- Photonic Crystals Integrated into VCSELs
Single-fundamental-mode vertical-cavity surface-emitting lasers (VCSELs) could benefit data transmission applications, but designing such a device to function over an entire pump range is difficult because of eventual material deformations such as thermal lensing. A team from the Korea Advanced Institute of Science and Technology in Taejon has integrated a single-defect photonic crystal -- with a 5-µm-hole pitch and a 3.5-µm-hole diameter -- into the top mirror of an 850-nm VCSEL to produce a side-mode suppression ratio of 35 to 40 dB. This method has allowed continuous-wave, single-mode operation in the entire current range. The researchers say it can be adapted for any VCSEL. The technique is reported in the May 27 issue of Applied Physics Letters.
MORE FROM PHOTONICS MEDIA