# US 6,295,150 B1 · Wavelength division multiplexing device

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- Number: US 6,295,150 B1
- Document ID: US6295150B1
- Status: Granted
- Kind: B1
- Application number: 09/412,615
- Filed: 1999-10-06
- Granted: 2001-09-25
- Earliest claimed: 1998-10-06
- Assignees: Mitsubishi Gas Chemical Company, Inc.
- Inventors: Hisashi Ohwada; Toshihiko Takano; Norio Takeda; Kuniaki Jinnai
- Web page: https://patentgrep.com/patent/US6295150B1

## CPC

- H04J 14/02: Wavelength-division multiplex systems
- H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S)

## Abstract

A wavelength division multiplexing device which can easily utilize existing optical fibers for increasing the transmission capacity by approximately several fold mainly in a short-range information communication network, comprising, as essential elements, a pair of 1×N optical couplers (2≦N≦16), N light emission devices in which one of peak wavelengths thereof differs from every other one by at least 30 nm and N light receivers having optical filters having light-transmission wavelength bands adjusted to correspond to said peak wavelengths, wherein the light emission devices and the light receivers having optical filters corresponding to peak wavelengths of the light emission devices form pairs, and said light emission devices of said light receivers are optically connected to N-port-side ports of one of the 1×N optical couplers.

## Claims

### Claim 1

A wavelength division multiplexing device comprising: a pair of 1×N optical couplers (2≦N≦16), N light emission devices in which one of peak wavelengths thereof differs from every other one by at least 30 nm and N light receivers having optical filters having light-transmission wavelength bands adjusted to correspond to said peak wavelengths,
wherein the light emission devices and the light receivers having optical filters corresponding to peak wavelengths of the light emission devices form pairs, said light emission devices or said light receivers are optically connected to N-port-side ports of one of the 1×N optical couplers, and each optical filter is defined by the following expression (1),
|λ−λn|≧0.01λ+2(nm) (1)
wherein λ (nm) is a light wavelength of a light emission device, which is to form a pair with an optical filter, at a room temperature, and λn (nm) is a wavelength corresponding to 50% of transmittance of the optical filter in an optical absorption curve near λ.

### Claim 2 (depends on 1)

The wavelength division multiplexing device of claim 1, wherein the light emission devices are laser diodes and condenser lenses are provided before light emission sides thereof.

### Claim 3 (depends on 1)

The wavelength division multiplexing device of claim 1, wherein the light receivers are photodiodes.

### Claim 4 (depends on 1)

The wavelength division multiplexing device of claim 1, wherein the 1×N optical couplers are optical waveguides each of which is formed of a polymer film having a refractive index distribution.

### Claim 5 (depends on 1)

The wavelength division multiplexing device of claim 1, wherein the light emission devices have peak wavelengths in the range of from 800 to 1,550 nm.

### Claim 6 (depends on 1)

The wavelength division multiplexing device of claim 1, wherein each of the optical filters is at least one selected from the group consisting of a long wavelength path filter, a band path filter and a short wavelength path filter.