An image-forming device has a plurality of cylindrical image-carrying members, and an optical scanning unit. The plurality of cylindrical image-carrying members is provided in a main casing for rotating about respective rotational axes. The rotational axes are parallel to one another and juxtaposed in a single direction. The optical scanning unit is provided in the main casing and has a plurality of laser generators, a single rotatable polygon mirror, a plurality of mirrors, and a plurality of lenses. The plurality of laser generators is provided one-to-one relationship to the plurality of image-carrying members to emit respective laser beams. The single rotatable polygon mirror deflects the respective laser beams to scan the respective image-carrying members therewith. The plurality of mirrors is provided one-to-one relationship to the plurality of image-carrying members to guide the respective laser beams along respective optical paths to the respective image-carrying members. The plurality of lenses is provided one-to-one relationship to the plurality of image-carrying members and provided in the respective optical paths and between the respective mirrors and the respective image-carrying members. Distances from the respective mirrors to the respective image-carrying members being equal to one another.

Image-forming device

An optical switch formed of a holographic optical element (HOE) disposed above a top surface of a substrate and moveable relative thereto is shown. Light is traveling through the substrate under total internal reflection, which creates an evanescent field extending beyond the reflecting surfaces of the substrate. The HOE is characterized, in one embodiment, by being formed from a plurality of strips that are moveable between a first position in which the strips are above the evanescent field and a second position in which the strips are inside the evanescent field. In the first position, the light in the substrate propagates unaffected by the HOE in a primary direction of propagation. In the second position, the light in the substrate is altered by the HOE and made to propagate in a reflected direction oblique to that of the primary direction of propagation.

Optical switch with moveable holographic optical element

An optical device for use either as a waveguide demultiplexer or a waveguide multiplexer characterized by a compact transparent member having a surface forming optical means such as an imaging mirror, an opposite surface portion having a diffraction grating formed thereon and first and second coupling surfaces so that light can be coupled into the member reflected by the mirror and the diffraction grating and then coupled out of the member. The device has various embodiments with different structures for the optical mirror and the transparent member, with the structure of the coupling surfaces being flat or curved, and with either flat or curved additional mirrors for reflecting the incoming and outgoing light adjacent to the coupling surfaces.

Optical device for use as a multiplexer or demultiplexer in accordance with the diffraction grating principle

A dual directional, wavelength demultiplexer including an optical fiber mounted and adhered to a curved surface having a clad single-fiber core, a planar surface extending partially into and along the fiber through the cladding, a prism mounted on the surface having two reflective surfaces positioned to receive multiple signals from the fiber travelling in opposite directions, optical gratings positioned at the reflective surfaces effective to diffract and demultiplex the signals, and photodiode arrays mounted adjacent the prism to receive the demultiplexed reflected signals.

Dual directional wavelength demultiplexer

The disclosed multiplexer/demultiplexer (10, 40) features input and output optical fibers (20, 22, 24, 42, 44, 46, 48, 50) coupled to one face (16) of a graded refractive index rod collimating lens (12). Associated with the other face (18) of the lens (12) are a plurality of multi-layer dielectric interference filters (26, 32, 52, 54, 56, 58) which selectively reflect the input signals at different angles according to the wavelength and thereby direct them back through the lens (12) to the appropriate output fiber.

Optical multi/demultiplexer using interference filters

PURPOSE:To provide an optical transmission device of high coupling efficiency and low branching efficiency by accomplishing the coupling operation of two optical transmission passages through an insert having a smaller refractive index than the passages.

Optical trasmission device

PURPOSE:To reduce leakage without increasing the loss of a branching filter much by providing a filter at one terminal of a self-focusing type lens and a reflective mirror, reflecting transmitted light, outside of the filter with an inclination to the optical axis of the lens. CONSTITUTION:At one terminal of self-focusing type lens 3, filter 1 that reflects light of wavelength lambda1 and allows light of wavelength lambda2 to pass through it is provided and outside of it, reflective mirror 2 that reflect transmitted light lambda2 is also provided being inclined to optical axis 4 of lens 3. Lights including those of wavelengths lambda1 and lambda2 from light emission diodes, etc., strike optical fiber 5; and then light of wavelength lambda1 is reflected by filter 1 to strike fiber 6 at fixed position (d) and light of wavelength lambda2, on the other hand, penetrates filter 1 and is reflected by reflective mirror 2 to strike fiber 7. Providing fiber 7 at an adequate position in accordance with wavelength lambda2 reduces leakage without increasing the loss much, so that S/N can be improved.

Light branching coupler

PURPOSE:To execute the conversion at a high speed, by providing an optical random access coupler for random-accessing an output of a light emitting element for executing the pulse light emission at a prescribed period, to plural waveguides, and a coupler for collecting its output light to one fiber. CONSTITUTION:An output 5 from a light emitting element 1 for executing the pulse light emission restrictively by some period is led to an optical random access coupler 2. Parallel electric signals a1-an to be transmitted are outputted from a transmitting signal generating part 3, the optical random access coupler 2 has optical output terminals b1-bn corresponding to said electric signals a1- an, and whether an output of light from each terminal b1-bn exists or not is decided by a level of the corresponding electric input signals a1-an. In this way, the optical outputs b1-bn from the optical random access coupler 2 are led to an optical fiber or a waveguide 6 corresponding to each output, and is coupled with a transmitting optical fiber or a waveguide 7 by a coupler 4.

Series-parallel converting device of optical signal

PURPOSE:To enable the light signal being transmitted to be branched by wavelengths and enable the light signals of different wavelengths to be superposed by providing a multilayer dielectric film having an inclination of a specified angle with respect to the axis of transmission paths to part of the light signal transmission paths.

Light signal propagator

PURPOSE:To enable light of plural wavelengths to be mixed or branched with one lens by forming a filter film which transmits light of a specified wavelength and reflects the other on one end face of a self-convergent type lens and forming an inclined reflecting mirror on the outer side thereof. CONSTITUTION:A filter film 16 which transmits light of a wavelength lambda1 and reflects light of a wavelength lambda2 is formed on the end face 19 of a self-convergent type lens 15 having a 1/4 period length, and a reflecting mirror 20 having inclination of an angle alpha to the perpendicular plane of the axis 21 of the lens 15 is forme on the outer side thereof. Fibers 17, 17', 18 are provided in the positions parallel to the axis 21 and 17, 18 in the position symmetrical to the axis 21. Now, if the light of the wavelength lambda1 propagates into the fiber 17 and the light of the wavelength lambda2 into the fiver 17', the light 22' of the wavelength lambda2 is reflected with the filter film 19 and the light of the wavelength lambda1 transmits through the filter film 19 and is then reflected by the reflecting mirror 20, after which it is converged to the same position at the end face on the incident side of the lens and efficiently enters the fiber 18. If the reflection is reversed from the incidence, the device becomes a distributor.

Akimoto Serizawa

Papers

Optical trasmission device

Light branching coupler

Series-parallel converting device of optical signal

Light signal propagator

Optical branching and mixing device