We clear up two issues regarding the eigenvalue problem for the Manakov system; these problems relate directly to the existence of the soliton effect in fiber optic cables. The first issue is a bound on the eigenvalues of the Manakov system. The second issue has to do with a chirped Manakov system. We show that if a system is chirped too much, the soliton effect disappears. While this has been known for some time experimentally, there has not yet been a theoretical result along these lines for the Manakov system.