one to many design struggle
optical_road {OPTR_ID, OPTR_NAME, OPTR_CLIENT}
          PK {OPTR_ID}


fiber {FIB_ID, FIB_NUMBER, FIB_OBJECT, FIB_COLOR}
   PK {FIB_ID}



fiber_road {FIB_ID, OPTR_ID}
        PK {FIB_ID}

       FK1 {FIB_ID}  REFERENCES fiber {FIB_ID} 
                     ON DELETE RESTRICT

       FK2 {OPTR_ID} REFERENCES optical_road {OPTR_ID} 
                     ON DELETE RESTRICT


Note:


PK  = PRIMARY KEY
AKn = ALTERNATE KEY (UNIQUE)
FKn = FOREIGN KEY