Extremely low threshold operation of 1.5 mu m GaInAsP/InP buried ridge stripe lasers

1.5 mu m Fabry-Perot lasers exhibiting extremely low threshold currents have been obtained with a buried ridge stripe (BRS) structure. Threshold currents are 5.7 and 15.5 mA for 300 mu m and 1 mm cavity lengths, respectively, in CW operation. The optical losses of the buried waveguide have been determined from the external quantum efficiency dependence with cavity length.<>     

1.32-μm GaInNAs-GaAs laser with a low threshold current density

In this letter, we report on a recent development of diluted nitride laser diodes operating at the wavelengths around 1.3 μm. The lasers grown by molecular beam epitaxy and processed into 20-μm-wide ridge waveguide structures, mounted episides up on subcarriers, exhibit a threshold current density as low as 563 A/cm², slope efficiency of 0.2 W/A per facet, light power up to 40-mW continuous-wave, and characteristic temperature of 97-133 K     

Extremely low threshold current 1.52 ?m InGaAsP/InP MS-DFB lasers with second-order grating

Threshold currents of 1.52 ?m InGaAsP/InPGaAsP/InP DFB lasers with second-order gratings have been reduced to 12 mA in single-longitudinal-mode operation. External differential efficiencies exceed 25%/feet with a ?/4 Si3N4 coating on the front facet.     

Low threshold operation of 1.5-µm DFB laser diodes

Highly reliable distributed feedback (DFB) laser diodes operating at 1.5-μm wavelength range are fabricated through optimizing the device parameters. Thickness control of the active layer is found to be an essential factor in achieving low threshold operation of DFB lasers. The threshold current as low as 11 mA and stable single longitudinal mode CW operation up to 106°C is achieved with these DFB lasers.     

1.5 ?m region InP/GaInAsP buried heterostructure lasers on semi-insulating substrates

InP/GaInAsP buried heterostructure (BH) lasers for the 1.5 ?m region have been fabricated on semi-insulating InP substrates. The threshold current of the lasers is as low as 38 mA under CW operation at 25°C, which is nearly the same as for BH lasers fabricated on n-type InP substrates.     

Low threshold current 1.5-μm buried heterostructure lasers usingstrained quaternary quantum wells

Buried heterostructure lasers operating at a wavelength of 1.5 μm with four compressively strained quaternary quantum wells (strain ~1.8%, thickness ~90 Å) and current blocking layers were made using atmospheric pressure metalorganic chemical vapor deposition. Pulsed room-temperature threshold currents for uncoated devices as low as 4.1 mA and as low as 0.8 mA for devices with high reflectivity mirror coatings are reported. The dependence of threshold current on active region width is consistent with broad-area laser measurements     

Pulsed electrical operation of 1.5-μm vertical-cavitysurface-emitting lasers

Vertical cavity surface emitting lasers operating in the 1.3- and 1.5-μm wavelength ranges are highly attractive for telecommunications applications. However, they are far less well-developed than devices operating at shorter wavelengths. Pulsed electrically-injected lasing at 1.5 μm, at temperatures up to 240 K, is demonstrated in a vertical-cavity surface-emitting laser with one epitaxial and one dielectric reflector. This is an encouraging result in the development of practical sources for optical fiber communications systems     

High-temperature, low threshold current, and uniform operation1×12 monolithic AlGaInAs/InP strain-compensated multiple quantumwell laser array in 1.5 μm

In this paper, we describe the fabrication of a monolithically integrated 1×12 array of 1.5-μm AlGaInAs/InP strain-compensated multiple-quantum-well (MQW) lasers, which has high reliability and highly uniform characteristics in low threshold current, slope efficiency, and lasing wavelength. Besides, each diode on the array exhibits a high characteristic temperature of 88 K and a low slope-efficiency drop of less than 1 dB between 20-80°C and a lasing wavelength of 1510 nm at 20°C and 20 mA. Also, the diode on the array has a maximum resonance frequency of above 8 GHz or 3-dB modulation bandwidth of 12 GHz     

Very low threshold operation of 1.52 μm GaInAsP/InP DFB buriedridge structure laser diodes entirely grown by MOCVD

1.52 μm GaInAsP/InP DFB laser diodes with a buried ridge structure were fabricated entirely by MOCVD, with a second-order corrugation on the GaInAsP guiding layer. The 5 mA minimum threshold current achieved is believed to be the lowest yet reported for DFB lasers. Single longitudinal-mode operation with a side-mode suppression ratio greater than 35 dB was obtained from 20°C (up to 16 mW) to 90°C (up to 3 mW)     

High-power broad-band superluminescent diode with low spectralmodulation at 1.5-μm wavelength

A 1.5-μm wavelength superluminescent light source operating at a heat sink temperature of 13°C with the following properties was realized: 20-mW continuous wave output power, 130-nm spectral bandwidth, and 0.2-dB spectral modulation. This light source consists of an angled facet single-mode waveguide with a rear absorption region. These results were obtained by optimizing the epitaxial design, the waveguide design, and the device mounting     

Extremely low threshold (0.56 mA) operation in 1.3 μmInGaAsP/InP compressive-strained-MQW lasers

A record low threshold current of 0.56 mA, as a long-wavelength laser, has been obtained in a 1.3 μm InGaAsP/InP strained-MQW laser, at room temperature (25°C), by optimising an active layer and by employing a short cavity with high-reflection coatings     

A 0.15-μm 60-GHz high-power composite channel GaInAs/InP HEMTwith low gate current

This letter presents recent improvements and experimental results provided by GaInAs/InP composite channel high electron mobility transistors (HEMT). The devices exhibit good dc and rf performance. The 0.15-μm gate length devices have saturation current density of 750 mA/mm at V_GS=+0 V. The Schottky characteristic is a typical reverse gate-to-drain breakdown voltage of -8 V. Gate current issued from impact ionization has been studied in these devices, in the first instance, versus drain extension. At 60 GHz, an output power of 385 mW/mm has been obtained in such a device with a 5.3 dB linear gain and 41% drain efficiency which constitutes the state-of-the-art. These results studied are the first reported for a composite channel Al_0.65In_0.35As/Ga_0.47In_0.53 As/InP HEMT on an InP substrate     

CW operation of DFB-BH GaInAsP/InP lasers in 1.5 ?m wavelength region

Distributed-feedback buried heterostructure (DFB-BH) GaInAsP/InP lasers in the 1.5 ?m wavelength region have been operated continuously at heat-sink temperatures as high as 310 K. A threshold current of 55 mA at 300 K and single longitudinal mode operation have been obtained.     

1.5-μm tapered-gain-region lasers with high-CW output powers

High-power diode lasers consisting of a a tapered region have waveguide section coupled to fabricated in 1.5-μm InGaAsP-InP multiple-quantum-well material. Self-focusing at high current densities and high intensity input into the taper section has been identified as a fundamental problem in these devices that has to be dealt with. To date, continuous-wave output powers of >1 W with ≈80% of the power in the near-diffraction-limited central lobe of the far field have been obtained through a judicious choice of device parameters     

High-coupling-efficient 1.3-μm laser diodes with goodtemperature characteristics

We have proposed uniformly beam-expanded structures based on the advanced concept for realizing high coupling efficiency and good temperature characteristics. Beam expansion (optical confinement reduction) by narrowing the core layer width as well as a carrier confinement are strongly enhanced by adopting a larger bandgap InGaAsP for MQW barriers and separate confinement heterostructure layers. These laser diodes (LD's) were fabricated by the conventional buried heterostructure laser process, which is very important in reducing the cost. Our results have proven the effectiveness of our proposition. The LD's with high coupling efficiency (-3.2 dB) and good temperature characteristics have been achieved even using the simple approach of reducing optical confinement. The threshold currents at 25 and 85°C are 9.3 and 39.4 mA, respectively. The slope efficiency at 25°C is 0.39 W/A and still high (0.26 W/A) even at 85°C     

AlGaInAs/InP 1.5 μm MQW DFB laser diodes exceeding 20 GHzbandwidth

Buried mushroom multiquantum well DFB laser diodes with compressively strained GaInAs quantum wells and asymmetric confinement layer design are fabricated with a combined MBE/MOCVD technology. Packaged devices exhibit high -3 dB IM bandwidths for very low bias levels and a record bandwidth for this material system of 21 GHz     

Crosstalk in 1.5-μm InGaAsP optical amplifiers

A dynamical model for multichannel amplification by near-traveling-wave optical amplifiers is presented, and results on crosstalk induced by either amplitude modulation or frequency modulation are given. The mechanisms influencing the crosstalk most are the residual facet reflectivities and the detuning of the channels relative to the amplifier Fabry-Perot spectrum. Calculations of worst-case crosstalk levels are included. The model is verified experimentally for amplitude-modulated signals, and crosstalk levels up to -7 dB are reported. For frequency-modulated signals, estimated crosstalk is significantly lower and can be reduced by high quality facet coatings     

Low threshold current CW operation of GaInAsP/InP buried heterostructure distributed Bragg-reflector integrated-twin-guide laser emitting at 1.5?1.6 ?m

Low threshold current CW operation of a 1.5?1.6 ?m-wavelength GaInAsP/InP buried heterostructure distributed Bragg reflector integrated twin guide (BH-DBR-ITG) laser was obtained up to 12°C. Single wavelength operation was obtained at a temperature range of 25 deg. The temperature dependence of lasing wavelength was 0.10 nm/deg. At 248 K, the threshold current, the differential quantum efficiency and the maximum output power were 37 mA, 16.3%/facet and 6 mW, respectively.     

High-speed operation of 1.5 μm GaInAsP/InP optoelectronicintegrated laser drivers

A 1.5 μm-wavelength high-speed self-aligned constricted-mesa laser diode and an InP MESFET have been integrated monolithically without deterioration in the performance of either device, by using a gate projection process. A broad 3 dB bandwidth of 6.6 GHz was demonstrated for the first time     

Submilliampere-threshold 1.5-μm strained-layer multiple quantumwell lasers

The effect of high-reflection facet coatings on strained-layer multiple-quantum-well lasers was studied and submilliampere-threshold lasers were made in the 1.5-μm wavelength region with a short cavity and high-reflection-coated facets. As a result of the compressive strain, the threshold current density is loss-limited instead of transparency-limited. By the use of the step-graded-index separate confinement heterostructure to reduce the waveguide loss, a threshold current density of 550 A/cm² was measured on 30-μm wide broad area lasers with 1-mm long cavity