Seamless bandwidth growth with RFoG

1. A radio frequency over glass (RFoG) system comprising:

a wave division multiplexer (WDM) capable of receiving an upstream optical signal from a headend;

a splitter for splitting the upstream optical signal, the signal remaining in an optical domain;

an optical network unit (ONU) connected to the splitter;

a cable modem termination system (CMTS) connected to the splitter, wherein the CMTS adjusts and maximizes an Optical Modulation Index (OMI) of a reverse transmitter modem in the splitter that transmits combined detected signals to the ONU in the RFoG system;

a gateway including the modem connected to the ONU having an express upstream port for providing upstream signals including extended range signals in an extended spectrum to the ONU,

wherein the gateway is configured for processing legacy RFoG signals in an upstream direction and for at least one of generating or processing, via the express ports on the modem, RFoG signals in the extended spectrum beyond 42 MHz in the upstream direction; and

wherein the modem is located directly adjacent to the ONU to provide accurate OMI control, the modem connected to the ONU via the upstream RF port, the gateway configured to set the accurate OMI on the ONU by calibrating output levels of the ONU and the modem.

2. The RFoG system of claim 1 , wherein the CMTS adjusts the optical modulation index of the ONU in response to a modulation profile on said ONU and at least one modulation profile of at least one other ONU transmitting to a same CMTS upstream RF port.

3. The RFoG system of claim 1 , wherein the modem sends a radio frequency (RF) signal to the ONU, the ONU having a calibrated RF level that responds with a calibrated optical modulation index.

4. The RFoG system of claim 1 , wherein the modem and the ONU control the OMI without input from the CMTS.

5. The RFoG system of claim 1 , wherein a precise optical modulation index enables an upstream bandwidth of up to 10 Gbps.

6. The RFoG system of claim 1 , wherein the modem and ONU control the optical modulation index in response to a modulation profile to be transmitted.

7. The RFoG system of claim 6 , wherein the modulation profile is at least one of the following: an RF frequency spectrum occupied by a transmission, an RF level being provided to the reverse transmitter, a modulation format being transmitted, a signal to noise ratio (SNR), or an optical modulation index required for transmission.

8. The RFoG system of claim 1 , wherein the modem includes one or more reverse transmitters in the RFoG system for setting the OMI to a reverse transmit modem level following a fixed pattern.

9. The RFoG system of claim 8 , wherein the fixed pattern maximizes the optical modulation index of the one or more reverse transmitter, increasing the optical modulation index per-channel when a spectrum out of a respective one or more reverse transmitter is narrowed.

10. The RFoG system of claim 1 , wherein the modem puts out a first reference signal to the ONU, the ONU reports a second reference signal to the modem in response to the first reference signal, and the modem determines the optical modulation index based on the second reference signal.

11. The RFoG system of claim 1 , wherein a per channel optical modulation index (OMI) is adjusted for a plurality of ONUs as a function of a spectral width of a signal provided to each of the respective plurality of ONU, wherein the spectral width of the signal is known to both the modem and the CMTS that instructs the modem to adopt a particular modulation profile.

12. The RFoG system of claim 1 , wherein the ONU reports a modulation index to the modem or to the cable modem termination system (CMTS).

13. The RFoG system of claim 1 , wherein the ONU embeds a reference signal in transmissions to the cable modem termination system (CMTS) with a known optical modulation index.

14. The RFoG system of claim 1 , wherein the optical modulation index is set higher for signals with a Peak to Average Power Reduction (PAPR) than for signals without PAPR.

15. The RFoG system of claim 1 , wherein legacy RFoG signals are signals operating in frequency bands matching those on a hybrid fiber coax (HFC) system, the frequency bands covering 5-42 MHz for upstream traffic and 54-1000 MHz for downstream traffic and these signals are provided on a connector separate from the express upstream or downstream connector.

16. The RFoG system of claim 1 , wherein at least one of: the ONU is adapted to receive the modem having the express RF ports for the extended RF spectrum, or the modem is adapted to receive the ONU having the express RF ports for the extended RF spectrum.

17. The RFoG system of claim 1 , wherein ONU and gateway connectors are normalized and mate when the gateway is placed in a base also connected to the ONU, the gateway being interchangeable for modifying bandwidth capabilities of the ONU.

18. The RFoG system of claim 1 , wherein the extended spectrum RFoG signals include overlapping frequency ranges in the upstream and downstream traffic.

19. The RFoG system of claim 1 , wherein the ONU comprises:

a band-limited bidirectional connector for the legacy RFoG signals; and

an express port for upstream traffic operating in an extended bandwidth matched by the express port for upstream traffic on the gateway.

20. The RFoG system of claim 1 , wherein the modem's express upstream port provides a larger upstream bandwidth using an upstream laser and bypassing a diplex filter in the ONU.

21. The RFoG system of claim 1 , wherein the ONU has an additional dedicated express high frequency downstream connector carrying signals above 1 GHz.

22. The RFoG system of claim 1 , further comprising an RF power amplifier for in-home distribution, the RF power amplifier using PAPR in a forward transmission format for reducing power dissipation of the RF power amplifier.

23. The RFoG system of claim 1 , wherein the gateway provides a digital interface for at least one of an Ethernet or WiFi connection.