Masaru Mukaikubo

High extinction ratio operation at 40-Gb/s direct modulation in 1.3-/spl mu/m InGaAlAs-MQW RWG DFB lasers

Direct modulation of 1.3-mum InGaAlAs DFB RWG lasers at 40 Gb/s is experimentally demonstrated. This laser achieves a record extinction ratio of 5 dB under 40-Gb/s modulation. Moreover, it can provide 40-Gb/s modulated transmission over 2 km

Transmission properties of 1.3-/spl mu/m InGaAlAs MQW FP lasers in 10-gb/s uncooled operation

Limitations on transmission by an uncooled InGaAlAs Fabry-Perot (FP) laser in 10-Gb/s operation are experimentally and theoretically investigated. The InGaAlAs laser has both high relaxation-oscillation frequency and superior light-current characteristics over a wide temperature range, making it suitable for uncooled operation at 10 Gb/s. Over most of the temperature range used in transmission testing with standard-dispersion fiber, a small power penalty of 1 dB for a bit error rate (BER) of 10/sup -12/ was obtained in transmission over 4-7 km at the measured temperature range, whereas an error floor was seen in transmission over greater distance, despite the negative chromatic dispersion between the fiber and laser light. Theoretical analysis of these results indicates that mode-partition noise (MPN) imposes the major limitation on transmission distance. Moreover, the minimum transmission distance was estimated as 2.1 km, even when the production tolerance of lasing characteristics and zero-dispersion range of installed fiber are taken into account.

Reflective semiconductor optical amplifier with segmented electrodes for high-speed self-seeded colorless transmitter

A self-seeded reflective semiconductor optical amplifier (RSOA) has been viewed as an attractive candidate for the low-cost colorless transmitter in wavelength-division-multiplexed passive-optical networks (WDM-PON). In this paper, we propose and demonstrate the use of two-section RSOA with segmented electrodes to simultaneously improve the modulation bandwidth and extinction ratio in a self-seeded operation. We first find the optimal driving condition to induce strong modulation cancellation by analyzing the gain dynamics inside the RSOA. In addition, we experimentally confirm the improvement in direct modulation bandwidth by segmenting the electrodes. Finally, we employ the two-section RSOA in a self-seeded system and successfully demonstrate transmission over a 25-km standard single-mode fiber at 5 Gb/s as well as improved back-to-back modulation at 10-Gb/s in C-band by using the optimal driving condition.

Uncooled (25–50 °C) operation of self-seeded RSOA for low-cost colorless WDM-PON transmitter

Modulation-cancellation property of InGaAlAs/InP MQW reflective semiconductor optical amplifier (RSOA) and its temperature dependence are investigated for uncooled colorless WDM transmitter applications. Using the optimized RSOA length, we demonstrate self-seeded 2.5-Gb/s transmission over 25-km SSMF at 25oC and 50°C.

Wide temperature (-20/spl deg/C /spl sim/ 100/spl deg/) operation of an uncooled direct-modulation 1.3 /spl mu/m InGaAlAs MQW DFB laser for 10.7 Gbit/s SONET applications

We report a wide temperature range (-20/spl deg/C/spl sim/100/spl deg/C), uncooled operation of a direct-modulation 1.3 /spl mu/m, InGaAlAs MQW DFB laser diode with the highest-ever relaxation frequency (>20 GHz at 100/spl deg/C) and high mask margin for 10.7 Gbit/s SONET applications.

1310-nm InGaAlAs short-cavity lasers for 10-Gbit/s low-power-consumption transceivers

An InGaAlAs short-cavity DBR laser enabling 1.3-μm, uncooled, 10-Gbit/s operation at lower drive currents is demonstrated. This laser consists of a short InGaAlAs-MQW active region butt-jointed to an InGaAsP-DBR region. This structure provides moderate chip power, low threshold current, and a large relaxation oscillation frequency simultaneously, because it has an optimum cavity length in the range between 10 and 100 μm, at which both VCSELs and conventional edge-emitters cannot be formed because of their difficulty of manufacture. The fabricated 75-μm short-cavity laser demonstrated 100°C, 10-Gb/s operation at a record low drive current of 14 mAp-p. Furthermore, it achieved side-mode suppression ratio of more than 37 dB at a high yield of 95%, because of the naturally high single-mode stability of its short-cavity DBR structure.