1. An optical coupler integrated on a substrate, designed to optically couple a laser and a waveguide, said optical coupler comprising:
an external element, with a base starting from which two arms extend separated by a notch, said notch being delimited laterally by two first walls, the distance from one wall to the other decreasing towards the bottom of the notch;
a central element located in the notch, delimited laterally by two second walls, and with a first region in which said two second walls are in direct contact with said two first walls as far as the bottom of the notch; and
an intermediate element, extending between the external element and the central element, directly between a first wall and a second wall where a first wall is not in direct contact with a second wall;
the optical index of the central element being greater than the optical index of the intermediate element, itself greater than the optical index of the base of the external element.
2. The optical coupler according to claim 1, wherein the intermediate element also extends inside the notch directly on an upper face and on a lower face of the central element.
3. The optical coupler according to claim 1, wherein the central element is made of germanium or a germanium and silicon alloy.
4. The optical coupler according to claim 1, wherein the intermediate element is made of silicon or a germanium and silicon alloy.
5. The optical coupler according to claim 1, wherein the external element includes silica, aluminium oxide or aluminium nitride or a gas or a vacuum.
6. The optical coupler according to claim 5, wherein the external element is composed of an envelope containing a gas or a vacuum.
7. The optical coupler according to claim 1, comprising it is composed of three slices extending one after the other and comprising:
a first slice, designed to be located under the laser except for a laser exit region, and composed of at least part of the base of the external element;
a second slice, directly adjacent to the first slice, and designed to be located under said laser exit region, and comprising one end of the central element; and
a third slice, directly adjacent to the second slice.
8. The optical coupler according to claim 7, wherein said optical coupler is designed to optically couple a laser and a waveguide, such that the optical index of the first slice is less than the effective index of the laser, and the optical index of the intermediate element is higher than the effective index of the laser.
9. The optical coupler according to claim 6, wherein the first slice comprises pads containing germanium and silicon.
10. The optical coupler according to claim 7, wherein said optical coupler is designed to optically couple a laser and a waveguide such that:
the effective index in the second slice progressively increases from the entry to the exit of the second slice, from a face adjacent to the first slice as far as a face adjacent to the third slice;
the effective index at the entry to the second slice is less than the effective index of the laser; and
the effective index at the exit from the second slice is higher than the effective index of the laser.
11. The optical coupler according to claim 7, wherein said optical coupler is designed to optically couple a laser and a waveguide such that:
a region of the optical coupler with the same width as the optical coupler, located under the central element and in direct contact with its lower face, defines a lower cladding of the coupler;
a region of the optical coupler with the same width as the optical coupler, located on the central element and in direct contact with its upper face, defines an upper cladding of the coupler; and
at the exit from the second slice, the equivalent optical index of the lower cladding of the coupler and the equivalent optical index of the upper cladding of the coupler are each less than the effective index of the laser.
12. The optical coupler according to claim 7, wherein said optical coupler is designed to optically couple a laser and a waveguide such that:
a region of the optical coupler with the same width as the optical coupler, located under the central element and in direct contact with its lower face, defines a lower cladding of the coupler; and
the thickness of the lower cladding of the coupler is higher than or equal to \u03bb02, where \u03bb0 is the laser emission wavelength in a vacuum.
13. The optical coupler according to claim 7, wherein said optical coupler is designed to optically couple a laser and a waveguide such that the effective index in the third slice progressively increases from the entry to the exit from the third slice until it reaches the value of the effective index of the waveguide.
14. The optical coupler according to claim 1, wherein said optical coupler is designed to optically couple a quantum cascade laser and a waveguide.
15. A method of manufacturing an optical coupler according to claim 1, said method comprising the following steps:
depositing on a substrate a first layer that will form the central element, and etch the first layer;
depositing a second layer, covering the etched first layer and planarise the second layer;
etching at least the first layer to form a recess surrounding one end of the etched first layer;
filling the recess to form the external element of the optical coupler.
16. An optical guidance system integrated onto a substrate said system comprising:
an optical coupler according to claim 1;
a waveguide, located in the extension of the optical coupler such that a core of said waveguide extends in the extension of the central element and is formed from the same material as the central element, and a cladding of said waveguide extends in the extension of the intermediate element and is formed from the same material; as the intermediate element and
a laser, located above at least part of the optical coupler;
the optical coupler being designed to optically couple said laser and said waveguide.
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. A method comprising
beginning a session to send a file segment of a remaining portion of a file yet to be received by a receiving system between a sending system and the receiving system, the receiving system being connected to a first portion of a network and having a first network address;
during the session after a first portion of the file segment has been received by the receiving system and a second portion of the file segment has yet to be received by the receiving system, disconnecting the receiving system from the first portion of the network;
after disconnecting the receiving system from the first portion of the network, connecting the receiving system to a second portion of the network, the receiving system having a second network address different than the first network address; and
after connecting the receiving system to the second portion of the network, automatically resuming the session to send ta second portion of the file segment from the sending system to the receiving system.
2. The method of claim 1 wherein the sending system receives the second network address from the receiving system to resume the session.
3. The method of claim 1 wherein the sending system receives a request from the receiving system to resume the session.
4. The method of claim 1, further including retaining state of the session substantially at the time of disconnection of the receiving system from the first portion of the network.
5. The method of claim 1 wherein the receiving system uses a count-down timer to initiate sending a request to the sending system to resume the session.
6. The method of claim 1 wherein after the session is resumed, only the second portion of the file segment is sent from the sending system to the receiving system.
7. The method of claim 1, further including determining a minimum transfer rate for transferring the file segment based in part on a determined size for the remaining portion of the file and an amount of time available to transfer the remaining portion of the file; and
determining a maximum transfer rate for transferring the file segment of the remaining portion of the file based in part on the minimum transfer rate and a maximum transfer capacity of the sending system.
8. The method of claim 1, further including sending the unsent portion of the file segment from the sending system to the receiving system based upon a session state retained in storage of the sending system.
9. The method of claim 1 further including sending the unsent portion of the file segment to the receiving system from a sending system other than the sending system.
10. The method of claim 1, further including receiving the unsent portion of the file segment;
determining an actual transfer rate that the file segment was sent from the sending system to the receiving system based in part on size of the file segment and an elapsed time between when the file segment was sent from the sending system and when the file segment was received at the receiving system;
determining a wait period based in part on the maximum transfer rate, the minimum transfer rate, and the actual transfer rate;
after receiving the file segment at the receiving system, waiting the wait period before sending an acknowledgement message from the receiving system, the acknowledgement message acknowledging receipt of the file segment by the receiving system; and
sending the acknowledgement message from the receiving system.
11. The method of claim 1 wherein the first portion of the network is of a type different than the second portion of the network.
12. A method comprising:
sending one of a plurality of segments of a file from a sending system to a receiving system, the receiving system being connected to a first portion of a network and having a first network address;
disconnecting the receiving system from the first portion of the network;
connecting the receiving system to a second portion of the network, the receiving system having a second network address; and
sending another of the plurality of segments of the file from the sending system to the receiving system, the receiving system having the second network address.
13. The method of claim 12 wherein the first portion of the network is of a different type than the second portion of the network.
14. The method of claim 12 wherein the sending system receives the second network address from the receiving system to begin sending the other of the plurality of segments of the file to the receiving system.
15. The method of claim 12 wherein the sending system receives a request automatically from the receiving system to send the other segment of the file upon connection of the receiving system to the second portion of the network.
16. The method of claim 12, further including retaining information regarding sending the one of the plurality of segments of the file substantially at the time of disconnection of the receiving system from the first portion of the network.
15. The method of claim 12 wherein the receiving system uses a count-down timer to initiate sending a request to the sending system to send the other of the plurality of segments of the file.
17. The method of claim 12 wherein after the receiving system is connected to second portion of the network, the other of the plurality of file segments is sent to the receiving system without re-sending the one of the plurality of file segments to the receiving system.
18. The method of claim 12, further including determining a minimum transfer rate for transferring the one of the plurality of file segments based in part on a determined size for a remaining portion of the file not already sent and an amount of time available to transfer the remaining portion of the file; and
determining a maximum transfer rate for transferring the one of the plurality of segments of the file based in part on the minimum transfer rate and a maximum transfer capacity of the sending system.
19. The method of claim 12, further including sending the other of the plurality of segments of the file from the sending system to the receiving system based upon a session state retained in storage of the sending system.
20. The method of claim 12, further including sending the other of the plurality of segments of the file to the receiving system from a sending system other than the sending system.
21. The method of claim 12, further including determining an actual transfer rate that the one of the plurality of segments of the file was sent from the sending system to the receiving system based in part on size and time sent and time received of the one of the plurality of segments of the file;
determining a wait period based in part on the actual transfer rate;
after receiving the one of the plurality of segments of the file at the receiving system, waiting the wait period before sending an acknowledgement message from the receiving system, the acknowledgement message acknowledging receipt of the file segment by the receiving system; and
sending the acknowledgement message from the receiving system from the second network address.
22. A method comprising:
sending a portion of a file made up of a plurality of file segments from a sending system to a receiving system, the sending the portion of the file including sending the file segments one at a time by a plurality of transmissions with a different one of a plurality of wait periods occurring after each transmission;
for each file segment transmissions, determining an actual transfer rate that the file segment was sent from the sending system to the receiving system;
for at least one of the file segment transmissions, receiving the file segment transmission at the receiving system being connected to a first portion of a network having a first network address;
for at least one of the file segment transmissions, receiving the file segment transmission at the receiving system being connected to a second portion of the network having a second network address;
for each file segment transmission to the receiving system having the first network address and having a previous file segment transmission to the first network address, determining size of the file segment to be sent in the file segment transmission to the receiving system having the first network address based in part by the actual transfer rate of the previous file segment transmission to the first network address; and
for each file segment transmission to the receiving system having the second network address and having a previous file segment transmission to the second network address, determining size of the file segment to be sent in the file segment transmission to the receiving system having the second network address based in part by the actual transfer rate of the previous file segment transmission to the second network address.
23. The method of claim 22 wherein the first portion of the network is of a different type than the second portion of the network.
24. A method comprising:
ordering a file to be delivered by a delivery deadline to occur at least a first plurality of hours after the ordering; and
electronically delivering the file a file segment at a time to a receiving system over a time period at least a second plurality of hours to be delivered by the delivery deadline, for some portion of the time period, the receiving system being connected to a first portion of a network having a first network address and for another portion of the time period the receiving system being connected to a second portion of the network having a second network address other than the first network address.
25. The method of claim 24 wherein the first portion of the network is of a different type than the second portion of the network.