Optical module

Patent metadata

Field	Value
Publication number	US-9787423-B2
Application number	US-201615375031-A
Country	US
Kind code	B2
Filing date	Dec 9, 2016
Priority date	Mar 3, 2014
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

An integrated apparatus with optical/electrical interfaces and protocol converter on a single silicon substrate. The apparatus includes an optical module comprising one or more modulators respectively coupled with one or more laser devices for producing a first optical signal to an optical interface and one or more photodetectors for detecting a second optical signal from the optical interface to generate a current signal. Additionally, the apparatus includes a transmit lane module coupled between the optical module and an electrical interface to receive a first electric signal from the electrical interface and provide a framing protocol for driving the one or more modulators. Furthermore, the apparatus includes a receive lane module coupled between the optical module and the electrical interface to process the current signal to send a second electric signal to the electrical interface.

First claim

What is claimed is:

1. An integrated apparatus with optical/electrical interfaces and protocol converter on a single silicon substrate, the apparatus comprising:
an optical module comprising one or more modulators respectively coupled with one or more laser devices for producing a first optical signal to an optical interface, and one or more photodetectors for detecting a second optical signal from the optical interface to generate a current signal;
a transmit lane module coupled between the optical module and an electrical interface, the transmit lane module comprising at least a modulation driver configured to receive a first electric signal from the electrical interface and provide a framing protocol for driving the one or more modulators;
a receive lane module coupled between the optical module and the electrical interface, the receive lane module comprising at least a transimpedance amplifier configured to process the current signal to send a second electric signal to the electrical interface;
a control module configured to drive the transmit lane module and the receive lane module;
wherein the first/second optical signal is associated with one or more wavelengths configured in a coarse wavelength division multiplex (CWDM) grid or a dense wavelength division multiplex (DWDM) grid;
wherein each of the one or more laser devices is DFB characterized with a sufficiently low noise to meet a PAM N transmission over 100 km, whereupon N ranges from 2 to 8.

2. The apparatus of claim 1 wherein each of the laser devices is uncooled allowing temperature-dependent wavelength float.

3. The apparatus of claim 1 wherein each of the laser devices is further comprising a TEC (thermoelectric cooler) to provide temperature stabilize for wavelength.

4. The apparatus of claim 1 wherein the optical module further comprises a first multiplexer coupled between the one or more modulators and the optical interface to provide temperature stabilized wavelength locking for multiplexing the one or more wavelengths from the one or more laser devices into the first optical signal and a second multiplexer coupled to the optical interface for demultiplexing the second optical signal into multiple wavelengths respectively being detected by the one or more photodetectors.

5. The apparatus of claim 4 wherein the second multiplexer is a delay-line interferometer based on silicon or silicon-nitride and configured to interleave the second optical signal to at least two wavelengths in 50 GHz DWDM grid or some other frequency spacing.

6. The apparatus of claim 4 wherein the multiplexer is configured to combine four CWDM wavelengths with 20 nm spacing or at least two DWDM wavelengths with 50 GHz spacing respectively modulated with data combined into a single stream of information carried by the first optical signal.

7. The apparatus of claim 1 wherein each of the one or more modulators is a Si Mach-Zehnder modulator operated in a carrier depletion mode.

8. The apparatus of claim 7 wherein the framing protocol for converting the first electrical signal to the first optical signal is configured for both NRZ and PAM signal encoding modulation by the Si Mach-Zehnder modulator in the optical module driven by the modulation driver in the transmit lane module.

9. The apparatus of claim 8 wherein the Si Mach-Zehnder modulator is a segmented modulator comprising a plurality of segments and the PAM signal coding encoded to a thermometer coding.

10. The apparatus of claim 8 wherein the NRZ signal encoding modulation is achieved by driving all the segments together.

11. The apparatus of claim 8 wherein the PAM signal coding modulation includes a PAM4 encoding scheme using 3 sections grouped from 9 segments of the segmented modulator.

12. The apparatus of claim 8 wherein the segmented modulator is configured with a segment length between 350 μm and 450 μm and a segment pitch between 10 μm and 50 μm for minimal device parasitics and suitable for high speed operation.

13. The apparatus of claim 1 wherein each of the one or more photodetectors is a high speed photodetector made of Germanium material integrated on the same single silicon substrate for forming the one or more modulators.

14. The apparatus of claim 1 wherein the CWDM grid comprises four wavelengths having respective peaks at 1270 nm, 1290 nm, 1310 nm, and 1330 nm.

15. The apparatus of claim 1 wherein the DWDM grid comprises up to 96 wavelengths with 50 GHz channel spacing.

16. The apparatus of claim 1 wherein the modulation driver in the transmit lane module comprises a limiting driver configured in CMOS 28 nm architecture.

17. The apparatus of claim 1 wherein the transmit lane module further comprises a clock data recover device (CDR), a forward error correction device (FEC), a digital encoder device (ENC) coupled to the modulation driver in a distributed Mach-Zehnder modulator configuration to drive the one or more modulators in the optical module for encoding each laser generated by the one or more laser devices at one wavelength in either CWDM grid or DWDM grid including 50 GHz or 100 GHz spacing based on the first electrical signal.

18. The apparatus of claim 17 wherein the modulation driver comprises a parallel array of a plurality of amplifiers, each of which is optimized to drive a single segment of one of the one or more modulators.

19. The apparatus of claim 1 further comprising a modulator device coupled to the CWDM or DWDM grid using a flip chip configuration.

20. The apparatus of claim 1 wherein the receive lane module further comprises a clock data recover device (CDR), a forward error correction device (FEC), and a digital signal processor device (DSP) coupled to the transimpedance amplifier (TIA) to digitalize the current signal.

21. The apparatus of claim 20 wherein the TIA is configured in CMOS 28 nm architecture.

22. The apparatus of claim 1 wherein the control module comprises a power supply, a microcontroller, and circuits with ASIC interface.

23. The apparatus of claim 22 wherein the control module further comprises a self test block configured to digitally monitor the performance of the transmit lane module and generate diagnostics information through the ASIC interface.

24. The apparatus of claim 23 wherein the self test block comprises a broad band source including LED configured to emit electromagnetic radiation from 1200 nm to 1400 nm or 1500 to 1600 nm.

25. The apparatus of claim 1 wherein the electrical interface is configured for either 4×10 Gb/s or 4×25 Gb/s rate data communication over Ethernet.

26. The apparatus of claim 1 is configured within a QSFP-28 package comprising a metal shield for electromagnetic radiation.

27. An integrated apparatus with optical/electrical interfaces and protocol converter on a single silicon substrate, the apparatus comprising:
an optical module comprising one or more modulators respectively coupled with one or more laser devices for producing a first optical signal to an optical interface, and one or more photodetectors for detecting a second optical signal from the optical interface to generate a current signal;
a transmit lane module coupled between the optical module and an electrical interface, the transmit lane module comprising at least a modulation driver configured to receive a first electric signal from the electrical interface and provide a framing protocol for driving the one

Assignees

• Inphi Corp

Inventors

• Nagarajan Radhakrishnan L

Classifications

• H04J14/02 Primary

  Wavelength-division multiplex systems · CPC title

• H04B10/40 Primary

  Transceivers · CPC title

• H04J14/0307

  Multiplexers; Demultiplexers · CPC title