What is claimed is:
1. An electronic mail system comprising:
a transmission apparatus including;
first storing means for holding a signature of an electronic mail by associating it with identification information;
identification information reading out means for reading out from said first storing means identification information corresponding to a signature included in an electronic mail to be transmitted;
converting means for converting the signature of said electronic mail to the identification information read out by the identification information reading out means; and
transmitting means for transmitting said electronic mail with its signature part being converted to the identification information by said converting means to its destination; and
a reception apparatus including;
second storing means for holding a signature of an electronic mail by associating it with identification information;
receiving means for receiving an electronic mail transmitted from said transmission apparatus;
signature reading out means for reading out from said second storing means a signature corresponding to the identification information included in said electronic mail received by said receiving means; and
restoring means for converting the identification information included in the electronic mail to the signature read out by the signature reading out means.
2. An electronic mail system according to claim 1 wherein;
said first storing means and said second storing means hold a signature and identification information corresponding to the signature by associating them with a sender’s mail address of an electronic mail.
3. An electronic mail system according to claim 1 or 2 wherein;
said transmission apparatus further includes extracting means for, when contents held by said first storing means are renewed, extracting information concerning the renewal as renewal information, and transmits said renewal information; and
said reception apparatus further includes renewing means for, when said receiving means receives said renewal information, renewing contents held by said second storing means in accordance with said renewal information.
4. An electronic mail system according to claim 3 wherein;
said transmitting means transmits an electronic mail having renewal information including a signature registered anew in said first storing means and identification information allocated to this signature, and said renewing means renews contents held by said second storing means in accordance with said renewal information included in said electronic mail received by said receiving means.
5. An electronic mail system according to claim 4 wherein;
said electronic mail is an electronic mail for renewing the contents of said second storing means.
6. An electronic mail system according to claim 4 wherein;
said electronic mail is an electronic mail with a signature registered anew in said first storing means and identification information corresponding to the signature being added to an electronic mail to be transmitted to said reception apparatus.
7. A transmission apparatus of an electronic mail comprising:
storing means for holding a signature of an electronic mail by associating it with identification information;
identification information reading out means for reading out from said storing means identification information corresponding to a signature included in an electronic mail to be transmitted;
converting means for converting the signature of said electronic mail to the identification information read out by the identification information reading out means; and
transmitting means for transmitting said electronic mail with its signature part being converted to the identification information by said converting means to its destination.
8. A reception apparatus of an electronic mail comprising:
storing means for holding a signature of an electronic mail by associating it with identification information;
receiving means for receiving an electronic mail transmitted by said transmission apparatus;
signature reading out means for, if identification information of a signature is included in said electronic mail received by said receiving means, reading out a signature corresponding to the identification information from said storing means; and
restoring means for converting the identification information included in said electronic mail to the signature read out by said signature reading out means.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An apparatus comprising:
a waveguide;
a laser diode positioned adjacent to the waveguide and having an active region producing light in a plane substantially parallel to a plane of the waveguide;
a first grating positioned to couple light out of the laser diode and to direct the light toward the waveguide;
a reflective layer positioned adjacent to a side of the first grating opposite to the waveguide; and
a second grating having the same period as the first grating and positioned to couple light into the waveguide.
2. The apparatus of claim 1, wherein the laser diode and the waveguide are separated by a gap that is less than about one-tenth of the free space wavelength of the light.
3. The apparatus of claim 1, wherein the laser diode forms a single mode channel waveguide.
4. The apparatus of claim 1, further comprising:
an anti-reflective coating on at least one of an output surface of the laser diode, or a surface of a cladding layer of the waveguide.
5. The apparatus of claim 1, further comprising:
an anti-reflective coating on one end of the laser diode.
6. The apparatus of claim 1, further comprising:
a rough surface on one end of the laser diode.
7. The apparatus of claim 1, wherein the first grating is positioned between the reflective layer and a substrate
8. The apparatus of claim 1, wherein the reflective layer comprises a distributed Bragg reflector.
9. The apparatus of claim 1, further comprising:
a partially reflecting grating and a reflective surface positioned at opposite ends of a cavity in the laser diode.
10. An apparatus comprising:
a data storage medium;
a recording head including a waveguide, a laser diode positioned adjacent to the waveguide and having an active region producing light in a plane substantially parallel to a plane of the waveguide, a first grating positioned to couple light out of the laser diode and to direct the light toward the waveguide, a reflective layer positioned adjacent to a side of the first grating opposite to the waveguide, and a second grating having the same period as the first waveguide and positioned to couple light into the waveguide; and
an arm for positioning the recording head with respect to the data storage medium.
11. The apparatus of claim 10, wherein the laser diode and the waveguide are separated by a gap that is less than about one-tenth of the free space wavelength of the light.
12. The apparatus of claim 10, wherein the laser diode forms a single mode channel waveguide.
13. The apparatus of claim 10, further comprising:
an anti-reflective coating on at least one of an output surface of the laser diode, or a surface of a cladding layer of the waveguide.
14. The apparatus of claim 10, further comprising:
an anti-reflective coating on one end of the laser diode.
15. The apparatus of claim 10, further comprising:
a rough surface on one end of the laser diode.
16. The apparatus of claim 10, wherein the first grating is positioned between the reflective layer and a substrate
17. The apparatus of claim 10, wherein the reflective layer comprises a distributed Bragg reflector.
18. The apparatus of claim 10, further comprising:
a partially reflecting grating and a reflective surface positioned at opposite ends of a cavity in the laser diode.
19. An apparatus comprising:
a structure including a p-side layer and an n-side layer on opposite sides of an active region;
a reflective coating on a first end of the structure;
a rough surface or an anti-reflection coating on a second end of the structure;
an output grating positioned adjacent to the active region; and
a partial reflection grating adjacent to the output grating.
20. The apparatus of claim 19, wherein the partial reflection grating and the first end of the structure form a laser cavity.