Shinji Takano

High performance and highly reliable lambda /4 shifted MQW-DFB-DC-PBH-LDs for Gb/s coherent optical communication systems

The authors demonstrate high-performance and highly reliable single-frequency quarter-wave ( lambda /4)-shifted multiple-quantum-well distributed-feedback laser diodes with double-channel planar buried heterostructure (MQW-DFB-DC-PBH LDs). Superior characteristics, such as narrow spectral linewidth (about 1 MHz) and flat FM response (several GHz bandwidth with less than 50-kHz dip frequency) at high light output power, have been obtained with small values of coupling coefficient and cavity length product ( kappa L), and thick separate-confinement-heterostructure (SCH) layers. An estimated lifetime in terms of spectral linewidth, FM response, and lasing wavelength of over 10/sup 5/ has been obtained, demonstrating that these devices are suitable for practical use in gigabit/second coherent optical fiber communication systems. >

Spectral linewidth reduction in metalorganic vapor phase epitaxy grown 1.5 μm separate‐confinement‐heterostructure quantum well distributed feedback laser diodes

Spectral linewidth reduction in 1.5 μm InGaAs/InGaAsP separate‐confinement‐heterostructure quantum well distributed feedback laser diodes (SCH‐QW‐DFB LD’s) is achieved for the first time. A 2.0 MHz minimum linewidth and a 5 MHz mW minimum linewidth power product are obtained.

Improvements in resonance frequency and T0 value by 1.5 μm InGaAs MQW lasers grown by MOVPE

High quality InGaAs/InP quantum well structures and 1.5 μm MQW lasers, grown by low pressure MOVPE are reported. PL linewidth, PL peak energy shift, X-ray satellite peaks and transmission spectroscopy have demonstrated that the InGaAs/InP quantum wells were of high quality. The first improvements in T0 and resonance frequency in 1.5 μm MQW lasers are reported. Superior performances due to a quantum effect are: (1) high T0 value, 105 K (15–45°C), (2) large TE/TM mode gain difference, 45 cm−1 and (3) high resonance frequency, 4 GHz/mW12.

250-mW high-power operation and 100-mW APC aging test with 1.48-µm InGaAs/InGaAsP MQW-DC-PBH LD's

High-power semiconductor lasers at 1.48-μm wavelength have been increasingly im portant as the pumping light sources for Er3+-doped fiber amplifiers (EDFA’s). High reliability, as well as high power characteristics, is required in optical communication systems. Reliability testing has been reported for bulk 1.48-μm high-power laser diodes (LD’s).1 Although the output power was as high as 100 mW at 25 °C, it was limited to 65 mW at 50 °C. To assure their applicability as high-power pumping sources, aging tests at high powers and high temperatures will be required. In this respect, multiple-quantum-well (MQW) LD’s are promising candidates because of their high-power capability at high temperatures.2 This paper reports 100-mW APC aging tests for 1.48-μm MQW double-channel planar buried heterostructure (DC-PBH) LD’s at 20 °, 50 °, and 70 °C, as well as high-power cw operation at over 250 mW.