Optical switch and optical communication system using the same

Details Optical switch and optical communication system using the same Optical switch and optical communication system using the same

1999-06-16

2001-10-02

Chan, Jason (Department: 2633)

Optical: systems and elements

Deflection using a moving element

Using a periodically moving element

C385S019000, C385S047000

Reexamination Certificate

active

06297896

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical switch for transmitting optical signals and detecting a specific signal and an optical communication system using the optical switch.
2. Description of the Related Art
As an alternative to a telecommunication system for transmitting electric signals, an optical communication system using an optical fiber has recently been put into practical use with a view toward achieving prevention of electromagnetic noise, an increase in transfer capacity, a weight reduction in system, simplification of work, etc.
FIG. 5
is a block diagram showing a conventional optical communication device employed in such a system. This is equivalent to an optical communication system wherein a light-emitting unit
1
is electrically turned on/off to thereby transmit such on/off information to a photo-detector
3
through an optical fiber
2
. The light-emitting unit
1
has a light-emitting device
1
a
comprised of an LED or the like for converting an electric signal into an optical signal, a switch
1
b
for turning on/off the light-emitting device
1
a
according to information ┌1┘and ┌0┘, and a lens
1
c
for focusing light emitted from the light-emitting device
1
a
on an end surface of the optical fiber
2
. An electrical switch is used as the switch
1
b.
In the optical communication system constructed in this way, the switch
1
b
performs switching at high speed when an optical signal is subjected to time sharing, followed by transmission from one light-emitting unit
1
to a plurality of photo-detectors
3
on a time-sharing basis. When optical signals are transmitted from a plurality of light-emitting units
1
to a plurality of photo-detectors
3
in a one-to-one correspondence, the plurality of light-emitting units
1
and the plurality of photo-detectors
3
respectively having selectivity with respect to wavelengths &lgr;
1
, . . . &lgr;n are placed on the optical fiber
2
in a one-to-one correspondence by their wavelength multiplexing.
As such an optical communication system, there is known a system for monitoring or supervising the operations of a plurality of switching devices employed in an automatic vending machine, a plant, etc. or the operations of a plurality of door switches for automobiles.
However, the above-described optical communication system has a problem in that since the light-emitting device
1
a
in the light-emitting unit
1
on the transmitting side is turned on and off by the switch
1
b
to generate the optical signal, the life of the light-emitting device la becomes short and the system is low in reliability.
Another problem also arises in that since there is need to supply power to the light-emitting device
1
a
of the light-emitting unit
1
on the transmitting side, it is necessary to place a power line in the same place in addition to the optical fiber
2
, so that the optical communication system cannot take full advantage of their merits such as a weight reduction in system and simplification of work, whereby the optical communication system cannot be applied to a system required at a location placed under hostile environmental conditions apt to cause an explosion or the like.
SUMMARY OF THE INVENTION
A first arrangment for solving the above problems, there is provided an optical switch, comprising within a case:
a first optical guide path;
a second optical guide path which branches off from the first optical guide path and leads to the first optical guide path again;
optical filters placed in a branching point and an introducing point of the first optical guide path; and
a switching device for cutting off light introduced into the second optical guide path or allowing the light to pass therethrough,
whereby the optical filters pass or reflect light having a predetermined wavelength band and reflect or pass lights having other wavelength bands, so that the light having the predetermined wavelength band introduced into the second optical guide path is selectively combined or merged with the lights having other wavelength bands at the introducing point by the switching device.
Further, as second solving arrangement, there is provided an optical switch wherein optical filters for reflecting light having a predetermined wavelength band, which are identical to the optical filters placed in the branching point and introducing point of the first optical guide path, are interposed in the second optical guide path to thereby bend the light at the right angle.
Moreover, as third solving arrangment, there is provided an optical communication system, comprising:
a light source for emitting light having a wide wavelength band;
an optical fiber for transmitting the light emitted from the light source;
a plurality of optical switches placed in a one-to-one correspondence along the optical fiber; and
a plurality of receivers;
the plurality of receivers respectively including optical filters for selectively splitting light having a predetermined wavelength band of the wide wavelength band transmitted through the optical fiber and the plurality of optical switches, and photo-detectors for respectively detecting the light of wavelengths split by the optical filters.
Typical ones of the present invention have been shown in brief. However, the various inventions of the present application and specific configurations of these inventions will be understood from the following description.


REFERENCES:
patent: 4707057 (1987-11-01), Takahashi et al.
patent: 5077813 (1991-12-01), Dorsel et al.
patent: 5589933 (1996-12-01), Osgood et al.
patent: 5652814 (1997-07-01), Pan et al.
patent: 6061484 (2000-05-01), Jones et al.
patent: 6115517 (2000-09-01), Shiragaki et al.
patent: 60/060620 (1985-04-01), None
patent: 60/133407 (1985-07-01), None
patent: 0 973 054 A2 (2000-01-01), None

Affiliated with

Also associated with

Rating

Optical switch and optical communication system using the same does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Optical switch and optical communication system using the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical switch and optical communication system using the same will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2579651