1.3 μm InAsyP1-y-InPstrained-layer quantum-well laser diodes grown by metalorganic chemicalvapor deposition

The authors have fabricated 1.3-μm InAsP-InP separate-confinement-heterostructure (SCH) strained-layer double-quantum-well (SL-DQW) laser diodes (LDs) by metalorganic chemical vapor deposition (MOCVD). A low threshold current density of 410 A/cm ² was obtained. The CW threshold current was as low as 1.8 mA at 20°C, and maximum CW operating temperature of 120°C was obtained. These characteristics are almost the same as those of well-designed GaInAsP-InP SL-QW LDs. Further improvement of the characteristics of InAsP-InP LDs is expected by optimizing the device structure     

High-power CW-DFB laser diode modules for CATV applications operating at 1550 nm

Investigation of the correlation between longitudinal photon density distribution and spectral linewidth re-broadening, in conjunction with carefully designed coupling optics, enable laser modules that simultaneously achieve very high fibre-coupled power of 175 mW and very narrow linewidth<1 MHz even at /spl sim/120 mW of output power to be successfully fabricated.     

Wideband and high-power compressively strained GaInAsP/InPmultiple-quantum-well ridge waveguide lasers emitting at 1.3 μm

Compressively strained 1.3-μm GaInAsP/InP multiple-quantum-well (MQW) ridge waveguide lasers were fabricated. Through optimizing the total well thickness, large bandwidth over 11 GHz was achieved, together with high quantum efficiency of about 0.48 W/A and high power output of 60 mW before rollover. The laser also showed less temperature sensitivity up to an elevated temperature of 85°C     

Optical Burst Switching Router With 40-,10-Gb/s Bit-Rate Transparent Contention Resolution

We report a bit-rate transparent optical burst switching (OBS) router prototype using a fast 5 times 5 PLZT [(Pb,La)(Zr,Ti)O₃ ] optical matrix switch. Dynamic switching in a two-wavelength, 2 times 2 OBS switch is demonstrated. Contention resolution using a tunable Mach-Zehnder interferometer wavelength converter for both 40- and 10-Gb/s bursts is demonstrated for the first time. Error-free operation was achieved for both bit rates under the same settings, as required in autonomous networks     

High fibre coupled output power 37 nm tunable laser module using matrix DFB laser

The thermally-controlled laser module, integrating 12 distributed feedback (DFB) lasers in the form of a 2/spl times/6 matrix to realise both high output power and wide wavelength tunability, has been fabricated. The module has shown excellent characteristics, such as high fibre coupled power over 30 mW and tunability over 37 nm.     

Compressively strained 1.3 μm InAsP/InP and GaInAsP/InP multiplequantum well lasers for high-speed parallel data transmission systems

Turn-on delay times in the pulse response of compressively strained InAsP/InP double-quantum-well (DOW) lasers and GaInAsP/InP multiple-quantum-well (MQW) lasers emitting at 1.3 μm were investigated. DQW lasers with 200-μm cavity length and high-reflection coating achieved both a very low threshold current (1.8 mA) and a small turn-on delay time (200 ps), even under a biasless 30-mA pulse current. Compressively strained or lattice-matched GaInAsP MQW lasers and GaInAsP double-heterostructure (DH) lasers were also fabricated and compared. It was observed that the carrier lifetime was enhanced for InAsP DQW lasers and strained GaInAsP MQW lasers compared to the lattice-matched GaInAsP MQW lasers and conventional double-heterostructure lasers. To explain this increase in the carrier lifetime, the effect of the carrier transport on the carrier lifetime was studied. The additional power penalty due to the laser turn-on delay was simulated and is discussed     

Small turn-on delay time in 1.3 μm InAsP/InP strained doublequantum-well lasers with very-low threshold current

It is demonstrated for the first time that compressively strained InAsP/InP double quantum-well (DQW) lasers emitting at 1.3 μm performed a very small turn-on delay time by a significant reduction in threshold current. Lasers with 200 μm cavity length and high reflection coating achieved both very low threshold current of 1.8 mA and a small turn-on delay time (200 ps) even under a bias-less 30 mA pulse current. An additional power penalty was simulated, and it was shown that these small-delay and low-threshold performances are suitable for high-speed optical parallel data transmitters in computer networks     

High performance CW 1.26 μm GaInNAsSb-SQW and 1.20 μmGaInAsSb-SQW ridge lasers

Long-wavelength GaInNAsSb SQW lasers and GaInAsSb SQW lasers that include small amounts of Sb have been successfully grown by gas-source molecular beam epitaxy (GSMBE) and processed into ridge lasers. The GaInNAsSb lasers oscillated under CW operation at 1.258 μm at room temperature. A low CW threshold current of 10.2 mA and high characteristic temperature (T₀) of 146 K were obtained for the GaInNAsSb lasers which is the best result for GaInNAs-based narrow-stripe lasers. Furthermore. The GaInAsSb lasers oscillated under CW operation at 1.20 μm at room temperature. A low CW threshold current of 6.3 mA and high characteristic temperature (T₀) of 756 K were obtained for the GaInAsSb lasers, which is also the best result for the 1.2 μm-range of highly strained GaInAs-based narrow-stripe lasers     

Detailed investigation on reliability of wavelength-monitor-integrated fixed and tunable DFB laser diode modules

A highly reliable integration of a wavelength monitor (WM) in an industry standard 14-pin butterfly package has been successfully achieved by using soldering and YAG welding techniques. Mechanical integrity and endurance tests for fixed and tunable distributed-feedback (DFB) laser diode modules (LDMs) were performed according to an extended Telcordia GR-468-CORE in order to appreciate the fixtures of the WM part composed of a prism, a Fabry-Pe/spl acute/rot etalon, power, and WM photodiodes. Wavelength and a fiber output power were evaluated as a function of duration time for each test. Incident light angles change against an etalon and an optical coupling deviates due to the separation between a laser diode part and a WM part for tunable DFB LDMs. The two occurrences have a profound influence on wavelength drifts. It was found that the wavelength drifts were less than /spl plusmn/5 pm under mechanical and thermal stresses for both types of DFB LDMs. It was also confirmed that the coated and mounted etalon itself was also highly reliable under thermal stresses. These results show that the WM-integrated fixed and tunable DFB LDMs were fully applicable to next-generation dense-wavelength-division-multiplexing (DWDM) systems of 50- and 25-GHz channel spacing.     

GaxIn1-xAsyP1-y-InPtensile-strained quantum wells for 1.3-μm low-threshold lasers

Ga_xIn_1-xAs_yP_1-y-InP tensile-strained multiple quantum wells (MQWs) grown by low pressure metalorganic chemical vapor deposition (LP-MOCVD) are studied for the application to 1.3-μm lasers. High-resolution X-ray diffraction curves show good agreement with theoretical simulation. Clear energy separation of light hole and heavy hole bands is observed in the room temperature photoluminescence measurement. Threshold characteristics of -1.15% tensile-strained MQW lasers with graded index separate confinement heterostructure (GRINSCH) are investigated. The minimum threshold current density per well (J_th/N_w) for infinite cavity length obtained is 100 A/cm² for the device with a well number of 3. Tensile strain dependence of J_th/N _w for an infinite cavity is also clarified