This paper summarizes recent advances on InAs/InP quantum dashes (QD) materials for lasers and amplifiers, and QD device performance with particular interest for optical communication. We investigate both InAs/InP dashes in a barrier and dashes in a well (DWELL) heterostructures operating at 1.5 µm. These two types of QDs can provide high gain and low losses. Continuous-wave room-temperature lasing operation on ground state of cavity length as short as 200µm has been achieved, demonstrating the high modal gain of the active core. A threshold current density as low as 110 A/cm 2 per QD layer has been obtained for infinite-length DWELL laser. An optimized DWELL structure allows achieving of a T0 larger than 100 K for broad area lasers and of 80 K for single transverse mode lasers in the temperature range between 25°C and 85°C. Buried ridge stripe type single mode DFB lasers are also demonstrated for the first time, exhibiting a side-mode suppression-ratio as high as 45 dB. Such DFB lasers allow the first floor free 10 Gb/s direct modulation for back-to-back and transmission over 16 km standard optical fiber. In addition, novel results are given on gain, noise and four wave mixing of QD-based semiconductor optical amplifiers. Furthermore, we demonstrate that QD FP lasers, owing to the small confinement factor and the 3D quantification of electronic energy levels, exhibit a beating linewidth as narrow as 15 kHz. Such an extremely narrow linewidth, compared to their QW or bulk counterparts, leads to the excellent phase noise and time jitter characteristics when QD lasers are actively mode-locked. These advances constitute a new step towards the application of QD lasers and amplifiers to the field of optical fiber communications.

We report on advanced millimeter-wave (mm-wave) photonic components for broadband wireless transmission. We have developed self-pulsating 60 GHz range quantumdash Fabry-Perot mode-locked laser diodes (MLLD) for passive, i.e. unlocked, photonic mm-wave generation with comparably low phase noise level of-76 dBc/Hz @ 100 kHz offset from 58.8 GHz carrier. We further report on high-frequency 1.55 µm waveguide photodiodes (PD) with partially p-doped absorber for broadband operation (f 3dB~7 0-110 GHz) and peak output power levels up to +4.5 dBm @ 110 GHz as well as wideband antenna integrated photomixers for operation within 30-300 GHz and peak output power levels of-11 dBm @ 100 GHz and 6 mA photocurrent. We further present compact 60 GHz wireless transmitter and receiver modules for wireless transmission of uncompressed 1080p (2.97 Gb/s) HDTV signals utilizing the developed MLLD and mm-wave PD. Error-free (BER=10-9 , 2 31-1 PRBS, NRZ) outdoor transmission of 3 Gb/s over 25 m is demonstrated as well as wireless transmission of uncompressed HDTV signals in the 60 GHz band. Finally, an advanced 60 GHz photonic wireless system offering record data throughputs and spectral efficiencies is presented. For the first time, we demonstrate photonic wireless transmission of data throughputs up to 27.04 Gbit/s (EVM 17.6 %) using a 16-QAM OFDM modulation format resulting in a spectral efficiency as high as 3.86 bit/s/Hz. Wireless experiments were carried out within the regulated 57-64 GHz band in a lab environment with a maximum transmit power of-1 dBm and 23 dBi gain antennas for a wireless span of 2.5 m. This span can be extended to some 100 m span when using highgain antennas and higher transmit power levels.

Several applications are pushing the development of high performance mode-locked lasers: generation of short pulses for extremely high bit rate transmission at 100 Gb/s and beyond, all-optical MLLs. For instance, they are very compact, with a length usually not exceeding 4 mm. The pulse repetition rate can be as high as 500 GHz [4]. They are very efficient, having a high power conversion efficiency.