The present invention comprises tunable optical wavelength filters and multi-level optical integrated circuits which use resonant optical cavities in a vertical arrangement with input and output waveguides. In the apparatus, parallel clocks are counted by an N counter to be supplied to the latch circuit, which latches the output count of a p-bit counter, RTSs are supplied from the latch circuit, as the result of comparison gated by a gate circuit is supplied to a PLL circuit and multiplied by N, parallel clocks of 74. The converting generally uses a lookup table-based conversion that performs both a color correction and a tone correction. To suppress vibration of the valve body occurring at its open position due to pulsating fluid pressure supplied from the pump, a biasing force is applied to the valve body in a direction slanted from the fluid pressure-imposing direction. The present invention also discloses agonists of the polypeptide and their therapeutic uses.