Quantum-well Superluminescent Diodes Research Articles

Bonding stress and reliability of low-polarization quantum-well superluminescent diode

Mechanical stress induced by bonding low-polarization GaAsP/AlGaAs quantum-well superluminescent diodes with p-side-up and p-side-down bonding methods has been observed using measurements of the degree of polarization. Due to the closer distance from the heat-sink to active region and the thermal expansion coefficient mismatch between the oxygen-free copper heat-sink and GaAs-based chip, p-side-down bonding configuration were observed to have a larger stress than p-side-up one. The high temperature accelerated aging test of SLDs with both bonding methods was carried out and discussed. Results suggested that such a bonding stress in superluminescent diode might degrade device's performance, i.e. reducing the threshold level of catastrophic optical damage and improving the failure rate on accelerated aging test.

Measurement of junction temperature and thermal resistance in InGaAlAs/AlGaAs quantum-well superluminescent diodes (SLDs)

This paper reports on the experimental method of the determination of junction temperature and thermal resistance in 840 nm InGaAlAs/AlGaAs compressive strained single quantum well (SQW) superluminescent diodes (SLDs). The linear relation between forward voltage and junction temperature clearly occurs by utilizing the forward voltage–temperature ([Formula: see text]–[Formula: see text]) method. The temperature coefficient [Formula: see text] has been determined. Under 100 mA continuous-wave (CW) operation condition, the thermal resistance is measured to be 81.6[Formula: see text]C/W, which is not significantly different with the theoretical calculation result.

Single-transverse-mode near-IR superluminescent diodes with cw output power up to

A series of light-emitting modules based on single-mode quantum-well superluminescent diodes with centre emission wavelengths of about 790, 840, 960 and and a cw output power up to in free space is developed. A sufficiently long service life of these devices is demonstrated.

Broadband superluminescent diodes with bell-shaped spectra emitting in the range from 800 to

Quantum-well superluminescent diodes (SLD) with extremely thin active (AlGa)As and (InGa)As layers and centre wavelengths about 810, 840, 860 and are experimentally studied. Their emission spectrum possesses the shape close to Gaussian, its FWHM being depending on the length of the active channel and the level of pumping. Under cw injection, the output power of light-emitting modules based on such SLDs can amount to at the output of a single-mode fibre. It is demonstrated that the operation lifetime of these devices exceeds 30000 hours. Based on the light-emitting modules the prototypes of combined BroadLighter series light sources are implemented having a bell-shaped spectrum with the width up to .

Variations in the output characteristics of broadband superluminescent diodes during long-term operation

A method of service life tests of SLD-37 quantum-well superluminescent diodes (SLDs), which are widely used in optical coherence tomography, is described and the results of tests are presented. Special attention is given to variations in the emission spectra of SLDs during their aging. It is shown that this method can be used as an incoming test to select processed semiconductor heterostructures with the longest expected lifetime for fabrication of active elements of SLD modules.

Effect of optical feedback on the output parameters of quantum-well superluminescent diodes

The effect of a weak optical feedback on the power and spectral parameters of light-emitting modules based on near-IR quantum-well superluminescent diodes (SLDs) is studied. It is shown that even very weak parasitic feedback (kfb < -30 dB) distorts the emission spectrum of high-power SLDs and noticeably reduces their output power.

Broadband light source based on quantum-well superluminescent diodes for high-resolution optical coherence tomography

Emission of single quantum-well superluminescent diodes of two types in spectral ranges between 810 and 870 nm and between 860 and 970 nm is combined with the help of an original broadband fibre Y-coupler. Such a light source produces more than 5 mW of the cw output optical power and has a record small coherence length of about 5 μm. Its relative intensity noise does not exceed −135 dB Hz-1 in the 100-kHz—10-MHz frequency range. The use of this source in an optical coherence tomography provides the recording of tomograms of biological objects in vivo with a spatial resolution of 2–3 μm.

Broadband radiation sources based on quantum-well superluminescent diodes emitting at 1550 nm

The emission spectra of superluminescent diodes (SLDs) based on a multilayer quantum-well (InGa)PAs heterostructure are studied in the wavelength range from 1450 to 1650 nm. The FWHM of these spectra exceeds 120 nm in certain operating regimes. The experimental samples of light-emitting modules with output single-mode fibres are fabricated based on the SLDs studied, which produce the output power spectral density above -45 dBm nm-1 within the band over 200 nm. The spectrum of such an emitter covers the main bands (S, C, and L) of WDM telecommunication systems. The possibilities of a further broadening and flattening of the emission band of these SLDs are considered.