Photodetection properties of semiconductor laser diode detectors

“…The measured responsivities can be analyzed by using a general expression for the external quantum efficiency of a waveguide detector, neglecting surface recombination effects [ 41] raib (…”

Section: B Responsivitymentioning

confidence: 99%

Tunable superlattice p-i-n photodetectors: characteristics, theory, and application

Larsson

Andrekson

Eng

et al. 1988

IEEE J. Quantum Electron.

105

View full text Add to dashboard Cite

Abstract-We report on extended measurements and theory on the recently developed monolithic wavelength demultiplexer consisting of voltage tunable superlattice p-i-n photodetectors in a waveguide configuration. This includes a reduced wavelength spacing, an investigation of the polarization dependence of the crosstalk and bit-error-rate measurements for various crosstalk levels. We show that the device is able to demultiplex and detect two optical signals with a wavelength separation of 20 nm directly into different electrical channels at a data rate of 1 Gbit/s and with a crosstalk attenuation varying between 20 and 28 dB, depending on the polarization. The minimum acceptable crosstalk attenuation at a data rate of 100 Mbits/s is determined to be 10 dB. The feasibility of using the device as a polarization angle sensor for linearly polarized light is also demonstrated. The paper includes a theory for the emission of photogenerated carriers out of the quantum wells since this is potentially a speed limiting mechanism in these detectors. We show that a theory of thermally assisted tunneling by polar optical phonon interaction is able to predict emission times consistent with the observed temporal response.

show abstract

“…The use of a laser as a photodetector was pioneered in the near-infrared regime some years ago, directly benefiting from the amplification performance of weak signals. [12][13][14] Furthermore, for QCLs, the in-principal capability to serve as a conventional photodetector under reverse bias has been demonstrated successfully. 15 The SM signals, obtained by a HgCdTe photovoltaic detector placed at the rear facet of the laser, where a carefully adjusted aperture guaranteed a clean mixing geometry, and the SM signal obtained from the amplified ac voltage signal of the QCL itself are shown in Figs.…”

mentioning

confidence: 99%

Measurements of the α factor of a distributed-feedback quantum cascade laser by an optical feedback self-mixing technique

et al. 2006

View full text Add to dashboard Cite

We demonstrate measurements of the ␣ factor of a distributed-feedback quantum cascade laser (QCL) by using a newly modified self-mixing interferometric technique exploring the laser itself as the detector. We find a strong dependence of the ␣ factor on the injection current, ranging from −0.44 at 120 mA to 2.29 at 180 mA, which can be attributed to the inherent physics of QCLs. © 2006 Optical Society of America OCIS codes: 140.5960, 140.3070, 040.5570, 120.3180. Today, quantum cascade lasers (QCLs) have evolved to be among the most important light sources in the mid-infrared (MIR) to far-infrared (FIR) wavelength range. The lasing transition in QCLs occurs between subsequently cascaded quantized energy levels within the conduction band. Hence the emitted wavelength does not depend on the energy bandgap as in conventional semiconductor lasers, but it is determined by the energy difference of discrete levels in the conduction band originating from the bandgapengineered design of the laser device.1 With the advent of this new type of laser structure, a series of questions on the laser performance and the relevant physical mechanisms have been brought up. For example, it has been found experimentally, and verified theoretically, that the scaling behavior of the intensity noise as a function of the emitted power is different with respect to interband lasers, resulting directly from the cascaded level scheme and the different carrier lifetime.2,3 The linewidth enhancement factor (␣ factor) determines the dynamics of semiconductor lasers, because it accounts for the coupling between amplitude and phase of the light as defined in Eq. (1),Here, r and i are the real and the imaginary parts of the susceptibility, respectively, and n is the carrier density. 4 The ␣ factor therefore describes how gain and refractive index change with respect to each other when the carrier density varies.5 From the very beginning of the first technological realizations of QCLs, there has been an urgent need to measure the ␣ factor of QCLs and to check whether the particular level scheme gives rise to a different physics, e.g., ifQCLs exhibit an ␣ factor close to zero as expected for a nondetuned atomiclike level scheme. The standard technique used for interband semiconductor lasers is the Hakki-Paoli method, which relies on measuring the wavelength shift of the longitudinal laser modes below threshold. However, this method gives only access to ␣ values below threshold, and for low ␣ values its accuracy may be affected by temperature effects. 6 An approach based on injection locking 7 is the only method, to date, that has been applied to QCLs above threshold.Our purpose in this paper is fourfold. First, we apply the self-mixing (SM) technique to the MIR spectral range using QCLs. Second, by directly using the laser itself as a detector instead of an external photodetector, we are able to obtain nice and clean SM signals. Third, by applying a modified analysis method, we are able to extract the ␣ factor from the measurement of these wavefo...

show abstract

Photodetection properties of semiconductor laser diode detectors

Cited by 30 publications

References 25 publications

A free-space alignment technique for active optical waveguide components

A free-space alignment technique for active optical waveguide components

Tunable superlattice p-i-n photodetectors: characteristics, theory, and application

Measurements of the α factor of a distributed-feedback quantum cascade laser by an optical feedback self-mixing technique

Contact Info

Product

Resources

About