The GaInAs light absorbing layer having an energy bandgap smaller than {HEAD ~ the InP layer}, being a dark current generating region, is under {TAIL ~ a tension stress} at minus Δa/a, but is under a compression stress at plus Δa/a 
is under
The GaInAs light absorbing layer having an energy bandgap smaller than { HEAD ~ the InP layer } , being a dark current generating region , is under { TAIL ~ a tension stress } at minus Δa / a , but is under a compression stress at plus Δa / a
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH