M. W. Maeda

Acoustically tuned erbium-doped fiber ring laser

We report what is to our knowledge the first narrow-linewidth, continuously tunable laser that uses an acousto-optic filter to achieve a broad tuning range. The unidirectional ring-laser configuration incorporates an erbium-doped fiber amplifier as the gain medium and an integrated, frequency-shift-compensated acousto-optic filter as the tuning element. Using a 980-nm optical pump with 60 mW of launched power, we obtained nearly 2 mW of laser output with 10% output coupling. A tuning range of 40 nm was achieved, centered about 1545 nm. Single-longitudinal-mode operation with a 10-kHz linewidth was demonstrated, although the laser wavelength hopped between nearby longitudinal modes because of path-length fluctuations. Wavelength switching at rates up to 100 kHz was examined.

Monolithic multiple wavelength surface emitting laser arrays

A two-dimensional (2-D) surface emitting laser array emitting 140 unique, nonredundant, uniformly separated, single-mode wavelengths in the 980-nm regime is described. The wavelength separation between neighboring lasers is as small as 0.3 nm. A large total wavelength span of 43 nm was obtained without compromising the performance of the lasers. All 140 lasers have nearly the same threshold currents, voltages, and resistances. The techniques used are generic and can be readily extended to both longer and shorter wavelength lasers. The authors also report the first wavelength division multiplexing system experiment using part of this laser array. A BER (bit-error ratio) of 10/sup -9/ at 155 Mb/s was obtained with simultaneous operation of four lasers at a wavelength separation of 1.5 nm. Negligible optical and electrical crosstalk was observed between the lasers. >

Use of a multiwavelength surface-emitting laser array in a four-channel wavelength-division-multiplexed system experiment

The first wavelength-division-multiplexed system experiment using a monolithically integrated two-dimensional surface-emitting laser array is reported. Four lasers at a wavelength separation of 1.5 nm in the 980-nm region were operated simultaneously and a bit-error rate of 10/sup -9/ (155 Mb/s) was attained with negligible optical and electrical crosstalk between the lasers.<<ETX>>

A 7 x 20 surface-emitting laser array with uniform wavelength rastering

Recently there have been many advances in vertical-cavity surface-emitting (VC-SE) lasers. VC-SE lasers are promising because they facilitate simple fabrication of high-density, low-threshold, and cost-effective two dimensional (2-D) laser arrays. Monolithic 2-D multiple-wavelength laser arrays are potentially useful for applications in optical communications and interconnects using wavelength-division multiplexing (WDM).1

Recent progress of coherent lightwave systems at Bellcore

The progress in selected areas of coherent lightwave systems technology at Bellcore over the past year is reviewed. Studies of the demodulator portion of a polarization diversity receiver show that a polarization sensitivity of less than 0. 5 dB can be achieved and that squaring circuits with wide dynamic range and very high sensitivity can be realized. We also report the results of frequency stability measurements made on packaged DFB laser transmitters over an extended time period. Four-wave-mixing (FWM) experiments show that high power in the range of 5 to 10 mW launched into dispersion shifted fiber can cause FWM crosstalk. Reports of FWM in a semiconductor optical amplifier are also reported. 1. )