Design and fabrication of tunable laser with digital concatenated grating

Abstract

A novel tunable laser with digital concatenated grating reflectors, which has a flatter envelope of reflection peaks, is designed and fabricated. The key concept of the approach is to utilize multi-sampled gratings which have different Bragg wavelengths and the same sampling period. The difference of each Bragg wavelength is integer multiple of the space between the peaks of sampled gratings. Here, nanoimprint lithographic technology is used to fabricate the complex gratings. The typical threshold current of the tunable laser is 34 mA, and the tuning range is larger than 32 nm. The non-uniformity of the output power is less than 2 dB.