Efficiency limits for space multi-junction concentrator solar cells

Efficiency limits of single-junction and multi-junction concentrator solar cells are established from the thermodynamic principle of detailed balance. The maximum efficiency limit of single-junction solar cells is35% at500 suns, while that of2-junction solar cells which meet the current matching condition is46%. At the same condition, the maximum efficiency limit of3-junction solar cells with GaAs as middle subcell is52%.?2011 IEEE

Mode Analysis and Design of a Low-Loss Photonic Crystal 60 degrees Waveguide Bend

The guided modes of a two-dimensional photonic crystal straight waveguide and a waveguide bend are studied in order to find the high transmission mechanism for the waveguide bend. We find that high transmission occurs when the mode patterns and wave numbers match, while the single-mode condition in the waveguide bend is not necessarily required. According to the mechanism, a simply modified bend structure with broad high transmission band is proposed. The bandwidth is significantly increased from 19 to 116 nm with transmission above 90%, and covers the entire C band of optical communication

Design of Photonic Crystal Semiconductor Optical Amplifier With Polarization Independence

Slow-light effects in photonic crystal (PC) waveguides can enhance light-mater interaction near the photonic band edge, which can be used to design a short cavity length semiconductor optical amplifier (SOA). In this paper, a novel SOA based on slow-light effects in PC waveguides (PCSOA) is presented. To realize the amplification of the optical signal with polarization independence, a PCSOA is designed with a compensated structure. The cascaded structure leads to a balanced amplification to the TE and TM polarized light

Design of surface mode photonic crystal T-junction waveguide using coupled-mode theory

We design a photonic crystal T-junction waveguide on the basis of the nonradiative surface mode and further optimize the transmission ratio of our surface mode photonic crystal T-junction waveguide with the guide of coupled-mode theory. Compared with a traditional bandgap photonic crystal T-junction waveguide, our surface mode T-junction waveguide can obtain almost zero reflectance and good transmission. Better still, its size is just half of the size of bandgap photonic crystal waveguide branches. To the best of our knowledge, it is the first time that such a high-efficiency T-junction waveguide that uses the surface mode as the guided mode is proposed. (C) 2011 Optical Society of Americ