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