A novel, compact, polarization insensitive mode-locked erbium-doped fiber laser producing 2 ps pulses was constructed. The laser was passively mode-locked using a 75 period InGaAs/InAlAs multiple quantum well saturable absorber grown lattice matched on an InP substrate. The laser was constructed in a linear cavity, Fabry-Perot configuration with the saturable absorber at one end of the cavity and a chirped fiber Bragg grating at the other end. The output pulses are chirped and were further characterized by varying their energies and propagating them down different lengths of standard optical fiber. The laser cavity was modeled using the complex Ginzburg-Landau equation derived under the condition that nonlinear changes to the pulse must be small per round-trip. The contribution of the semiconductor saturable absorber was modeled using a two-level rate equation. The free carrier absorption within the semiconductor contributes to the refractive index which was shown numerically to result in an additional frequency shift. The modeling is in close agreement with the pulse propagation experiments.

We present an optical delay line structure incorporating In_xGa_1-xAs quantum wells in the GaAs quarter- wave layers of a GaAs/AlAs distributed Bragg reflector. Applying an electric field across the quantum wells shifts and broadens the e1-hh1 exciton peak via the quantum- confined Stark effect. Resultant changes in the index of refraction thereby provide a means for altering the group delay of an incident laser pulse. Theoretical results predict tunable delays on the order of 50 fs for a 30-period structure incorporating 3 quantum wells per GaAs layer. Structure design, growth and fabrication are detailed. Preliminary group delay measurements on large-area samples with no applied bias are presented.

We demonstrate an optoelectronic interconnect based on an 8 by 8 array of vertical-cavity surface-emitting lasers, an 8 by 8 array of photodetectors, and a single compound lens. The substrate-emitting VCSEL array and back-illuminated photodetector array were flip-chip bonded to a CMOS driver circuit and a Si fan-out pad array, respectively. The CMOS driver provides laser addressing, signal conditioning and modulation current.In this paper we will describe the interconnect configuration, device structures and characteristics, and CMOS driver circuits. We then discuss the system operation and performance.

Bacteriorhodopsin (BR) is a light transducing photochromic protein in the purple membrane of a salt-loving microorganism that inhabits salt marshes. It has strong absorption in a broad region of the visible spectrum. The B- state in the photocycle can be considered to be the ground state, which has absorption maxima at 570 nm. Perhaps, the most intriguing features of this organic photopolymer are its extraordinary stability in the chemical, thermal and photochemical sense, its large optical nonlinearity, dynamic nature, durability, real-time holographic recording capabilities, and information storage potential. Furthermore, BR-doped polymer film can be fabricated for a large-scale application, whereas photorefractive crystals like BSO or KNSBM cannot be grown easily to the same dimension as BR. Hence, BR's potential in optical system includes transient dynamic applications of an M-type hologram and 3D optical memories of a branched photocycle that shows a great promise for data storage and retrieval due to its high capacity. The major advantages of this organic photopolymer include high density, low cost, low weight and portability which are a projected requirement for the Air Force and commercial applications.

A fully phase image encryption technique which uses double random phase encoding method is presented. The encryption method can be implemented optically. Robustness of the fully phase encryption and amplitude based encryption in the presence of noise is investigated. Using computer simulations, mean squared error for the decrypted images are obtained. The fully phase based encryption is shown to be robust with respect to the additive noise added to the encrypted image in terms of the mean squared metric. Based on the tests conducted in this paper, the fully phase based encryption method shows better performance than the amplitude based encryption in terms of mean square error metric.

Parallel transmission and processing of high-speed data may be accomplished by using multiple wavelength channels. To process this type of wavelength division multiplexed information, it is necessary to be able to switch the multiple wavelengths, simultaneously. In this paper we demonstrate multiwavelength switching with a single switch, utilizing a nonlinear optical loop mirror with a semiconductor optical amplifier. Switching is shown for 14 wavelength channels across a 14-nm bandwidth for data rates up to 2.5 GHz. Switching contrasts of 10 dB are shown with control energy as low as 1.6 pJ.

Optical frequency comb generator have many practical applications including difference frequency measurement, optical frequency division multiplexing, and heterodyne optical phase locking.

A new method for implementing a general linear system using multi-stage architecture was recently published. In this method an iterative procedure determines the architecture to be used to simulate a linear system with a small number of stages and with a small error. Multi-stage IC architectures allow easy switching between different channels. There are many known algorithms for optimizing the interconnection net in terms of minimizing the number of alterations required to switch form one set of channels to a similar set. In optics, however, there exists the probe of implementation. Not all the routing architectures can be easily constructed optically and there is an advantage in implementing routing architectures with a symmetric structure. Therefore an optical setup might be limited to the use of non-blocking setup is known. Thus, the optimization that can be made refers to a specific set of input-output connections and results in finding the smallest number of routing stages required to achieve the full permutation set. In this work we present an algorithm for optimizing the routing scheme. We also show an algorithm for minimizing the number of changes required in a given routing scheme while shifting form one input-output connection to a similar connection.

This paper present a theoretical assessment of the performance of subcarrier optical communication systems using sideband-injection locking and heterodyning. In this scheme, a master laser is strongly intensity modulated. The modulation sidebands of the master laser are injected into two slave lasers for the production of the subcarrier. One of the slave lasers is directly modulated to produce the amplitude and phase modulation on the subcarrier. First, using the Van der Pol equations for coupled oscillators, the small-signal response of the output power and phase of injection-locked semiconductor lasers was derived. Then the performances of the subcarrier optical communication systems based on amplitude modulation and phase modulation were assessed in terms of optimum power injection ratio and phase detuning between the master and slave lasers. For phase modulation, the performance was limited for two cases: lowest AM to PM conversion and highest PM modulation efficiency. The distortion and noise were calculated assuming coherent detection for phase modulation and envelope detection for amplitude modulation. Finally the signal to noise ratio is calculated and plotted.

This paper presents a modified version of a true time delay, broadband nulling approach to beamforming for a linear antenna array. The approach begins with the well known Davies method of narrowband beamforming; alters it to include time delays via tunable lasers and high dispersion optical fiber; and finally modifies the Davies tree itself to resemble decomposition filters from wavelet theory. This last modification cuts the required number of tunable lasers for an N element array but also decreases the number of independent null.

In conventional satellites, the RF and microwave signal transmissions between electronic modules are accomplished using waveguide or coaxial lines. Advances in fiber-optic technology have made it possible to modulate low-noise RF and microwave signal on fiber-optic distribution lines, resulting in weight and space savings. These optical communication systems enable intrasatellite communications among the electronic modules like transmitters, receivers, and clocks. This paper summarizes findings from several studies on the use of fiber-optic lines for RF/microwave signal transmission on-board satellites. It will also update some experimental results of prototype systems developed previously for intrasatellite signal distribution.

Fiber Bragg gratings were examined in situ while exposed to gamma-ray and proton environments that emulated or exceeded nominal low earth orbit radiation doses. Radiation and temperature induced changes to the reflected Bragg grating amplitude and spectral characteristics were observed in fiber gratings not formed under hydrogen loading. THe irradiations were performed in situ, while the ambient temperature near the Bragg grating was allowed to vary. Shifts in the reflected spectra from the Bragg gratings were observed and attributed to ionization and thermal effects. During irradiation, the spectral shifts were observed to move to longer wavelengths, saturate at low dose and to decrease exponentially following the cessation of radiation.

Cumulative effects on fiber optic system are presented based on the test results of combined temperature and total dose gamma irradiation testing of a PIN diode, an IR light emitting diode, an optical fiber and a laser diode.

A method to qualify Commercial-Off-The-Shelf optocouplers for use in a space-based application is presented. Emphasis is placed on quantifying the degradation from total dose at several operational temperatures for use by Design Engineers in estimating worst-case circuit performance. Total dose and higher temperature result in changes to the optocoupler's current-transfer-ratio depending on the amount of forward bias in the LED. These changes may require redesign or modification of the optocoupler circuit within a system.

The 3D shape measurement and recognition of surroundings are expected for advanced space robot missions, such as on-orbit inspections, autonomous navigation of robots, and so on. We have been studying small size scanning laser range finders for space applications for years, and have just developed a new compact model for small on-orbit robots and small rovers. In this paper, its design and test results are described, comparing them with our previous model, which have been used for research test of autonomous rover navigation these years.

A novel superresolution imaging system with line-array CCD sensor is introduced in the paper. The system is consisted of a high resolution lens, the beam splitter and two line- array CCD sensors. The two same line-array CCD sensor which the pixel size is b micrometers by b micrometers are set up in the two imaging planes of the imaging systems and their central coordinates are respectively (0,0) and (b/2, 0). In order to get the high spatial resolution along the pushbroom direction, the sample spacing between line images is decreased. The line array is moved only half a pixel width instead of a full pixel width for each line image scan. Two different images would be simultaneously got through the novel linear pushbroom imaging system for the moving scenes. Processing specially, a new image with higher spatial resolution than the original two images would be obtained. The novel imaging system will be suitable for space application because the configuration is stable and rugged. If the new method is used in the design of remote sensing payloads to perform. Earth observation, the focal length of the new remote sensing system could be reduced about 50 percent keeping the same spatial resolution comparing with the traditional imaging system. If the sensor is area-array CCD in the imaging system, the superresolution imaging system would be consisted of a high resolution lens, the beam splitter and four area-array CCD sensors with subpixel displacements in the focal planes.

Proposed is the novel method of dynamic nonlinear-optical correction for distortions in wide spectral band. The method is based on combining of the negative feedback correction and dynamic holography correction in the system, using optically addressed phase modulators. State-of-the-art of key technologies is evaluated.

Large numerical aperture telescope with nonlinear optical correction for distortions, designed for the remote self- luminous object imaging, was realized in experiment and investigated. Dynamic hologram, recorded in optically addressed liquid crystal spatial light modulator, was used as the corrector. Nearly diffraction limited performance of the system was demonstrated.

Given are the results of experimental study on the quasi real time holographic correction for the lens distortions in the passive observational telescope in the visible range of spectrum, using the liquid crystal optically addressed spatial light modulator.

At Institute of High Performance Computing Systems of Russian Academy of Science four modifications of waveguide acoustooptical deflector, four modifications of integrated optical RF spectrum analyzer, integrated acoustooptical optical radiation spectrum analyzer, multichannel RF receiver on the base of integrated optical RF spectrum analyzer, two modifications of waveguide acoustooptical frequency modulator, two modifications of the time integrating acoustooptical correlator have ben designed, developed and investigated. Special software for computer simulation of the waveguide acoustooptical devices and calculation of its elements have been designed, produced and investigated.

An ultranarrow bandwidth sodium Faraday anomalous dispersion optical filter is studied theoretically and experimentally for the 3P_3/2 $IMP 3S_1/2 transition including hyperfine Zeeman effects. With a Na cell of 3cm in length in an axial magnetic field of 316 Gauss, the peak transmission has reached about 38 percent with a FWHM bandwidth of only 1.5GHz. Theoretical and experimental results are in good agreement for the transition.

All-optical signal processing by >= 2D lightwave circuits (LCs) is (i) aimed to allow the (later) inclusion of the frequency domain and is (ii) subject to photonic integration and thus the architectural and algorithmic framework has to be prepared carefully. Much work has been done in >= 2D algebraic system theory/modern control theory which has been applied in the electronic field of signal and image processing. For the application to modeling, analysis and design of the proposed 3D lightwave circuits (LCs) some elements are needed to describe and evalute the system efficiency as the number of system states of 3D LCs increases dramatically with regard to the number of i/o. Several problems, arising throughput such an attempt, are made transparent and solutions are proposed.

For the proposed all-optical 3D grids of directional couplers and Mach-Zehnder interferometers, network models (1) and (6) and their routing algorithms are reviewed and some are presented and discussed in more details. (1) Planar cellular arrays superposed by by-passing networks (2) 3D cellular arrays described by their projection onto Cayley graphs (3) shuffle networks (4) Clos networks (5) Projection onto 2D grids mapped onto hypercubes and onto star and pancake graphs and (6) Sorting in all-optical 3D grids. The extension to geometries N >= 5 and the introduction of wavelengths is briefly discussed.