Linearized optical digital-to-analog modulator

• US 10,270,535 B1
• Filed: 12/28/2018
• Issued: 04/23/2019
• Est. Priority Date: 06/13/2007
• Status: Active Grant

• Current Assignee: Ramot at Tel Aviv University Limited (Tel Aviv University)
• Original Assignee: Ramot at Tel Aviv University Limited (Tel Aviv University)
• Inventors: Ehrlichman, Yossef, Amrani, Ofer, Ruschin, Shlomo
• Primary Examiner(s): Jeanglaude, Jean B
• Application Number:
  US16/234,635
• Time in Patent Office: 116 Days
• Field of Search: 341131, 341137, 341143, 341155
• CPC Class Codes: G02F 1/0121 Operation of devices; Circuit arrangements, not otherwise provided for in this subclass
• CPC Class Codes: G02F 1/015 based on semiconductor elements having potential barriers, e.g. having a PN or PIN junction G02F1/03 takes precedence
• CPC Class Codes: G02F 1/212 Mach-Zehnder type
• CPC Class Codes: G02F 1/225 in an optical waveguide structure
• CPC Class Codes: G02F 2203/19 linearised modulation; reduction of harmonic distortions
• CPC Class Codes: G02F 7/00 Optical analogue/digital converters
• CPC Class Codes: H03M 1/002 Provisions or arrangements for saving power, e.g. by allowing a sleep mode, using lower supply voltage for downstream stages, using multiple clock domains or by selectively turning on stages when needed
• CPC Class Codes: H03M 1/70 Automatic control for modifying converter range
• CPC Class Codes: H04B 10/2575 Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier
• CPC Class Codes: H04B 10/25891 Transmission components H04B10/40 takes precedence
• CPC Class Codes: H04B 10/505 using external modulation
• CPC Class Codes: H04B 10/5055 using a pre-coder
• CPC Class Codes: H04B 10/516 Details of coding or modulation
• CPC Class Codes: H04B 10/541 Digital intensity or amplitude modulation
• CPC Class Codes: H04B 10/556 Digital modulation, e.g. differential phase shift keying [DPSK] or frequency shift keying [FSK]

Abstract

A system for converting digital data into a modulated optical signal, comprises an electrically controllable device having M actuating electrodes. The device provides an optical signal that is modulated in response to binary voltages applied to the actuating electrodes. The system also comprises a digital-to-digital converter that provides a mapping of input data words to binary actuation vectors of M bits and supplies the binary actuation vectors as M bits of binary actuation voltages to the M actuating electrodes, where M is larger than the number of bits in each input data word. The digital-to-digital converter is enabled to map each digital input data word to a binary actuation vector by selecting a binary actuation vector from a subset of binary actuation vectors available to represent each of the input data words.

Claims

1. A method of modulating and transmitting an optical signal over an optical fiber in response to N bits of digital data in parallel, the method comprising:

inputting the N bits of digital data into an optical modulator having a plurality of waveguide branches, where each branch has an input of an unmodulated optical signal;

converting the N bits of digital data to M drive voltage values, where M>

N and N>

1;

coupling the M drive voltage values to the unmodulated optical signal, said coupling enabling pulse modulation of the unmodulated optical signal, thereby generating a pulse modulated optical signal; and

transmitting the pulse modulated optical signals over an optical fiber.

2. A method of modulating and transmitting an optical signal over an optical fiber in response to N bits of digital data in parallel, the method comprising:

inputting the N bits of digital data into an optical modulator having a plurality of waveguide branches, where each branch has an input of an unmodulated optical signal;

converting the N bits of digital data to M drive voltage values, where M>

N and N>

1;

coupling the M drive voltage values to the unmodulated optical signal, said coupling enabling modulation of the unmodulated optical signal by QAM, thereby generating a QAM modulated optical signal; and

transmitting the QAM modulated optical signal over an optical fiber.