A surgical instrument is provided, including: at least one articulatable arm having a distal end, a proximal end, and at least one joint region disposed between the distal and proximal ends; an optical fiber bend sensor provided in the at least one joint region of the at least one articulatable arm; a detection system coupled to the optical fiber bend sensor, said detection system comprising a light source and a light detector for detecting light reflected by or transmitted through the optical fiber bend sensor to determine a position of at least one joint region of the at least one articulatable arm based on the detected light reflected by or transmitted through the optical fiber bend sensor; and a control system comprising a servo controller for effectuating movement of the arm.

Robotic surgery system including position sensors using fiber bragg gratings

Cooling of mechanical resonators is currently a popular topic in many fields of physics including ultra-high precision measurements1, detection of gravitational waves, and the study of the transition between classical and quantum behaviour of a mechanical system. Here we report the observation of self-cooling of a micromirror by radiation pressure inside a high-finesse optical cavity. In essence, changes in intensity in a detuned cavity, as caused by the thermal vibration of the mirror, provide the mechanism for entropy flow from the mirror's oscillatory motion to the low-entropy cavity field. The crucial coupling between radiation and mechanical motion was made possible by producing free-standing micromirrors of low mass (m ≈ 400 ng), high reflectance (more than 99.6%) and high mechanical quality (Q ≈ 10,000). We observe cooling of the mechanical oscillator by a factor of more than 30; that is, from room temperature to below 10 K. In addition to purely photothermal effects we identify radiation pressure as a relevant mechanism responsible for the cooling. In contrast with earlier experiments, our technique does not need any active feedback. We expect that improvements of our method will permit cooling ratios beyond 1,000 and will thus possibly enable cooling all the way down to the quantum mechanical ground state of the micromirror.

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Self-cooling of a micromirror by radiation pressure

A surgical instrument is inserted through a guide tube. A telemanipulation system moves the distal end of the surgical instrument in all six Cartesian degrees of freedom independently of any guide tube movements.

Minimally invasive surgical system

We describe a technique for polarization sensitive optical frequency domain reflectometry (OFDR) that achieves 22 micrometer two-point spatial resolution over 35 meters of optical length with -97 dB sensitivity in a single measurement taking only seconds. We demonstrate OFDR’s versatility in both time- and frequency-domain metrology by analyzing a fiber Bragg grating (FBG) in both the spectral and impulse response domains. We also demonstrate how a polarization diversity receiver can be used in an OFDR system to track changes in the polarization state of light propagating through a birefringent component.

High resolution optical frequency domain reflectometry for characterization of components and assemblies.

Apparatus and method for increasing the sensitivity in the detection of optical coherence tomography and low coherence interferometry (“LCI”) signals by detecting a parallel set of spectral bands, each band being a unique combination of optical frequencies. The LCI broad bandwidth source is split into N spectral bands. The N spectral bands are individually detected and processed to provide an increase in the signal-to-noise ratio by a factor of N. Each spectral band is detected by a separate photo detector and amplified. For each spectral band the signal is band pass filtered around the signal band by analog electronics and digitized, or, alternatively, the signal may be digitized and band pass filtered in software. As a consequence, the shot noise contribution to the signal is reduced by a factor equal to the number of spectral bands. The signal remains the same. The reduction of the shot noise increases the dynamic range and sensitivity of the system.

Apparatus and method for ranging and noise reduction of low coherence interferometry LCI and optical coherence tomography OCT signals by parallel detection of spectral bands

Theory and Measurement Techniques for the Noise Figure of Optical Amplifiers

In this letter, we demonstrate coherent optical spectrum analysis with /spl sim/70-dB dynamic range based on a swept-tuned optical local oscillator and a coherent receiver operating in the 1.5-/spl mu/m wavelength hand. Measurement principles are presented along with high-resolution measurements of distributed feedback laser spectra.

Coherent optical spectrum analyzer

Method and system are disclosed for de-embedding optical component characteristics from optical device measurements. In particular, the invention uses frequency domain averaging of the RBS on both sides of an optical component to determine one or more of its optical characteristics. Where the RBS has a slope (e.g., as in the case of a lossy fiber), a frequency domain least square fit can be used to determine the optical component characteristics. In addition, the invention uses a reference DUT to correct for variations in the frequency response of the photoreceiver. A reference interferometer is used in the invention to correct for sweep non-linearity of the TLS. The optical component characteristics are then de-embedded from optical device measurements to provide a more precise analysis of the optical device.

De-embedment of optical component characteristics and calibration of optical receivers using rayleigh backscatter

An optical heterodyne detection system includes a tunable optical pre-selector that is adjusted to track the frequency of a swept local oscillator signal. The tunable optical pre-selector is adjusted in response to a measure of the frequency of the swept local oscillator signal and in response to a measure of a portion of the swept local oscillator signal after the portion of the swept local oscillator signal has optically interacted with the optical pre-selector. In an embodiment, at least some portion of the swept local oscillator signal is modulated before it interacts with the optical pre-selector. In an embodiment, the portion of the swept local oscillator signal that interacts with the pre-selector is detected and used in a feedback control circuit to generate a control signal which causes the error between the center frequency of the pre-selector and the frequency of the swept local oscillator signal to be small.

System and method for optical heterodyne detection of an optical signal including optical preselection that is adjusted to accurately track a local oscillator signal

An optical system such as an add and/or drop WDM multiplexer allows the wavelength fluctuation of an optical carrier to be tracked so that a corresponding fiber Bragg grating (FBG) can be responsively tuned. The preferred embodiment of the wavelength tracking system in an optical system such as an add and/or drop module includes a three-port optical circulator, three optical fibers, a series of tunable FBGs, a source of a broadband optical noise signal, an optical spectrum analyzer (OSA), and an FBG tuner. In operation, an LED generates modulated probe lightwaves that are inserted into a drop module. The LED lightwaves and the optical carriers propagating through the drop module are monitored by an OSA. The monitoring procedure determines the conditions, in terms of target wavelengths of the FBGs, and the stability or instability of the optical carriers. The FBGs are then tuned in response to the FBG and optical carrier information. In another embodiment, the wavelength of an optical carrier is tracked using a modulated tracking grating and an FBG is adjusted in response to the tracking information.

Douglas M. Baney

Papers

Theory and Measurement Techniques for the Noise Figure of Optical Amplifiers

Coherent optical spectrum analyzer

De-embedment of optical component characteristics and calibration of optical receivers using rayleigh backscatter

System and method for optical heterodyne detection of an optical signal including optical preselection that is adjusted to accurately track a local oscillator signal

Wavelength tracking in adjustable optical systems