MONITORING AND CONTROLLING TEMPERATURE ACROSS A LASER ARRAY IN A TRANSMITTER OPTICAL SUBASSEMBLY (TOSA) PACKAGE

• US 20160377822A1
• Filed: 06/04/2014
• Published: 12/29/2016
• Est. Priority Date: 06/04/2014
• Status: Active Grant

• Current Assignee: Applied Optoelectronics
• Original Assignee: Applied Optoelectronics
• Inventors: Zheng, Jun, Wang, Yi, Ho, I-Lung, Wang, Chong
• Granted Patent: US 9,964,720 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02B 6/12019 characterised by the optical interconnection to or from the AWG devices, e.g. integration or coupling with lasers or photodiodes coupling integrated waveguide to fibre G02B6/30, to optoelectronic element G02B6/42; monolithic integration of integrated waveguides with other optical elements G02B6/12004
• CPC Class Codes: G02B 6/29329 Diffractive elements operating in transmission
• CPC Class Codes: G02B 6/2938 for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM
• CPC Class Codes: G02B 6/4271 with thermo electric cooling
• CPC Class Codes: G02B 6/4292 the light guide being disconnectable from the opto-electronic element, e.g. mutually self aligning arrangements
• CPC Class Codes: H01S 5/0014 Measuring characteristics or properties thereof measuring techniques per se G01J, G01K, G01N, G01R
• CPC Class Codes: H01S 5/02216 Butterfly-type, i.e. with electrode pins extending horizontally from the housings
• CPC Class Codes: H01S 5/02415 by using a thermo-electric cooler [TEC], e.g. Peltier element
• CPC Class Codes: H01S 5/02453 Heating, e.g. the laser is heated for stabilisation against temperature fluctuations of the environment H01S5/0612 takes precedence, for monolithically integrated heaters see also H01S5/0261
• CPC Class Codes: H01S 5/0612 controlled by temperature
• CPC Class Codes: H01S 5/06804 by monitoring an external parameter, e.g. temperature
• CPC Class Codes: H01S 5/12 the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers comprising a photonic bandgap structure H01S5/11; surface-emitting lasers H01S5/18
• CPC Class Codes: H01S 5/4025 Array arrangements, e.g. constituted by discrete laser diodes or laser bar H01S5/42 takes precedence
• CPC Class Codes: H01S 5/4087 emitting more than one wavelength
• CPC Class Codes: H04B 10/503 Laser transmitters
• CPC Class Codes: H04B 10/506 Multiwavelength transmitters
• CPC Class Codes: H04B 10/572 Wavelength control
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04J 14/0256 at the optical channel layer
• CPC Class Codes: H04J 14/0307 Multiplexers; Demultiplexers

Abstract

The temperature at different locations along a multiplexed laser array may be monitored by sensing temperature at two locations within a transmitter optical subassembly (TOSA) package housing the laser array. The temperature at the two locations is used to determine a temperature tilt across the laser array. Estimated temperatures may then be determined at one or more other locations along the laser array from the temperature tilt. The estimated temperature(s) may then be used to adjust the temperature proximate the other locations, for example, for purposes of tuning lasers at those locations along the laser array to emit a desired channel wavelength. The TOSA package may be used in an optical transceiver in a wavelength division multiplexed (WDM) optical system, for example, in an optical line terminal (OLT) in a WDM passive optical network (PON).

Claims

1. A method for monitoring and controlling temperature of a laser array in a multi-channel transmitter optical subassembly (TOSA) package, the method comprising:

sensing at least first and second temperatures at first and second locations within the TOSA package proximate at least first and second ends of the laser array;

determining a temperature tilt across the laser array and within the TOSA package, wherein the temperature tilt represents a change in temperature as a function of distance;

determining, from the temperature tilt, an estimated local temperature at at least a third location along the laser array; and

adjusting a temperature proximate the third location along the laser array in response to the estimated temperature.

2. The method of claim 1 wherein the laser array includes a plurality of lasers and the at least a third location is proximate at least one of the lasers, and wherein adjusting the temperature includes heating the at least one of the lasers proximate the third location with a heater adjacent the at least one of the lasers.

3. The method of claim 2 wherein the heater includes a resistor, and wherein adjusting the temperature include adjusting a current applied to the resistor.

4. The method of claim 1 wherein the laser array includes a plurality of lasers and the at least a third location is proximate at least one of the lasers, and wherein adjusting the temperature includes cooling the at least one of the lasers.

5. The method of claim 4 wherein the at least one of the lasers is cooled with a thermoelectric cooler (TEC).

6. The method of claim 1 wherein the temperature is adjusted at the at least a third location for tuning a laser proximate the third location to emit a desired channel wavelength.

7. The method of claim 1, wherein sensing at least first and second temperatures includes receiving signal from at least first and second thermistors located at the first and second locations.

8. The method of claim 1, wherein the laser array includes a plurality of tunable distributed feedback (DFB) lasers coupled to an arrayed waveguide grating (AWG).

9. The method of claim 1, wherein the laser array includes a plurality of gain regions coupled to an arrayed waveguide grating (AWG) forming an array of external cavity lasers.

10. A temperature controlled multi-channel transmitter optical subassembly (TOSA) package comprising:

a TOSA housing;

a laser array located in the TOSA housing and configured to generate laser light associated with a plurality of optical channels;

an optical multiplexer located in the TOSA housing and optically coupled to the laser array, the optical multiplexer being configured to combine the laser light at different respective channel wavelengths;

at least first and second temperature sensors located in the TOSA housing at first and second locations proximate at least first and second ends of the laser array, the first and second temperature sensors being configured to sense at least first and second temperatures at the first and second locations; and

temperature control devices located in the TOSA housing and thermally coupled to the laser array for adjusting temperatures at different locations along the laser array, wherein the temperature control devices are configured to adjust the temperature proximate at least a third location along the laser array in response to an estimated temperature at the third location, the estimated temperature being estimated from a temperature tilt determined from the first and second temperatures at the first and second locations.

11. The temperature controlled multi-channel TOSA of claim 10, wherein the laser array includes a plurality of tunable distributed feedback (DFB) lasers.

12. The temperature controlled multi-channel TOSA of claim 10, wherein the temperature control devices include a plurality of heaters associated with respective lasers in the laser array for heating the respective lasers.

13. The temperature controlled multi-channel TOSA of claim 11, wherein the temperature control devices include at least one thermoelectric cooler for cooling the lasers in the laser array.

14. The temperature controlled multi-channel TOSA of claim 11, wherein the heaters are resistors located adjacent the respective lasers.

15. The temperature controlled multi-channel TOSA of claim 10, wherein the optical multiplexer is an arrayed waveguide grating (AWG).

16. The temperature controlled multi-channel TOSA of claim 10, wherein the channel wavelengths include ITU channels wavelengths.

17. The temperature controlled multi-channel TOSA of claim 10, wherein the temperature sensors include thermistors located at the first and second locations.

18. A multi-channel transceiver module comprising:

a transceiver housing;

at least one temperature controlled multi-channel transmitter optical subassembly (TOSA) package located in the transceiver housing, the TOSA package being configured to transmit a wavelength division multiplexed (WDM) optical signal on multiple channel wavelengths, the TOSA package comprising;

a TOSA housing;

a laser array located in the TOSA housing and configured to generate laser light associated with a plurality of optical channels;

an optical multiplexer located in the TOSA housing and optically coupled to the laser array, the optical multiplexer being configured to combine the laser light at different respective channel wavelengths;

at least first and second temperature sensors located in the TOSA housing at first and second locations proximate at least first and second ends of the laser array, the first and second temperature sensors being configured to sense at least first and second temperatures at the first and second locations; and

temperature control devices located in the TOSA housing and thermally coupled to the laser array for adjusting temperatures at different locations along the laser array;

a temperature control system configured to determine a temperature tilt from the first and second temperatures sensed at the first and second locations and to determine at least one estimated temperature at at least a third location along the laser array, wherein the temperature control devices are configured to adjust the temperature proximate the third location along the laser array in response to the at least one estimated temperature; and

at least one multi-channel receiver optical subassembly (ROSA) located in the transceiver housing, the ROSA being configured to receive a wavelength division multiplexed (WDM) optical signal on multiple channel wavelengths.

19. The temperature controlled multi-channel transceiver module of claim 18, wherein the temperature control devices include a plurality of heaters associated with respective lasers in the laser array for heating the respective lasers.

20. The temperature controlled multi-channel transceiver module of claim 19, wherein the temperature control devices include at least one thermoelectric cooler for cooling the lasers in the laser array.