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Electronic control of coherence in a two-dimensional array of photonic crystal surface emitting lasers.

Taylor RJ, Childs DT, Ivanov P, Stevens BJ, Babazadeh N, Crombie AJ, Ternent G, Thoms S, Zhou H, Hogg RA - Sci Rep (2015)

Bottom Line: We demonstrate a semiconductor PCSEL array that uniquely combines an in-plane waveguide structure with nano-scale patterned PCSEL elements.This novel geometry allows two-dimensional electronically controllable coherent coupling of remote vertically emitting lasers.Mutual coherence of the PCSEL elements is verified through the demonstration of a two-dimensional Young's Slits experiment.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic &Electrical Engineering, Centre for Nanoscience &Technology, North Campus, The University of Sheffield, Broad Lane, Sheffield, S3 7HQ, United Kingdom.

ABSTRACT
We demonstrate a semiconductor PCSEL array that uniquely combines an in-plane waveguide structure with nano-scale patterned PCSEL elements. This novel geometry allows two-dimensional electronically controllable coherent coupling of remote vertically emitting lasers. Mutual coherence of the PCSEL elements is verified through the demonstration of a two-dimensional Young's Slits experiment. In addition to allowing the all-electronic control of the interference pattern, this type of device offers new routes to power and brightness scaling in semiconductor lasers, and opportunities for all-electronic beam steering.

No MeSH data available.


Schematic of the coupler Fabry-Pérot modes (green lines), and lasing linewidths of neighbouring PCSELs (blue and red curves).For sufficiently long coupler lengths, the phase-matching condition between neighbouring PCSELs is met for several Fabry-Pérot modes within the lasing line-width.
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f2: Schematic of the coupler Fabry-Pérot modes (green lines), and lasing linewidths of neighbouring PCSELs (blue and red curves).For sufficiently long coupler lengths, the phase-matching condition between neighbouring PCSELs is met for several Fabry-Pérot modes within the lasing line-width.

Mentions: The application of a small change in coupler current therefore allows the switching of communication between PCSEL elements of the array. In addition to coupling, phase matching between the PCSELs must also be achieved to enable coherent outputs. This is shown schematically in Fig. 2 which illustrates the Fabry-Perot mode spacing (indicated by the vertical green lines) of a short and long coupler cavity with regard to the lasing linewidths of two PCSELS of the array (indicated by the blue and red curves). The linewidth of the PCSEL elements here is 0.5 nm. So long as the two PCSELS are tuned such that there is a common area within their linewidth, injection locking can occur. The final requirement for coherent emission is that the in-plane locking light is phase matched from one PCSEL to the other. In order to ensure that the phase matching condition is always met regardless of the refractive index and length of the coupler (both of which will change due to free carrier and thermal effects as coupler current is changed) a coupler length of 1 mm is selected. The Fabry-Pérot mode spacing (from waveguide modeling to deduce the effective index of the mode) for the 1 mm long coupler is calculated as 0.14 nm, resulting in a number of Fabry-Pérot modes within the linewidth of the PCSEL emission (see supplementary S3). As such, one of these coupler modes will always be coincident with the grey area under the lower curve. This large distance between PCSEL elements of the array also guarantees that the PCSELs are thermally isolated. We note that for future use in beam steering applications, much shorter coupler sections (along with technologies to realize transparent coupler sections such as intermixing or re-growth) are required.


Electronic control of coherence in a two-dimensional array of photonic crystal surface emitting lasers.

Taylor RJ, Childs DT, Ivanov P, Stevens BJ, Babazadeh N, Crombie AJ, Ternent G, Thoms S, Zhou H, Hogg RA - Sci Rep (2015)

Schematic of the coupler Fabry-Pérot modes (green lines), and lasing linewidths of neighbouring PCSELs (blue and red curves).For sufficiently long coupler lengths, the phase-matching condition between neighbouring PCSELs is met for several Fabry-Pérot modes within the lasing line-width.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542471&req=5

f2: Schematic of the coupler Fabry-Pérot modes (green lines), and lasing linewidths of neighbouring PCSELs (blue and red curves).For sufficiently long coupler lengths, the phase-matching condition between neighbouring PCSELs is met for several Fabry-Pérot modes within the lasing line-width.
Mentions: The application of a small change in coupler current therefore allows the switching of communication between PCSEL elements of the array. In addition to coupling, phase matching between the PCSELs must also be achieved to enable coherent outputs. This is shown schematically in Fig. 2 which illustrates the Fabry-Perot mode spacing (indicated by the vertical green lines) of a short and long coupler cavity with regard to the lasing linewidths of two PCSELS of the array (indicated by the blue and red curves). The linewidth of the PCSEL elements here is 0.5 nm. So long as the two PCSELS are tuned such that there is a common area within their linewidth, injection locking can occur. The final requirement for coherent emission is that the in-plane locking light is phase matched from one PCSEL to the other. In order to ensure that the phase matching condition is always met regardless of the refractive index and length of the coupler (both of which will change due to free carrier and thermal effects as coupler current is changed) a coupler length of 1 mm is selected. The Fabry-Pérot mode spacing (from waveguide modeling to deduce the effective index of the mode) for the 1 mm long coupler is calculated as 0.14 nm, resulting in a number of Fabry-Pérot modes within the linewidth of the PCSEL emission (see supplementary S3). As such, one of these coupler modes will always be coincident with the grey area under the lower curve. This large distance between PCSEL elements of the array also guarantees that the PCSELs are thermally isolated. We note that for future use in beam steering applications, much shorter coupler sections (along with technologies to realize transparent coupler sections such as intermixing or re-growth) are required.

Bottom Line: We demonstrate a semiconductor PCSEL array that uniquely combines an in-plane waveguide structure with nano-scale patterned PCSEL elements.This novel geometry allows two-dimensional electronically controllable coherent coupling of remote vertically emitting lasers.Mutual coherence of the PCSEL elements is verified through the demonstration of a two-dimensional Young's Slits experiment.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic &Electrical Engineering, Centre for Nanoscience &Technology, North Campus, The University of Sheffield, Broad Lane, Sheffield, S3 7HQ, United Kingdom.

ABSTRACT
We demonstrate a semiconductor PCSEL array that uniquely combines an in-plane waveguide structure with nano-scale patterned PCSEL elements. This novel geometry allows two-dimensional electronically controllable coherent coupling of remote vertically emitting lasers. Mutual coherence of the PCSEL elements is verified through the demonstration of a two-dimensional Young's Slits experiment. In addition to allowing the all-electronic control of the interference pattern, this type of device offers new routes to power and brightness scaling in semiconductor lasers, and opportunities for all-electronic beam steering.

No MeSH data available.