissue using a pulsed laser beam (L), an ophthalmological device includes a projection optical unit for the focused projection of the laser beam (L) into the eye tissue, and a scanner system upstream of the projection optical unit for the beam-deflecting scanning of the eye tissue with the laser beam (L) in a scanning movement (s?) performed over a scanning angle along a scanning line(s). The projection optical unit is tilted about an axis of rotation (q) running perpendicularly to a plane defined by the scanning line(s) and the optical axis (o) of the projection optical unit, the tilting of the projection optical unit tilting the scanning line (s) in said plane. Tilting of the scanning line(s) enables a displacement—dependent on the scanning angle—of the focus of the laser pulses projected into the eye tissue without vertical displacement of the projection optical unit.

Abstract: Various embodiments include apparatus and methods to operate a tool downhole in a well, where the tool has an optical computation element to determine different properties of downhole structures. Such an optical computation element can be structured to provide optical analysis of fluid and material composition of the downhole environment associated with a drilling operation. The data measurements from the optical computation element can be used in a geosteering operation. Additional apparatus, systems, and methods are disclosed.

Abstract: There is provided a system for measuring temperature and strain simultaneously utilizing Brillouin Scattering within an optical fiber. The system has a cladding, a first optical core within the cladding and a second optical core within the cladding and having a different refractive index profile and/or composition than the first core. Means to couple light into and out of said individual optical cores and/or from one optical core to the other within the fiber is provided along with means for calculating strain and temperature characteristics based on measured Brillouin frequencies for said optical cores.

Abstract: A first measured value of a specific physical quantity at a target portion is correlated with a damage evaluation index to calculate a damage degree corresponding to the first measured value. The specific physical quantity is measured at least once at a position corresponding to the first measurement position in another time period having a different usage elapsed time from that of the first measurement, and these second and subsequent measured values are correlated with damage degrees calculated based on temporal changes corresponding to the second and subsequent measurements. A new damage evaluation index is approximately calculated based on a relationship between the first, second, and subsequent measured values and the damage degrees corresponding to the first, second, and subsequent measured values.

Abstract: Small profile apparatus for pressure and/or temperature sensing within a wellbore are provided. The apparatus may include optical sensing assemblies designed for inclusion in traditional or coiled production tubing deployments and suitable for use in high pressure, high temperature environments. One example assembly generally includes a housing having a divider for separating a first volume from a second volume inside the housing, a compressible element disposed in the first volume, wherein a first end of the compressible element is coupled to the divider and a second of the compressible element is sealed, and a large diameter optical waveguide disposed in an internal volume of the compressible element. The waveguide typically includes a first portion with a first grating and a second portion with a second grating, wherein the first portion has a greater outer diameter than the second portion.