Fabrication of InGaAsP Double Shallow Ridge Rectangular Ring Laser With Total Internal Reflection Mirror by Cascade Etching Technique

InGaAsP double shallow ridge rectangular ring laser photonics integration circuits have been successfully fabricated by cascade etching technique. Varied thresholds with coupling current I_c and coupling length L_c are observed. The lowest threshold current of 75 mA, including I_c and I_d, at I_c = 30 mA in the device of L_c = 300 mum is obtained. The device of L_c = 200 mum exhibits single-mode operation with sidemode suppression ratio = 15 dB and Q = 6513 just beyond the threshold. The cascade etching technique is of interest for fabrication of other multilayer monolithic photonic integration circuits.