An optically-pumped mode-locked fiber ring laser for optical clock recovery of multiple wavelength division multiplexed optical signals actively mode-locks a plurality of outputs of the laser as a plurality of recovered clocks for a plurality of the multiple wavelength division multiplexed optical signals. With the hooking parts engaging the projections of the flange, the roll and the detacher are relatively displaced so that the spool is detached from the roll. In one embodiment of the adaptive filter of the present invention, a filter, preferably an adaptive finite impulse response filter, of an appropriate length, N, is chosen. Each cooling tube is designed to direct the coolant fluid towards and then away from said at least one heat-transfer surface.