Multiple users could be multiplexed into a single Coarse Wavelength Division Multiplexing (CWDM) channel of metropolitan area networks using an Optical Code Division Multiple Access (OCDMA) scheme increasing the total number of users of the system. Thermally tunable holographic filters operated using an edge illuminated transmission hologram configuration, can provide a compact and tunable solution for this application. The filters are realized by a thick unslanted grating. The gratings are recorded in PQ (phenanthrenequinone)-doped PMMA (poly methylmethacrylate) photopolymer substrate in a holographic setup. The gratings are designed to filter light from the propagation direction for specific segments of a CWDM channel. The filters can be thermally tuned using thermo-electric cooler plates to change the period of the grating. In this paper we present the construction and performance characteristics of these filters.