GaInAsP/InP lasers with monolithically integrated monitoring photodiodes fabricated by inclined reactive ion etching

Monolithic fabrication of a GaInAsP/InP laser (LD) with a monitoring photodiode (PD) is described. LDs and PDs have etched facets fabricated by inclined reactive ion etching (RIE). The etched LD facing facet PD is perpendicular to the junction plane and the etched PD facet facing LD is inclined by 55 degrees to the plane by the ´windward-leeward effect´ of the inclined RIE. Therefore, coupling efficiencies between LDs and PDs are uniform because the multireflection effect of double mirrors does not exist for the LD-PD devices with inclined PD facets. Typical CW threshold current ranges from 20 to 30 mA and light output power from a single facet exceeds 15 mW at 25 degrees C. A PD can detect about 2% of the light beam emitted from an LD facing it.