In the present project leading research institutes in the field of microfabrication for optoelectronic devices and major telecommunication companies will make a co-ordinated effort to develop gain coupled laser structures for telecommunication and sensor applications, which are based on nanopatterning of the active material of the devices.
In the GaInAsP/InP material system single mode lasers based on gain coupling at 1.55 µm are promising light sources for high speed modulation due to a large bandwidth and a small chirp. Gain coupling is expected to improve significantly the yield of monomode lasers compared to index guided distributed feedback lasers without requiring anti reflective coatings and phase shifted gratings. This makes gain coupled lasers especially attractive for wavelength multiplexing applications.
Using GaAs based heterostructures, single mode gain coupled lasers in the 0.8 µm range will be developed for sensor applications. Here the development focuses on a high side mode suppression ratio and narrow linewidths. In both wavelength ranges the potential of gain coupling for low cost monomode lasers will be evaluated.
Gain modulation will be obtained by holographic and electron beam exposure in combination with etching as well as by focused ion beam patterning. In particular the patterning of first order gain coupled structures is very challenging, because the gain sections for lasers at 1.55 µm and 0.8 µm have widths on the order of 100 nm and 50 nm, respectively. For example, ultra low damage processes have to be developed for the different materials.
Broad area lasers, ridge wave guide lasers and buried heterostructure lasers will be developed from overgrown first order gain grating structures. The gain coupled lasers will be evaluated in the laboratories of the consortium regarding device performance as well as economic criteria. For InP and GaAs based gain coupled lasers the device characterization focuses on laser threshold current density, differential quantum efficiency, single mode yield, side mode suppression ratio, laser linewidth, back reflection sensitivity and temperature stability. For InP based lasers for telecommunication in addition the high frequency properties (modulation bandwidths, chirp) will be evaluated. The economic criteria of the evaluation include the manufacturing cost as well as the reliability of the processes and of the devices.
Funding SchemeCSC - Cost-sharing contracts
91131 Issy-les- Moulineaux
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