Abstract: An optical isolator (100) includes an input port (10), an output port (20), an optical isolating means (30) and a mounting tube (40). The input port includes an optical fiber (13) having an exposed end, a ferrule (12) defining a through hole 121 for holding the optical fiber, a molded lens (11), a sleeve (14) and a metal holder (15). The molded lens collimates optical signals transmitted from the optical fiber. The output port is constructed like the input port. The optical isolating means is disposed in an optical path between the input port and the output port, and transmits optical signals in an input direction and blocks reflected of optical signals in the reverse direction. The mounting tube accommodates and fixes the input and output ports and the optical isolating means.

Abstract: An optical collimator (10) for collimating light beams coming from an optical fiber (13) includes the at least one optical fiber, a ferrule (12), a molded lens (11), a mounting tube (14) and a metal holder (15). The optical fiber has an exposed end and the ferrule defines a through hole for receiving and fixing the optical fiber therein. A forward face (122) of the ferrule is ground at an oblique angle and is flush with the exposed end of the optical fiber. The molded lens is cylindrical in shape and has an oblique surface coinciding with that of the ferrule and the exposed end of the optical fiber. The molded lens has a convex surface at its forward face (111).

Abstract: An optical filter device (100) for collimating input signals and selecting optical signals in a predetermined wavelength band includes a dual fiber pigtail (DFP) (112) receiving an input and output optical fibers (113, 114), a molded lens (111), a sleeve (130) and a filter (120). The molded lens between the DFP and the filter has a single index and collimates the dispersed light beams coming from the input optical fiber to parallel-light beams, and converges the parallel light beams reflected by the filter for transmission into the output optical fiber. The filter absorbs optical light beams in predetermined wavelength bands. The sleeve allows connection of the filter to the lens without requiring use of epoxy on optically functional parts of the molded lens.

Abstract: A wavelength division multiplexer according to the present invention includes a first collimator (10), a second collimator (20), a filter (30), a holder (40) and an outer sleeve (50). The first collimator has a first ferrule (12) within which input and reflective optical fibers (112), (111) are secured. The first ferrule has an oblique face (122) that is mounted opposite an oblique face (132) of a first molded lens (13). A first inner tube (14) partially encloses the first ferrule, and a first outer tube (15) then encloses the first inner tube. The holder has a seat (44) receiving an aspherical face (131) of the first molded lens therein. The filter is fixed onto a free end of the holder. The second collimator has a structure similar to that of the first collimator. The two collimators are aligned with each other and retained in the outer sleeve by welding.

Abstract: An optical assembly includes an input fiber (30) and an output fiber (31), a ferrule (32) receiving the input and output fibers therein, a molded lens (33) and a filter (34). The molded lens includes a solid cylindrical main body (334), and an annular protrusion (333) extending from a front end of the main body. The main body has an oblique rearward end face (331), and an aspherical forward end face (332) opposite to the rearward end face. The ferrule also has an oblique forward end face (322) which is close to and substantially parallel to the oblique rearward end face of the molded lens. The filter is attached to a forward end of the annular protrusion. Light rays from the input fiber pass through and are made parallel by the molded lens. Parallel rays of a predetermined wavelength are transmitted through the filter. Those having other wavelength are reflected at the filter and transmit through the output fiber.

Abstract: An optical switch (1) for switching light beams between one input optical fiber (21) and a plurality of output optical fibers (31) has a first port (2), a second port (3) and a switching element (4) between the first and second ports. The input port aligns with the input optical fiber and collimates input light beams. The output port aligns with the output fibers and decollimates output light beams. The switching element includes at least one rotatable optical element (41) for deflecting the light beams and a holder (42) for containing the rotatable optical elements. The rotatable optical element is rotatable among a plurality of positions, whereby, when the optical element is in different positions, the light beams from the input optical fiber are switched to different output fibers, respectively.