Design and fabrication of a 2×2 two-mode interference (TMI) coupler based on-chip polarization splitter is presented. By changing the angle between the access waveguides, one can tune the effective TMI length for the mode with less optical confinement (transverse magnetic, TM) to coincide with the target TMI length for a desired transmission of the mode with higher optical confinement (transverse electric, TE). The fabricated 0.94 μm long 2×2 TMI splits the input power into TM (bar) and TE (cross) outputs with splitting ratio over 15 dB over 50 nm bandwidth. Fabrication tolerance analysis shows that the device is tolerant to fabrication errors as large as 60 nm.

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Ultracompact and fabrication-tolerant integrated polarization splitter.

An apparatus, method, signal and computer program product is provided to generate an image file that can correctly reproduce image data at a predetermined output device. The image file includes an image data storage area that stores image data, and a control information storage area stores output control information. The image data is stored in JPEG format for example, and output control information is stored in TIFF format. The output device control information is information set so as to be able to obtain an optimal image output results according to a paired-combination of the input device and output device, taking into consideration their respective image processing characteristics.

Apparatus, method, signal and computer program product configured to provide output image adjustment of an image file

A multimode interference device and method of making the same comprises at least one input port, at least one output port, a multimode interference region separating the input port from the output port, and at least one subregion in the multimode interference region, wherein a self-image length within the multimode interference region is reduced by a factor that is approximately equal to one plus a number of subregions configured in the multimode interference region, wherein the at least one subregion is configured to have an effective width and effective refractive index running longitudinally through the multimode interference region. Additionally, the subregion may comprise at least one slot.

Slotted multimode interference device

A pressure measurement system and method are described. The system uses a tunable laser and a Fabry-Perot sensor with integrated transducer. A detector senses the light modulated by the Fabry-Perot sensor. A signal conditioner, which can be located up to 15 km away, then uses the detector signal to determine the displacement of the diaphragm, which is indicative of pressure exerted against the diaphragm. Use of a temperature sensor to generate a signal, fed to the signal conditioner, to compensate for temperature is also contemplated.

Method and apparatus for continuous readout of Fabry-Perot fiber optic sensor

In a Fabry-Perot interferometer based sensor if insufficient light reflected from the sensor re-enters the fiber, the results from the Fabry-Perot interferometer-based sensor are compromised. Accordingly, a sensor assembly is provided that comprises an optical fiber having an optical axis, a lens in optical communication with the optical fiber, the lens having an optical axis and the lens capable of transmitting a beam of light, a reflective surface, the reflective surface spaced from the lens such that the beam of light transmitted from the lens is capable of reflecting from the reflective surface back to the lens, and an alignment device capable of aligning the beam of light transmitted from the lens substantially perpendicular with the reflective surface.

High intensity fabry-perot sensor

An integrated optical device for the separation/combination of orthogonal polarizations is described. The device relies on simultaneous symmetric and antisymmetric 131 off-center self-imaging. Calculations show that 90% throughput and 0.1% crosstalk can often be attained, with device length less than or comparable to other integrated optical polar- ization separation devices. The device is passive, requires only a single mask, and is not restricted to a specific fabrication method or material system. Devices can even be made in isotropic material systems with a deep etch. Simulation results are presented for the lithium niobate and glass waveguide material systems. © 2001 Society of Photo-Optical Instrumen- tation Engineers. (DOI: 10.1117/1.1402623)

Polarization separation'combination based on self-imaging

A method and system for stabilizing and demodulating an interferometer at quadrature are described. In response to receipt of a signal indicative of optical power of the interferometer, an interferometer control system determines an optical path length correction required to stabilize the interferometer at quadrature utilizing signal amplitudes appearing at multiple harmonics of the signal. In a particularly preferred embodiment, the signal amplitudes are calculated utilizing the Goertzel algorithm, a computationally efficient discrete Fourier transform. The interferometer control system then outputs an error signal indicative of the optical path length correction. In a preferred embodiment, the error signal forms the DC component of a composite stabilization signal, whose AC component is the reference modulation signal utilized to excite a transducer to modulate the optical path length of the interferometer. With the interferometer stabilized at quadrature, the interferometer control system determines a first signal amplitude of a particular harmonic without target oscillation and a second signal amplitude of the same harmonic with target oscillation. Based upon the relative magnitudes of the first and second signal amplitudes, the interferometer control system determines a solution set for the displacement amplitude of the interferometer target. Any ambiguity in the displacement amplitude can then be eliminated utilizing additional information gained from the signal amplitude present at a harmonic of a target oscillation frequency.

Method and system for stabilizing and demodulating an interferometer at quadrature

An optical fiber interferometer is described for measuring the out-of-plane displacement of microelectromechanical structures. The in- terferometric system has a theoretical measurement dynamic range greater than 10 8 . Experimental results characterizing an electrostatically actuated polysilicon flexure beam are presented. The results are in good agreement with modeling data based on coupled boundary-element and finite-element analysis. © 2003 Society of Photo-Optical Instrumentation Engineers.

Optical fiber interferometer for measuring the in situ deflection characteristics of microelectromechanical structures

The quantum-noise-limited sensitivity is derived for a two-beam interferometer, which uses a phase generated carrier demodulation scheme. For surface-disturbance-detecting sensors, this sensitivity limit is expressed in terms of the smallest displacement that may be detected if the signal-to-noise ratio is unity. We determine the quantum-noise-limited displacement of the classical Michelson interferometer to be 5 pm.

Quantum-noise-limited sensitivity of an interferometer using a phase generated carrier demodulation scheme

In this paper, we present a metrology system to characterize the refractive index profile of intraocular lenses (IOLs).
Our system is based on interferometric optical phase computed tomography. We believe this metrology system to be a
key enabling technology in the development of the next generation of IOLs. We propose a Fizeau-based optical
configuration and present a simulation study on the application of computed tomography to IOL characterization.

Tristan J. Tayag

Papers

Polarization separation'combination based on self-imaging

Method and system for stabilizing and demodulating an interferometer at quadrature

Optical fiber interferometer for measuring the in situ deflection characteristics of microelectromechanical structures

Quantum-noise-limited sensitivity of an interferometer using a phase generated carrier demodulation scheme

Simulation of an interferometric computed tomography system for intraocular lenses