A Multiple Phase-Shifted Distributed Feedback (DFB) Laser Fabricated by Nanoimprint Lithography

Multiple phase-shifted (MPS) diffraction grating is an effective way proposed to overcome the spatial hole burning (SHB) effect in a distributed feedback (DFB) laser. We present two symmetric λ/8 phase-shifted DFB lasers by using nanoimprint lithography (NIL). The threshold current of a typical laser is less than 15 mA. The side mode suppression ratio (SMSR) is still above 42 dB even at 100 mA current injection. To show the versatility of NIL, eight different wavelength MPS-DFB lasers on this single chip are also demonstrated. Our results prove that NIL is a promising tool for fabricating high performance complex grating DFB lasers.