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Erbium-doped modclocked fiber lasers provide a potentially attractive short pulse source1 near 1.5 microns for applications to high speed fiber optic communication systems and interconnection networks.

We present a micromechanical optical interference device that produces changes in the slope (in dB) of its transmitted spectrum via a single voltage control, without changes in attenuation level, a Spectrally Linear Optical Power Equalizer, or SLOPE device. Simple linear power equalization is sometimes all that is required in optical networks, especially in optical amplifiers, and this device can perform this function inexpensively and with easier control than multi-element equalizers. The device element is a vertically moving membrane similar to the MARS modulator. The reflectivity of the element is varied by the adjustment of the air gap via a bias applied to the element's electrode. The element can be thought of as a thin-film optical stack where one of the films (the air gap) is variable. Its reflectivity is transmitted via a dual fiber ferrule arrangement, in which the light comes into the device in one fiber, is reflected off the device and focused onto the outgoing fiber.

Many optical devices, but particularly vertical-cavity surface emitting lasers (VCSEL's), require high reflectivity mirrors. These mirrors are typically stacks of quarter-wavelength thick layers (as measured in the material), of alternating high and low index layers, placed on the device either by epitaxial techniques, or by dielectric deposition techniques such as evaporation. For bottom emitters, the thickness of these mirrors can be greatly reduced by capping the stack with a low optical loss metal (the thickness of the last dielectric layer would be adjusted for optical phase matching).

Current state-of-the-art Ti:sapphire laser systems operate in a dispersion-limited regime at around 10 fs pulsewidth. This remarkable progress has been made as a result of intracavity dispersion optimization, as initial results in self-focusing modelocking produced pulses of /spl sim/90 fs duration. The recently developed technique of Frequency-Domain Dispersion (FDD) can provide measurements of the complete intracavity group delay under operating conditions. Since dispersion is a linear optical property, one might wonder whether it is meaningful to measure the dispersion inside a nonlinear system while it is operating. In the paper, the author discusses the magnitude and origin of nonlinear corrections to the measured intracavity group delay in FDD measurements. The author also raises the general questions: (a) since a modelocked laser is a nonlinear optical system, is it correct to measure its dispersion when it's lasing ?; and (b) since a modelocked laser is a nonlinear system, is it correct to measure the dispersion when it's not lasing?. >

We present an application of femtosecond laser pulses that is not directly related to high speed, but rather makes use of the large spectral bandwidth of these pulses to address a systems issue in wavelength-division-multiplexed (WDM) communication links. One inherent difficulty of currently proposed WDM systems is the need for multiple lasers operating at different wavelengths, which hence have to be wavelength-selected and stabilized at that particular wavelength for years to come. We demonstrate a WDM system based on a single short-pulse laser source that covers all WDM channels simultaneously, hence eliminating many of the source problems of conventional WDM systems.