A fiber optic panel assembly, comprising: a ceiling, a bottom cover, and two opposing sides (712, 714) defining an interior opening therein; a mounting bracket disposed on the bottom cover in the interior opening, the mounting bracket comprising a plurality of protruding posts extending outward from a supporting structure of the mounting bracket; a sliding tray having a plurality of protruding structures, each protruding structure having a tip end configured to engage with an inner surface of the supporting structure; characterized by the sliding tray further comprising a plurality of apertures defined between the plurality of protruding structures, wherein the apertures are configured to receive the protruding posts of the mounting bracket, the mounting bracket further comprising a plurality of second apertures defined between the plurality of protruding posts, wherein the second apertures are configured to receive the protruding structures of the sliding tray therein, wherein each of the plurality of protruding posts of the mounting bracket is configured to engage with a fiber optic module of a first set of fiber optic modules and each of the plurality of protruding structures of the sliding tray is configured to engage with a fiber optic module of a second set of fiber optic modules, wherein the first set of fiber optic modules is engaged under the plurality of protruding posts of the mounting bracket and the second set of fiber optic modules is engaged under the plurality of protruding structures of the sliding tray, and wherein, when the sliding tray is retracted in a non-extended position, each of the protruding structures of the sliding tray abuts against and is interleaved with the respective protruding post from the mounting bracket with the tip end mating with the inner surface, wherein, in the non-extended position, the first set of fiber optic modules and the second set of fiber optic modules are staggered at a depth relative to each other, and the first set of fiber optic modules is extended and protruded outward and forward from the second set of fiber optic modules. a ceiling, a bottom cover, and two opposing sides (712, 714) defining an interior opening therein; a mounting bracket disposed on the bottom cover in the interior opening, the mounting bracket comprising a plurality of protruding posts extending outward from a supporting structure of the mounting bracket; a sliding tray having a plurality of protruding structures, each protruding structure having a tip end configured to engage with an inner surface of the supporting structure; characterized by the sliding tray further comprising a plurality of apertures defined between the plurality of protruding structures, wherein the apertures are configured to receive the protruding posts of the mounting bracket, the mounting bracket further comprising a plurality of second apertures defined between the plurality of protruding posts, wherein the second apertures are configured to receive the protruding structures of the sliding tray therein, wherein each of the plurality of protruding posts of the mounting bracket is configured to engage with a fiber optic module of a first set of fiber optic modules and each of the plurality of protruding structures of the sliding tray is configured to engage with a fiber optic module of a second set of fiber optic modules, wherein the first set of fiber optic modules is engaged under the plurality of protruding posts of the mounting bracket and the second set of fiber optic modules is engaged under the plurality of protruding structures of the sliding tray, and wherein, when the sliding tray is retracted in a non-extended position, each of the protruding structures of the sliding tray abuts against and is interleaved with the respective protruding post from the mounting bracket with the tip end mating with the inner surface, wherein, in the non-extended position, the first set of fiber optic modules and the second set of fiber optic modules are staggered at a depth relative to each other, and the first set of fiber optic modules is extended and protruded outward and forward from the second set of fiber optic modules. each of the protruding structures of the sliding tray abuts against and is interleaved with the respective protruding post from the mounting bracket with the tip end mating with the inner surface, wherein, in the non-extended position, the first set of fiber optic modules and the second set of fiber optic modules are staggered at a depth relative to each other, and the first set of fiber optic modules is extended and protruded outward and forward from the second set of fiber optic modules.