Electrically injected double-taper semiconductor laser based on parity-time symmetry

An electrically injected semiconductor laser based on parity-time symmetry with a double-taper structure is fabricated and measured. The double-taper semiconductor lasers are defined by contact-type standard photolithography and then etched by inductively coupled plasma. The double-taper parity-time-symmetric laser can obtain an output power of more than 0.5W @0.3A, which is significantly higher than the 0.35W@0.3A of the traditional single-ridge laser. The parity-time-symmetric breaking point or exceptional point is tuned below lasing threshold to get narrower linewidth compared with traditional single-ridge lasers and double-ridge lasers, and performs single-lobe far field.