A 1.3μm Low-Threshold Edge-Emitting Laser with AlInAs-Oxide Confinement Layers

A 1.3μm low-threshold edge-emitting AlGaInAs multiple-quantum-well(MQW) laser with AlInAs-oxide confinement layers is fabricated.The Al-contained waveguide layers upper and low the active layers are oxidized as current-confined layers using wet-oxidation technique.This structure provides excellent current and optical confinement,resulting in 12.9mA of a low continuous wave threshold current and 0.47W/A of a high slope efficiency of per facet at room temperature for a 5-μm-wide current aperture.Compared with the ridge waveguide laser with the same-width ridge,the threshold current of the AlInAs-oxide confinement laser has decreased by 31.7% and the slope efficiency has increased a little.Both low threshold and high slope efficiency indicate that lateral current confinement can be realized by oxidizing AlInAs waveguide layers.The full width of half maximum angles of the Al-InAs-oxide confinement laser are 21.6° for the horizontal and 36.1° for the vertical,which demonstrate the ability of the AlInAs oxide in preventing the optical field from spreading laterally.

Low threshold GaAs/AlGaAs double Quantum Well Lasers

于2010-11-23批量导入

Low-threshold conjugated polymer distributed feedback lasers on InP substrate

We demonstrate a low threshold polymer solid state thin-film distributed feedback (DFB) laser on an InP substrate with the DFB structure. The used gain medium is conjugated polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene] (MEH-PPV) doped polystyrene (PS) and formed by drop-coating method. The second order Bragg scattering region on the InP substrate gave rise to strong feedback, thus a lasing emission at 638.9nm with a line width of 1.2nm is realized when pumped by a 532nm frequency-doubled Nd: YAG pulsed laser. The devices show a laser threshold as low as 7 nJ/pulse.

Low threshold amplified spontaneous emission based on coumarin 151 encapsulated in mesoporous SBA-15

Amplified spontaneous emission (ASE) characteristics of a blue dye coumarin 151 encapsulated in a highly ordered mesoporous SBA-15 were studied. The spectra narrowing was observed and found that the threshold and loss were greatly reduced, and the gain is significantly increased compared with spin-coated coumarin 151 doped poly(4-vinylphenol) film. The ASE threshold, gain, and loss, respectively, reached 0.55 mJ pulse(-1) cm(-2), 44.78 cm(-1), and 8.9 cm(-1) for the coumarin 151 encapsulated in mesoporous SBA-15 film. The optimized lasing action owes much to the effects of the better spatial confinement of the molecules in the ordered mesoporous structure of the host SBA-15.

Synthesis and random laser application of ZnO nano-walls: a review

This review paper summarises briefly some important achievements of our recent research on the synthesis and novel applications of nanostructure ZnO such as honeycomb shaped 3-D (dimension) nano random-walls. A chemical reaction/vapour transportation deposition technique was employed to fabricate this structure on ZnO/SiO2/Si substrate without any catalyst and additive in a simple tube furnace to aim the low-cost and high qualified samples. Random laser action with strong coherent feedback at the wavelength between 375 nm and 395 nm has been firstly observed under 355 nm optical excitation with threshold pumping intensity of 0.38 MW/cm(2).

Efficient laser oscillation of Yb : Y3Al5O12 single crystal grown by temperature gradient technique

Low-threshold and highly efficient continuous-wave laser performance of Yb:Y3Al5O12 (Yb:YAG) single crystal grown by a temperature gradient technique (TGT) was achieved at room temperature. The laser can be operated at 1030 and 1049 nm by varying the transmission of the output coupler. Slope efficiencies of 57% and 68% at 1049 and 1030 nm, respectively, were achieved for 10 at. % Yb:YAG sample in continuous-wave laser-diode pumping. The effect of pump power on the laser emission spectrum of both wavelengths is addressed. The near-diffraction-limited beam quality for different laser cavities was achieved. The excellent laser performance indicates that TGT-grown Yb:YAG crystals have very good optical quality and can be potentially used in high-power solid-state lasers.

40-Gb/s Low Chirp Electroabsorption Modulator Integrated With DFB Laser

A 40-Gb/s monolithically integrated transmitter containing an InGaAsP multiple-quantum-well electroabsorption modulator (EAM) with lumped electrode and a distributed-feedback semiconductor laser is demonstrated. Superior characteristics are exhibited for the device, such as low threshold current of 20 mA, over 40-dB sidemode suppression ratio at 1550 nm, and more than 30-dB dc extinction ratio when coupled into a single-mode fiber. By adopting a deep ridge waveguide and planar electrode structures combined with buried benzocyclobutene, the capacitance of the EAM is reduced to 0.18 pF and the small-signal modulation bandwidth exceeds 33 GHz. Negative chirp operation is also realized when the bias voltage is beyond 1.6 V.

Tandem electroabsorption modulators integrated with DFB laser by ultra-low-pressure selective-area-growth MOCVD for 10 GHz optical short pulse generation

　

A 10-GHz bandwidth electroabsorption modulated laser by ultra-low-pressure selective area growth

A novel integration technique has been developed using band-gap energy control of InGaAsP/InGaAsP multi-quantum-well (MQW) structures during simultaneous ultra-low-pressure (22 mbar) selective-area-growth (SAG) process in metal-organic chemical vapour deposition. A fundamental study of the controllability of band gap energy by the SAG method is performed. A large band-gap photoluminescence wavelength shift of 83nm is obtained with a small mask width variation (0-30 mu m). The method is then applied to fabricate an MQW distributed-feedback laser monolithically integrated with an electroabsorption modulator. The experimental results exhibit superior device characteristics with low threshold of 19 mA, over 24 dB extinction ratio when coupled into a single mode fibre. More than 10GHz modulation bandwidth is also achieved, which demonstrates that the ultra-low-pressure SAG technique is a promising approach for high-speed transmission photonic integrated circuits.

High-performance EML grown on taper-masked pattern substrates by ultra-low-pressure MOCVD

A novel in-plane bandgap energy controlling technique by ultra-low pressure (22 mbar) selective area growth (SAG) has been developed. To our knowledge, this is the lowest pressure condition during SAG process ever reported. In this work, high crystalline quality InGaAsP-InP MQWs with a photoluminescence (PL) full-width at half-maximum (FWHM) of less than 35meV are selectively grown on mask-patterned planar InP substrates by ultra-low pressure (22 mbar) metal-organic chemical vapor deposition (MOCVD). In order to study the uniformity of the MQWs grown in the selective area, novel tapered masks are designed and used. Through optimizing growth conditions, a wide wavelength shift of over 80 nm with a rather small mask width variation (0-30 mu m) is obtained. The mechanism of ultra-low pressure SAG is detailed by analyzing the effect of various mask designs and quantum well widths. This powerful technique is then applied to fabricate an electroabsorption-modulated laser (EML). Superior device characteristics are achieved, such as a low threshold current of 19mA and an output power of 7mW. (c) 2005 Elsevier B.V. All rights reserved.

10 GHz optical short pulse generation using tandem electroabsorption modulators monolithically integrated with distributed feedback laser by ultra-low-pressure selective area growth

In this work, a novel light source of tandem InGaAsP/InGaAsP multiple quantum well electroabsoption modulator( EAM ) monolithically integrated with distributed feedback laser is fabricated by ultra-low-pressure ( 22 x 10(2) Pa ) selective area growth metal-organic chemical vapor diposition technique. Superior device performances have been obtained, such as low threshold current of 19 mA, output light power of 4.5 mW, and over 20 dB extinction ratio at 5 V applied voltage when coupled into a single mode fiber. Over 10 GHz 3dB bandwidth in EAM part is developed with a driving voltage of 2 V. Using this sinusoidal voltage driven integrated device, 10 GHz repetition rate pulse with an actual width of 13.7 ps without any compression elements is obtained due to the gate operation effect of tandem EAMs.

Tandem electroabsorption modulators integrated with DFB laser by ultra-low-pressure selective-area-growth MOCVD for 10 GHz optical short pulse generation - art. no. 60200O

A novel device of tandem multiple quantum wells (MQWs) electroabsorption modulators (EAMs) monolithically integrated with DFB laser is fabricated by ultra-low-pressure (22 mbar) selective area guowth (SAG) MOCVD technique. Experimental results exhibit superior device characteristics with low threshold of 19 mX output light power of 4.5 mW and over 20 dB extinction ratio when coupled into a single mode Fiber. Moreover, over 10 GHz modulation bandwidth is developed with a driving voltage of 2 V. Using I this sinusoidal voltage driven integrated device, 10GHz repetition rate pulse with a width of 13.7 ps without any compression elements is obtained.

High-performance EML grown on taper-masked pattern substrates by ultra-low-pressure MOCVD

A novel in-plane bandgap energy controlling technique by ultra-low pressure (22 mbar) selective area growth (SAG) has been developed. To our knowledge, this is the lowest pressure condition during SAG process ever reported. In this work, high crystalline quality InGaAsP-InP MQWs with a photoluminescence (PL) full-width at half-maximum (FWHM) of less than 35meV are selectively grown on mask-patterned planar InP substrates by ultra-low pressure (22 mbar) metal-organic chemical vapor deposition (MOCVD). In order to study the uniformity of the MQWs grown in the selective area, novel tapered masks are designed and used. Through optimizing growth conditions, a wide wavelength shift of over 80 nm with a rather small mask width variation (0-30 mu m) is obtained. The mechanism of ultra-low pressure SAG is detailed by analyzing the effect of various mask designs and quantum well widths. This powerful technique is then applied to fabricate an electroabsorption-modulated laser (EML). Superior device characteristics are achieved, such as a low threshold current of 19mA and an output power of 7mW. (c) 2005 Elsevier B.V. All rights reserved.