An optical transversal programmable filter can realize arbitrary filter characteristics in one circuit and can vary the filter characteristic adaptively, so it is a promising device. This filter consists of a variable splitter for splitting a input light to N paths(taps), variable phase shifters, delay lines and a variable combiner for combining the split lights to an output light. We can obtain the desired filter characteristics by setting up the arbitrary tap coefficients and minimize the principle loss by designing a symmetrical arrangement of the variable splitter and the variable combiner with each other. However, in order to set those, it is necessary to control the circuit characteristics accurately with compensating for the fabrication errors. We fabricated the low loss optical transversal programmable filter with the monitor waveguides and a novel method which adjusts the circuit characteristics and compensates the fabrication errors, using silica-based PLC. And we demonstrated three types of filter spectra having a Gaussian-shape, a flat-top-shape and a flat-top-shape with a low loss ripple adaptively using the one optical transversal programmable filter.