Wavelength references in the telecom spectrum have applications in communications and dimensional metrology. However, they typically consist of bulk optics and vapor cells. Photonic integration of these components may lead to low cost, portable devices.
Here we demonstrate the incorporation of a photonic Rb spectrometer with an AlN microresonator frequency doubler. Light at 1560 nm is coupled onto a chip containing the AlN microresonator frequency doubler. The resulting 780 nm light is sent to the photonic Rb spectrometer, which consists of an apodized grating beam expander and microfabricated MEMS vapor cell. We perform Doppler broadened spectroscopy of the D2 line and demonstrate preliminary laser stabilization to these features.
In the pursuit of developing a portable wavelength reference, a photonically integrated chip (PIC) was developed to perform high resolution spectroscopy in a small package. The PIC outcouples light from one grating into free space where it is reflected and directed into an adjacent grating that couples into a separate waveguide. These gratings are extreme-mode-converters which convert the confined mode with a characteristic mode size of less than a micron to a collimated 100 micron diameter beam in order to mitigate transit time broadening for high resolution spectroscopy as well as reduce the diffraction angle. A miniature atomic vapor cell is inserted in the path of the beam to complete the spectroscopic platform. Preliminary results demonstrate sub-Doppler features. Coupling into the chip is achieved using fiber arrays enabling the spectroscopic signal to be routed back through an optical fiber and monitored. A laser is then locked to these sub-Doppler features completing an integrated wavelength reference. Analysis of the atom-light interactions made available by this platform will be discussed with an emphasis on the application of such structures to portable wavelength metrology.
KEYWORDS: Sensors, Temperature metrology, Silicon, Resonators, Finite element methods, Transducers, Near field optics, Optical resonators, Near field, Neck
There exists a tradeoff between the mechanical resonant frequency (fm) and the mechanical quality factor (Qm) of a nanomechanical transducer, which resulted in a tradeoff between the band width and sensitivity. Here, we present monolithic silicon nitride (Si3N4) cavity optomechanical transducer, in which high fmand Qmare achieved simultaneously. A nanoscale tuning fork mechanical resonator is near-field coupled with a microdisk optical resonator, allowing the displacement of mechanical resonator to be optically read out. Compared with a single beam with same length, width, and thickness, the tuning fork simultaneously increases fmand Qmby up to 1.4 and 12 times, respectively. A design enabled, on-chip stress tuning method is also demonstrated. By engineering the clamp design, we increased the stress in the tuning fork by 3 times that of the Si3N4 film. A fundamental mechanical in-plane squeezing mode with fm ≈ 29 MHz and Qm ≈ 2.2×105 is experimentally achieved in a high-stress tuning fork device, corresponding to a fmQm product of 6.35×1012 Hz. The tuning fork cavity optomechanical sensors may find applications where both temporal resolution and sensitivity are important such as atomic force microscopy.
A MEMS SLM with an array of 64×64 pixels, each 120 μm ×120 μm in size, with 98% fill-factor, has been developed.
Each reflector in the array is capable of 5 μm of stroke, and ±4° tip and tilt. From a prototype array, 14 contiguous pixels
have been independently wired-out to off-chip drive electronics. These 14 pixels have been demonstrated to be effective in
an off-the-shelf AO system (with requisite modifications to suit the SLM). For a low-order static aberration, the measured
Strehl ratio has been improved from 0.069 to 0.861, a factor of 12 improvement.
We review the fabrication process of a recently introduced phase only MEMS based spatial light modulators for
maskless lithography. A brief description of this device is presented. The physical properties of its structural layers and
the difficulties encountered during its fabrication process are described in detail.
Flavio Pardo, Vladimir Aksyuk, Susanne Arney, H. Bair, Nagesh Basavanhally, David Bishop, Gregory Bogart, Cristian Bolle, J. Bower, Dustin Carr, H. Chan, Raymond Cirelli, E. Ferry, Robert Frahm, Arman Gasparyan, John Gates, C. Randy Giles, L. Gomez, Suresh Goyal, Dennis Greywall, Martin Haueis, R. Keller, Jungsang Kim, Fred Klemens, Paul Kolodner, Avi Kornblit, T. Kroupenkine, Warren Lai, Victor Lifton, Jian Liu, Yee Low, William Mansfield, Dan Marom, John Miner, David Neilson, Mark Paczkowski, C. Pai, A. Ramirez, David Ramsey, S. Rogers, Roland Ryf, Ronald Scotti, Herbert Shea, M. Simon, H. Soh, Hong Tang, J. Taylor, K. Teffeau, Joseph Vuillemin, J. Weld
As telecom networks increase in complexity there is a need for systems capable of manage numerous optical signals. Many of the channel-manipulation functions can be done more effectively in the optical domain. MEMS devices are especially well suited for this functions since they can offer large number of degrees of freedom in a limited space, thus providing high levels of optical integration.
We have designed, fabricated and tested optical MEMS devices at the core of Optical Cross Connects, WDM spectrum equalizers and Optical Add-Drop multiplexors based on different fabrication technologies such as polySi surface micromachining, single crystal SOI and combination of both. We show specific examples of these devices, discussing design trade-offs, fabrication requirements and optical performance in each case.
We present a new MEMS mirror device that fulfills the requirements
needed for its use in a wavelength selective switch.
The MEMS device consists of a 1D array of individually
controllable tilt micromirrors with almost 100% filling factor.
Each mirror in the array is used to manipulate an individual
wavelength channel, attenuating or redirecting it into a
different output. The mirrors are electrostatically rotated
around a fixed pivot and they use a novel concept of angle
amplification to increase their out-of-plane angular rotation.
A detailed analysis of their mechanical and optical response is
presented.
Optical Micro-Electro-Mechanical Systems (Optical MEMS, or MOEMS) comprise a disruptive technology whose application to telecommunications networks is transforming the horizon for lightwave systems. The influences of materials systems, processing subtleties, and reliability requirements on design flexibility, functionality and commercialization of MOEMS are complex. A tight inter-dependent feedback loop between Component/ Subsystem/ System Design, Fabrication, Packaging, Manufacturing and Reliability is described as a strategy for building reliability into emerging MOEMS products while accelerating their development into commercial offerings.
Electrostatically actuated, 500micrometers diameter, Si surface micromachined 2-axis tilting micromirrors were designed and fabricated in a 2 structural + 1 interconnect layer polysilicon process. The mirrors are capable of large, continuous, controlled, DC tilt in any direction at moderate actuation voltages. The lowest-mode resonance frequency is sufficiently high to decouple from the ambient vibration noise and allow setting times of less than a few milliseconds. The Au- coated reflectors, suspended in gimbal mounts via torsional springs and bearings, are tilted by applying voltage to four electrically independent sets of fixed electrodes on the substrate. The electrodes and the springs are designed to optimize actuation voltages, resonance frequencies and the deflection range. To achieve the range, the mounts are lifted and fixed fifty microns above the substrate surface during the release process by a self-assembly mechanism powered by tailored residual stress in a separate metalization layer. Square arrays with 1 mm pitch containing independently addressable identical 16, 64 and 256 mirrors were fabricated and hermetically packaged. Based on these devices, fully functional, bitrate and wavelength independent, single stage, low insertion loss, single mode fiber optical crossconnect system are built.
Silicon micromechanics in an emerging field which is beginning to impact almost every area of science and technology. In areas as diverse as the chemical, automotive, aeronautical, cellular and optical communication industries, Silicon micromachines are becoming the solution of choice for many problems. In this paper we will describe what they are, how they are built, and show how they have the potential to revolutionize lightwave systems. Devices such as optical switches, variable attenuators, active equalizers, add/drop multiplexers, optical crossconnects, gain tilt equalizers, data transmitters and many others are beginning to find ubiquitous application in advanced lightwave systems. We will show examples of these devices and describe some of the challenges in attacking the billions of dollars in addressable markets for this technology.
Silicon micromechanics in an emerging field which is beginning to impact almost every area of science and technology. In areas as diverse as the chemical, automotive, aeronautical, cellular and optical communication industries, Silicon micromachines are becoming the solution of choice for many problems. In this paper we will describe what they are, how they are built, and show how they have the potential to revolutionize lightwave systems. Devices such as optical switches, variable attenuators, active equalizers, add/drop multiplexers, optical crossconnects, gain tilt equalizers, data transmitters and many others are beginning to find ubiquitous application in advanced lightwave systems. We will show examples of these devices and describe some of the challenges in attacking the billions of dollars in addressable markets for this technology.
Silicon micromechanics in an emerging field which is beginning to impact almost every area of science and technology. In areas as diverse as the chemical, automotive, aeronautical, cellular and optical communication industries, Silicon micromachines are becoming the solution of choice for many problems. In this paper we will describe what they are, how they are built, and show how they have the potential to revolutionize lightwave systems. Devices such as optical switches, variable attenuators, active equalizers, add/drop multiplexers, optical crossconnects, gain tilt equalizers, data transmitters and many others are beginning to find ubiquitous application in advanced lightwave systems. We will show examples of these devices and describe some of the challenges in attacking the billions of dollars in addressable markets for this technology.
Silicon micromechanics in an emerging field which is beginning to impact almost every area of science and technology. In areas as diverse as the chemical, automotive, aeronautical, cellular and optical communication industries, Silicon micromachines are becoming the solution of choice for many problems. In this paper we will describe what they are, how they are built, and show how they have the potential to revolutionize lightwave systems. Devices such as optical switches, variable attenuators, active equalizers, add/drop multiplexers, optical crossconnects, gain tilt equalizers, data transmitters and many others are beginning to find ubiquitous application in advanced lightwave systems. We will show examples of these devices and describe some of the challenges in attacking the billions of dollars in addressable markets for this technology.
Silicon micromechanics in an emerging field which is beginning to impact almost every area of science and technology. In areas as diverse as the chemical, automotive, aeronautical, cellular and optical communication industries, Silicon micromachines are becoming the solution of choice for many problems. In this paper we will describe what they are, how they are built, and show how they have the potential to revolutionize lightwave systems. Devices such as optical switches, variable attenuators, active equalizers, add/drop multiplexers, optical crossconnects, gain tilt equalizers, data transmitters and many others are beginning to find ubiquitous application in advanced lightwave systems. We will show examples of these devices and describe some of the challenges in attacking the billions of dollars in addressable markets for this technology.
The PolytecTM laser Doppler vibrometer was used to characterize the dynamics mechanical reliability and lifetimes of surface-micromachined self-assembling MEMS tilting mirrors. The mechanical modes of micromirror can be identified and corresponding resonance frequencies measured. It was found, for certain experimental conditions, that micromirror operation simulating contact between poly-Si surfaces may result in device lifetime reduction due to stiction at the point of contact. The appropriate modifications in device design eliminate the effect of stiction on device lifetime. Moreover, for up to 109 mechanical cycles completed no friction-related device degradation has been observed. In controlled dry ambient at room temperature, micromirrors have been able to complete about 2x1010 switching operations without signs of mechanical degradation. The results validate the robustness and long term mechanical ability of evaluated micromirror devices.
Silicon micromechanics in an emerging field which is beginning to impact almost every area of science and technology. In areas as diverse as the chemical, automotive, aeronautical, cellular and optical communication industries, Silicon micromachines are becoming the solution of choice for many problems. In this paper we will describe what they are, how they are built, and show how they have the potential to revolutionize lightwave systems. Devices such as optical switches, variable attenuators, active equalizers, add/drop multiplexers, optical crossconnects, gain tilt equalizers, data transmitters and many others are beginning to find ubiquitous application in advanced lightwave systems. We will show examples of these devices and describe some of the challenges in attacking the billions of dollars in addressable markets for this technology.
While considerable press has been given to characterization of mechanical properties of MicroElectroMechanical Systems (MEMS) as related to reliability, environmental robustness, and lifetimes studies, characterization of electrical properties of MEMS have not been widely published. In this paper we present an examination of electrical properties (surface and substrate leakage currents, sheet resistance, substrate contact resistance and interlayer contact resistances) of polysilicon thin films used in surface micromachined MEMS test structures. Environmental and electrical overstress conditions that affect leakage have been studied. Two test structures have been used to independently study surface and substrate leakage currents at different levels of humidity (0% to 80% RH) and applied voltage (100 to 150 volts). Both static and lifetime studies have been conducted. Significant differences in surface and substrate leakage lifetime characteristics are observed, suggesting different failure mechanisms for these two important electrical phenomena in MEMS reliability.
The synergy that exists between MEMS technology and free- space optics can be exploited to provide low cost solutions to many of the problems arising in modern dynamic WDM networks. We describe an optical modulator, an electrically controlled variable attenuator, a WDM equalizer, and a programmable wavelength add/drop system.
Residual stress and stress gradients play an important role in determining equilibrium shape and behavior of various Si surface-micromachined devices under applied loads. This is particularly true for system having large-area plates and long beams where curvature resulting from stress can lead to significant deviations from stress-free shape. To gain better understanding of these properties, we have measured the equilibrium shapes of various structures built on the MCNC MUMPs using an interferometric profiler. The structures were square plates and long beams composed of various combinations of polysilicon an oxide layers. Some of the structures had additional MUMPs metal layer on top, while on others in-house chromium-gold stacks of varying thickness have been deposited. Temperature dependence of the curvature was measured for some plates. We have used these data in conjunction with simple models to significantly improve the performance of our micromachined devices. While for some structures such as large area reflectors the curvature had to be minimized, it could be advantageously exploited by others, for example vertical actuators for self-assembly.
Despite their almost universal application in science and technology, optical microscopes with submicron spatial resolution remain large, expensive pieces of laboratory equipment. In this paper, we report on our construction of a near-field scanning optical microscope (NSOM) using the MCNC MUMPs technology. The construction of our microscope required the solution of a number of technological challenges including the assembly of an XYZ stage capable of moving the sample out of the plane of the silicon wafer, the macro alignment of the fiber used as the optical probe and efficient collection of the scattered light. In this paper we describe how the NSOM was built and show some preliminary images taken with it.
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