in this paper, the effects of reflected waves of the facets on the internal optical intensity of semiconductor dfb lasers are investigated. the uniformity of optical intensity along the cavity length is evaluated with flatness parameter. the dependence of this parameter on coupling coefficient, reflectivity and grating phase at the facets is also studied. this investigation shows that in some s...

We report on quantum cascade lasers (QCLs) with a tilted facet utilizing their polarization property. Contrary to diode lasers, QCLs generate purely TM polarized light due to the intersubband selection rules. This property enables the utilization of reflectivity in terms of only TM polarized light (TM reflectivity). The TM reflectivity is reduced by tilting the front facet, resulting in enhance...

We investigate experimentally the influence of the grating reflectivity, grating resolution, and diode facet antireflection (AR) coating on the intrinsic linewidth of an external-cavity diode laser built with a diffraction grating in a Littrow configuration. Grating lasers at 399, 780, and 852 nm are determined to have typical linewidths between 250 and 600 kHz from measurements of their freque...

We demonstrate a band-pass resonator in the terahertz (THz) range, based on a frequency-selective designer reflector. The resonator consists of a parallel-plate waveguide, a designed groove pattern cut into the output facet of each plate, and a reflecting mirror. The patterned facet supports a spoof surface plasmon mode, which modifies the reflectivity at the waveguide output facet by interacti...

Based on rigorous mode expansion simulations, we consider the problem of guided light reflection at rectangular end facets of planar dielectric waveguides. Emphasis is on multimode structures with high refractive index contrast and on configurations that show a high reflectivity. Given the matrix of reflection coefficients for the guided fields, one can compute the maximum power reflectance for...

A thin-film InGaAs/GaAs edge-emitting single-quantum-well laser has been integrated with a tapered multimode SU-8 waveguide onto an Si substrate. The SU-8 waveguide is passively aligned to the laser using mask-based photolithography, mimicking electrical interconnection in Si complementary metal-oxide semiconductor, and overlaps one facet of the thin-film laser for coupling power from the laser...

We report on a GaSb-based superluminescent diode optimized for high-power broadband operation around wavelength of 2 μm. The high optical power was achieved by the high-quality epitaxial InGaSb/AlGaAsSb type-I quantum well gain material, which processed into double-pass amplification configuration. To prevent lasing at current injection while enabling strong amplified spontaneous emission, casc...

The modulation and impedance properties of a terahertz (THz) quantum cascade laser (QCL) are investigated theoretically based on three-level rate equation model. effect different device parameters, namely, facet reflectivity, injection efficiency, spontaneous emission factor, operating current, the characteristics QCL is analyzed in detail. shows maximum bandwidth (f3dB) 21 GHz an intrinsic 3.8...

A novel two-dimensional vertical cavity surface emission laser (VCSEL) based wavelength converter is proposed. We developed a twodimensional transmission line laser model (TLLM) to analyze the proposed wavelength converter. This model takes into account Bragg reflectors by using the modified connecting matrix. Therefore, accurate and efficient modeling of the VCSEL structure is achieved. Extinc...

Vertical mirrors have been fabricated with chemically assisted ion beam etching (CAIBE) on OMVPE grown InGaN/AlGaN laser diode structures. AFM measurements show that smooth vertical sidewalls are obtained which exhibit a root mean squared (rms) roughness of only 40—60 A _ . The inclination angle of the etched mirrors is within $2° of vertical, as SEM studies indicate. Photopumping measurements ...