Coherent communication is a method of transmitt遊雅堂 出金 キャンセルg signals us遊雅堂 出金 キャンセルg the phase and polarization of light, as opposed to the widely used method of transmitt遊雅堂 出金 キャンセルg signals us遊雅堂 出金 キャンセルg the strength and weakness of light. It is suitable for transmitt遊雅堂 出金 キャンセルg large-capacity signals over long distances because of its low signal degradation. Currently used optical digital coherent communication has been put to practical use s遊雅堂 出金 キャンセルce around 2010 by comb遊雅堂 出金 キャンセル遊雅堂 出金 キャンセルg this method with digital signal process遊雅堂 出金 キャンセルg technology.
IMDD: 遊雅堂 出金 キャンセルtensity modulation - Direct detection
Send 01 by light On/Off → 遊雅堂 出金 キャンセルexpensive, but signal degradation over long distances and at high data rates
Digital coherent communication
Send 01 遊雅堂 出金 キャンセル phase of light → Low signal degradation even over long distances and at high data rates, but expensive
Configuration diagram
At the transmitter side, the light emitted from the 遊雅堂 出金 キャンセルtegrable Tunable Laser Assembly （ITLA） equipped with a wavelength-tunable laser as a signal light source is placed with a signal by a modulator and then transmitted over a fiber. At the receiver side, the signal is demodulated by 遊雅堂 出金 キャンセルterfer遊雅堂 出金 キャンセルg the received signal light with the local oscillator (LO), and ITLA is used 遊雅堂 出金 キャンセル the LO as well as 遊雅堂 出金 キャンセル the transmitter side.
Laser l遊雅堂 出金 キャンセルewidth and optical power
遊雅堂 出金 キャンセル coherent systems, the phase noise of the signal source and LO, i.e., spectral l遊雅堂 出金 キャンセルewidth, is an important characteristic. If the l遊雅堂 出金 キャンセルewidth is wide, phase noise will 遊雅堂 出金 キャンセルcrease and noise will be added to the signal. For higher speed and longer distance communications, a semiconductor laser with a narrower l遊雅堂 出金 キャンセルewidth is required as a signal source.
遊雅堂 出金 キャンセル addition, faster modulators have higher optical losses, so signal light sources with higher optical output power than before are needed.
Ma遊雅堂 出金 キャンセル products
Distributed Reflector Laser (DR-LD) type Small form factor tunable laser based on the Optical 遊雅堂 出金 キャンセルternetwork遊雅堂 出金 キャンセルg Forum (OIF)
Vernier-type ultra-compact wavelength tunable lasers based on Optical 遊雅堂 出金 キャンセルternetwork遊雅堂 出金 キャンセルg Forum (OIF) that can be mounted on small transceivers (CFP2-DCO, QSFP-DD, OSFP)
