Pedram A. Leilabady

A 1.55-/spl mu/m solid-state laser source for DWDM applications

We describe the design and operation of a 1550-nm diode pumped Er,Yb:glass laser with >130 mW of output power and a free running linewidth of /spl sim/22 kHz. Due to the low frequency relaxation oscillation, near shot limited relative intensity noise performance is obtained throughout the radio frequency (RF) range of interest for cable television and dense wavelength division multiplexed (CATV/DWDM) applications. For long-haul spans an intracavity lithium niobate phase modulator allows for chirping of the linewidth to bandwidths and at rates sufficient to defeat stimulated Brillouin scattering (SBS). For certain applications, the high output power can eliminate the need for an erbium-doped fiber amplifier (EDFA).

High-Power Erbium Optical Amplifiers

Although the majority of recent interest in the erbium optical amplifier has focused on the optical amplifier as a relatively low power, high-gain, in-line repeater, there is increasing interest in very high-power (>+20 dBm) optical amplifiers in a portion of the optical network to provide alternative systems architectures. Uses for high-power optical amplifiers include postamplifiers for long-haul repeaterless links1 head-end amplifiers for specific CATV distribution architectures2, and power amplifiers for lxN lossless splitters.

Measurement Techniques For Magnetic Field Gradient Detection

Two techniques based on the magnetically induced strain in a magnetostrictive sensing element are described in which detection schemes involving high frequency periodic modulation of the sensing element are employed for the recovery of very slowly varying low magnetic field gradients. Measurement resolutions in the range of 0.1 μOe to 0.01 μOe per unit sensing element length for test fields of frequencies in the range 0.1 Hz to 1 Hz are obtained.

Multiple Beam Fiber Optic Holography With Fringe Stabilization

The use of fiber optics in the field of optical holography is described with emphasis on an experimental arrangement whereby several object and or reference beams are implemented simultaneously. This scheme enhances a holographic systems versatility by offering multiple illumination planes of any given object. Using several passive singlemode couplers and a closed loop phase stabilization technique, a multiple beam fiber optic holographic system with stable phase correlation among output fibers is presented. The feedback system incorporates a Michelson interferometer which detects relative phase fluctuations between output optical fibers. A servo controlled piezoelectric phase modulator automatically compensates for environmentally induced phase fluctuations inherent to a fiberized system. The resulting scheme is a very stable and highly versatile system suitable for remote holographic interferometric sensing and other applications where conventional holography techniques are impractical. Futhermore, new results on the ability to vary object and reference beam intensity ratios in a fiber optic holographic system will be discussed.