1. An optical waveguide connector comprising:
a ferrule including an optical pathway for light transmission through the ferrule; and
a mating arrangement to mechanically attach the ferrule to a complementary optical device, the mating element defining an insertion direction, and
an end longitudinal section of the optical pathway to optically couple the optical pathway to the optical device, said end longitudinal section being angled with respect to the insertion direction.
2. The connector of claim 1, wherein the mating arrangement is integrated in the ferrule
3. The connector of claim 2, wherein the mating arrangement includes a hole arrangement formed in the ferrule.
4. The connector of claim 1, wherein the connector is to connect multiple terminals, the ferrule including a plurality of pathways, end longitudinal sections of the plurality of pathways to optically couple the optical pathways to the optical device, said pathway end longitudinal sections being angled with respect to the insertion direction.
5. The connector of claim 1, further comprising a sub-wavelength grating arrangement aligned with respect to said optical pathway end longitudinal section so as to implement beam expansion.
6. The connector of claim 1, the end longitudinal section of the optical pathway forming an angle between 70\xb0 and 110\xb0 with the insertion direction.
7. A ferrule for an optical waveguide connector comprising:
an optical pathway for light transmission through a ferrule body;
a mating arrangement defining an insertion direction;
an optical pathway end to optically couple the optical pathway to a complementary optical device, said optical pathway end abutting an optical connection surface of the ferrule forming an angle between \u221220\xb0 and 20\xb0 with the insertion direction.
8. The optical fiber ferrule of claim 7, wherein the optical pathway is to receive an optical fiber with an oblique facet.
9. A method of manufacturing an optical system, the method comprising:
forming a mating arrangement at a connector, the mating arrangement to mechanically attach a ferrule of the connector to a complementary optical device, the mating arrangement defining an insertion direction, the ferrule including an optical pathway for light transmission through the ferrule, an end longitudinal section of the optical pathway to optically couple the optical pathway to the complementary optical device, wherein
the mating arrangement is formed such that the insertion direction is angled with respect to said pathway end.
10. The method of claim 9, wherein disposing the mating arrangement includes lithographically defining the mating arrangement on a surface of the ferrule.
11. The method of claim 9, further comprising mechanically coupling the ferrule to the complementary optical device by engaging a mating arrangement of the complementary optical device to the mating arrangement of the ferrule.
12. The method of claim 11, further comprising
bonding the ferrule to the complementary optical device, and
removing a mating arrangement.
13. The method of claim 11, wherein mechanically coupling the ferrule to the complementary optical device includes aligning an optical pathway of the complementary optical device to the optical pathway of the ferrule such that adjacent end portions of the optical pathways are arranged parallel to each other.
14. The method of claim 11, wherein mechanically coupling the ferrule to the complementary optical device includes optically aligning an optical pathway of the complementary optical device to the optical pathway of the ferrule through a coupling element at the complementary optical device.
15. The method of claim 14, wherein mechanically coupling the ferrule to the complementary optical device includes optically aligning an optical pathway of the complementary optical device to the optical pathway of the ferrule through a sub-wavelength assembly.
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 downhole telemetry and power system for use with a borehole extending into a formation, the borehole including a casing positioned within the borehole and a piping structure contained within the casing, the system comprising:
a surface modem having an input coupled to data source and an output electrically coupled to the casing and piping structure, the surface modem operative to modulate a signal having a first frequency band with data received from the data source in a first modulation scheme and to multiplex the carrier signal using orthogonal frequency division multiplexing (OFDM) to provide a downhole OFDM signal containing downhole transmitted data;
a downhole modem operative to recover the downhole OFDM signal, to demodulate the first demodulation scheme and to recover the downhole transmitted data.
2. The system of claim 1 wherein the digital modulation scheme is QPSK.
3. The system of claim 1 wherein the OFDM signal includes 64 channels.
4. The system of claim 3 wherein a predetermined number of channels having the lowest bit error rates are selected to transmit up-channel data.
5. The system of claim 4 wherein the number of predetermined channels is less than 32.
6. The system of claim 5 wherein the number of predetermined channels is 16.
7. The system of claim 1 wherein the first frequency band extends from 60 kHz to 124 kHz.
8. The system of claim 1 wherein the downhole modem is further operative to modulate a second carrier signal having a second frequency band with data received from a downhole data source in a second modulation scheme and to multiplex the carrier signal using orthogonal frequency division multiplexing (OFDM) to provide uphole OFDM signal containing uphole transmitted data.
9. The system of claim 8 wherein the second digital modulation scheme is QPSK.
10. The system of claim 8 wherein the uphole OFDM signal includes 64 channels.
11. The system of claim 10 wherein a predetermined number of channels having the lowest bit error rates are selected to transmit up-channel data.
12. The system of claim 11 wherein the number of predetermined channels is less than 32.
13. The system of claim 12 wherein the number of predetermined channels is 16.
14. The system of claim 8 wherein the first frequency band is between 60 kHz and 124 kHz.
15. The system of claim 1 wherein the downhole signal includes the modulated data including a destination identifier, and wherein the downhole system includes a middle downhole modem and a bottom downhole modem each having a unique identifier and a relay module associated therewith, the relay module of the middle downhole modem being operative to receive a message from the surface modem having an identifier corresponding to the bottom downhole modem and to retransmit the received message after a first predetermined time period.
16. The system of claim 15 wherein the relay system of the bottom downhole modem is operative to transmit an acknowledgement signal upon receiving the message having an identifier corresponding to the unique address of the bottom downhole modem;
the relay module of the middle downhole modem operative to receive the acknowledgement signal and to retransmit the acknowledgement signal after a second predetermined time period, the relay module of the middle downhole modem further operative to not retransmit the received message when the acknowledgement signal has been received within the first predetermined time period.
17. The system of claim 16 wherein the relay module of the surface modem is operative to receive the acknowledgment signal and to transmit a second acknowledgment signal and to retransmit the message addressed to the bottom downhole modem when no acknowledgment signal is received within a second predetermined time period.
18. The system of claim 17 wherein the relay module of the middle downhole modem is operative to receive the second acknowledgment signal and to not retransmit the acknowledgment signal when the second acknowledgment signal is received within the second predetermined period of time.