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 >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

Application of optical proximity correction for 193 nm deep UV enabled InP photonic integrated circuits

We present the first-time application of rule-based optical proximity correction for InP based photonic integrated circuits fabricated with 193 nm deep UV lithography. Simulations of the lithography process were used to systematically predict and preserve pattern fidelity of sidewall gratings to find optimal correction parameters. Optical proximity corrected designs were exposed in ArF resist, demonstrating high correlation with lithography simulation results and exhibiting up to 70% improved pattern fidelity

Two-dimensional optical beam steering with InP-based photonic integrated circuits

Two-dimensional optical beam steering using an InP photonic integrated circuit has been demonstrated. Lateral beam steering controlled by a 1-D phased array has been made easier through on-chip interferometer monitors. Longitudinal beam steering controlled by the input wavelength has demonstrated an efficiency of 0.14 degrees/nm. Very fast beam steering (>10(7) degrees/s) in both dimensions has been demonstrated as well. As the latest development, a widely tunable sampled-grating distributed Bragg reflector laser has been monolithically integrated and 2-D beam steering has been demonstrated with this on-chip tunable laser source

Kink power in weakly index guided semiconductor lasers

A periodic dependence of kink power on laser length is observed and explained. Weakly index guided high power stripe lasers in the AlGaAs, InGaAlP, and InGaAs–AlGaAs material systems are studied and oscillation periods of 100–350 µm are found. Relative kink power differences exceeding a factor of 4 are observed. Facet coatings lead to differences in the oscillation amplitude but not in the oscillation period. The observations indicate that phase-locked fundamental and first-order modes exist at certain preferred laser lengths. This general model fully explains the oscillatory behavior of the kink power and the correlated changes in lateral far field distributions at the front and rear mirrors. It is concluded that the optimum diffraction limited power output can be obtained by choosing the proper laser length