InP LD with PD fabricated by Br2–reactive—ion–etching technique

Abstract

AbstractIt is important to monitor the optical output of a laser diode (LD) in an opto‐electric integrated circuit (OEIC). Therefore, in monolithic fabrication of an LD with a photodetector (PD), chlorine (Cl)‐based gas has been used to carry out dry etching for forming a laser facet in InP‐based materials. However, in this technique, selectivity of etching is not sufficient. In our study, Br2 was employed as the etching gas using Ti for the etching mask. Our technique can provide a selectivity of etching as high as 34 and has been found to be effective in forming a laser facet.Using reactive ion etching (RIE) with Br2 gas, a laser facet was formed in a buried heterostructure laser diode (BHLD) with a PD. The threshold current and optical output of the LD were 35 ‐ 50 mA and 5 ‐ 10 mW, respectively, while the sensitivity of the PD was 0.49 A/W. The isolation resistance between the LD and PD was 1 Mω.The result of this study indicates that our technique will be effective in high‐density integration of OEICs.