Optical memory device incorporating photodetector devices and light emitting devices

• US 5,717,627 A
• Filed: 01/30/1997
• Issued: 02/10/1998
• Est. Priority Date: 02/02/1996
• Status: Expired due to Fees

• Current Assignee: Hamamatsu Photonics KK
• Original Assignee: Hamamatsu Photonics KK
• Inventors: Mizushima, Yoshihiko
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): Tran, Andrew Q.
• Application Number:
  US08/790,790
• Time in Patent Office: 376 Days
• Field of Search: 365/112, 365/115, 365/159, 365/175, 250/205, 250/214 LS
• US Class Current: 365/112
• CPC Class Codes: G11C 11/42 using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically- coupled or feedback-coupled
• CPC Class Codes: H01L 31/14 the light source or sources being controlled by the semiconductor device sensitive to radiation, e.g. image converters, image amplifiers or image storage devices

Abstract

The optical memory device of the present invention comprises a photodetector device which generates a current when light is incident thereon and a light-emitting device which is connected to the photodetector device in series so as to emit light upon receiving a supply of current from the photodetector device and feed back thus emitted light toward the photodetector device.

Claims

1. An optical memory device comprising:

a first photodetector device for receiving an optical signal;

a first light-emitting device, connected to said first photodetector device in series, for emitting light responsive to a current from said first photodetector device, said first light-emitting device being disposed such that a part of the light emitted therefrom is fed back to said first photodetector device;

a first device, connected to said first light-emitting device, having a resistance value higher than an internal resistance of said first light-emitting device;

a second device, connected to said first photodetector device, having a resistance value higher than an internal resistance of said first photodetector device

a second photodetector device, connected to said first photodetector device in parallel; and

a second light-emitting device connected to said first light-emitting device in series.

2. An optical memory device comprising:

a first photodetector device for receiving an optical signal;

a light-emitting device, connected to said first photodetector device in series, for emitting light responsive to a current from said first photodetector device, said light-emitting device being disposed such that a part of the light emitted therefrom is fed back to said first photodetector device;

a first device connected to said light-emitting device, said first device having a resistance value higher than an internal resistance of said light-emitting device;

a second device, connected to said first photodetector device, having a resistance value higher than an internal resistance of said first photodetector device; and

a second photodetector device, connected to said light-emitting device in parallel and connected to said first photodetector device in series, wherein, when said second photodetector device is irradiated with reset light while said light-emitting device emits light, current flowing through said light-emitting device decreases to extinguish said light-emitting device.

3. An optical memory device comprising:

a first photodetector device to which an optical signal is input;

a light-emitting device connected to said first photodetector device in series, said light-emitting device being disposed such that a part of light emitted therefrom is fed back to said first photodetector device;

a first resistor connected to said first photodetector device in parallel and connected to said light-emitting device in series, said first resistor having a resistance value greater than an internal resistance of said light-emitting device, wherein, when said optical signal is input to said first photodetector device, a current from said first photodetector device and a constant current from said first resistor are supplied to said light-emitting device, and wherein the constant current from said first resistor is sufficiently lower than said current from said first photodetector device so as to allow said light-emitting device to emit light in a sub-Poisson state;

a second resistor connected between said first photodetector device and said light-emitting device, having a resistance value greater than an internal resistance of said first photodetector device; and

a second photodetector device, connected to said first photodetector device in series and connected to said light-emitting device in parallel, wherein, when said second photodetector device is irradiated with reset light while said light-emitting device emits light, the current flowing through said light-emitting device decreases to extinguish said light-emitting device.