Low-loss passive waveguides in a generic InP foundry process via local diffusion of zinc

Generic InP foundry processes allow monolithic integration of active and passive elements into a common p-n doped layerstack. The passive loss can be greatly reduced by restricting the p-dopant to active regions. We report on a localized Zn-diffusion process based on MOVPE, which allows to reduce waveguide loss from 2 dB/cm to below 0.4 dB/cm. We confirm this value by fabrication of a 73 mm long spiral ring resonator, with a record quality factor of 1.2 million and an extinction ratio of 9.7 dB.</p

High-efficiency ultrasmall polarization converter in InP membrane

An ultrasmall (99% with insertion losses o

Widely tunable multimode-interference based coupled cavity laser with integrated interferometer

We present a simple to process tunable laser, fabricated in a low-cost generic fabrication process and based on two coupled Fabry-Perot cavities. The complex coupling coe cients of the coupling element are analytically derived from a 3x3 MMI using coupled mode theory and chosen to maximize the SMSR during lasing operation. Additionally, one of the cavities contains a reflective interferometer, which acts as coarse wavelength selector. This interferometer is derived from a Michelson Interferometer, by replacing the two independent mirrors with our optimized coupling element, leading to a doubled Free Spectral Range. As a result, we obtained a tuning range of 26 nm with potential for beyond 40 nm, a SMSR larger than 40 dB and fiber coupled power up to 9 dBm

Widely tunable multimode-interference based coupled cavity laser with integrated interferometer

\u3cp\u3eWe present a simple to process tunable laser, fabricated in a low-cost generic fabrication process and based on two coupled Fabry-Perot cavities. The complex coupling coe cients of the coupling element are analytically derived from a 3x3 MMI using coupled mode theory and chosen to maximize the SMSR during lasing operation. Additionally, one of the cavities contains a reflective interferometer, which acts as coarse wavelength selector. This interferometer is derived from a Michelson Interferometer, by replacing the two independent mirrors with our optimized coupling element, leading to a doubled Free Spectral Range. As a result, we obtained a tuning range of 26 nm with potential for beyond 40 nm, a SMSR larger than 40 dB and fiber coupled power up to 9 dBm.\u3c/p\u3

Integrated laser with optical feedback shows suppressed relaxation-oscillation dynamics

We experimentally demonstrate a monolithically integrated laser with built-in weak optical feedback, which shows broad regions of operation without relaxation-oscillation-induced instabilities. The side mode suppression is &gt;40 dB for all values of the feedback phase. The measured linewidth varied from 740 KHz to 14 MHz, depending on the feedback phase value

Thermal comparison of buried-heterostructure and shallow-ridge lasers

\u3cp\u3eWe present finite difference thermal modeling to predict temperature distribution, heat flux, and thermal resistance inside lasers with different waveguide geometries. We provide a quantitative experimental and theoretical comparison of the thermal behavior of shallow-ridge (SR) and buried-heterostructure (BH) lasers. We investigate the influence of a split heat source to describe p-layer Joule heating and nonradiative energy loss in the active layer and the heat-sinking from top as well as bottom when quantifying thermal impedance. From both measured values and numerical modeling we can quantify the thermal resistance for BH lasers and SR lasers, showing an improved thermal performance from 50K/W to 30K/W for otherwise equivalent BH laser designs.\u3c/p\u3