Feature Issue on Optical Interconnection Networks (OIN). We propose access-restriction-based quality-of-service differentiation schemes, suitable for an asynchronous optical packet switch with a contention resolution pool that contains both tunable wavelength converters and fiber delay lines. The schemes aim at obtaining a high degree of packet-loss-rate isolation, for a low increase in overall packet loss rate, at the same time respecting the jitter tolerance of each class of service. Numerical simulations quantify how the performance depends significantly on the jitter tolerance of the traffic in general, and of the highest-priority class of service in particular.