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The intermode beat frequency stability of a 1 mm long quantum dash self mode‐locked semiconductor laser emitting optical frequency combs centred at 1535 nm is improved by single‐cavity optical self‐injection. A novel all‐fibre based cavity employing a piezo‐stretchable fibre spool provides both macroscopic optical path cavity length of 76 m and microscopic fine‐delay fibre length control. The maximum achieved intermode beat frequency tuning is 2 MHz. The intermode beat frequency line width indicating the optical frequency comb stability is improved from 67 kHz to below 900 Hz constituting an improvement by a factor of 74. An independent free‐space stabilisation experiment and stochastic time‐domain modelling confirm the demonstrated intermode beat frequency tuning range. [ABSTRACT FROM AUTHOR]

Photoluminescence (PL) quantum efficiency (QE) is experimentally investigated, using an integrating sphere, as a function of excitation power on both InAs/InP quantum rod nanowires (QRod‐NWs) and radial quantum well nanowires (QWell‐NWs) grown on silicon substrates. The measured values of the QE are compared with those of the planar analogues such as quantum dash and quantum well samples, and found to be comparable for the quantum well structures at relatively low power density. Further studies reveal that the values of QE of the QRod‐NWs and QWell‐NWs are limited by the low quality of the InP NW structure and the quality of radial quantum well, respectively. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) Part of Focus Issue on “Semiconductor Nanowires” (Eds.: Chennupati Jagadish, Lutz Geelhaar, Silvija Gradecak) The quantum efficiency of InAs/InP nanowire heterostructures grown on silicon, such as quantum rod and quantum well nanowires, is studied as a function of excitation power. The experimental results are compared to that measured on analogues InAs(P)/InP planar heterostructures (quantum dashes and quantum well). From the obtained results we conclude about possible ways to improve the quantum efficiency of the nanowire heterostructures which can serve for the fabrication of high‐efficiency light emitting devices working in telecommunication window. [ABSTRACT FROM AUTHOR]

An innovative 10 Gbit/s single mode optical transmitter with the capacity of error‐free transmission is demonstrated in the range of 0–100 km with constant biasing conditions by using a quantum dash directly modulated laser. A commercially available etalon filter is used as a passive optical filter to achieve penalty‐free transmission with a dynamic extinction ratio >6 dB over a large range of fibre spans. [ABSTRACT FROM AUTHOR]