Question: Does anyone make a single fiber cwdm 10g sfp or xfp that will do 10g over a single fiber using a single 1510nm wavelength?

Answer: 
They're called BiDi optical transceivers. [I see some](http://connect.physicsworld.com/sfp-plus-10gsrlrmlrerzrcwdmdwdmbidi-transceivers/2003609.article) 1270nm / 1330nm Bi-Directional 40km Single Mode but I don't see any 1510nm.

### [Cisco SFP-10G-BX40D-I and SFP-10G-BX40U-I (for 40Km Single-Fiber Bidirectional Applications)](http://www.cisco.com/c/en/us/products/collateral/interfaces-modules/transceiver-modules/data_sheet_c78-455693.html)

[![enter image description here](https://i.stack.imgur.com/pRm7A.jpg)](https://i.stack.imgur.com/pRm7A.jpg)

The Cisco SFP-10G-BX40D-I and SFP-10G-BX40U-I SFPs operate on a single strand of standard SMF.

A SFP-10G-BX40D-I device is always connected to a SFP-10G-BX40U-I device with a single strand of standard SMF with an operating transmission range up to 40 km.

The communication over a single strand of fiber is achieved by separating the transmission wavelength of the two devices. SFP-10G-BX40D-I transmits a 1330-nm channel and receives a 1270-nm signal. The SFP-10G-BX40U-I transmits at a 1270-nm wavelength and receives a 1330-nm signal.

The SFP-10G-BX40D-I and SFP-10G-BX40U-I SFPs support digital optical monitoring (DOM) functions according to the industry-standard SFF-8472 multisource agreement (MSA). This feature gives the end user the ability to monitor real-time parameters of the SFP, such as optical output power, optical input power, temperature, laser bias current, and transceiver supply voltage.
As Ecnerwal states, you can't transmit signal with the same wavelength in both directions. 

I'm pretty sure you know how one-eyed SFPs work, but here (<http://www.cisco.com/c/en/us/products/collateral/interfaces-modules/transceiver-modules/data_sheet_c78-455693.pdf>) you can find a diagram explaining it on page 3.

If you are planing yo use single fiber SFPs/XFPs, your CWDM muxes should support them. ( like this one <http://www.pandacomdirekt.com/en/products/wdm/passive-multiplexer/cwdm-multiplexer/48-channel-single-fiber.html>)