ABSTRACT
A 4-channel distributed feedback (DFB) semiconductor laser array with incorporation of a grating reflector utilizing reconstruction-equivalent-chirp technique is theoretically studied and experimentally demonstrated. By integrating with a grating reflector, 40% increase of slope efficiency, about 10mA decrease of threshold current and 7dB increase of side mode suppression ratio (SMSR) are achieved with a deviation of wavelength spacing being less than 0.07nm. The SMSRs of all the lasers are higher than 60dB.
ABSTRACT
Multiwavelength distributed feedback (DFB) semiconductor laser arrays (MLA) with asymmetric structures are studied in this paper. Thanks to the sampling technique, the asymmetric structures, including asymmetric phase shift and asymmetric coupling coefficient, can be achieved by common holographic exposure. Therefore, the cost of fabrication is remarkably reduced. In addition, due to the large scale of the sampling pattern, the wavelength precision of these kinds of MLA can be simultaneously improved. As an example, we designed and fabricated an asymmetrically phase-shifted MLA with 10 wavelengths for the first time. Compared with the common phase-shifted DFB laser, slope efficiency is significantly improved and single longitudinal mode is still guaranteed. Besides, relatively high wavelength precision is also obtained. The proposed MLA configurations may significantly benefit multiwavelength emitters for future photonic integration.
Subject(s)
Feedback , Lasers, Semiconductor , Signal Processing, Computer-Assisted/instrumentation , Equipment Design , Equipment Failure AnalysisABSTRACT
The distributed-coupling-coefficient and distributed-coupling-coefficient corrugation-pitch-modulated DFB lasers are experimentally demonstrated. The proposed lasers maintain good side mode suppression ratio over 50dBfrom 2.5 times to 12.5 times threshold current. The grating profiles of varying longitudinal parameters are equivalently obtained by specially designed sampled Bragg gratings and fabricated by conventional holographic exposure and µm-level photolithography.
